Chipping Workpieces At Headstock

[hobby ist]

I am very much a metal lathe newbie and I am running into a problem using my LMS Deluxe 5200. I am trying to turn a plastic pen parts but on the headstock end the plastic always chips out right at the end. The tailstock doesn't have this issue. And I really have no idea why it's causing it. I am using a QTCP and tried the triangle cutters that angle both "away" and "toward" the headstock. The lathe is pretty much in factory settings/condition. Thanks for any help.

 

[TommyD]

What kind of chip you trying to take? It almost sounds like you are turning on centers? What rpm's and cutter feed rate?

 

[Wreck™Wreck]

You have not mentioned how you are holding the parts at the spindle.

 

[derf]

Insert tooling won't work well with acrylics. Use a sharp edge HSS tool.

 

[hobby ist]

I forgot to say, I tried it at very slow speed and high speed and in between and it still would happen.

I am turning between centers as well.

"Insert tooling won't work well with acrylics. Use a sharp edge HSS tool."
The inserts are these: TCMT-21.52 Carbide http://littlemachineshop.com/products/product_view.php?ProductID=3417

 

[seasicksteve]

Wild guess on my part but it looks like the center is flaring the metallic tube causing the acrylic to chip. If your turning with the carriage moving toward the HS the tool pressure could cause the flaring effect on the HS end. If you have a chuck try to turn a tight fitting mandrel with a shoulder so end of the pen body can butt up against it. +1 on the High speed steel tool

 

[hobby ist]

Wild guess on my part but it looks like the center is flaring the metallic tube causing the acrylic to chip. If your turning with the carriage moving toward the HS the tool pressure could cause the flaring effect on the HS end. If you have a chuck try to turn a tight fitting mandrel with a shoulder so end of the pen body can butt up against it. +1 on the High speed steel tool

I tried with and without bushings but it didn't help. As far as that flare effect I think that's just from debur/reaming it to clean up the inside and it pushes into essentially "empty" space as the tolerance is not super super tight between the tube and the plastic.

 

[ARKnack]

My son use to do a lot of pen turnings. They are really ment to be done free hand on a wood lathe using a skew chisel. Crank the speed up and use a high angle HSS tool bit that is very sharp. Maybe even a vertical shear bit grind. Also be sure you have 100% glue coverage on your brass insert. Personally I think you are also taking to heavy if a cut.

You could make a tool rest for your metal lathe and use a skew chisel free hand. I have an old metal lathe converted like that.

 

[hobby ist]

My son use to do a lot of pen turnings. They are really ment to be done free hand on a wood lathe using a skew chisel. Crank the speed up and use a high angle HSS tool bit that is very sharp. Maybe even a vertical shear bit grind. Also be sure you have 100% glue coverage on your brass insert. Personally I think you are also taking to heavy if a cut.

You could make a tool rest for your metal lathe and use a skew chisel free hand. I have an old metal lathe converted like that.

I thought taking even a tiny tiny fraction of a mm off would solve it, but it still chipped out on the headstock end. I was just baffled why this is happening... took a light cut and used a brand new insert and it would happen. I'm still trying to learn the thing so it's hard if not impossible for me to diagnose the issue on my own.

 

[hobby ist]

I'd just like to say I really appreciate all the input as well!