Looking for Acrylic drilling secrets...

[Warren White]

I am in a bit of a production mode, drilling out a number of Slimline blanks for future turning, finishing and assembly. I am drilling on my lathe.

In spite of going slowly, and backing out the drill often, I still am finding too much heat build up. (In fact, during the drilling of the Slimlines, I decided to drill a couple of longer 8 mm acrylic blanks. The second one, despite my best efforts, got sufficiently hot to 'stick' the bit in the blank. Had to cut if off!

I am drilling at a slow speed, and am using quality drill bits.

There must be a secret to aiding in the cooling process. I am presently using compressed air on the drill bit and in the blank when I withdraw the drill bit.

Do you have suggestions for what else I might try?

Thank you so very much.

 

[Curly]

Make sure you have a good quality sharp drill bit.

Run the lathe at its lowest speed.

Squirt soapy water into the blank. A few drops of dish soap in a cup of water will do. Rinse the blanks in clean hot water afterwards.

Cooking oil applied with an acid brush or small paint brush. Wash in soapy water and rinse afterwards to clean.

Some will tell you to use alcohol but since you can't see it burn and it has a low flash point I avoid it. But those are the same guys that don't worry about tossing boiled linseed oil and CA rags and paper towels in the trash.

 

[Dale Allen]

I use spray cooking oil and I also set my shop vac suction right next to the blank to help draw off the heat.

 

[thewishman]

I use a squirt bottle with plain water. Drilling in production mode, I take breaks and use the time to do other things - glue in tubes, cut other blanks, trim barrels... It may not be as efficient, but drilling is boring.:biggrin::wink:

And drilling gets dull after a while.:tongue::biggrin:

 

[ed4copies]

If you want to be in production mode, have additional drill bits and, ideally, additional Jacobs chucks. Replace after every pen or two so the drill bit doesn't gain heat from one pen to the next.

 

[Warren White]

Curly, Dale and the Wishman

Thank you all of the great suggestions. I put a bit of dish soap in a squirt bottle of water and gave it a try. SUCCESS! I successfully drilled 8 sets of Slimline blanks and it went very, very well.

I knew two things: 1) there must be a better way, and 2) IAP members would be there when I needed them, with the help I needed.

Thank you all!

 

[TonyL]

Congratulations!


All of the above...and/or I use this: Dricote blade and bit cutting lubricant - Woodworker's Hardware

 

[Charlie_W]

What type of drill bits are you using?
I only use twist bits. Drill a little at a time and eject chips often.

 

[Warren White]

Charlie

Thanks for the question. I use the Fisch Master Pen drill from CSUSA, or a brad point drill from another supplier.

 

[jttheclockman]

Make sure you have a good quality sharp drill bit.

Run the lathe at its lowest speed.

Squirt soapy water into the blank. A few drops of dish soap in a cup of water will do. Rinse the blanks in clean hot water afterwards.

Cooking oil applied with an acid brush or small paint brush. Wash in soapy water and rinse afterwards to clean.

Some will tell you to use alcohol but since you can't see it burn and it has a low flash point I avoid it. But those are the same guys that don't worry about tossing boiled linseed oil and CA rags and paper towels in the trash.

Now Pete why in the world would you say that???????????????????????? I have used Denatured alcohol to cool both drill bits off and forstner bits and will continue to do so with no fear of igniting. The Key and I say this with all sincerity is not to get the bit red hot and you will come nowhere near the flash point of igniting. Then to lump it in with carelessness of the BLO in the trash. Man that is poor taste. You could have left that statement out and just gave your method.

No one else has to use it and it can be hazardous as well as everything in a workshop. But I take extreme resentment to that statement. I have stopped promoting it as a use for others. Yes it can be hazardous. Extreme care in whatever we do in the shop is a must.

As an example your comment to use dishwasher liquid and water. Use water around an electrical tool. Now if care is not taken then bad things can happen. Same goes for when people wet sand their finishes. Water and electricity do not play well together.

 

[Woodnick43]

Drilling acrylic

Curley's suggestion made perfect sense to me, same for his sugestion on the oily rag/paper towel disposal. I am very sure, his suggestions were done in the interest and safety of the OP and others who viewed it.
Thank You Curley.

