Modifications to the Pro-Filer Hand Sharpener (Actual and Proposed)

[tstop4me]

(1) This thread is a spinoff of a previous thread (http://skatingforums.com/index.php?topic=8378.0), which in turn was a spinoff of an even earlier thread (http://skatingforums.com/index.php?topic=8371.0). 

(2) The scope of this thread is to discuss modifications to the Pro-Filer hand skate sharpener.  The modifications can include both (a) modifications that have actually been tried (accounts of both successes and failures are welcome) and (b) modifications that are proposed (e.g., modifications that may require special equipment or materials not available to the poster, but may be available to someone else here).

[tstop4me]

TOPIC I:  TAPING THE PRO-FILER CHASSIS

In (http://skatingforums.com/index.php?topic=8378.0, Reply #12), Query wrote:

I've tried to tape the Pro-Filer gap itself - but can't figure out a way to apply enough pressure to make it stick well, while keeping the tape in the right position.

I've had good success using a reconfigured pocket scribe, shown in Pix1.  The disassembled tool, shown in Pix1(a), comprises a handle, a chuck, and a tool insert.  The tool insert is fabricated from tool steel, with a tungsten-carbide scribe point at one end and a tool-steel ball end at the other.  The diameter of the cylindrical shank of the tool insert (as well as the diameter of the ball end) is 1/8", smaller than the gap width of the guide slots of the Pro-Filer chassis.  Both the cylindrical shank and the ball end can be used for pressing tape onto a substrate.

The tool insert is inserted in the chuck, which is then tightened to clamp the tool insert firmly.  Pix1(b) shows the tool assembled in the standard configuration, with the scribe point extended from the chuck.  Pix 1(c) shows the tool assembled as a pressing tool, with the ball end extended from the chuck.  Note that, in some pocket scribes, the tool insert has a flat end opposite the scribe point. A ball end is more versatile, since it can be used for contoured (non-planar) surfaces; see below. [The pressing-tool configuration is typically just a storage configuration:  the ball end keeps the tool from poking a hole in the pocket of a user who does not wish to be branded as a gnurd by wearing a plastic pocket protector.]

Pix2 shows the pressing tool inserted within the guide slot of a Pro-Filer chassis.

Pix3 shows tape applied to one quadrant of the Pro-Filer chassis.  One continuous piece of tape is wrapped around the thumb notch/inside slot/outer end of the chassis.  View A shows the portion of the tape on the thumb notch and inside slot.  View B shows the portion of the tape on the inside slot and outer end.  The pressing tool is used to apply pressure on all tape surfaces; the ball end is particularly useful to press the tape on the contoured surface of the thumb notch. The other three quadrants are similarly taped.

The tape shown is an industrial polyimide tape previously cited here:

(http://skatingforums.com/index.php?topic=6837.0, Reply #18); various thicknesses are available.  Since it is readily trimmed with a fresh single-edge razor blade, I first attached an oversized piece of tape, and then trimmed it along the periphery of the chassis.  This doesn't work with some other tapes (such as the masking tape supplied with the Pro-Filer); in that case, simply cut a rectangular strip of suitable size. 

I've found that if I simply use a rectangular strip of tape to cover only the inside slot, the tape tends to peel off during a sharpening session.  Wrapping the tape as shown is more robust:  enough to last one sharpening session, but not for multiple sharpening sessions (which is a major goal of taping the Pro-Filer chassis instead of taping the blades).  I've also heated the tape (after it has been applied to the chassis) with a hot-air gun, and run the pressing tool over it.  Not much improvement.  Although the adhesive is strong, this particular tape is intended to be removable; perhaps a different tape would adhere better for this purpose.  This tape works fine when applied to the blades (only needs to last one sharpening session).

I've not played with other tapes, because I started playing with brass shims (similar wrap-around configuration) attached with adhesive instead. That will be the subject of a separate post.  But if others have suggestions for better tape, please post.

[Query]

The brass shim idea sounds interesting. Of course, as with the Pro-Filer itself, it would scratch the blade less if you oil or water it. Help me to understand why adhesive brass shim is better than tape?

One of the problems I ran into was that I couldn't get mount tape exactly parallel to the gap edge, so it didn't do exactly what I wanted. I'm not sure if your idea can fox that.

All this to modify a tool that isn't quite the right size for your blades to begin with, or as a substitute for lubricating the blade.

Could we construct an ideal tool from off-the-shelf components? I'm not an engineer, but as best I understand it, real engineers are trained to seek off-the-shelf components before making their own stuff.

Perhaps one could start with a "T-clamp for two hoses or pipes"...

  https://www.grainger.com/product/2ZJX2?gclid=EAIaIQobChMIocq8vpmu4wIVkbXACh2zlA9jEAQYBCABEgJHyvD_BwE&cm_mmc=PPC:+Google+PLA&ef_id=EAIaIQobChMIocq8vpmu4wIVkbXACh2zlA9jEAQYBCABEgJHyvD_BwE:G:s&s_kwcid=AL!2966!3!50916716037!!!g!82496526597!

  https://www.fastenal.com/products/details/0214200

  etc.

They have an adjustable gap, so you can open them up enough to add compressible foam tape in an easy way.

Most of those aren't super-high precision-crafted tools - but I'm not sure they entirely need to be. They only need to be symmetrical, so that the gap runs down the middle of the cylinder - and if they weren't quite, you could add a little tape next to a cylinder to make them so.

As with the Berghman tools, I think they would self-adjust to make the gap the same width along the blade.

Just an idea.

I looked in some clamp catalogs - the closest I could come are the types of clamp I linked to above, which are all quite cheap, but there is no reason for them to be built to high accuracy or consistency standards.

I was also looking at pictures of "Kant half-twist clamps". I couldn't find any shaped to fit a cylinder well, but I love the idea of a surface that always lays perfectly flat against the sides of the blade. Or would that shift around?

For that matter, I was looking over my old Berghman sharpeners. I've always assumed they were purpose-built for skates. But now I wonder whether they were actually made from off-the-shelf components. If so, I don't know what those components are called.

