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Thread: Rotary Broach

  1. #1

    Default Rotary Broach

    Just watched this video (Old Tony's) on his new rotary broach. Looks interesting. Do any of you have one, and what are your thoughts? https://www.youtube.com/watch?v=GWyHJVOxKK4

  2. #2
    Join Date
    Jan 2003
    Posts
    4,012

    Default

    My thoughts are that's not a rotary broach holder that you can center on the hole to be broached. Not as good as the adjustable type. The only non-center adjusting type I've seen were for Swiss type screw machines. I actually didn't find much good info is in the video, parts of the video are almost misleading.

    You can rotary broach without the relatively expense holder. Make the broach tool out of an old end mill or anything that has a center in the end opposite the cutting end. Once ground and the business end dished you're ready to go. Offset yout tailstock so the angle of your cutter with respect to the bed ways is 1-1/2 degrees offset (in the video he said the cutter is offset 1 degree). I think 1-1/2 degree is more the usual. Crank the tailstock in to push the broach. This method requires a way to pull the broach out of the broached hole.

  3. #3
    Join Date
    Jul 2017
    Location
    Buffalo NY USA
    Posts
    533

    Default

    Never used one, but Hemingway Kits has a kit:

    http://www.hemingwaykits.com/acatalo...ry_Broach.html

    Supposed to be very good, requires good lathe work to build it. Very reasonable pricing IMHO.

  4. #4

    Default

    Quote Originally Posted by DR View Post
    My thoughts are that's not a rotary broach holder that you can center on the hole to be broached. Not as good as the adjustable type. The only non-center adjusting type I've seen were for Swiss type screw machines. I actually didn't find much good info is in the video, parts of the video are almost misleading.

    You can rotary broach without the relatively expense holder. Make the broach tool out of an old end mill or anything that has a center in the end opposite the cutting end. Once ground and the business end dished you're ready to go. Offset yout tailstock so the angle of your cutter with respect to the bed ways is 1-1/2 degrees offset (in the video he said the cutter is offset 1 degree). I think 1-1/2 degree is more the usual. Crank the tailstock in to push the broach. This method requires a way to pull the broach out of the broached hole.
    Thanks for the "how to". Never have seen one, wondering if they work that well. So much of those videos are showing off what they just bought.

  5. #5
    Join Date
    Mar 2018
    Location
    Finland
    Posts
    395

    Default

    One of the reasons I got a mill was so I could build the hemingway kit

  6. #6
    Join Date
    Mar 2018
    Location
    Finland
    Posts
    395

    Default

    Quote Originally Posted by Tungsten dipper View Post
    Thanks for the "how to". Never have seen one, wondering if they work that well. So much of those videos are showing off what they just bought.
    Here's a video showing how to build the hemingway kit.


  7. #7

    Default

    Thanks Dennis!!

  8. #8
    Join Date
    Nov 2006
    Location
    durban s africa
    Posts
    1,474

    Default

    I made one from free plans from HMEM. They used two bearings but I changed it to have a third,a thrust bearing. It works real well.

  9. #9

    Default

    Here's a follow up video that show how it really works! https://www.youtube.com/watch?v=4-3gPWl6wfU

  10. #10
    Join Date
    Jan 2008
    Posts
    798

    Default

    Heh - a guy at work also watches TOT.. He liked the video but didn't understand how it worked.. I told him - it would have been easier to understand if he showed the rotary broach spinning....

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