Re: Broaching , a question

On 3/26/2024 12:23 PM, Jim Wilkins wrote:

"Snag"  wrote in message news:ututu3$1u2oj$1@dont-email.me...
    I'm getting ready to broach my first keyway with an actual broach .
My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the broach
I get .062" and I'm wondering if that is the correct thickness for the
shims .
Snag
 -----------------------------
 My 3/16" keyway broach came with an 0.050" shim. For the others I shear strips of scrap sheetmetal and add one between passes until the key fits. My guide bushings are all shop-made to eyeballed depth.
 Thinner shims leave less unsupported broach, but if the shim is too thin to hold the bend the broach may pull it through.
 

   I made a couple of shims from some .050" galvanized sheet . Probably going to make some more of varying thickness so I can fine tune the depth . I made the slot in the guide bushing the same depth - measured from the round - as the width of the broach at the bottom end .
   The project got delayed a bit because I stripped the old DRO off the mill . The new ones are a lot better but there was a good bit of fabrication to adapt to my mill .
--
Snag
  "They may take our lives but
they'll never take our freedom."
  William Wallace