Take a look at the picture on this box:

  https://www.ebay.com/itm/BX1-Vintage-Berghman-Ice-Skate-Sharpener-w-Box/293130649750?hash=item443ff2c096:g:mf8AAOSwv5RdD5vj

Notice the wingnut adjusts the gap width by fighting a couple springs, fit around two bolts. They worked really well, except for the fact that, back then, abrasive cylinders were made out of something that tended to crumble. With modern material abrasive cylinders, that goes away. Also, they were made with very coarse grit abrasive, which was great for speed, like if you your blades has no hollow yet, or you want to change your rocker profile, but not for making precise consistent edges - a problem easily fixed by using a finer grit cylinder. (Or by swapping cylinders, something that can be done in a few seconds.)

The gap adjusts itself to be the same width along the blade if you lock it down onto the blade, then you back it off a bit to let it slide. The abrasive cylinder is also clamped in place, not held with pins as in the Pro-Filer, and can be held right up to the edge of the tool (or slightly beyond), so you see exactly can work very precisely near the toe pick and/or sweet spot and/or tail end of the skate. You can loosen the wingnut to rotate the cylinder, or add tape, without needing special tools or techniques.

For some strange reason, all the Berghmans were designed for 1/2" ROH, but if there are similar off-the shelf parts, one could do the same thing for other ROH sizes.

Do you know what those part-cylinder clamping pieces are called? Once I know that, I can look for similar things on the web, with various radii.

I once tried to adapt a Berghman sharpener to use the 3/8" abrasive cylinder from a Pro-Filer. I wrapped many layers of cloth athletic tape half-way around the cylinder. The result was too squishy, and didn't stay in place very well. Which shows that my mechanical intuition isn't very good - I was certain it would work.

Maybe I should just try to force myself to use 1/2" ROH, so I could live with the Berghman tool...

I thought of making a tool using a 3D printer. Many public libraries now let you use their 3D printers, which is very cool. The home-made 3D printer I have personally seen (a lot of people try o make junky 3D printes using other junky 3D printers) had 1-2 mm errors - not good enough. I wonder if the ones in libraries are sufficiently better.

[tstop4me]

Query, I'd like to keep the scope of this thread to modifications to the Pro-Filer (see opening post).  As I mentioned in the opening post, this is already a spinoff of a spinoff.  You have a separate thread on resurrecting the Berghman sharpener; I suggest that anyone interested in the Berghman design, and modifications thereof, pursue it there.   If you wish, you could also start another thread on new designs for DIY hand sharpeners to complement Bill's thread on DIY power sharpeners. 

[tstop4me]

One of the problems I ran into was that I couldn't get mount tape exactly parallel to the gap edge, so it didn't do exactly what I wanted. I'm not sure if your idea can fox that.

There is no need for the tape to be exactly parallel to the gap edge; you just want to be close to provide maximum coverage.  More importantly, you want to ensure that no tape is hanging down dangling free into the cylindrical chamber. 

Using the wrap-around tape method that I described (rather than trying to manipulate a rectangular strip on the inside of the slot only), I can easily line up one edge of the tape with the inner edge of the slot (edge closest to the cylindrical chamber) and pull the tape taut.  Easy to do since I have a free end by the thumb notch and another free end by the outer end of the chassis.   If you want to make the process even easier, you can clamp the chassis in a small vise (with soft jaw protectors to prevent marring of the chassis):   you'll have both hands free to grasp the ends of the tape, position and orient it, and press the two ends into place.  Then I use the pressing tool to tack the tape down at several places to secure the tape before using the pressing tool to more aggressively rub the tape; that way the tape doesn't move while you're rubbing it (to prevent unwanted shifting of the tape, it further helps to use three stages of rubbing:  under light, medium, and heavy pressure).

[tstop4me]

The brass shim idea sounds interesting. Of course, as with the Pro-Filer itself, it would scratch the blade less if you oil or water it. Help me to understand why adhesive brass shim is better than tape?

As I mentioned above, I plan to have a future post on brass shims.

[Bill_S]

This is copied from an earlier post called Pro-Filer Maintenance where I showed a method for dressing/cleaning the fine stone. In the thread, we wanted an easier, faster way to remove the stones instead of using a hammer and pin punch.

I appreciated the way that tstop4me used a quick-release method for holding the sharpening stones in place. It made me think about alternate ways to do it. I spent a couple hours in the shop this morning and came up with this...



With this modification completed, I timed the removal of a stone and it took 10 seconds to unscrew and drop out the stone. Now I have no further excuse not to keep the stones in great condition.

Doing this was very simple using a drill press. With care, you could probably do it using a hand drill too, but use techniques to ensure drilling steps are made square.

Because I used common 8-32 threads, I first drilled the existing holes through with a #29 drill. That's what's required for tapping 8-32 threads.



I then used an 11/64 drill on one side to provide a loose-fit clearance for the screw. I cut the threads on the far side only. This picture shows another reason you want a larger hole on one side. The un-threaded part of the tap is larger than the threads...



I then followed that up with a countersink step so that the flat-head screws are flush with the surface...



I used screws that were originally 1-1/2 inch long and trimmed their length to fit the Pro-Filer without protruding.

It took about 2 hours to do, and makes removal of the stones for cleaning dead simple and very fast.

The original thread is found here http://skatingforums.com/index.php?topic=7896.0

[tstop4me]

TOPIC II:  ADJUSTING THE GAP WIDTH VIA SCREWS (PROPOSED)

(a) Preliminary Discussion.  In the standard Pro-Filer procedure, the clearance between the blade and the guide slot of the Pro-Filer is adjusted by applying tape over the surfaces of the blade.  In this procedure, the tape also protects highly-polished surfaces of the blade (such as chrome plate) from scratches.  The tape is removed after completion of sharpening, and fresh tape needs to be re-applied for the next sharpening.  In practice, taping the blades is time consuming, and often unreliable and frustrating; see previous discussion here:  http://skatingforums.com/index.php?topic=6837.0, Replies #12 – 26.

An alternative approach would be a method or a mechanism to adjust the gap width of the guide slot on the Pro-Filer chassis.  One such approach is applying tape to the inside surfaces of the slot, as discussed in Reply #1 of this present thread.  A principal goal of an alternative approach is to achieve a quasi-static solution:  a sharpener that does not require extensive preparation for every operation, yet can be adjusted [infrequently] to accommodate different blade thicknesses as needed.  The assumption here is that the typical Pro-Filer user sharpens the same set of blades over an extended period, but wants to be able to reuse the same Pro-Filer when he gets a new set of blades; i.e., the typical Pro-Filer does not need to dynamically change the gap width to accommodate multiple sets of blades over the same period.

