Annular cutters or drill bits?

[AGCB97]

Any other bargains at the shop you're helping to liquidate?

Mostly gone. Been selling for going on 2 years. Was a 100 x 100' building packed full so you could barely walk

 

[tjb]

Mostly gone. Been selling for going on 2 years. Was a 100 x 100' building packed full so you could barely walk

Why didn't you call me?

 

[tjb]

They come in handy . Plus , use them in a mill , on a drill press , or a lathe . Bet your countertop is emptier than mine !

I plan on getting one whether I use it for this project or not.

Your countertop may be fuller than mine most of the year, but I bet mine's got you beat around Christmas: me, wife, 5 kids, 13 grandkids, and a handful of our kids' in-laws - usually about 30 people. EVERYBODY wants to be here when my wife makes her world famous spaghetti, sauce cooked for two days with meatballs and beef and pork ribs (my grandmother's recipe from Sicily - over 100 years old), antipasto, cheesecake, etc. The list goes on and on.

Regards,
Terry

(All of a sudden, for some unknown reason, I'm getting hungry.)

 

[Latinrascalrg1]

If this was already mentioned then please disregard......

Im not sure about the specific material you are working with but i was taught when cutting plastic, especially thin sheet material, to cut in reverse using a fine tooth hole saws to get the cleanest cuts. In my experience, You dont need to apply much pressure and it tends to be much easier on the plastic breakthrough without tearout and cracking the work piece.

 

[pontiac428]

Terry, you got lucky drilling all those holes! I've tried hole saws (great when concentric), plain bits (okay if you go slow) , forstner bits (utter fail), and a cheap trepanning tool (also a destructive attempt). Mixed luck with acrylic. People who work plastics often say to use drill bits that have the cutting edges dulled (blunted square to the cut) with a stone. It supposedly prevents cracking. I have bought "acrylic" bits as singles for larger projects in the past. They work best in a drill press as opposed to a hand drill. Either way, that's a lot of holes you've successfully drilled without a crack, time to go buy a lotto ticket!

 

[tjb]

Terry, you got lucky drilling all those holes! I've tried hole saws (great when concentric), plain bits (okay if you go slow) , forstner bits (utter fail), and a cheap trepanning tool (also a destructive attempt). Mixed luck with acrylic. People who work plastics often say to use drill bits that have the cutting edges dulled (blunted square to the cut) with a stone. It supposedly prevents cracking. I have bought "acrylic" bits as singles for larger projects in the past. They work best in a drill press as opposed to a hand drill. Either way, that's a lot of holes you've successfully drilled without a crack, time to go buy a lotto ticket!

Thanks for the response. I just hope my 'beginner's luck' doesn't run out until I've completed the project. I failed to mention in the earlier posts, I've been doing the cuts with the adhesive paper still intact on both sides. I suspect that probably has something to do with the success. Also, these holes were drilled on my milling machine using the power quill. I have it set on the slowest speed possible, and I'm milling at 600 RPM's. The quill feed seems painfully slow but is probably a significant reason for the favorable outcome. I've been tempted a time or two to feed by hand, but I'm sure there's no way I could be as uniformly steady and slow as the power feed. Hopefully, I'll have the same outcomes on the larger holes. We'll know in a day or two.

Regards,
Terry

 

[tjb]

If this was already mentioned then please disregard......

Im not sure about the specific material you are working with but i was taught when cutting plastic, especially thin sheet material, to cut in reverse using a fine tooth hole saws to get the cleanest cuts. In my experience, You dont need to apply much pressure and it tends to be much easier on the plastic breakthrough without tearout and cracking the work piece.

The material I'm using is 1/4" 'cast acrylic'. It was recommended by RJSakowski in response to a separate thread on a completely separate issue (see my thread titled 'How to make an aluminum drawer liner' - not sure how to access it here). It seems to be very easy to machine but as so many have pointed out (including RJ), it is susceptible to chipping and breaking.

Never heard of the technique you mentioned. I'm going to try that on a piece of scrap to see how it turns out.

Regards,
Terry

 

[stupoty]

I've used regular holesaws on acrylic with good results, I use dish soap as a coolant to reduce melting the chips.

A sacrificial piece of wood or ply for a backer has definitely helped with not shattering on the last bit of the cut.

Stu

 

[tjb]

I've used regular holesaws on acrylic with good results, I use dish soap as a coolant to reduce melting the chips.

A sacrificial piece of wood or ply for a backer has definitely helped with not shattering on the last bit of the cut.

Stu

Dish soap sounds like an easy trick for cooling. Melting (so far) has not been a problem - I'm assuming because of the slow RPM's and quill feed rate.

Regards,
Terry

 

[tjb]

Several of you who have responded clearly have experience working with acrylic or other plastics. 'Slow' seems to be the order of the day, so I'm curious. What speeds have you used to drill/cut holes? Do any of you use your power quill? If so, what speed?

Regards,
Terry