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Broach Styles (A, B, C, etc.). . .what's the difference?

atomicjoe23

Aluminum
Joined
Aug 9, 2011
Location
Poulsbo, WA
I was looking at individual broaches today on the Dumont website and see a wide variety of broach styles (A, B, C, etc.) many with the same dimensions available.
I tried to find information about the broach styles both on the Dumont website and in the Machinery's Handbook and was unable to find any information. Could anyone
shed some light on this for me? I am primarily interested in American Standard push-through keyway broaches (inch) at this point in time, but I will take additional
information for future reference as well.

Thanks!
 
It has to do with the width of the broach. For size A you would need bushings with a 1/8" guide groove, size B 3/16 & not sure about size C but it is bigger than A & B. All I've used is A & B
 
Yeah, A/B/C tells you which broachs, bushings and shims are compatible with one another, based on the rectangular cross-section of the broach body. Nothing to do with tooth geometry, etc.
 
A longer broach can cut a longer keyway, but while this implies that you're better off using bigger broaches, there will come a limitation in how small of a bore you can fit that large broach into. So, you need 'em all if you want to do everything :D
 
Thanks for the responses guys. . .I thought it might be more involved than that. I never paid very much attention to the broach sets in the shop. . .since they are in sets in a box and I had never needed to order one I didn't realize there were different styles. Pretty straight forward. . .appreciate the help.
 
It does get confusing. There is a crossover where some broaches will take a B bushing or a C bushing...depending on the ID of the part being pushed. I can't believe DuMont doesn't spell this out. As metal slave indicated, it's all relative to the back side of the broach...not the key it cuts.

Stuart
 
Nope, nowhere on their website. . .

. . .here's their brief response to my email inquiry:

"Good afternoon Joel

The primary difference in the styles is the length of the broach and the width of the back of the broach.

Let me know, if this helps or if we can be of further asssistance."
 
Nope, nowhere on their website. . .

. . .here's their brief response to my email inquiry:

"Good afternoon Joel

The primary difference in the styles is the length of the broach and the width of the back of the broach.

Let me know, if this helps or if we can be of further asssistance."

I found the answer on McMaster Carr listing for broaches. There's nothing on their bushings page. The styles A,B,C,D and E represent base groove/broach widths of 1/8", 3/16", 3/8", 1/2" and 3/4" respectively. The depth of the groove is dependent on the diameter of the bushing/hole being worked. This needs to be calculated from the height of the broach and the depth of keyway required. The overall length of the bushing can be determined from their bushings page.
RonW
Canada
 








 
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