Shop Made Rotary Broach, Down And Dirty!

[Tony Pisano]

We used to do that in a lathe by offsetting the tailstock. I always thought that it was fascinating that it worked. I watched the video but cringed seeing the guy wearing gloves while running the machines. That was always a no no as far as safety goes in the shop I worked in. A spinning drill bit or cutter can grab a glove just as it will a shirt sleeve and you'll be wrapped up in a split second. We could wear gloves when handling sheet metal or cleaning out chips in the bed of a lathe that wasn't running, but never while operating a lathe, drill press, or milling machine.
Otherwise, I enjoyed the video.

 

[mikey]

The broach is cool but I really enjoyed your commentary! This was the most fun machining video I've seen in a long time - thanks, Doc!

 

[Ulma Doctor]

Thank you very much mikey, i really appreciate your kind words.
i'm glad you enjoyed the post

 

[Suzuki4evr]

I

Shop Made Rotary Broach
i have a job that requires a square hole to be pierced through a piece of machined steel. the material is too thin to be push broached for fear of fracture.
i don't have pull broaches or the puller for that matter, so i'm doing the next easiest method i have seen.
i copied the design from a fellow youtuber, the credit is all his, i just copied the idea.
here is a link to his video

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one improvement i made was that i added a relief for a small ,but powerful, rare earth magnet to retain the ball in the upper half, after dropping the ball a couple times.
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mine is not as nice as the video's producer.

here is a video of my rotary broach in action!

thanks forwatching and reading!
#rotarybroach

I saw that youtube video as well and am planning to make one myself. Magnet is a nice idea.

 

[stioc]

Nice video, I didn't know you were AvE! lol
But...does the HSS cutting broach has to be about as big as the hole? Meaning if I want to make a 2" hole a square I'm SOL?

 

[Ulma Doctor]

I
I saw that youtube video as well and am planning to make one myself. Magnet is a nice idea.

thanks for looking, i hope you have fun making your rotary broach!

Nice video, I didn't know you were AvE! lol
But...does the HSS cutting broach has to be about as big as the hole? Meaning if I want to make a 2" hole a square I'm SOL?

yes sir, you'll need a piece of tool steel large enough for the hole -
but it can be any tool steel that can be made harder than the stuff you intend to broach.
i can envision a turned and then hand ground tool that has a 3/4" to 1-1/2" shank and a 2" square on the other end
you'll give some side relief. 3 to 5° should be sufficient and you'll hollow out the end of the tool to create the cutting edge

 

[Silverbullet]

Down an dirty , works better then mega bucks for a broach and quicker too.