Countersinks

[Jim Mims]

When making a countersink for flat head screws in jigs, and with material such as phenolic, melamine, acrylic, etc. what type of countersink do you use?
I ordered a Rockler HSS 82 degree countersink, are there any others I should purchase?
Thanks,
Jim

[Greg Hines, MD]

For those materials, the same countersink you use in wood is adequate. One thing I do differently on melamine is to put a piece of tape over the hole to help prevent chip-out around the holes, but for your acrylic and phenolic plates, they can be drilled and countersunk normally.

Doc

[Mike Hoyt]

I second the use of tape on melamine, I have made a couple of inserts with phenolic and they machined beautifully.

Mike

[Jim Mims]

That's just it. I don't have any countersinks yet. I'm sure ya'll have quite a collection assembled over the years. Are there some good sizes to have for a workshop?
Thanks,
Jim

[Tom Henderson2]

For limited use, ordinary woodworking twist driles etc will work with acrylic, but you may encounter some chipping. If you have more than a few holes, buying a special drill bit will probably make sense. The larger the hole diameter, and the deeper the hole, the more important that becomes.

I did a quick google search on "working with acrylic" and found this informative brochure: http://tinyurl.com/2rlwzb

I'm sure you can find more info with a little effort. Google "working with acrylic" and you'll get tons of hits with a lot of good info.

There is probably less info available on phenolic, but the same google search techniques should get you the info you need.

Stop by your local plastics retailer and they will probably have info available as well.

Hope this helps....

-Tom H.

[Dick Bringhurst]

I've found that a single flute countersink works best in the plactic material. Doesn't melt it. I don't know about melamine. Dick B.