 

[jttheclockman]

Curley's suggestion made perfect sense to me, same for his sugestion on the oily rag/paper towel disposal. I am very sure, his suggestions were done in the interest and safety of the OP and others who viewed it.
Thank You Curley.

I am glad you saw it that way but I did not. If that be the case then he could have listed a dozen things the OP should be aware of and the one I pointed out was key about water used around an electrical tool.

Listen I am not going to get into defending my post as well I do not want to see people getting on here defending his statement either. I took offense to his statement and just because I happen to use DNA for my purpose does not mean I am careless about rags with BLO. I have been woodworking for over 40 years. No need for it.

The OP got an answer that worked out for him. But just as with every other aspect in our entire LIVES there is many ways to do things. Just because someone does not do something the same way does not make it wrong.

 

[Curly]

John you are right about my oily rag remark. I can't take it back but will apologize for it. It wasn't specifically directed at you or anyone else and I didn't intend for anyone to come under fire or feel the need to defend. I sit corrected.

With respect to the Alcohol. I looked at several MSDS sheets and the flash point is 55 to 57 degrees Fahrenheit, depending on which one you look at. It doesn't take a red hot bit to light it up. So on that I'll let my remarks stand. Shop safety is an individual's responsibility so you can proceed as you see fit and are comfortable with. I won't knock you for it.

We good?

 

[jttheclockman]

John you are right about my oily rag remark. I can't take it back but will apologize for it. It wasn't specifically directed at you or anyone else and I didn't intend for anyone to come under fire or feel the need to defend. I sit corrected.

With respect to the Alcohol. I looked at several MSDS sheets and the flash point is 55 to 57 degrees Fahrenheit, depending on which one you look at. It doesn't take a red hot bit to light it up. So on that I'll let my remarks stand. Shop safety is an individual's responsibility so you can proceed as you see fit and are comfortable with. I won't knock you for it.

We good?

Pete all is good. The topic of using DNA has been brought up many times here and the MSDS sheets were printed out. It is known by many of the older people here that I do use it. Not all DNA is the same. It was also brought up about using rubbing alcohol as a lubricant and that was beat to death. You can take every product we use in the shop and run the MSDS sheets and you will not like what you read. Responsibility has to start somewhere and to me it lies with the individual. I have said this so many times here that I sound like a broken record. When someone gives advice soooooooooooooo many little things are left out. Then others add their experiences. But everyone's results may not be the same.

I will go on record here that using alcohol of any type is a bad idea for cooling. Do not do it!!!!!!! Highlighted for all to read.


Many other methods out there. I will add many people like to use WD40. But remember whatever you use if not cleaned off it may have a negative effect on gluing or finishing.

Pete we are cool. I will not be responding any more to this thread.

 

[Leatherman1998]

Thanks for the question. I use the Fisch Master Pen drill from CSUSA, or a brad point drill from another supplier.

In acrylic I haven't had much success with bradpoint bits on acrylic. I use a 9/32 big from ace hardware for all my drilling for 7mm and a 5/16 (I think) for my 8 mm holes.

 

[Bryguy]

I have used specialized acrylic drill bits for my acrylic blanks. Since getting them I've none of hte problems I used to get with regular jobber's bits. The angle of the tip is much greater. I don't have the source handy, but I did mention it in a previous post. If you let the guy know you are a hobbiest you get a break on the shipping. They are used to working with plastic manufacturers so they ship everything by truck. Not worth it for two or three drill bits, so let them know and they will send them USPS

 

[Nick Rocco]

PSI sells bits specifically for drilling acrylic blanks. I was having the problem of blowing out the blank just as the bit was exiting the blank. The PSI bit solved the problem for me.

 

[farmer]

No help at all

This looks pretty full proof to me :biggrin:

https://www.bing.com/videos/search?...5332F381245BFCBCB97C5332F381245BFC&FORM=VIRE3

 

[conandy]

Just converted today to drilling blanks on the lathe. Had the choice of investing in a better pen blank holding vice or jig set-up on the drill press, or getting some pen jaws. Decided to go pen jaws.