(b) Important Note.  Even if the slot is lined with a soft material, such as plastic tape, the surfaces of the blades can still be scratched if tape is not applied over the blade surfaces; e.g., if abrasive grit, such as from swarf, comes in contact with the blade surfaces, it likely will cause scratches when the Pro-Filer chassis is slid over the blade.  I myself am not particularly concerned with scratches because I'm now using Paramount blades with stainless steel runners:  these are not chrome plated or mirror polished.  I have previously used Wilson Coronation Ace (chrome-plated carbon steel) and Eclipse Aurora (mirror-polished stainless steel); these blades invariably accumulated scratches from slipping blade guards on and off the blades and from clamping the blades in skate holders for power sharpening.  Light scratches on such blades, however, are purely cosmetic.  [Some runners for hockey skates are fabricated from mirror-polished stainless steel and coated with diamond-like-carbon (DLC) or other materials all the way to the edges; manufacturers caution that scratches can affect skating performance; however, I've not seen these coatings applied to figure skate blades yet.]

(c) Proposed Modification for Adjusting the Gap Width with Screws. 

(1)  Pix4 shows a rough sketch (not to scale) of the proposed modification superimposed on a photo (end view) of the Pro-Filer chassis (stone removed).  The chassis is fabricated from a single block of aluminum alloy.  It has a cylindrical chamber for holding the stone and a guide slot with a fixed gap width for sliding over the blade.  Viewed from the end, the chassis has an approximately rectangular shape with rounded shoulders and a pair of extended rails.  The inner walls of the slot extend along the rails and shoulders.

(2)  In the proposed modification, the gap width is adjusted by two rows of opposing screws; the longitudinal axes of the screws are orthogonal to the planes of the inner walls of the slot.  One row is installed along the rails; the other row is installed along the shoulders.  Since the shoulders are relatively deep, the screws there are installed in wide counterbored clearance recess holes.

(3)  In the proposed modification, 0-80 screws are used.  The 80 refers to 80 threads per inch (TPI); therefore, one full rotation advances the screw by 0.0125" (under ideal conditions).  This should provide sufficient control of the gap width.  These screws are readily available and inexpensive.  They are available in a variety of materials, including brass, stainless steel, and (surprising to me) nylon up to a 1/2" long.  There are even special combos with a metal body and a nylon tip.  Also of importance, 0-80 taps are readily available; see further discussion below. 

(4)  For initial setup, the blade surfaces would be covered with tape, approximately .002 – .003" thick to provide adequate clearance (after the tape is removed).  The screws are adjusted such that the tips just contact the tapes.  Centering of the blade is done by inserting feeler gauges between the inner walls of the slot and the taped sides of the blades.  [This assumes that the slot in the chassis is properly centered to begin with; if not, the screws can be adjusted to provide a proper offset, again using feeler gauges between the inner walls of the slot and the taped sides of the blades.]

(5)  To hold the screws in place, gasket adhesive or other suitable thread-locking compound can be applied to the threads before the screws are inserted.  After adjustment, a small dab of suitable adhesive can be applied at the interfaces between the screws and the chassis.

(6)  Pix5 shows a rough sketch (not to scale) of the proposed modifications to the chassis superimposed on photos of the chassis.  Pix 5(a) shows an end view; Pix 5(b) shows a side view; and Pix 5(c) shows a top view.  As shown in Pix5(c), the thumb notch partitions the chassis into four similar quadrants.  In each quadrant, a row of 0-80 holes are drilled and tapped along the rail.  In each quadrant, a row of recessed clearance holes are counterbored along the shoulder, and a row of 0-80 holes are drilled and tapped.  For illustration, each row has four screw holes; but depending on the particular screws used (different diameters of screw heads), more screw holes can be added; in particular, the screw holes in the rail can be more closely spaced than the screw holes in the shoulders, since no counterbores are needed in the rails.  The configuration of screw holes along the rails can be different from the configuration of screw holes along the shoulders.

(7)  The above operations are difficult to do with a hand drill and a hand-held tap wrench (especially the drilling operations on the shoulders).  They are more readily done with a good drill press (small run out).  For tapping, a spring-loaded tap-wrench guide is held in the drill chuck and used to maintain alignment of the tap wrench.  I personally haven't tried this modification because I don't have a drill press (good or bad).  When I was a grad student many moons ago, I had access to a good machine shop; and I personally drilled and tapped 0-80 threads.

(8)  Note that each Pro-Filer kit for figure skates comes with two chassis:  one outfitted with a cylindrical diamond-coated mandrel for sharpening, and another outfitted with a cylindrical ceramic stone for polishing.  As supplied, the cylinders are captured with roll pins, not intended to be routinely removed.  If you remove one or both roll pins, you only need one chassis, because you can readily interchange cylinders.  [See Bill's elegant solution in Reply #6 of this current thread, or my simpler solution in Reply #1 of this previous thread:  http://skatingforums.com/index.php?topic=7896.0.]  In this case, you've got two chassis that you can customize.   

(9)  The proposed modification will work only for parallel blades, not tapered or parabolic.  I think it will also work for slimline/thinline dance blades, as long as they are parallel.  Similarly, for side-honed blades, as long as they are parallel, though the screws may need to be adjusted after repeated sharpenings (most side-honed blades I'm familiar with are tapered or parabolic, but I believe a few are parallel).

[Bill_S]

I've also thought of drilling and tapping a Pro-Filer. Some thoughts...

Even using a standard drill on a drill press, you're not going to get good counterbores or pilot holes on the curved Pro-Filer sides. A drill bit, especially a small one, will wander away from where you want the hole or counterbore to go, and the bit might even break. It might be possible to chuck an end mill bit into the drill press to make a flat spot face, then do standard drilling operations. Spot faces and counterbores on curved surfaces are the usually domain of a very rigid machine like a mill. A drill press isn't really rigid enough. Suppliers of carbide mill bits even warn against it because the bits are brittle and may break in a drill press if any side loads develop.

Next, I'd increase the screw size to at least a #2. The smallest bit that my current Jacobs chuck can, well, chuck, is 1/16". A number 0 screw requires a tiny 3/64" tap drill, which is too small for my larger drill press. Even better for me, I'd reduce holes to one row, and use easy-to-tap #6 set screws.

I took some photos in the shop of a #2 and a #3 screw, both of which are larger than your suggested screw size...



Here are some #8 set screws with nylon and with brass tips. I've used these a lot in the shop, and wouldn't have much more difficulty with a smaller #6 version of these.



