Which drill bits for drilling acrilic

[alexkuzn]

Guys, what type/brand of drill bits produce good results on acrylic and resin?
I have some good quality metal working bits. Do I need to get some special type of drill bits for acrylic?

 

[ed4copies]

What you have should work.

Keep the blank from getting hot. Water in hole if necessary, fairly slow rotation (<1000rpm IMO)

 

[OKLAHOMAN]

They shold work fine, the only bit of advice other than what Ed gave is be sure to cut the blanks long so you don't drill through, more great acrylic blanks have blown out when the drill bit exits the blank.....I've been told..

 

[Glass Scratcher]

Drill bits that are sharp.

 

[Rifleman1776]

Those machine/twist bits preferably sharpened to a split point are good. Brad points are my favorites.
I'll ditto the cut long and drill short advise.
Also going slow, backing out frequently is very important.
I do very few synthetics and, as a result, do not keep a back-up supply on hand. Meaning, a blow out is a real disaster to me. It is a project ender. So, to keep things cool, I have syringes on hand and use them to drip water into the holes for cooling.
You can buy syringes at veterinary supply stores. But don't tell that to your drug addict friends.

 

[Billman]

I would add that you should be sure to clear the millings out very often and also to be sure that the bit does not get too warm/hot. The combination of the two can cause the hole to become larger than you intended.

 

[PTJeff]

combination of scary sharp bits, speed of turning, clearing out the shavings and keeping things cool are the things i have learned to consider.
If you look at the barrel of this prototype you can see how the material melted. I was going too fast with not enough clearing of the chips. they melt and make a big mess for the cutting tool.
My rule of thumb: big hole = slow spindle speed, and alot of clearing with time for bit/plastic to cool down.

 

[bitshird]

Any good 118 degree split point drill will do the trick, as long as it's sharp, like every one else said cut long and drill short, I just bought some outstanding drill bits from Fastenall supply, they have them in most cities , and they will order stuff they don't have in stock, plus their prices are good.

 

[dow]

Any good 118 degree split point drill will do the trick, as long as it's sharp, like every one else said cut long and drill short, I just bought some outstanding drill bits from Fastenall supply, they have them in most cities , and they will order stuff they don't have in stock, plus their prices are good.

Ken, what can you tell me about that set of bits?

Thanks!

 

[dogcatcher]

This is where I buy my bits for drilling acrylic call blanks.

http://www.craftics.com/products.cfm?Category=111

I have to polish the insides of clear acrylic, and these leave the smoothest drill marks.

 

[Bill Sampson]

Everyone has a favorite, but whatever works for you is the "best one". I personally use Colt bits; they stay cool, don't clog, and drill faster than any others I have used. Pricey, but well worth the additional cost. Now carried by WoodCraft.

Bill Sampson, Richmond

 

[HSTurning]

I'm doing 75 inlace pens right now. Any sharp bit you have should work. Here is how I have been doing it. Not the best way but it is working for me.

Cut blank 1/4" longer then needed.
Drill the first 3/4" to 1" then clear bit.
Look at depth gauge on drill and clear every 1/4" to 3/8" from that point on.
I tear out the last 1/16" to 1/8" on most blanks but I dont lighten up the pressure at the end. I want to finish the drilling as soon as possible to cut back on heat.

I have had one blank crack on me. I wanted to see if a few drops of water would help and I think I wasnt clearing enough. Heat build up and the bottom 1" of the blank cracked on 2 sides. I just drill dry now.

your milage may vary

 

[randyrls]

Guys, what type/brand of drill bits produce good results on acrylic and resin?
I have some good quality metal working bits. Do I need to get some special type of drill bits for acrylic?

I use a set of Cleveland & Latrobe bits made for metalworking. They have a 90 degree cutting edge that works well on acrylic. Like others said, cut long, drill short and slow with cooling, and cut off the excess.