- Joined
- May 7, 2023
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- 2,094
I always thought if you ran in reverse it would put the material back on.
That only works if you sprinkle the chips over the tool bit.
I always thought if you ran in reverse it would put the material back on.
It looks like you were turning Nylon or UHMW polyethylene. Delrin machines well using standard tooling and chips much more easily than Nylon type plastics.Also I was pleasantly suprised- the best cutting I had on it was with a parting tool (new chinese carbide insert) and heavy sideways cuts. It streamed off like ribbon in manageable sizes. Still a complete mess, but a lot easier. If I remember right, it was cutting at about a 7tpi rate while i was hogging it down to size.
If you are aggressive with Nylon the cutter will bite and destroy the work.It looks like you were turning Nylon. Delrin machines well using standard tooling and chips much more easily than Nylon type plastics.
I think this applies to all materials.If you are aggressive with Nylon the cutter will bite and destroy the work.
Nor haveI, even using a 3" chuck on the 6x18 but running with 11" or more of stickout is asking for trouble. It appears that the issue has been isolated to steady rest misalignment. The OP stated that the problem occurs before any machining is started.I think the jaw length of a 8" chuck is an advantage holding Delrin, But I never had any difficulty using my Atlas 618s 5" 3 jaw chuck either
That would only be true if the steady rest was twisted,causing the rollers to travel a helical path. If there is radial misalignment, the direction of rotation won't matter.If as suspected, the steady is misaligned and is pulling the part out. Run the lathe in reverse with an inverted tool & it should drive the rod towards the chuck.
It also depends on whether the helical path is right or left handed. If it is pulling out in forward rotation then it would do the opposite in the other direction.That would only be true if the steady rest was twisted,causing the rollers to travel a helical path. If there is radial misalignment, the direction of rotation won't matter.
On the contrary, the radial misalignment is what causes the pullout. As an example , if the misalignment is .05" towards the front, the rod will be twisted in the chuck towards the front which causes the end of the rod facing the touching the chuck face to lift slightly. As the spindle rotates, the end of the stock will be precessing, lifting a little more with each revolution until it eventually works its way out of the chuck jaws.It also depends on whether the helical path is right or left handed. If it is pulling out in forward rotation then it would do the opposite in the other direction.
If it were radial misalignment, it would not be pulling out of the chuck. So it seems clear that the steady is twisted. This variable is often not considered as important as it should be & not generally checked.