The concept has merit though. Even though it isn't a mill, for ~$25 I can get a 1/8" HSS (not carbide) end mill to experiment with in my drill press. If it breaks, then it's just another of life's lessons.

[Bill_S]

Now here's a concept, but it has hurdles. But if it could be done, then any Pro-Filer would work with any thickness blade. The concept is based on a clamp that always self-centers on a blade.

In woodworking, there are mortise jigs, and this particular dowel jig, that rely on a parallelogram clamp to always center on the work, regardless of thickness (within limits).

Clamped on thick material...



And clamped on a thinner edge...



End view showing how it locates on the edges of the work...



For this doweling jig, slip a drill bit into the guide holes, and drill wood. The holes in the wood are always in the middle, regardless of stock thickness.

For skates, if this clamp were somewhat longer than the blade, then the "stuff in the center" could be a slotted channel, mounted on top, that guides the outside edges of a Pro-Filer. Not screws, no shims, .... and works with any blade.

The problems arise from needing machine-shop tolerances to make it. That means big money unless it's a production item.

Still, it's a possibility, and you don't need the guide-slot of the Pro-Filer anymore (file it out!), and no taping required to reduce scratching.

The beauty of this is that it will work with ANY thickness blade. Just clamp it over the blade, and it will self-center in the proper position.

[tstop4me]

I've also thought of drilling and tapping a Pro-Filer. Some thoughts...

Even using a standard drill on a drill press, you're not going to get good counterbores or pilot holes on the curved Pro-Filer sides. A drill bit, especially a small one, will wander away from where you want the hole or counterbore to go, and the bit might even break. It might be possible to chuck an end mill bit into the drill press to make a flat spot face, then do standard drilling operations. Spot faces and counterbores on curved surfaces are the usually domain of a very rigid machine like a mill. A drill press isn't really rigid enough. Suppliers of carbide mill bits even warn against it because the bits are brittle and may break in a drill press if any side loads develop.

Next, I'd increase the screw size to at least a #2. The smallest bit that my current Jacobs chuck can, well, chuck, is 1/16". A number 0 screw requires a tiny 3/64" tap drill, which is too small for my larger drill press. Even better for me, I'd reduce holes to one row, and use easy-to-tap #6 set screws.

I took some photos in the shop of a #2 and a #3 screw, both of which are larger than your suggested screw size...



Here are some #8 set screws with nylon and with brass tips. I've used these a lot in the shop, and wouldn't have much more difficulty with a smaller #6 version of these.



The concept has merit though. Even though it isn't a mill, for ~$25 I can get a 1/8" HSS (not carbide) end mill to experiment with in my drill press. If it breaks, then it's just another of life's lessons.

I agree that a milling machine would make life a lot easier.  I did think about the problems of drilling into the contoured shoulder.  I thought one simple (though inelegant) approach would be to use a Dremel tool to grind small flats at the proper locations, and then use a rigid bit to start the holes.  These are variously referred to as starter bits or center bits; a #4 bit is shown in the attached photo.  A #2 screw may work; standard fine pitch is 64 TPI.   I wasn't sure that would be easy enough to tweak; but certainly a lot easier to drill and tap.

[Bill_S]

Good thinking. I have a #3 center bit. Smaller versions are available, and all of them are relatively inexpensive.

[tstop4me]

Now here's a concept, but it has hurdles. But if it could be done, then any Pro-Filer would work with any thickness blade. The concept is based on a clamp that always self-centers on a blade. In woodworking, there are mortise jigs, and this particular dowel jig, that rely on a parallelogram clamp to always center on work, regardless of thickness (within limits).

That's one interesting gizmo.  I looked it up on the Woodpecker's website.  It was retired in April 2014, which is the date marked on your unit.  Looks like you got in on the last production run.

Yeah, self-centering skate clamps are all the rage.  Several of the latest automated skate sharpeners (e.g., Sparx, ProSharp, CAG) now come equipped with self-centering skate clamps.   I found a listing for a vintage self-centering Blackstone skate holder
https://www.k-bid.com/auction/15097/item/26.  But their current units are not self-centering.

[Bill_S]

Woodpeckers occasionally offers single-run tools ("OneTime Tools"), and they have a brief pre-order period for them. Then they retire them after the limited production run to fulfill pre-orders.

They've had lots of interesting items for their one-time tool offerings, including that dowel jig. They do a superb job of machining and finishing their products, although some of the offerings have been a solution in search of a problem. Always clever thinking though.

Here's a YouTube video showing a simple shop-built version of a doweling jig with a method for adjusting center. It's yet another dowel-hole drilling jig, but the adjustable center might be something to incorporate into any shop-built skate blade holder. That might be a way to overcome fabrication errors.

https://www.youtube.com/watch?v=gQfPAxskDtk&t=353s

----
I was thinking about your 2-row series of holes/screws for guiding the Pro-Filer alone, and concede that it's probably necessary to have 2-rows as you first proposed. It's apparent that you've thought about the problems.

[Query]

I believe Edge Specialties (the pro-filer manufacturer) at least used to do custom work - e.g., made Pro-Filers with custom gap sizes, for specific blade types. They are a for-profit company. I would think they ought to welcome a chance to charge more money for deluxe version tools.

I wonder if Edge Specialties could be persuaded to make a modified (and more expensive?) tool with an adjustable self-centering adjustable gap. Presumably they already have the low-tolerance metal working equipment, right? Though you are talking about something with moving parts, which might not be within their training.

Again, to replace the punch pins with bolt (and you do mean to use bolts, not screws, right?) - wouldn't it be better to have Edge Specialties make the modified tools, instead of trying to carefully center the bolts or screws yourself?

BTW, help me to understand where you are going with this: You can't tap the existing punch-pin holes because the diameter isn't right for any standard tap (English or metric sizing), or because you think it isn't large enough to be strong enough to let you tighten the bolt to modify the gap size?

If the latter - is aluminum (isn't that what Pro-Filers are made from?) a durable enough material to be repeatedly reshaped in such a way? I've heard that lightweight aluminum bicycles eventually more or less fall apart, though I don't know the details - maybe it's only at the welded joints.

[tstop4me]

I believe Edge Specialties (the pro-filer manufacturer) at least used to do custom work - e.g., made Pro-Filers with custom gap sizes, for specific blade types. They are a for-profit company. I would think they ought to welcome a chance to charge more money for deluxe version tools.

