How to drill acrylic rods?

[sanyalsoumitra]

Sirs,
I am new to working with acrylic and facing lot of problems trying to drill acrylic rods on lathe-the material is melting like jelly at the drill head and sticking to the flute of the drill. I have tried to reduce speed even down to 100 rpm to reduce heat- but no improvement.
I was using metal drills on clear acrylic rod.

Please , I need some advice how to correctly drill acrylic material.

 

[ed4copies]

Most likely this is not acrylic, but a celluloid of some type.

A picture might help identify the material.

In all cases, if it is melting, sharpen your drill bit, and cool the bit and hole---use water or air. Retract the bit often. Once the bit gets stuck in the blank, you have a much more difficult problem to resolve---so avoid that by retracting the bit from the blank often!!

Some celluloids are very heat sensitive--sounds like that is what you have.

 

[wyone]

I go in no more than 1/4 inch.. pull it back out.. and go deeper and pull out.. and all the time blowing air onto the bit to cool both it and the blank and also help to get rid of any material that is being removed so that heat does not build up

 

[Paul in OKC]

Did a similar material a few years ago. Agree with pulling drill out often, even every 1/8" or less. You can't feed too slow when doing something like this. You don't want to let the drill rub in the hole, but feeding in and out in small bites wont hurt at all. You can use either a spray bottle with water, or even a brush and a cup to apply it.

 

[KenV]

According to Ed Davidson (Yo-Yo Spin) there is a huge difference between extruded rod and cast rod. The cast rod works on a lathe. The extruded rod melts, gums, and does not work well. Ed used rod for making yo-yos with an artistic bent.

Cast or extruded rod???

 

[sanyalsoumitra]

According to Ed Davidson (Yo-Yo Spin) there is a huge difference between extruded rod and cast rod. The cast rod works on a lathe. The extruded rod melts, gums, and does not work well. Ed used rod for making yo-yos with an artistic bent.

Cast or extruded rod???

It must be extruded rod, commercially available clear acrylic rod.

 

[endacoz]

Here in the winter in Minnesota I bring in a dish of fresh snow from the yard and have that sitting under the drill on the lathe. (driliing at 700 RMPS) Once the bit gets hot I wrap a hand full of snow on it and then keep drilling. I can drill (with snow) acrylics in half the time it takes in the summer due to heating up and melting. I lost one drill bit once because I tried to just "finish that last 1/2 inch..." acrylic molded around the bit and I threw it against the floor in anger! Should have hung it on my all of lessons / mistakes (wall of shame in my mind)

Let the drill do the work, keep it cool and go slow.

 

[butchf18a]

Lube with mixture of water and dish washing liquid, i like Dawn. Ditto previously offered advice

 

[Rich L]

I've machined lots of acrylic pen parts using both extruded and cast rod. Yes, cast is easier but extruded is not a problem if you go slow and do not let heat build up. Sharp bits and on center! Acrylic does not not conduct heat well so one thing I do sometimes after I detect the stock getting warm is to wrap a cool wet cloth around it for about 5-10 seconds. If the drill bit gets hot I do the same with that. Sometimes RPM is as slow as 300-400. Feed in and get out quick without dwelling. I usually peck about 1/2" at a time.

I also use WD40 as a lube (spray it) and as a marginal coolant so I don't have to worry about wiping water of my lathe when I'm done. With me, it's a metal lathe.

Rich

 

[dansills]

I may be insane and doing it all wrong but I use the same Mobil 1 synthetic when drilling that I use to oil the lathe itself. Just a drop or two seems to make all go well plus I don't have to worry about water on the lathe. I use the synthetic the same way when threading and tapping. Probably wrong but it seems to work for me.

 

[Jim Smith]

Interesting responses on the coolant to help the drilling process. For those of you who use petroleum-based coolants like WD-40 or even synthetic oil, do you ever experience any difficulties with residue on the drilled blank not allowing the glue (whichever kind you use) from sticking to the inside of the blank?

Jim Smith

 

[79spitfire]

It should wash up with a good de-greasing dish soap.

 

[Rich L]

It should wash up with a good de-greasing dish soap.

Exactly

 

[manojd]

With acrylics, I would recommend using a coolant. Also, start with smaller drill bits and work your way up to the final drill size. Sharp drill bits is very important.

 

[lwalper]

And, if you're going to be drilling a lot of acrylics I believe a 135 degree grind is recomended??--instead of the more common 118 degree.

 

[Willee]

I use what they call a wash bottle in a chemical lab (the one with a long bent spout) and squirt cold water into the hole around the drill bit flutes while drilling.
A small pan under the end of the blank catches the water coming out.
It dont take much to carry away the excessive heat and allow the drill bit to make a nice clean hole.
Using this method I can drill a hole the length of the blank with the need to stop.

Hope this works for you.

Willee

 

[jttheclockman]

I am from the denatured alcohol school of cooling. Works well and does not contaminate the lathe or the blank. I use the same thing when I drill billiard balls for my desk clocks. Sharp bits are always a must. I suggest not drilling or pushing so hard. Let the bit do the work.

 

[JPMcConnel]

I use paraffin turbine oil from my local hardware store for lubrication when drilling, tapping, and threading. I keep water away from my metal lathes, even though I clean frequently and keep them well oiled with synthetic motor oil (adheres well in very cold weather and doesn't attract moisture with temperature changes). Water just seems to find the spot you didn't coat recently. I got started using the paraffin based turbine oil because it was recommended for use with celluloid, which is a material that doesn't like heat, as well as being expensive and hard to come by. Surprisingly it isn't expensive $2.99 for a 4 ounce bottle.

 

[sanyalsoumitra]

I visited the supplier again yesterday- they only have clear acrylic rods. But another item found in their store is quite useful- acrylic tubes. Saves the drilling part!!