I will later take measurements of the thickness of my old Matrix I blades. Near the bottom of the blades, they were ground a little thinner than the rest of the runner - and in a way that pre-scratched them there - which I don't understand since they were Stainless 440 (440C??) alloy blades. It's hard to tell if any additional scratches I create could possibly matter. But measurements of the old Matrix I blades won't do anyone much good - people bought out Jackson Ultima's remaining stock rather quickly (I think a few weeks or less) after they stopped making them, and it's very hard to find them or the chassis for sale over the Internet.

I realize that the Matrix I blades have been discontinued many years now.  My question concerns the width, not the thickness, of the runner. To avoid ambiguity, what I mean by the width is shown in the attached pix (Paramount blade in this instance).  If you are able to use the Pro-Filer as is, the width of the Matrix I runner must be much greater than the width of the current Matrix runners; so I'm curious as to what it is.  The width will likely vary along the length of the blade.  A typical value near the middle will do.  Thanks.

Query, your mention of cloth has made me think about stretching some jersey knit rag cloth inside the Profiler to minimise scratches.  Or another idea would be to cut pieces of index card or something to insert.  This could be switched out each time and not build up grit? 

I'm largely unconcerned with cosmetic issues too. A few people on this forum have claimed they can tell they are slower with scratched blade sides, so maybe it isn't just cosmetic. Intuitively, it makes sense, if you consider boats in water, and studded tires on ice - but those are a lot different. Without objective measurements under conditions similar to figure skating, it's hard to tell.

In my case, I'm personally certain that getting stronger would make much more difference than minor scratches.

At the moment, I'm pleased with and used to what Pro-Filers do for me. Refinements are mostly a curiosity issue for me. But it would be very cool if Kaitsu were to offer his 3D printed tools, assuming they work well.

I've also thought about simply pulling an abrasive cylinder against the bottom of the blade, using a stretched cloth, pulled tight with my hands and fingers across the sides of the blade - but suspect that would be slower, and possibly harder to control.

I will later take measurements of the thickness of my old Matrix I blades. Near the bottom of the blades, they were ground a little thinner than the rest of the runner - and in a way that pre-scratched them there - which I don't understand since they were Stainless 440 (440C??) alloy blades. It's hard to tell if any additional scratches I create could possibly matter. But measurements of the old Matrix I blades won't do anyone much good - people bought out Jackson Ultima's remaining stock rather quickly (I think a few weeks or less) after they stopped making them, and it's very hard to find them or the chassis for sale over the Internet.

Holding the blade with the edges down, and pushing up with the sharpener would likely reduce the number of particles that get in between the chassis and polished surfaces, but I don't think it would eliminate them...

And maybe it would leave more particles next to the hollow surface - which might matter more.

I guess almost any abrasive process could have problems with scratching. Do you think it is better or worse with powered sharpening tools?

I've seen powered sharpening tools on which the tech failed to clean the filings off the surface on which the side of the blade glides - but that is a correctable error.

Another issue, now that I think of it - I'm not sure the entire 2" length of the abrasive cylinder ("stone") is in contact with the blade - it seems like the rocker curvature would confine it to one short length of contact at a time. Does that mean a shorter tool would do as well?

Just a though: if Blademaster's variant on the Pro-Filer (which they don't seem to call Pro-Filer) has no extensions, just a gap, does that make it harder to align, because the gap isn't as high as the gap+extension? But does it also mean that the tool could sharpen some current generation Matrix and Paramount blades that Pro-Filer might have trouble with?

* The Blademaster website calls their product a "DIAMOND PROFILER".  But if you click on the photo of the complete kit, the packaging reads "PRO-FILER", and even still bears the "Edge SPECIALTIES" mark.  Don't know whether this is just a transitionary phase or what.

* What we don't know (and it's difficult to judge from the Blademaster photo) is how deep/high the slot/gap on the current version is compared with how deep/high the total slot/gap (taking into account the main body of the chassis plus the extension rails) of the original version is.

* I have Paramount blades (their Gold Seal version in 440C stainless steel).  When new, the runners are ~6 mm wide.  For the old Pro-Filer to work, I had to file the extension rails off completely. Needs more careful control.  Some versions of the latest intermediate-grade Paramount blades I saw on display have runners ~8 mm wide. Likely easier to handle.  The Matrix blades I saw on display had narrower runners, only ~4 mm wide.  Not sure that provides sufficient guide surfaces if you modified the chassis to accommodate the narrower runners. 

Approximately how wide are your old Matrix I runners?