Re: Re: Re: Re: equipment geeks solicited...


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Posted by Check page 9... on May 19, 2003 at 13:01:38:

In Reply to: Re: Re: Re: equipment geeks solicited... posted by js on May 19, 2003 at 00:22:05:

On page 8, backbores are discussed and identified by the Bach tool number (a particularly opaque way to list them, I think) and on page 9, the throat sizes are listed separately.

If I read the Bach manual correctly, the throat size and backbore are somewhat independent. The throat is one size, a simple diameter measurement, but the backbore (I assume the whole inside of the shank) is not a simple diameter measurement, not even a straight taper measurement, but a profile graduating from the throat to the end of the shank.

If that's true, I think drilling out the throat with a straight sided bit is not going to change the backbore. It will increase the size of the throat and change the relationship to both the cup and the backbore, but the Bach manual seems to be saying that the profile of the backbore is important. No amount of straight drilling will affect the profile of the backbore.

Well, this subject is getting too deep and wide for my brain. Think I'll go buy a Kellyberg and have done with it.

ttfn
jlb


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