I wonder if Edge Specialties could be persuaded to make a modified (and more expensive?) tool with an adjustable self-centering adjustable gap. Presumably they already have the low-tolerance metal working equipment, right? Though you are talking about something with moving parts, which might not be within their training.

Again, to replace the punch pins with bolt (and you do mean to use bolts, not screws, right?) - wouldn't it be better to have Edge Specialties make the modified tools, instead of trying to carefully center the bolts or screws yourself?

BTW, help me to understand where you are going with this: You can't tap the existing punch-pin holes because the diameter isn't right for any standard tap (English or metric sizing), or because you think it isn't large enough to be strong enough to let you tighten the bolt to modify the gap size?

If the latter - is aluminum (isn't that what Pro-Filers are made from?) a durable enough material to be repeatedly reshaped in such a way? I've heard that lightweight aluminum bicycles eventually more or less fall apart, though I don't know the details - maybe it's only at the welded joints.

Query, you are confounding two entirely separate and unrelated posts:  Bill's Reply #6 and my Reply #7. 

The topic of Reply #6 concerns removing the roll pins that capture the stones and replacing the roll pins with screws.  This requires drilling and tapping the chassis.  The purpose of this operation is to make removing and replacing the stones for cleaning a routine operation (since removing and re-inserting the roll pins is not).  It has nothing to do with adjusting the gap width; particularly, nothing to do with squeezing the chassis under great force to deform it.  As mentioned by Bill, Reply #6 was previously posted in another thread, but he reprised it here because it does concern a modification (definitely an improvement) to the Pro-Filer.

The topic of Reply #7 concerns adjusting the gap width with adjustable screws.  But the gap here is no  longer defined by the fixed walls of the slot in the chassis.  It is defined by the spacing between the tips of opposing screws whose longitudinal axes are orthogonal to the planes of the fixed walls of the slot.  The array of screw tips would slide along the sides of the blades; see pix4 in Reply #7.  This also involves drilling and tapping the chassis, but in a different manner and for a different purpose as those in Reply #6.  But again, no great force is applied to the chassis to deform it.

[Query]

I didn't confound them - I was merely saying it may make sense in both cases to let Pro-Filer's manufacturer do the work.

Also, that if you can make a self-centering jig, that they should be able to build one into the the tool, and remove the problem altogether. So there would be no need for you folks to modify it to incorporate something like that.

But you are right I didn't read your post carefully enough, and mis-understood what you were trying to accomplish. (I believe some of the older Pro-Filers actually did let you tighten the gap using screws. I seem to remember having trouble, because I had limited strength.)

In terms of what you are proposing to do, you would need a way to accurately center things, wouldn't you? In other words, every time you adjust the gap by screwing in or out, you have to move the exact same amount in all the screws. That would be hard to get exactly right.

[Query]

The whole point of a good purpose-built tool is that you shouldn't have to work this hard. You should be able to use it without modification, and it should be easy and quick to use.

I've been using several generations of Pro-Filer for over a dozen years now (some of the tools bought used, older than that), and have been fairly happy with them - compared to what I have gotten from pro-shops, but sometimes I've had to do a lot of trial-and-error things. And sometimes I've made mistakes.

I think it would be great if the manufacturer made it easier on us, so there are fewer mistakes to be made.

It's partly because of the mistakes I've made, and the lack of well-trained shop experience, that I tend to prefer temporary solutions like tape. I wouldn't dare do some of what you have done or proposed, to such an expensive tool.

But it is nice to see I'm no longer the only one I know of on this forum using these tools. When I first mentioned them, some people here felt that a hand-held tool couldn't possibly do as good a job as pro-shop-grade powered tool, and that they couldn't do as good a job as ordinary pro-shop skate techs.

And nice to see that you two, at least, have a lot more shop experience, and know what you are doing with tools. Does that mean you no longer make mistakes?

One of the things I've noticed is that all the best professional skate techs I've known had a lot of prior shop training and work, before they started working on skates.

[Bill_S]

Does that mean you don't make mistakes?

Hah!!!

[tstop4me]

In terms of what you are proposing to do, you would need a way to accurately center things, wouldn't you? In other words, every time you adjust the gap by screwing in or out, you have to move the exact same amount in all the screws. That would be hard to get exactly right.

I addressed this issue in Reply #7; here are the pertinent passages:

"(a) ...  A principal goal of an alternative approach is to achieve a quasi-static solution:  a sharpener that does not require extensive preparation for every operation, yet can be adjusted [infrequently] to accommodate different blade thicknesses as needed.  The assumption here is that the typical Pro-Filer user sharpens the same set of blades over an extended period, but wants to be able to reuse the same Pro-Filer when he gets a new set of blades; i.e., the typical Pro-Filer does not need to dynamically change the gap width to accommodate multiple sets of blades over the same period."

"(c)
...
(4)  For initial setup, the blade surfaces would be covered with tape, approximately .002 – .003" thick to provide adequate clearance (after the tape is removed).  The screws are adjusted such that the tips just contact the tapes.  Centering of the blade is done by inserting feeler gauges between the inner walls of the slot and the taped sides of the blades.  [This assumes that the slot in the chassis is properly centered to begin with; if not, the screws can be adjusted to provide a proper offset, again using feeler gauges between the inner walls of the slot and the taped sides of the blades.]"

[Query]

(4)  For initial setup, the blade surfaces would be covered with tape, approximately .002 – .003" thick to provide adequate clearance (after the tape is removed).  The screws are adjusted such that the tips just contact the tapes.  Centering of the blade is done by inserting feeler gauges between the inner walls of the slot and the taped sides of the blades.  [This assumes that the slot in the chassis is properly centered to begin with; if not, the screws can be adjusted to provide a proper offset, again using feeler gauges between the inner walls of the slot and the taped sides of the blades.]"

So you are going to file away enough of the original slot to have room to insert feeler guages? Or would you just cut off the top? How do you make sure that your filed inner walls are still parallel to the axis of the abrasive cylinder. Wouldn't a hand-filed gap defeat the whole purpose of using a carefully measured and machined tool like the Pro-Filer in the first place?

I did once file a Pro-Filer tool for extra thick blades, but I hated doing it. I prefer not to modify expensive tools in a non-reversible fashion. Maybe because that's because I don't have the confidence that I will do everything right. But if you are confident that everything will work, and/or are willing to accept the possibility of irreparable damage...

