Re: Broaching , a question

On 3/26/2024 1:40 PM, Snag wrote:

On 3/26/2024 12:58 PM, David Billington wrote:

On 26/03/2024 16:42, Snag wrote:

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 .

>
Is it a shop made broach or bought. All my Dumont broaches come with appropriate shims to cut the keyway to the correct depth.
>

    It's a couple of broaches only from eBay . I machined a guide slug for it from some 416 SS I bought to "have some on hand in case I need it" and pushed it with my 12/20* ton HF press .

416 is nice stuff.  Fairly machinable, more rust resistant than chrome molly (4140/4130), and pretty strong.
I made shims from some

.050"  galvanized sheet I have on hand (being a Pack Rat is often a Good Thing) and it worked out quite well . I'll never broach another keyway on the lathe ...

Sometimes you gotta do what you gotta do.  Never say never.  That oddball will certainly curse your work shop now.

   *12 ton frame with a 20 ton air operated jack on it . I have beefed up the frame where it was necessary .

I ran a 12 ton air jack on a 12 ton press, and I still tore it apart.  I also bent a 20 ton with a 20 ton jack.  That being said, the 6 ton arbor press has done all the straight broaching I've needed to do so far.
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Bob La Londe
CNC Molds N Stuff
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