Drill Chatter in Acrylics

[AsaThor]

I recently started turning a lot of acrylic pens, and I find that when I'm drilling them out I get a lot of chatter on my drill press which is leaving me with very sloppy holes in the blank, and basically making it unusable. I've tried turning the speed all the way down on the press, drilling very slow and clearing the whole every 1/4-1/2 inch, but it still seems to hit the pieces of debris and jump, widening the hole. Anybody have any advice for anything else I can do to try to avoid this? At this point I'm ending up losing almost twice as many blanks as I'm completing, and a lot of the ones I'm completing have gaps on the ends between the acrylic and the tube...

 

[StephenM]

Have you tried drilling on the lathe? Once I started drilling on the lathe, my drill press has just been taking up space. I'll probably set something up so I can use the DP to apply finish but that's about the only use I have for it now...

 

[walshjp17]

Since I began drilling on the lathe, I only use my DP for running the pen mill and non-lathe projects.

 

[Ed McDonnell]

Do you keep your drill bits sharp? Using a drill doctor (or whatever) to keep your bits sharp will solve many different drilling problems.

You should pull out and clear chips from the bit when they stop self ejecting from the hole. Continuing to drill when your bit is packed with chips is a good way to not get the size hole you want and to overheat your blank / bit. The distance you've drilled doesn't matter. You want the the chips out of the hole. Lubricating the bit can help a lot with this.

Keep your bit cool. If your bit is too hot to touch, it's too hot to drill plastic.

Do you drill to final size in one shot? Maybe try drilling a 1/16" to 1/8" smaller to clear most of the material and then drill with your final size to finish.

Just my opinions.

Ed

 

[ed4copies]

If a bit is sharp, it cuts.

If it jumps, it is not sharp where it has to be---the tip.

 

[jttheclockman]

Agree with Ed your drill bit is not sharp at all. No matter if there is debris or not if the bit is sharp it will cut and not jump. Clear debris and keep bit sharp. If you are still getting widen holes or holes off center you have other issues. For now you mentioned drill bit bouncing.