Box core bit for plastic?

[loopacrylics]

Hello everyone I am trying to make a Chinese checker board out of cast acrylic material. A ball nose doesn't give me the holes I want. I read that people are using box core bits for this but the ones that I can find on Amana are all labeled for wood and not plastic. Can anyone recommend something to me that I might be able to make the proper holes out of? The holes are .4785 x .4785" and the material is .5" thick. Thank you!

[adze_cnc]

The holes are .4785 x .4785" and the material is .5" thick.

0.4785" diameter and 0.4785" deep?

[TReischl]

the ones that I can find on Amana are all labeled for wood and not plastic.

Just because they are not "labeled" as such does not mean they can't cut plastic.

That is like if you look for endmills you will normally see that they are labeled for cutting metals. The thing is no one told the end mill it could only cut metal, so it cuts wood, plastic, you name it.

If it were me I would order an el cheapo ball nose end mill from china and give it a try. If it doesn't work it will still work great in wood.

[maineshops]

I cut a lot of plastic. I use 1/8 cheep end mill . On advice from a job shop I rigged an air hose to the bit with 10lbs of pressure to cool the bit. Makes a big difference. Dan

[mtylerfl]

Hi Dan,

Can you post a photo or two of your air hose setup? Are you using a “regular” shop air compressor or something like an aquarium air pump to provide the air flow?

[loopacrylics]

Thanks for the replies. I have a compressor rated for 26.3 CFM and a Vortec cold air gun that cools my bits. I guess I will try a dovetail labeled for wood as they are only around $10. I have some nicer ball nose bits but am unsure how to get the holes for the Chinese Checker Board. I tried a ball nose bit and just a simple pocket tool path but the hole is flat on the bottom and I need it to be rounded if that makes sense. I attached a picture of a Chinese checker board so you can see how I need to make the holes. And im sorry I meant to say the holes are .4785" Diameter

[TReischl]

I guess I will try a dovetail labeled for wood as they are only around $10. I have some nicer ball nose bits but am unsure how to get the holes for the Chinese Checker Board. I tried a ball nose bit and just a simple pocket tool path but the hole is flat on the bottom and I need it to be rounded if that makes sense. ....And im sorry I meant to say the holes are .4785" Diameter

Huh? What???

How in the world are you planning on making rounded bottom holes with a dovetail bit? The bottom of a dovetail bit is flat, period.

What I recommend you do is use a .500 diameter ball nose bit. Use the DRILLING strategy. Pecking is probably a good idea.

There is no reason to get all hung up on a ".4785" diameter. Are you kidding? 5 tenths? Really? This is not a space shuttle but a board to hold round balls. All those pockets do is keep the balls from rolling around. Fact is you could just plunge a .5 endmill about .219 deep and it would work just fine. Just would not look as nice.

I would start by setting a cut depth for the .500 ball nose to about .219 and see how that holds the ball.

It seems to me that you are over thinking this.

[highpockets]

Here's what I'd do....

Use a 1/2" Ball Nose bit, create a toolpath using the Drilling Toolpath, check Set Peck Drill and set Cut Depth to .1772 (which will give a .4785 diameter hole). I'm assuming you're using 1/2" marbles.

[loopacrylics]

TReischl, I apologize for sounding like such an amateur. After reading your post and attempting your advice I realized I definitely was overthinking it. I could have sworn I read online that someone used a dovetail bit for this kind of project and that's why I had thought that would be the best solution for me. Also I just wanted to give you guys on here the exact size of the holes I had on my program. Like you said this obviously isn't work that needs precise to the thousandth measurements. After attempting the advice that you and highpockets gave me, I came back with results that I'm very happy with. Thank you for following this post for the past couple days and replying.

[jay pieper]

Haven't seen that game in awhile, Had to sit and think about that for a bit.
Hey thanks for posting I just might have to make my grandkids one so gramps
can play again.

[TReischl]

Mr Loop,

No need to apologize. I dunno about you, but I began life as an "amateur" at everything. Not a whole lot has changed in the last 70 years.