I found that several of the auger bits (Jennings pattern) that I recently
purchased are not accurately sized. Anybody know what the size tolerance
should be for the diameter at the spur and of the auger itself?

Thanks

John

John Gonser wrote:
I found that several of the auger bits (Jennings pattern) that I recently
purchased are not accurately sized. Anybody know what the size tolerance
should be for the diameter at the spur and of the auger itself?

No, I don't know but I do know there are ANSI and ISO standards for
twist drills and I presume there would be for other varieties as well.
I'd start looking in those directions if it is really that significant.
Of course, what a Standard says is of no benefit if the manufacturer
isn't following it...

Just out of curiousity, what's the application that requires such
precision and what kind of measurements are you getting?

I'm getting 1/32" of error in the spur diameter on some bits and up to 1/16"
( or more) on the auger. This is fairly critical in a 1/4" hole, and it
isn't very good in 3/4" either.

The application is using doweled tenons and in general dowel joints. I've
used brad point bits up to now but need to move to use of brace and bit. I
have only one bit that is an antique, but picked up a set of bits that
disappointed me in the variations in their dimensions.

I will seek out the ANSI standard, if it exists.

"dpb" wrote in message
oups.com...

John Gonser wrote:
I found that several of the auger bits (Jennings pattern) that I recently
purchased are not accurately sized. Anybody know what the size tolerance
should be for the diameter at the spur and of the auger itself?

No, I don't know but I do know there are ANSI and ISO standards for
twist drills and I presume there would be for other varieties as well.
I'd start looking in those directions if it is really that significant.
Of course, what a Standard says is of no benefit if the manufacturer
isn't following it...

Just out of curiousity, what's the application that requires such
precision and what kind of measurements are you getting?