And when all is said and done you still need to tape the blades in a carefully symmetric fashion? If you aren't afraid of scratching the sides, what is the tape for?

BTW, I try to avoid scratching the sides of the blade next to the working surface, to reduce friction (to keep the blades fast and improve glide length), not to keep the blades pretty. I've not tried to measure the effect, but some people think it's significant. I wonder if scratches can also affect how well the edges work, because it might make the edges more ragged...

Is there another solution instead of thread lock or glue, that is easier to undo when you need to?

If you do use thread lock, would differential thermal expansion be a problem - e.g., at some temperatures of blade and tool, could it become hard to slide the blade?

Also - how do you prevent electrochemical rust and/or corrosion, caused by the difference of material compositions between Pro-Filer and your screws or bolts (and set screws, if they are metal)? Or is that not a big issue, for some reason? Some people said they had that problem with Jackson Ultima Matrix I blades, because the chassis and bolts were aluminum, but the runner was (nominally stainless) steel. (Maybe I'm unduly sensitive to the issue because it's such a big problem that I've had personal experience with in watersports equipment, like kayaks, in roof rack components, in cars and trucks, and in the screws and skate blade mounting plates.)

I'm not trying to discourage you from doing it - just suggesting you try to think everything through.

[tstop4me]

I.

So you are going to file away enough of the original slot to have room to insert feeler gauges? Or would you just cut off the top? How do you make sure that your filed inner walls are still parallel to the axis of the abrasive cylinder. Wouldn't a hand-filed gap defeat the whole purpose of using a carefully measured and machined tool like the Pro-Filer in the first place?  ...

(1) Query, we've had this previous discussion of "feeler gauges":

You use the term "feeler gauges" to refer to a class of gauges, including radius gauges and rocker bars.  I don't believe this is correct.  I've checked several major tool catalogs and done a Google search on "feeler gauge".  I find no support for this usage.

"Feeler gauges" is a well-established term used by machinists, mechanical engineers, mechanics, and others.  They refer specifically to thickness gauges.  I have several sets.  Typically they are strips of steel (or other metal) sheet or plate ground to precise thicknesses.  You use them to measure the width of a gap or slot by consecutively inserting feeler gauges of increasing thickness until you reach a gauge that's too thick to insert.  A common application, e.g., is measuring the gap of a spark plug.  So, e.g., if a .034 in thick feeler gauge slides into the gap, but a .035 in thick feeler gauge doesn't, you know that the width of the gap is greater than .034 in, but less than .035 in.  This assumes you don't force the gauge into the gap such that you deform the gauge, the workpiece, or both.

Your notion of what a feeler gauge is apparently still differs from mine.  But here are examples of what machinists and mechanics typically think of when they see the term "feeler gauge". 

Let's start with the plain dictionary meaning:

https://www.merriam-webster.com/dictionary/feeler%20gauge:

feeler gauge    noun
Definition of feeler gauge
: a thin metal strip or wire of known thickness used as a gauge

And then proceed to:

* Wiki:  https://en.wikipedia.org/wiki/Feeler_gauge
* A catalog page from Bill's favorite hardware supplier:  https://www.mcmaster.com/feeler-gauges
* A catalog page from your favorite hardware supplier: https://www.harborfreight.com/Feeler-Gauge-32-Pc-63665.html

These are all in agreement.

(2) If you accept the above definition and examples of what a feeler gauge is and is not, then it becomes obvious that no filing, or other modification, of the inner walls of the slot is needed.

(3) An example:

Slot:  Properly centered, with a slot width of 170 mils (1 mil = 0.001 inch)
Blade thickness:  150 mils
Tape thickness:  2.5 mils
Total taped blade thickness (1 layer of tape on each side of blade):  155 mils
Difference (slot width – total taped blade thickness):  170 – 155 mils = 15 mils
Target spacing (calculated) between inner wall of slot and taped side of blade = 15 mils/2 = 7.5 mils
Actual spacing (provisioned) between inner wall of slot and taped side of blade:  7 or 8 mils [that is, you check the centering by inserting various feeler gauges between each inner wall of the slot and the corresponding taped side of the blade to measure the spacing; you adjust the screws such that the spacing on each side is 7 or 8 mils along the length of the slot.]

II.

And when all is said and done you still need to tape the blades in a carefully symmetric fashion? If you aren't afraid of scratching the sides, what is the tape for?

I addressed this in my original Reply #7:

4) For initial setup, the blade surfaces would be covered with tape, approximately .002 – .003" thick to provide adequate clearance (after the tape is removed). The screws are adjusted such that the tips just contact the tapes.  Centering of the blade is done by inserting feeler gauges between the inner walls of the slot and the taped sides of the blades.  [This assumes that the slot in the chassis is properly centered to begin with; if not, the screws can be adjusted to provide a proper offset, again using feeler gauges between the inner walls of the slot and the taped sides of the blades.]

<<Emphasis added.>>  The tape is used only for initial setup, and then removed.  It is not applied for each sharpening operation, which would defeat the entire purpose of the proposed modification.    In the proposed modification, an array of opposing screw tips would slide along the sides of the blade.  You don't want too tight a fit between the screw tips and the sides of the blade:  you want some clearance to provide smooth sliding action (just as in the standard Pro-Filer operation with a taped blade, you want some clearance between the inner walls of the slot and the taped surfaces of the blade).  By applying a 2 – 3 mil thick tape on each side of the blade, and adjusting the screws such that the tips just contact the tape, you will then have a resulting clearance of 4 – 6 mils when the tape is removed, and the Pro-Filer is used for actual sharpening.  Again, tape is used only during initial setup, and not for each sharpening operation.


III.

BTW, I try to avoid scratching the sides of the blade next to the working surface, to reduce friction (to keep the blades fast and improve glide length), not to keep the blades pretty. I've not tried to measure the effect, but some people think it's significant. I wonder if scratches can also affect how well the edges work, because it might make the edges more ragged...

For chrome-plated plain carbon steel blades, the shiny chrome finish is cosmetic.  The immediate region in which the edge is formed, and which contacts the ice, is the chrome-relief region, in which the chrome is ground away.  By eye, the chrome-relief region looks relatively rough, not polished. 

For Paramount blades, the sides of the stainless-steel runners are ground, and not polished at all.

For Eclipse Aurora blades, the sides of the stainless-steel blades are ground, and are polished to a mirror finish all the way to the very edge.

