Odd Problem

[Rob73]

I don't make a large amount of pens but during this season I always get a few friends that ask me to make a few for gifts. I've run into an issue that I can't quite figure out what it's cause.

I prepare my blanks and glue up with epoxy. I use a jig on a disk sander to square them off. I turn them between centers and don't have any issues. I then switch off to my finishing bushings, wet sand & polish with novus 2. When I'm finished and pull the blank off sometimes 1 side the brass tube will now be slightly sticking out past the blank.

These are squared up fine when I start. Mostly this happens on acrylics. Anyone have a clue what causes this? I was thinking maybe heat from when I'm polishing. I just take it back to the disk sander and lightly hit it to fix it but I'd rather figure out what causes it and avoid it that way.

 

[nava1uni]

Maybe there is a lot of heat generated when you are polishing and wet sanding. It is sticking out of one side, but has the other side slide further into the blank? If so the glue is getting soft from the heat and the tube is sliding from being pushed by one of the bushing.

 

[Rob73]

Never looked at the other side, I'll have to check it out next time it happens. I do get them fairly hot when I'm applying the nova.

 

[PenMan1]

How fast is your lathe turning when you MM and polish? Most woods are basically idiot-proof, but acrylics are a different story.

My guess on your lathe spped is WFO (wide open). When final sanding and polishing (especially with alternative materials), your lathe should be turning as slow as it will turn (or off, it you can't counter rotate). and don't forget to "cross sand".

I can actually make PR "grow" (or shrink, depending on the glue used) nearly a 1/4 inch when finishing in NASCAR mode.

If you are generating "heat" in the finish process, that is not a good thing (it could be you are applying WAY TOO MUCH PRESSURE). If you HAVE TO apply lots of pressure to remove tool marks, sharpen your tools.

Think BACKWARDS.... START FAST AND ROUGH...finish slow and easy.

I hope this helps.

 

[Rob73]

I don't have an issue with tool marks I use a carbide for the finish cuts, comes out real smooth. I'm running @ 1800 when putting on the novus and I do apply a decent amount of pressure. I'll slow it down and lighten up my grip next time

 

[SDB777]

I can actually make PR "grow" (or shrink, depending on the glue used) nearly a 1/4 inch when finishing in NASCAR mode.

Uh, grow a quarter inch? Really? That would almost double most of my finished blanks.... Is your lathe running 100,000RPM or something?





Scott (can an atom grow that big) B

 

[leestoresund]

Now if I could only get a wooden blank to grow 1/16" by polishing too fast!

Lee

 

[DurocShark]

Think BACKWARDS.... START FAST AND ROUGH...finish slow and easy.

Hey, I thought this was a FAMILY site!

:wink: