How can I broach a 7/8" square hole in a 3" diameter blind flange inexpensively
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 27
  1. #1
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default How can I broach a 7/8" square hole in a 3" diameter blind flange inexpensively

    I have a small job coming in the shop in a couple days and I don't have the proper size broach to do the job. And, the job isn't big enough to warrant buying a new or even a used 7/8" square broach (even if a good used one could be found). I have 6 of these square holes to broach and I believe the flanges are carbon steel. The tolerances are reasonable as I believe they are simply square drive holes.

    One idea is to drill holes then square the corners with a jig saw or scroll saw, then finish with files. Another is to drill the holes then mill them square with a 3/16" end mill, then file the corners square.

    How would you do it if you didn't have a 7/8" square broach?

  2. #2
    Join Date
    Apr 2019
    Country
    UNITED STATES
    State/Province
    Arkansas
    Posts
    882
    Post Thanks / Like
    Likes (Given)
    288
    Likes (Received)
    327

    Default

    Drill, mill, file, done.

  3. #3
    Join Date
    May 2019
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    450
    Post Thanks / Like
    Likes (Given)
    126
    Likes (Received)
    167

    Default

    Do you have a shaper or can find one for sale cheap? I keep one around for occasions just like that. My friends like to laugh and say you can make anything but money with a shaper but the few times I've put mine to work it made a pretty penny.
    Last edited by Hardplates; 11-06-2019 at 10:10 PM. Reason: spelling

  4. #4
    Join Date
    Oct 2019
    Country
    NICARAGUA
    Posts
    106
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    41

    Default

    Yea for 6 holes I would lay em out and walk the mill around em. File the corners and done.

  5. #5
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default

    Quote Originally Posted by Hardplates View Post
    Do you have a shaper or can find one for sale cheap? I keep one around for occasions just like that. My friends like to laugh and say you can make anything buy money with a shaper but the few times I've put mine to work it made a pretty penny.

    I have a shaper but it's not working at the moment otherwise I'd probably use it.

  6. #6
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default

    Quote Originally Posted by PocoLoco View Post
    Yea for 6 holes I would lay em out and walk the mill around em. File the corners and done.

    Yeah, it's looking like this is going to be the most cost effective way to get the job done.

  7. #7
    Join Date
    Feb 2006
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    12,940
    Post Thanks / Like
    Likes (Given)
    686
    Likes (Received)
    3904

    Default

    There are companies that sell round steel sleeves with square holes broached through them. Try MSC or your favorite mill supply company. The sleeves can be cut to length and silver brazed into a round hole in any steel part that needs a square hole. They are typically used to make boring bars and crank handles and are very cheap compared to buying a broach, a slotter or a shaper.

    Green Bay Manufacturing $19.30 each for 4.25" long x 1.313" dia.

    Larry

  8. Likes Marty Feldman, rcoope liked this post
  9. #8
    Join Date
    Apr 2004
    Location
    Modesto, CA USA
    Posts
    7,008
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1178

    Default

    How thick?

  10. #9
    Join Date
    Nov 2013
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    4,640
    Post Thanks / Like
    Likes (Given)
    1222
    Likes (Received)
    2602

    Default

    CNC Mill can plunge out a square pretty decently. Exactly the same Tool you would use in a Shaper.

    R

  11. #10
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default

    Quote Originally Posted by litlerob1 View Post
    CNC Mill can plunge out a square pretty decently. Exactly the same Tool you would use in a Shaper.

    R

    WOW, I never even thought about this approach. Thanks

  12. #11
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default

    Quote Originally Posted by Bill D View Post
    How thick?

    Not quite sure. I'm assuming a standard 3" blind flange thickness probably 1/2" to 5/8".

  13. #12
    Join Date
    Jan 2013
    Country
    UNITED STATES
    State/Province
    Alaska
    Posts
    159
    Post Thanks / Like
    Likes (Given)
    6
    Likes (Received)
    66

    Default

    Quote Originally Posted by L Vanice View Post
    There are companies that sell round steel sleeves with square holes broached through them. Try MSC or your favorite mill supply company. The sleeves can be cut to length and silver brazed into a round hole in any steel part that needs a square hole. They are typically used to make boring bars and crank handles and are very cheap compared to buying a broach, a slotter or a shaper.