But note, whether your blades are sharpened by machine or by hand, the hollow (and hence the sides of the edges within the hollow) are not polished to a mirror finish anyway (people seem to neglect the hollow in discussions of blade finish and are concerned only about the exterior half of the edge).

And as I mentioned, polished surfaces pick up scratches from blade guards and other handling anyway.  So to me, the trade-off between superficial cosmetic scratches and not having to tape the blades for each sharpening operation is definitely acceptable.

IV.

Is there another solution instead of thread lock or glue, that is easier to undo when you need to?

From my Reply #7:

(5)  To hold the screws in place, gasket adhesive or other suitable thread-locking compound can be applied to the threads before the screws are inserted.  After adjustment, a small dab of suitable adhesive can be applied at the interfaces between the screws and the chassis.

In many instances I prefer to use gasket adhesive to hold screws in place (e.g., I have used it for blade mounting screws).  It does not dry hard, but to a tacky, rubbery consistency.  Thread-locking compounds are not intended to be permanent adhesives, but to permit removal of screws when needed.  Different bond strengths and set times are available to meet different applications and operating environments.

V.

If you do use thread lock, would differential thermal expansion be a problem - e.g., at some temperatures of blade and tool, could it become hard to slide the blade?

Also - how do you prevent electrochemical rust and/or corrosion, caused by the difference of material compositions between Pro-Filer and your screws or bolts (and set screws, if they are metal)? Or is that not a big issue, for some reason? Some people said they had that problem with Jackson Ultima Matrix I blades, because the chassis and bolts were aluminum, but the runner was (nominally stainless) steel. (Maybe I'm unduly sensitive to the issue because it's such a big problem that I've had personal experience with in watersports equipment, like kayaks, in roof rack components, in cars and trucks, and in the screws and skate blade mounting plates.)

I worked for many years in telcom R&D.  We designed equipment to operate reliably under extreme environmental conditions for decades.  This is not the case for the Pro-Filer.  I'd also like to note that the Pro-Filer as supplied uses non-aluminum (steel) roll pins, and see no evidence of the pin/chassis interface corroding.  Also, corrosion is typically an issue in prolonged damp or wet environments.  You use water as a lubricant with the Pro-Filer, but I use mineral oil. 

[Query]

I've actually got a set somewhere of strip-type feeler gauges that matches your definition. I forget what I wanted them for, but they were cheap on eBay. They are delicate enough I would never force them into a space they didn't quite fit - but I suppose if you have enough thicknesses, that might not be needed.

* A catalog page from your favorite hardware supplier: https://www.harborfreight.com/Feeler-Gauge-32-Pc-63665.html

Not really my favorite - they are just cheap and readily available. I've had to return some things that weren't built well enough, including an electronic calipers that worked inconsistently. It literally counted differently going in than going out. (I've wondered if some manufacturers of high precision equipment sell the rejects to places like Harbor Freight - and the ones that Harbor Freight rejects to dollar stores.) Also, I've bought some tools there that wore out rather quickly. And their rechargeable batteries also don't last as many charges as the the Panasonic Eneloops I've switched to, and maybe couldn't deliver as much current for photo use.

An electrician of my acquaintance told me one should always buy hand tools from Klein (but viewed Snap-On as a semi-adequate substitute), and power tools from Milwaukee. (Klein later brought out some lower end tools, which annoyed him.) He didn't view Sears Craftsman, which I had bought, as serious tools, and told me they are dangerous because break they too easily. But when I checked his brands out, they were very expensive, and rather heavy. The only thing I bought from Klein was a $25  electrician's pliers. They are quite sturdy, and I still use them - but seriously, I could buy pliers at a dollar store. I can't afford Milwaukee power tools. What he, as a professional tool user, needed for day-in-day-out constant use, is not what I need.

The same is true of a $20,000 - $30,000 high end powered machine skate sharpening machine. Besides, they wouldn't fit in my skate bag.

you will then have a resulting clearance of 4 – 6 mils when the tape is removed, and the Pro-Filer is used for actual sharpening.

If you recall, I mentioned that a high end skate blade holders are adjustable in 0.5 mil increments. 4 - 6 mils is a lot of play. But if it makes you happy... I tend to seek very sharp blades, enough to create foil edges. Each to their own. (I didn't care that much about sharpness when I worked at a rink, because I sometimes had to walk on rubber without blade guards.)

For chrome-plated plain carbon steel blades, the shiny chrome finish is cosmetic.  The immediate region in which the edge is formed, and which contacts the ice, is the chrome-relief region, in which the chrome is ground away.  By eye, the chrome-relief region looks relatively rough, not polished.

The plated surface is partly there to retard rust. Even moderately priced blades use Nickel plate. But some skate techs polish what you are calling the Chrome relief region smooth, to make the blades faster. You must know that a lot of skate techs have little respect for factory sharpening, though that varies by brand. For one thing, the Chrome Relief is often factory milled (is milled the right term?) asymmetrically, which can create asymmetric edge heights if you aren't careful. BTW "Chrome relief region" is (I think) a term coined by and mostly used by Sid Broadbent (see http://www.iceskateology.com - he has a number of interesting skate sharpening tools too, and an interesting book on skate blades, though his minimum cost sharpener is perhaps too pricey for the home market). My Jackson Ultima Matrix I blade runners didn't quite have a mirror finish region next to the bottom, and I have scratched them up a little by being a bit less careful than I should be, but they are still smooth to the touch. They are stainless steel, and I'm not sure they have a Nickel or Chrome plate layer at all. Given reasonable care, they don't seem to have much of a rust problem, which is a definite plus.

But note, whether your blades are sharpened by machine or by hand, the hollow (and hence the sides of the edges within the hollow) are not polished to a mirror finish anyway (people seem to neglect the hollow in discussions of blade finish and are concerned only about the exterior half of the edge).

The best known skate tech I know often sights along the shiny reflection from the hollow to look for imperfections in the hollow surface. Making that almost mirror-smooth is one of the reasons for using a polishing compound or oil, especially on powered machines, and I've known more than one skate tech who did that. Maybe the ones you know don't think it is worth the time and effort, or it never occurred to them. Most skate techs focus on hockey, where blades get remarkably rough treatment anyway, so maybe polishing hockey blade surfaces would be pointless. OTOH, I've known people in the speed skating community who go to ridiculous extremes.

Also, corrosion is typically an issue in prolonged damp or wet environments.  You use water as a lubricant with the Pro-Filer, but I use mineral oil.