I have to say that today, after a bit of initial frustration and testing, was a joy. This forum got me some great insight into keeping my acrylic blanks from blowing out on the back side. My cheapo-lathe tail stock has a bit of a dip when entering the blanks, so after I start the hole I have to be sure NOT to pull the bit all the way out and then insert it back in while the lathe is running, or I end up with a big chamferred entry hole. Learned this on a $3.50 blank, fortunately, then tested a bunch of scraps to get my system working consistently.

I discovered an extra little tidbit that helped me tremendously: smear a large dab of hot glue on the end of the blank where the bit will exit, before chucking it onto the lathe. This will keep the tail end of the blank from chipping out as the bit exits. Granted, lubricating and clearing chips and keeping the bit cool, spinning at low RPM's, drilling slowly, all helped, but I would still get a bit of chip out (if not a full blank failure) when the bit would exit until I started doing the dab of hot glue.

I know that some of you recommend drilling an extra long blank without drilling through, then slicing off the end at final length to expose the hole. This can sometimes kill the ability to get two pens out of one blank, depending upon the blank length and the pen models. Doing it my way and cutting the blanks on the band saw meant for sure always getting two pen barrels from each blank.

Glad I chose to go this route, now.

 

[Hawkdave]

I use a squirt bottle with plain water. Drilling in production mode, I take breaks and use the time to do other things - glue in tubes, cut other blanks, trim barrels... It may not be as efficient, but drilling is boring.:biggrin::wink:

And drilling gets dull after a while.:tongue::biggrin:

Chris...a double pun, and I bet you are going to take it!!:wink:

The talk about disposal of rags and paper towels is important. I volunteer 2 days a week at a Men's Shed here in Australia. When I first started, I noticed that most of the members were throwing their soiled rags straight into the bin. These rags were used for wiping various substances up. Most of them were not aware of the possibility of spontaneous combustion. On some of the days, the temperature was pretty high which would add to the problem. After pointing this out, they all now drape their used rags over the bench or somewhere convenient, then they dispose of them at the end of the day, or the next working day.

Dave.

 

[efrulla]

When doing production runs on Acrylic or Allumilite I use just air to cool the bits and the blank. I must be lucky or something

 

[KenV]

Warren,

I like the Fisch bits when they are new. They cut well for a lot of holes. They do dull and the bit geometry makes them difficult to sharpen.

I have attempted to hone them with diamond files with some success. Pretty soon, only one flute is cutting and the other is along for the ride. The cutting edge dulls faster.

Brad points go through the drill doctor and become sharp regular twist bits when they dull ( and they dull about as fast as a good twist bit.

Cooling will extend the use of a less than sharp bit, but there are limits.

Will play with some dull Fisch bits next time I get the drill doctor out and see if they can be reshaped.

 

[Warren501]

I'm just getting around to answer what I do to keep my blanks and drill bit cool. I found out that WD Specialist Electrical contact cleaner (about $7 a can and available most places) works great for me. It didn't damage any plastic I have used it on and evaporates almost instantly. Because it is used on electrical connections it is non-flammable. I spray it into the hole in the blank and on the bit itself. It cools the bit almost immediately so you can keep on drilling.

 

[TonyL]

I use this: https://www.bostik.com/newzealand/bostik-products/BostikBladecote

 

[PenPal]

Hi Warren I use DeWalt Extreme 2 Drills with great success.

Kind regards Peter.

 

[Spinzwood]

Google "Dubbing Drill Bits" I don't believe the issue is so much the sharpness of the bits, rather than sharp angle of the flutes. When I worked as a machinist I did a fair amount of drilling acrylics and soft metals. When you dub the drill bit you are breaking that acute angle of the flute at the cutting end of the drill. This prevents the drill from grabbing the plastic (or soft metal) and causing extreme stress at that point where it will likely crack the plastic. Try it, you'll like it. It's not rocket science. Just remember, once you do this, unless you re-sharpen the bit, it will only be good for plastic or copper, etc. not steel or other hard metals. Also, only a very small portion of the cutting edge has to be broken.. maybe .005- .010". Try to make it as even as possible on each side.