Drilling inlace acrylester

[secureideas]

OK Me again with an issue I am hoping you all can advise on. I just got a few blanks of "Inlace Acrylester" from Rockler. (I know they are by someone else but I picked them up at Rockler<grin>) I turned one and it was beautiful. I am now trying to prep a few more and I had two break while drilling. The drill bit was a 12.5mm, so on the larger size. Is there something I can do to prevent this?

I did see the hints for working with inlace thread, but this is a different issue I believe.

Thanks
Kevin

 

[InkyMike]

How did they break exactly? Did they chip out at the end or did they break somewhere in the middle?

 

[magpens]

Drilling on a drill press ? Or on a lathe?

In my experience, drilling on a lathe is much more successful, but can't offer a definite reason although I think that the gripping pressures are more uniform. Gripping in a lathe chuck provides more symmetric stress distribution than a drill press vise. The drill press becomes more problematic for larger diameter hole and the longer the hole.

 

[MRDucks2]

Inlace is pretty heat sensitive. Make sure you are clearing chips/shavings often. Often being create no additional heat, say every quarter inch to half inch if not using a bit that clears well. Stop before you exit the other end.

Here you have two choices; either finish by flipping the blank and drilling from the other end or make your blank long enough you can cut the end off on the bandsaw or scroll saw. An eighth in or less is plenty.

I prefer super sharp brad point bits for Inlace. Quality bits clear nicely, are very sharp and once you see the tip at the end, stop and cut to length.

If you are breaking out the ends this will prevent it. If you are breaking in the middle you are generating too much heat from the bit being cleared or speed/advance of cut.

 

[bigcountry7]

Inlace is pretty heat sensitive. Make sure you are clearing chips/shavings often. Often being create no additional heat, say every quarter inch to half inch if not using a bit that clears well. Stop before you exit the other end.

Here you have two choices; either finish by flipping the blank and drilling from the other end or make your blank long enough you can cut the end off on the bandsaw or scroll saw. An eighth in or less is plenty.

I prefer super sharp brad point bits for Inlace. Quality bits clear nicely, are very sharp and once you see the tip at the end, stop and cut to length.

If you are breaking out the ends this will prevent it. If you are breaking in the middle you are generating too much heat from the bit being cleared or speed/advance of cut.

Thanks for this info.

 

[egnald]

Hello Kevin, I just responded to another thread regarding drilling plastic blanks like the Inlace Acrylester. WoodTurningz, the owner, manufacturer, of Inlace Acrylester recommends cutting the blank to allow a little extra length on each piece and not to drill through the bottom, but cut the excess off to expose the hole. When drilling any plastic It is common for drill bits to catch and crack the blanks, especially when they are making an exit hole.

If I have a 60-degree drill in the necessary size, that's what I use. These are made specifically for drilling plastics. Instead of the typical 118 & 135-degree point drills they are ground to a steeper, 60-degree point angle. This allows for more gradual penetration and significantly less friction (heating) when drilling. They are also less aggressive (grabby) in how they cut.

Otherwise I use standard twist drills (118 to 135-degree point angles) and I drill slowly in a pecking motion to clear the flutes of the bit very frequently to reduce heat buildup - in my opinion excessive heat is the number one cause of blowouts on blanks especially on brittle plastics like Inlace Acrylester and on some hard and brittle woods like Ebony. The peck drilling rule of thumb is to not exceed 3 times the drill diameter before withdrawing the bit on each peck.

Good luck with the Inlace. I think WoodTurningz published a guide for working with Inlace Acrylester that you might find helpful. They polish very nicely and produce stunning pens.

Regards,
Dave

 

[jttheclockman]

You can always CA glue a small waste block to the bottom side of the blank and also the top. Wood will help steady a bit as it goes through the blank and wont stress the plastic. Just remember one thing and it is important, whatever material you use and you find it to be very crack prone or shatter prone then it remains that way when it is finished. So dropping almost means you are looking for another blank for that pen. Another reason to use epoxy glue to adhere the blank to tube to give that extra cushion if at all possible. Good luck.

 

[jrista]

Inlace is pretty heat sensitive. Make sure you are clearing chips/shavings often. Often being create no additional heat, say every quarter inch to half inch if not using a bit that clears well. Stop before you exit the other end.

Here you have two choices; either finish by flipping the blank and drilling from the other end or make your blank long enough you can cut the end off on the bandsaw or scroll saw. An eighth in or less is plenty.

I prefer super sharp brad point bits for Inlace. Quality bits clear nicely, are very sharp and once you see the tip at the end, stop and cut to length.

If you are breaking out the ends this will prevent it. If you are breaking in the middle you are generating too much heat from the bit being cleared or speed/advance of cut.

Just want to second the bit about bradpoint bits. I too use them for harder materials. They cut both in the center, and at the edge, and I think that helps when the material is more brittle like inlace (or trustone, or other hard materials).

IMO, a bradpoint, due to cutting at the edge of the hole, also makes it easier if you do end up cutting all the way through. You have to go very slow at that point, but you can cut a very very neat hole in hard materials if you need to.

 

[thewishman]

I wrap the ends of inlace blanks with electrical tape, very tightly and several layers thick. The stress of breaking through the end of the blank is mitigated. A slight bit of flex is allowed, but only a small bit.