Acrylic Drill Problem - Help I'm Melting!!

[Jim in Oakville]

Hi All,

Awhile ago I bought some beautiful acrylic robs from Elliot. This is the link to the rods, http://www.penturners.org/forum/topic.asp?TOPIC_ID=32952

I cut up some blanks the other day and set out to drill one on my lathe, blank held in my Talon chuck, 10.5mm drill bit in a Jacobs chuck with the lathe running at 500 rpm.

I had an experience I have never seen before in 10 years of pen making, it appears the material has a low resistance to heat and the piece I was drilling essentially became deformed from heat, even melting.

I emailed Elliot about this problem and I received a kind response from him on how he drilled his, I understand that he indicates to drill through quickly.

I am also look for others here who had advice to share from experience drilling this same material. I want to make Jr Gents-States- Emp with these blanks, so I will be using 10.5 mm and 12mm bits but I am concerned that I will make a big mess of this and waste some really nice rods.

Thanks for your help.

 

[Texatdurango]

I had a similar experience lately with some acrylester blanks while drilling and tapping on the lathe. The blanks actually started to sag in the beall collet chuck (they felt like soft rubber) so I pulled up the tailstock to keep them centered.

After that I drilled about 1/4" at a time and let it cool between times. Took me 10 minutes to drill 3" but it was worth it.

 

[clewless]

I've adopted the sloppy approach for trustone and acrylics...I fill the hole with water, drill another 1/4-1/2 inch and fill again, drill and blank are both fine at the end.......

 

[Rudy Vey]

Jim,
many years ago I got the recommendation from Jim Heusinger of Berea to drill acrylics fast at about 1300 rpm. Best would be a parabolic drill bit, but I use the DeWalt pilot bits and this works fine for me.
I believe most people here drill too slow.....

 

[SuperDave]

Jim,

I have drilled all my Acrylics (even the 3/4" blanks for a Statesman... with not too much room for error) at a fairly high speed on my DP, taking 1/4-1/2" bites, except at the entry and exit. Have not lost any yet.

Dave

 

[follow3]

I have found the key to drilling acrylics is to clear the hole of debris every 1/4". It is the debris getting bound up that creates the heat. You may want to switch to a drill press where you can just zip it in and out fairly often. I also have recently switched from very slow speed (<500 rpm) to a medium speed (1200 rpm) on my drill press and have found it to be much better.

 

[pipeyeti]

The material from Elliot does indeed have a low melting point. I don't think drilling on a lathe for this material is optimum. You need to get the bit out of the hole fast and using the crank on the tail stock is not conducive to this. I have had very good success using my drill press. I also keep a small bottle of water handy and after every 2 stabs with the bit(cutting 1/4-1/2" each stab)I sqirt a little water in the hole,this lubes the bit reducing friction and cools the material and bit at the same time.Hope this helps.

 

[pipeyeti]

BTW I have done all of the Jr sized pens with that material. Your drilling on the cap needs to be spot on. I understand why you wanted to do it on the lathe butI used my DP for the reasons above.

 

[rherrell]

Jim, I bought the same rods from Elliott and noticed the same thing. I made one of those new "stretch" pens so I think I used a smaller bit, around 3/8", I think. I drilled at 500rpm and only took 1/8" bites at a time. I kept feeling the bit and if it got hot I stopped for a few minutes. A spray bottle of water probably would have helped but I didn't have one.

 

[gwilki]

Jim

I got the exact same rods from Elliot. I drill in my DP, and for all plastics, I drill at about 1000 rpm. I have a very small nozzle squeeze bottle of water, and I keep it wet all the way down. It works a treat. Before doing this, after drilling, sometime the hole would be too small from melting. Other times, it would be sloppy. Now, just like in Goldilocks, it's just right.

 

[Jim in Oakville]

Thanks Every One,

I appreciate the feed back, I have been having no problems with the tradional acrylics and I thank those of you have mentioned your process.

I thank those of you who have shared your experiences with Elliots acrylics, they look amazing and I will be trying it again, this time with a coolant and modified speed.

A friend of mine who has a strong a machinest background mentioned filling/grinding back the Lips on my drill bits, to reduce heat building up, do any of you do that?[:0]

 

[pipeyeti]

You want to leave the cutting pint alone but relieveing the upper part will reduce friction. I fact I believe that Elliot had recommended that. My prosses seems to work fine though.