How are blades measured for length?

[lutefisk]

OK, dumb question time (again):  How are blades actually measured for length?  I've got a pair of Ultima Mirage blades which are stamped "10 3/4".  My new pair of Aspire XP blades are stamped "11".  I assume inches are some how involved, but I'll temper that assumption by reminding y'all  that me and being wrong are firm friends; we go way back. 

If one measures either blade from the top pick or the drag pick to the end of the heel, neither one measures in at those lengths.  The Mirage measures 12 5/16" from drag pick to the end of the blade; The Aspire measures 12 9/16".  If I measure from the tail to 10 3/4" on the Mirage or from the tail to 11" on the Aspire that comes to about mid way on the front stanchion.  The hardened part of the blade tends to begin to "fade" in thickness *about* at those lengths on the respective blades, but is that really how blades are measured???  If one encountered a blade which had no markings how would one determine it's length?

[TreSk8sAZ]

The size of the blade (so the inches it is stamped with) is determined by measuring the front of the sole plate to the back of the heel plate. It seems counter-intuitive, as you would think they would go by the blade length. But, when you think about it, what you really want to know is how long the surface you're looking to put on the bottom of the boot is, regardless of what sticks out past it!

[lutefisk]

Thanks!  I just measured my two examples in the manner you described and indeed they do measure in as stamped.  Another mystery solved.

[Bill_S]

In preparing for my upcoming talk on boots and blades for the LTS parents and skaters, I created this graphic that shows how blade sizes are determined. This is a good thread in which to post it.



You saw it here first!

[nicklaszlo]

Do MK blades and Jackson blades use the same system of sizes?

[Isk8NYC]

Kudos!  Thanks for sharing, Bill!

In preparing for my upcoming talk on boots and blades for the LTS parents and skaters, I created this graphic that shows how blade sizes are determined. This is a good thread in which to post it.



You saw it here first!

[Query]

Do MK blades and Jackson blades use the same system of sizes?

AFAICT from a very limited set of examples, they do in terms of total length, and so do Wilson blades.

In addition, AFAICT they have correspondent hole positions, so that you can mount any of them using the same screw holes, and you will get approximately the same position for the sweet spot. Though that is complicated for Wilson blades, since many or all Wilson blades have two sweet spots up front. (By sweet spot, I mean a point at which the rocker radius changes.)

But:

The position of the toe pick and of the end of the tail, relative to those screw holes, varies with blade model. Perhaps with length too?

The positions and orientation of the oblong sliding holes relative to the other screw holes doesn't seem to be fixed for all blades, based on a couple examples I have looked at.

I've never checked whether hole position is the same for low level blades, such as those riveted onto cheap skates.

I've never checked out how hockey and speed skate hole positions and lengths work.

I think MK has made a very small number of co-planar mount blades for Sid Broadbent's designs - which can't possibly mount exactly the same as most of their other blades.