sharp/dull blade drawing Steve Elliott - CPM 3V small map
Finest abrasives.
Microbevels front and back.
Use a jig.
Copyright (c) 2002-15, Brent Beach

The Blade

Steve Elliott is a fellow plane blade tester. He has made a number of blades from an exotic steel named CPM 3V. CPM stands for Crucible Particle Metallurgy - which the manufacturer says are "high performance alloys ... produced by a powder metallurgy process". The main alloying components are: Carbon 0.80%, Chromium 7.50%, Vanadium 2.75%, Molybdenum 1.30%.

This is a 2" wide blade, which I tested in a Stanley #604-1/2. The blade is too thick, at 0.13", to use in most planes, but by moving the frog back was just able to work in this plane.



The Test

May 21-22, 2006.

As with all my other tests, I honed three front and back microbevels using 15, 5, and 0.5 micron 3M abrasive paper.

The front bevel, 200 X magnification, after sharpening.

The right half is the primary bevel. The microbevels are, from left to right:

  1. The third microbevel, 0.5 micron abrasive.
  2. The second microbevel, 5 micron abrasive.
  3. The first microbevel, 15 micron abrasive.
  4. The primary bevel, 120 grit abrasive belt.
The front bevel, 200 X magnification, showing the microbevels
The front bevel, 200 X magnification, after 100 passes along 4 foot douglas-fir board. The microbevels are numbered as before.

The wear bevel is very hard to see. If you look right at the edge though you can see a faintly darker line.

The front bevel, 200 X magnification, after 100 passes
The front bevel, 200 X magnification, after 200 passes.

By enlarging the picture (digitally) I can see that the wear bevel is about 4 pixels wide.

The front bevel, 200 X magnification, after 200 passes
The front bevel, 200 X magnification, after 300 passes.

By enlarging the picture (digitally) I can see that the wear bevel is about 5 pixels wide.

The front bevel, 200 X magnification, after 300 passes

Bottom Line

The CPM 3V blade is comparable to most HSS M2 blades, except the Academy Saw Works blades of recent manufacture.

At the end of the test the edge was defect free.

LINKS

Check out my jig page for a simple jig you can make in your shop, along with a sharpening set up using sheet abrasives, that reliably produces excellent edges, for all types of irons.

Blade Testing Page

Back to the Blade testing home page.

Home again

Back to the Sharpening and Testing Plane Irons home page.

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