New Tool Steel PM-V11 archive

Wednesday 14 November 2012

Rob Stoakley pits the latest development in tool steel from Lee Valley against some tried and tested alternatives

Gallery

Eagerly awaited and long anticipated, the new blade material from Veritas has arrived and judging by the copious amounts of information on the website Rob Lee, together with his merry band of stalwarts have been burning a lot of midnight - but have they succeeded?

PM-V11 has been developed for the next generation of Veritas planes and soon to come chisels, with three specific, practical requirements in mind. Firstly, that it should be able to hold an edge and secondly, it shouldn't degrade under impact.

Most importantly, the edge should be honed and easily maintained using common sharpening media.

Selection process

Many different alloys were tested under workshop and laboratory conditions and of these, 21 steels were eventually narrowed down. After months of rigorous testing and analysis, PM-V11 emerged as a clear 'front runner'. Under laboratory-like conditions and for practical purposes, three other additional alloys were used in the comparative tests that followed, the traditional O1, the newer A2 and an M4 variant. During the course of the exhaustive testing the Lee Valley engineers took over 5,600 digital microscope photographs to measure and evaluate blade performance. They created wood shavings that, if connected end-to-end would stretch 1.6 miles and in the process ground the equivalent of two complete plane blades to dust.

The F&C test

I was offered the chance to give the new blade material a swift assessment… something I jumped at, but given that it's already been extensively tested, my humble preliminary trial was a purely subjective one. I decided to keep it simple by planing a small lump of teak (Tectona grandis), notorious for reducing a honed edge to mush in a few passes. The aim was to use an O1, A2 and the new PM-V11 blade in my low-angle jack and attempt to remove as many full width shavings as possible before the blade became too dull.

Preliminary

My standard sharpening regime is to use 3M films - 30, 5 and 1 micron - on a plate glass surface, together with a Kell III honing guide. I also use a projection board with the Kell so that a repeatable honed angle of 30° can be achieved easily, though a bitter, edge-crumbling experience on an A2 blade meant that this was honed to 35°.

The primary bevels on the O1 and A2 blades were freshly ground to 23° on my Tormek, leaving just a tiny sliver of an edge to hone at the requisite 30° or 35°. I experienced no difficulties in honing the new blade and would expect equally good results on other sharpening systems. The effective pitch was 42° for the O1 and PM-V11 blades whilst it was 47° for the A2. Each blade was set up - using a piece of maple - to produce a shaving of .08mm, which was checked during the course of the test with a digital calliper.

The test

The O1 blade was used first and removed around 20 full width shavings before it became too difficult to push or they became fragmented; predictable but not encouraging! Checking the blade afterwards revealed that although reasonably sharp, it had now become noticeably jagged.

The next blade was the A2, honed at 35° with an effective pitch of 47°. This made it a lot more difficult to push the plane through the timber, but it did result in a creditable pile of shavings. After the blade was removed, the edge was smooth but quite blunt.

The final blade was the new PM-V11, but by this time my piece of teak had been very considerably reduced in thickness and so I had to resort to gluing it to a block of ply to remove the last few shavings. Even so, a very substantial pile had been produced and when I felt the blade afterwards, I was surprised to see it still had an impressively keen edge. I'm in no doubt that had I a little more teak, the PM-V11 would have quite happily planed it all away!


Tegan Foley

Tagged In:

Rob Stoakley , New Tool Steel PM-V11

F&c Verdict

Has Rob Lee succeeded in his quest? Without doubt, but more assessment needs to be done before PM-V11 can be fully recommended as a cast-iron, 24C gold-plated must-have in the workshop.

What Is Pm-v11?

To begin with, constituent metals are melted and mixed together, then atomised, creating very small particles that cool and harden, forming a powder. This powder is screened to ensure consistent particle size, and then heated under pressure to form a billet.
The billet is then rolled to the required thickness, ready to process, as conventionally smelted steel would be. The PM process yields steel with a very fine grain structure that is uniform throughout.