Hand Tools Archive

Re: Update
Response To:
Re: Update ()

david weaver
I have had chisels before that are hard tempered and hold up fine as long as the coarse work isn't done with an aggressive stone. That's sort of a double conundrum with a chisel like that because if there is damage, an aggressive stone is the only thing that will cut it quickly, and a mild stone is the only thing that won't lead to a crumbling edge.

The japanese refer to the very hard tempered tools as "not suitable for beginners" for obvious reasons. When they get too far out of balance, I consider them not really suitable for anyone.

I'd resort to a secondary bevel to allow use of a more easy going routine or more time on the finish stone with that before tempering it. Tempering may fix it if it's a pure hardness issue, but it may not if it's not. For actually getting work done, irons and chisels with that temperament are difficult to live with and will have you walking on egshells.

In the long term, i'd back it off to a 25 degree flat primary (I recognize it will take you eons to get it back to that by hand) and a 30 degree secondary. if the failure occurs just at the very edge and continues to do so, the tiniest of microbevels will let you experiment to push the failure further up the bevel (in the hope that rather than that, it just won't occur) without having to do much more work.

I think this concept is valuable (being able to manipulate where the failure occurs if an edge isn't behaving well), but probably underused in woodworking. Sometimes, if the temperament is easily solved, the result can be a hard and long wearing iron that's easy to refresh if it doesn't take damage.

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