View Full Version : Shaper cutter geometry

Bob Quale
02-10-2005, 01:38 PM
I am wondering what angles you guys are using on your shaper cutters for general work?

If you use top rake, do you run it from the tip flat back, like on a tilted tool holder, or off to the side or both?

I'm trying to perfect my cutters!

Thanks Bob

02-10-2005, 01:50 PM
The old shop books usually have a good description and diagrams of proper shaper tool relief angles. In general, clearances a lot like lathe tools only much less, 5 degrees or so. You don't want much if any top or back rake as this will cause the tool to pull into the work and chatter or worse.

02-10-2005, 01:52 PM
Hi Bob,

I grind the top rake down and away from the cutting edge. 2 or 3 degrees of clearance on the sides and point. The shaper will peel the chip off nicely when the top tool rake is ground like that....

Get yourself a few good sharpening stones. Norten's "INDIA" stones in coarse, medium and fine grit. Get one coarse and a couple each of the other grits. 1/2" square is a good size and keep them in a covered plastic tub or tin with some honing oil. Always hone your tool after grinding to get rid of the feather edges and to get the edge as sharp as you can. I stone ALL of my HSS tools.

If I have a concave radius; I'll make a pin up the same diameter as the radius and put it in the drill press on its lowest speed and lap the radius to final form with some clover compound. Usually about 400 grit to start. Be very careful doing this, by the way. I have a block with a 2 degree angle on it made just for drill press tool lapping.

Andy Pullen

02-10-2005, 06:51 PM

Be happy to fax you the two pages from my Atlas 7-B instruction manual, just need your fax #. (No scanner, can't email)

More top rake gives a finer, shearing cut, but like BWB said it tends to pull the cutter into the work.

Barry Milton

Mike Burdick
02-10-2005, 08:08 PM
From the South Bend Shaper Manual:


[This message has been edited by Mike Burdick (edited 02-10-2005).]

Ian B
02-10-2005, 11:36 PM
Thanks for posting those pics Mike,

I use one similar to the no. 14 - "Right Bent" shape, but with the front face angled across the tool even more steeply, at 45 degrees and with a larger nose radius. I use it as a finishing tool, taking the last few thou off.

The chip comes off as a long twisted spiral at right angles to the stroke of the ram, and it leaves a lovely finish.


02-11-2005, 01:41 AM
Hi Bob,
I don't know if the pic will show up, but I use this as a roughing/finishing tool bit when cutting steel plate. You can just see the plate in the lower corner of the pic. The chip breaker gives more control of the chips.
I have other bits for key seating I could post if required


Bob Quale
02-11-2005, 07:07 AM
Thanks for all the posts and help. I think I am on the right track. Now I have to work on what I have and refine it just a little.

I think I just might get the perfect cutter.