An interesting point. And it is true that I need to re-apply the water more often than I needed to re-apply oil. There are always trade-offs. If I did my sharpening on a dedicated home bench, instead of carrying my sharpening kit with me in a bag where oil once made a mess, I might use oil. The best pro-shops often use a polishing fluid containing oil, though I wonder if that is because water would boil at machine sharpening speeds, considering that the steel filings often fly off at close to red-hot temperatures.

Have you got a good tool modification to maintain a given rocker radius? Some of the powered sharpeners can follow a rocker bar (I think they call it) as a guide.

[tstop4me]

If you recall, I mentioned that a high end skate blade holders are adjustable in 0.5 mil increments. 4 - 6 mils is a lot of play. But if it makes you happy... I tend to seek very sharp blades, enough to create foil edges. Each to their own. (I didn't care that much about sharpness when I worked at a rink, because I sometimes had to walk on rubber without blade guards.)

Remember, in typical manually-guided power sharpeners, the skate holder glides along external (i.e., external to the blade) reference baseplates (e.g, Blackstone, Blademaster, Wissota, ...), external reference guide rails (Incredible Edger), or other external reference surfaces or devices (older sharpeners, no longer made).  But the Pro-Filer chassis slides along the sides of the blade itself [this is a major limitation of the Pro-Filer]:  the sides of the blade are the reference surfaces.  If you have only an 0.5 mil gap between the blade surfaces and the sliding surfaces of the Pro-Filer chassis (whether the sliding surfaces are those of the native slot or added screw tips), the Pro-Filer will bind (unless, perhaps, you creep it slowly along the blade; but impractical for sharpening).  Also, in practice, you won't be able to maintain an 0.5 mil gap along the length of the blade for the simple reason that the blade thickness is not that uniform.  But if you prefer a smaller gap, you can adjust the screws (in the proposed modification) all the way down to a 0 gap (do the initial setup with no tape).

ETA:  After my steeling operation (that I've discussed before), my edges are sharper than that produced by any skate tech I've gone to.  Other skaters including coaches (both figure and hockey) who have felt my edges are quite surprised.  Many skaters don't like them so sharp though.  But one high-level ice dancer likes really, really sharp edges ... and she asks me to steel her edges.

[Query]

Remember, in typical manually-guided power sharpeners, the skate holder glides along external (i.e., external to the blade) reference baseplates (e.g, Blackstone, Blademaster, Wissota, ...), external reference guide rails (Incredible Edger), or other external reference surfaces or devices (older sharpeners, no longer made).[/url]

Which is a big defect, if the blade is warped. Since the sharpening stone of the Pro-Filer is only about 2" long, much shorter than the blade, the centering of the sharpening surface on the blade is much less affected by warp than on pro shop machines. (The exception is that there is one expensive figure skate blade holder that clamps the blade straight. But most pro shops don't use it.)

By the way, on some of the cheaper (or is it older?) powered sharpeners, the blade itself slides along the reference surface, and there is no holder, other than the hands of the skate tech. Looks very hard to do well.

the Pro-Filer chassis slides along the sides of the blade itself [this is a major limitation of the Pro-Filer]: the sides of the blade are the reference surfaces.

If the "chrome relief" section was milled evenly and symmetrically, that's not a limitation - it's the right way to do it. And it pretty much is on high end Ultima blades, and maybe on Paramount blades.

Of coarse, the advantage of the pro shop machines with a holder is that. In theory, an asymmetric plating and milling of the "chrome relief" doesn't matter on pro shop machines, unless the blade is not parallel sided, since a careful skate tech adjusts the end of each side of the blade relative to the wheel.

However, skate techs who are in a hurry often sharpen similar blades in batches, and assume they are the same thickness and are unwarped, and don't adjust between blades, so they do in fact effectively assume that the blades are of uniform thickness. I suppose in one sense, those skate techs get very "good" at working quickly, about 1 minute/blade, less for rental blades. They are often pushed to do this by management, because time is money. (No wonder they sometimes make big mistakes.)

If you have only an 0.5 mil gap between the blade surfaces and the sliding surfaces of the Pro-Filer chassis (whether the sliding surfaces are those of the native slot or added screw tips), the Pro-Filer will bind (unless, perhaps, you creep it slowly along the blade; but impractical for sharpening). Also, in practice, you won't be able to maintain an 0.5 mil gap along the length of the blade for the simple reason that the blade thickness is not that uniform. 

I'm not sure how uniform it is. As a test. I just oiled a relatively unused Ultima Matrix I blade, and slide a sliding (plastic) calipers along it, set tight enough that it did bind a little. It had the same tightness the whole way. And I slid it back the same way, to make sure the calipers hadn't slippeed - it hadn't.

I'm pretty sure that means it varies by less than 1 mil.

I don't know which other major blade makers are that consistent.

Since you (and many skate techs) don't worry much about scratching the sides of your blades, maybe they are no longer that uniform in thickness, because of the scratches.

The best known skate tech I know (Mike C.) routinely returns blades to the manufacturer if they are warped by more than a mil or two - and if they are warped by less than that, he straightens them. (The reason he returns the ones with more is that blades often break when you straighten them. E.g., MK and Wilson figure blades, because they are attached to the base with nothing more than "silver solder". I think Paramount blades are attached with nothing more than glue.) A mil or two of warp wouldn't matter they weren't about that consistent or better in thickness from the factory. I think he also routinely returns asymmetrically milled blades. While I watched him work, he returned roughly 15% of the blade pairs. (Maybe that's part of why he charges premium prices - but also part of why people send him their blades and/or skates to work on from halfway around the world. He doesn't try to get the blade makers to pay the return shipping costs - he eats that cost, and spends a lot of time examining new blades very carefully. An economy pro shop or cheap mail order place probably couldn't do that.)

I'm not surprised that your edges are sharper than most skate techs produce - since most skate techs use a medium or coarse grit wheel, and then deliberately dull ("de-burr") the edges. I couldn't find any skate tech who consistently made the blades as sharp as I wanted, and the ones that came close have retired - which is one of the reasons I switched to doing it myself. Even the skate tech who sold me the Pro-Filer, and instructed on its use (an odd business decision) didn't produce blades as consistently sharp, when using powered machines. I have wondered if it is possible to do so, though - is the main limitation the amount of time the skate tech spends? That said, many very good skaters skate on relatively dull blades.