    Green Bay Manufacturing $19.30 each for 4.25" long x 1.313" dia.



    Larry
    Good Idea, many thanks.

  14. #13
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    5,051
    Post Thanks / Like
    Likes (Given)
    176
    Likes (Received)
    1559

    Default

    Would this work. It seems simple so could be made quickly.

    YouTube

  15. Likes MrWhoopee liked this post
  16. #14
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    15,633
    Post Thanks / Like

    Default

    Quote Originally Posted by nc5a View Post
    I have a small job coming in the shop in a couple days and I don't have the proper size broach to do the job. And, the job isn't big enough to warrant buying a new or even a used 7/8" square broach (even if a good used one could be found). I have 6 of these square holes to broach and I believe the flanges are carbon steel. The tolerances are reasonable as I believe they are simply square drive holes.

    One idea is to drill holes then square the corners with a jig saw or scroll saw, then finish with files. Another is to drill the holes then mill them square with a 3/16" end mill, then file the corners square.

    How would you do it if you didn't have a 7/8" square broach?
    Send it down the road to someone that is qualified/tooled properly.

    You can't doo every job that comes along, be helpful to your customer
    and suggest someone else.

  17. #15
    Join Date
    Aug 2012
    Location
    California, Central Coast
    Posts
    3,766
    Post Thanks / Like
    Likes (Given)
    2196
    Likes (Received)
    1484

    Default

    Joe Pie did a good video on how to do a really nice job using his mill to broach sharp square corners.
    YouTube

  18. #16
    Join Date
    Dec 2002
    Location
    Benicia California USA
    Posts
    8,140
    Post Thanks / Like
    Likes (Given)
    1843
    Likes (Received)
    2469

    Default

    Be careful doing slotting using a mill by vertical plunging.
    Spindle stopped, you will generate point loads on your spindle bearings.....Might never become a problem, but it could be an expensive hole in the end...

    Do this at times on my CNC Deckel, but i made a clamp that fits around the quill and takes the thrust loads rather than the spindle bearings.
    Cheers Ross

  19. Likes Rob F., litlerob1 liked this post
  20. #17
    Join Date
    Aug 2012
    Location
    California, Central Coast
    Posts
    3,766
    Post Thanks / Like
    Likes (Given)
    2196
    Likes (Received)
    1484

    Default

    Quote Originally Posted by AlfaGTA View Post
    Be careful doing slotting using a mill by vertical plunging.
    Spindle stopped, you will generate point loads on your spindle bearings.....Might never become a problem, but it could be an expensive hole in the end...

    Do this at times on my CNC Deckel, but i made a clamp that fits around the quill and takes the thrust loads rather than the spindle bearings.
    Cheers Ross
    Good point, he mentions wanting to make a clamp in the video. His clamp would also clamp the spindle to the quill to hold the spindle from rotating.

  21. #18
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    15,633
    Post Thanks / Like

    Default

    Quote Originally Posted by Rob F. View Post
    Joe Pie did a good video on how to do a really nice job using his mill to broach sharp square corners.
    YouTube
    But can you make money doing it that way ?

  22. #19
    Join Date
    Aug 2012
    Location
    California, Central Coast
    Posts
    3,766
    Post Thanks / Like
    Likes (Given)
    2196
    Likes (Received)
    1484

    Default

    Quote Originally Posted by digger doug View Post
    But can you make money doing it that way ?
    I would for 6 of them. For much more than that better tools would be needed.
    For one I would get out the hammer and chisel, then file. (after using the small end mill to get a rounded corner square) But only because I do not have the broach like in the vid.
    I would service the customer so they keep coming back, new guy might keep them.

  23. #20
    Join Date
    Nov 2013
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    4,640
    Post Thanks / Like
    Likes (Given)
    1222
    Likes (Received)
    2602

    Default

    Quote Originally Posted by digger doug View Post
    But can you make money doing it that way ?
    The money follows the quote. Not the other way around.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •