View Full Version : What is this called?
tony ennis
12-30-2007, 12:15 PM
My lathe had an improvised 3/4" countershaft. It was 5" too long and protruded beyond the drive pulley. The last 6" were threaded. To make matters worse the smooth part of the shaft was too short by at least an inch - the drive pulley was sitting on the threads. I cut the shaft to rough length and turned the remaining threads off, reducing the last inch or so of the shaft to 1/2" in diameter.
What is that turned-down part called? In woodworking, I'd call it a tenon.
I press-fitted a sleeve over it, turned the sleeve to the proper diameter, faced it, and eased the corners.
http://home.insightbb.com/~antinice/images/countershaft003.jpg
wierdscience
12-30-2007, 12:33 PM
I have heard and used several terms for that including,"shoulder".As in "turned down and back to a shoulder".Is there a correct term?Probably.
Did you include a radius filet in that corner?
I think the term used in Model Engineer magazine is "spigot."
tony ennis
12-30-2007, 01:49 PM
Did you include a radius filet in that corner?
Never heard of it. But it would have helped. I worked at getting that corner dead-on, ;) In retrospect I suppose I got lucky. There's no gap between the shoulder and the sleeve.
Your Old Dog
12-30-2007, 01:58 PM
What's a "boss"? I thought that was a protrusion from a main body?
wierdscience
12-30-2007, 03:01 PM
Never heard of it. But it would have helped. I worked at getting that corner dead-on, ;) In retrospect I suppose I got lucky. There's no gap between the shoulder and the sleeve.
For future use anytime you come to an inside corner it's a good idea to build in a small radius.On that size shaft a 1/16" radius would be plenty.The reason for it is sharp corners tend to concentrate stresses and make it easier for cracks to develop leading to failure(broken shaft).
Sleeving shafts I just turn a radius of the appropriate size and chamfer the ID end of the sleeve to clear the radius once the sleeve is pressed/shrank on.I also leave the length of the sleeve about 1/16" long and machine it off flush in place.
small.planes
12-30-2007, 03:43 PM
What's a "boss"? I thought that was a protrusion from a main body?
nope, thats the bloke (bird) who stops you doing what you want and makes you do what your being paid for :p
Dave
tony ennis
12-30-2007, 04:04 PM
to build in a small radius.
Ah, you mean to leave material in the "corner" of the shoulder, and chamfer the sleeve appropriately. Yep, I didn't do that.
BadDog
12-30-2007, 05:11 PM
nope, thats the bloke (bird) who stops you doing what you want and makes you do what your being paid for :p
Dave
Over here that's also often called a "wife".