Framing Chisel Widths

[THJ]

Hey Guys,

New member, long time lurker here. I've been collecting timber framing tools for the past 5 years or so and have amassed a decent pile of bits, chisels, slicks, axes, and boring machines. I've always loved old timber frame barns and one day I hope to have my own timber frame barn and home on a nice piece of acreage.

Anyways... In some of the reference material I have, they say that the 1.5" chisel is essential, which I understand why. A few of the books say the chisel MUST be EXACTLY 1.5" in width. Being somebody who's used to working on high speed boiler feed pump for power generation, I might have a different definition of exact that a carpenter. I've noticed all the antique framing chisels than I have seem to be 1/32" or 1/16" under nominal. So instead of a 2" it will be 1 31/32" or 1 15/16". Most of the chisels I've found have been around 2" or 1.25" in width. But I do have an JPH & Co Everkeen that I think is a framing chisel (has the length, but the cross section seems a bit thinner than the other framers I have) that measures out at 1.450", is that close enough to exactly 1.5" for a timber framing chisel?

Thanks,

Scott

[TimFromNB]

Hi Scott,

Welcome to the forums. In my opinion, that would be fine. Just don't use it as a measuring reference. I am currently cutting 2" mortises with a 1 1/2" chisel. Just makes for more work on the 2" face because I need to make two passes. I am trying to clean up an old 2" I have and that might save me some time.

I would just make sure the end grain is severed across the full 2" (or 1 1/2") ends before digging into the mortise sides and possibly splitting the wood past the mortise ends.

Tim

[Dave Shepard]

1/32" might be tolerable, but the chisel is used as a gauge, so it needs to be the right size. I have one chisel that has been lapped to 1.5000", but only because I have a strange sense of humor. Boring machine bits should also be the right size. 

[Roger Nair]

I just measured the width of nine antique framing chisels.  All but one was narrower at the heel compared to the tip in a range of .02 to .05 inches.  Width at the tip was less than nominal most around .02 to .03.  I think this is by design, in order to prevent chisels from jamming  while deep mortising.