holding a tapered pin for 2nd op

[cherokeechief79]

I had to make some tapered pins about 5 in long.

I got everything and parted them off just over the length.

now I need to put a large radius on the largest end.

any good ideas on how to hold them?

I could have formed most of it with the part off tool but they need to look much better than that.

[crazy^millman]

Make a set of tapered pie jaws and make a shoulder for them to bottom out on. Then make a pusher cap for your tail stock. Face off excess and make to desired length not going crazy with your speed. Now they you have it faced to length then bring your center drilled plug and and use it to push into your pie jaws. Then turn what you need and call it a day. May have to hand polish the end since I wouldn’t kick up above 1000 rpms to face off the excess. Really going to come down to your taper angle. The angle is shallow sayless than 15 degrees then what I said should work just fine start getting into more extreme angles then might need to think about a different way. Maybe standing them up in a vice inspftjaws so you can hold more of the taper. I able degree your already past the point of no return in my humble opinion. It can be done but would ha e to be done in sections where your machine part of it move the clamps then machine the other part of it. Maybe 1/3 at a time milling it with a lollipop tool. 

[Newbeeee™]

Unless I'm missing something...bored soft jaws?

[Guest]

3 minutes ago, Newbeeee™ said:

Unless I'm missing something...bored soft jaws?

Yeah, good Idea soft Jaws or a "sleeve" type jig :

JIG.bmp

[Guest]

23 hours ago, cherokeechief79 said:

I had to make some tapered pins about 5 in long.

I got everything and parted them off just over the length.

now I need to put a large radius on the largest end.

any good ideas on how to hold them?

I could have formed most of it with the part off tool but they need to look much better than that.

You could also get a nice finish with the "multidirectional" tool, by using the left to right motion.

You would want to be using some type of oscilation toolpath to reduce

notch and corner wear during your roughing sequence then do the finishing pass.

Sometimes you can get started with your finishing tool in the back as well so that the chips are

not dragged along the surface ruining the nice finish.

My rule of thumb is : 

If you can do it in one setup, do it in one setup, it is more precise.

[Guest]

Mitsubishi makes really good multi Directional tools, they cost like 10 bucks an insert, but I would do heavy duty roughing on stainless all day for a week or two without it getting dull. We didn't use coolant either cuz the tanks are hard to keep clean..but they don't wear out as long as you calculate your feeds and speeds at a lower cutting speed.They give a nice finish . I would only go like 100 sfm for 17-4 ph , but the 306 stainless is like an easy 350 - 400 no problem like .007 IPR. of course mild steel and aluminum are 1000 like .015 IPR.

[ostie01]

If you don't have too many parts, I would machine a tapered bushing and cut one wall on the band saw.

I think I would use a backstop also, in case there is some variation on the diameter so the length would not vary.