Hand Tools Archive

Subject:
Re: W-1 and A2; and preparing an edge.
Response To:
W-1 ()

Derek Cohen (in Perth, Australia)
Subjectively ...

I have two W1 LN blades. One is for a #4, and it has been trouble - it is difficult to even take an edge. I plan to re-heat treat it. The other is in a skew block plane, and it takes and holds an excellent edge. In this case, I do not see it as a BU vs BD issue.

The LN A2 blades I have are excellent. One is for a #3, and the other two are for a #4 1/2 and #51. I know the reputation of A2 for micro fracturing, but these blades have not shown up this way (or possibly I do not recognise this in the surfaces).

I have used LV A2 blades for many years as well. In recent years they have been replaced by PM-V11, mainly because I would rather hone the latter. A2 is more work to remove the wire. Nevertheless, the A2 blades have been really excellent on a shooting board, which is a pretty good test of durability. I have presented numerous examples (the Veritas Shooting Plane review being just one) where the irons are ground and honed at 25 degrees. In theory this should be a no-no for A2, yet it is not so in practice ... I can only put this down to the low bed angle. I am still getting my head around this. Perhaps a structural engineer here can say something: we assume that cutting angle is cutting angle, even when the bed angles are different. Do vector forces follow this as well? Is the low bed angle responsible for better edge life, or is this due to a lower cutting angle? Is it the same thing?

It makes logical sense to me that a lower cutting angle will wear better when shooting since there is less impact. It also makes logical sense to me that a progressively higher bevel angle will wear progressively faster since the edge moves increasingly away from the acute side and it has progressively less edge to hold onto. Logically, the higher the bevel angle, the tougher it is, but also the less leeway as well to retain sharp.

I'd welcome comments on the above since it seems to me that any discussion about steel type must include how the edge is prepared for optimal use.

Regards from Perth

Derek

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