Making a Rob Cosman kerf extender

[SteveMP]

Like the idea of Cosman’s x10 after doing several half blind dovetails on the travel chest. But its a little pricey for what it is: https://robcosman.com/products/rob-cosmans-kerf-x-10
The guy that sharpened my saws threw in some scrap plate and brass back. Had some free time on my lunch break. To be continued after i get my lathe out and set up.

 

[HOJ]

I came across one of these a few years ago when I visited Classic Hand tools, I was starting on a project to make a few drawers for an Oak storage case, but being frugal decided to make my own version from a gentleman’s saw I had knocking about, works really well, maybe not as refined as Mr Cosman’s version, or yours, but cost me nothing.

 

[SteveMP]

I came across one of these a few years ago when I visited Classic Hand tools, I was starting on a project to make a few drawers for an Oak storage case, but being frugal decided to make my own version from a gentleman’s saw I had knocking about, works really well, maybe not as refined as Mr Cosman’s version, or yours, but cost me nothing.

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Thats great! I would have probably done that too if i had an extra gents saw. I was looking for a way to make one as cheap as possible and kind of got lucky with these scraps. Otherwise was going to use a card scraper. The only problem is the card scrapers i have are too thick and i ended up splitting one of the dovetails i was working on.

 

[SteveMP]

Small update. Getting too hot to work in the garage now so atopping here. Turned a handle from a chunk of scrap cherry.
Did some more file work and sanding. Handle needs a couple more coats of finish and the brass some finer sanding and polish and remove the bluing.

 

[Mike G]

I cut the end off an old bone-handled table knife. I've since come to the conclusion that any form of this technique is too brutal, and liable to cause more damage than it's worth, so I stick with chopping with a bevel-edged chisel.

 

[Woodbloke]

I cut the end off an old bone-handled table knife. I've since come to the conclusion that any form of this technique is too brutal, and liable to cause more damage than it's worth, so I stick with chopping with a bevel-edged chisel.

Tend to agree with you Mike. I can't see how it'll work with very thin plate Japanese saws either so I think I do as you suggest and stick to a bevel edged chisel to pare away the offending material - Rob

 

[SteveMP]

I cut the end off an old bone-handled table knife. I've since come to the conclusion that any form of this technique is too brutal, and liable to cause more damage than it's worth, so I stick with chopping with a bevel-edged chisel.

I initially thought it was brutal as well as it split a piece i was working on. Then rewatched the Lie Nielsen video and noted he said to clamp it or put in vise. Once ai did that had zero issues.

 

[HOJ]

clamp it or put in vise

As I did:

 

[SteveMP]

One down. Will send this to the guy that gave me the scraps. Starting on a second one.

 

[SteveMP]

Tend to agree with you Mike. I can't see how it'll work with very thin plate Japanese saws either so I think I do as you suggest and stick to a bevel edged chisel to pare away the offending material - Rob

I'll try it an report back. I have a full array of japanese saws. some probably thinner than what you have seen.