Rotary Broaching

Al,

Great to hear you're considering rotary broaching! Please take a look at our website,

Click on video, and select one of the video players you may have. If you're new to rotary broaching, it's worth the wait. It will show you a few examples of rotary broaching in action.

Check out Slater tools if you haven't already.

What type of machine are you doing this on? Is it a round part on a lathe, or a rectangular part on a mill, or something totally different?

Giving a lot more info would help people with experience broaching to understand what it is you are trying to do, and what info you need.

Bryce, The work 1/2 x 5/8 rectangle CRS and the hole is 3/8 from the end, after the hole is broached the 1/2 dimension, I cut a slot in the end on the same center as the hole. I then drill the top half for aclearance and tap a 10-32 screw hole in the bottom half to use the 1/2 x 5/8 rectangle to clamp on a 3/8 square. The object is to slide the

3/8 square stock lengthwise and clamp at any position. Thanks .... Al Basham

Are you making only one of these clamps, or are you making a bunch of them? I would think if you were only making a few it would be easier to make it two pieces. Cut a slot on a 45° angle with an end mill in each piece, then assemble. Might be easier than broaching.

Be advised that you will have a 'slight" helix twist to the through square. Also you will need to mill a flat perpendicular to the bore for the broach to start. A shallow counter bore or appropriate chamfer can be helpful in starting the tool. Unless you need a full square through, drill the pilot hole oversize as much as you can. You may have problems on the exit side of the hole unless the exit surface is also perpendicular to the bore.

Good luck and let us know how you make out.

Unka George (George McDuffee)

There is something to be said for government by a great aristocracy which has furnished leaders to the nation in peace and war for generations; even a democrat like myself must admit this. But there is absolutely nothing to be said for government by a plutocracy, for government by men very powerful in certain lines and gifted with the "money touch," but with ideals which in their essence are merely those of so many glorified pawnbrokers.

Theodore Roosevelt (1858-1919), U.S. Republican (later Progressive) politician, president. Letter, 15 Nov. 1913.

F. George McDuffee wrote in news: snipped-for-privacy@4ax.com:

A trick to help alleviate the "twist" is to reverse the spindle part way into the hole. Usually halfway through will do the trick but if it's a deep hole you can reverse the spindle as often as needed.

Dat's a good idear.

I wish I had thought of that!!!

Unka George (George McDuffee)

There is something to be said for government by a great aristocracy which has furnished leaders to the nation in peace and war for generations; even a democrat like myself must admit this. But there is absolutely nothing to be said for government by a plutocracy, for government by men very powerful in certain lines and gifted with the "money touch," but with ideals which in their essence are merely those of so many glorified pawnbrokers.

Theodore Roosevelt (1858-1919), U.S. Republican (later Progressive) politician, president. Letter, 15 Nov. 1913.

Al:

Perhaps another option is to mill the hole you want broached with the smallest end mill that is feasible, then put a 3/8 square lathe tool bit in a holder (you may have to fabricate a square hole in a round piece of stock adding some set screws to hold the lathe toolbit) and then put the stock in a collet so you can align it to your work. Use an M19 to keep the spindle locked and feed downward "shaping" out the corners of your milled pocket square. Feed just a couple of thousandths at a time and it shouldn't hurt your spindle bearings.