Countersinking aluminum chassis - best method?

[OneWithNot]

Taylor,

Try different speeds on some scrap. Sheet aluminum is always "gummy" and doesn't cut very easily as it tends to stick to the cutting edges. Sometimes it will cut better at a certain speed, and chatter at others.

3 in 1 is not a very good cutting fluid. Try a mix of half dish soap and half water. The opaque dish soaps like Ivory, or Lux seem to work best. It's a little messy, but you don't need to use very much. I have some high grade cutting fluid I can send you if I can find a small flat bottle.

I will also send you a 3-flute carbide countersink that I don't want, but I can't promise it will solve your chatter problem.

I got the best results with a combined drill and countersink (82 degree for screws) the little drill in the center seems to help keep chatter down.

[renshen1957]

Taylor if you have some Type F automatic transmission fluid handy, try using that as a cutting lube.

TM

Hi TM,

I used to use WD40 when drilling as a drilling/cutting lube.

Best Regards,

Steve

[amplifiednation]

Taylor,

Try different speeds on some scrap. Sheet aluminum is always "gummy" and doesn't cut very easily as it tends to stick to the cutting edges. Sometimes it will cut better at a certain speed, and chatter at others.

3 in 1 is not a very good cutting fluid. Try a mix of half dish soap and half water. The opaque dish soaps like Ivory, or Lux seem to work best. It's a little messy, but you don't need to use very much. I have some high grade cutting fluid I can send you if I can find a small flat bottle.

I will also send you a 3-flute carbide countersink that I don't want, but I can't promise it will solve your chatter problem.

I got the best results with a combined drill and countersink (82 degree for screws) the little drill in the center seems to help keep chatter down.

Thanks!! I'll try the soap and water. I NEVER would have thought that would work.

Where did you find a quality drill/countersink? I went to the local stores and wasn't able to find anything that was specific to metal. I order from McMaster a lot, i bet they have something similiar.

[Cantplay]

www.mscdirect.com

I don't buy carbide for anything unless I can't avoid it.

I like M2 high speed steel. HSS has a much smaller grain size and gets sharper.

I mostly countersink dry. My main concern is the chips, and avoiding long chip strings that can wrap on the tool, or whip the work and create swirlies. When I do cut wet I use a water soluable cutting oil diluted about 4x. Around the shop we refer to WD40 as 'roach spray' and don't use it for anything. As a cutting oil it has about zero shear strength, so not good.

John

[OneWithNot]

Taylor,

Try different speeds on some scrap. Sheet aluminum is always "gummy" and doesn't cut very easily as it tends to stick to the cutting edges. Sometimes it will cut better at a certain speed, and chatter at others.

3 in 1 is not a very good cutting fluid. Try a mix of half dish soap and half water. The opaque dish soaps like Ivory, or Lux seem to work best. It's a little messy, but you don't need to use very much. I have some high grade cutting fluid I can send you if I can find a small flat bottle.

I will also send you a 3-flute carbide countersink that I don't want, but I can't promise it will solve your chatter problem.

I got the best results with a combined drill and countersink (82 degree for screws) the little drill in the center seems to help keep chatter down.

Thanks!! I'll try the soap and water. I NEVER would have thought that would work.

Where did you find a quality drill/countersink? I went to the local stores and wasn't able to find anything that was specific to metal. I order from McMaster a lot, i bet they have something similiar.

I bought a bunch of tooling from ENCO (http://www.use-enco.com/CGI/INSRHM). That's where I got the combination drill countersinks. If I had a production shop, I would source from someplace else, but I have drilled dozens of holes with the things in stainless and plain steel, and they work really well.

You don't need carbide for most things. Just get HSS or some other quality tool steel, and you'll be fine.

Using an effective lubricant increases tool cutting edge life and improves the quality of the cut.

You don't need lubricant for cast aluminum, cast iron, or brass, but the rolled sheet, and extruded aluminum sticks to the tool edge and causes trouble.

Also, chuck that countersink as short as possible to cut down on chatter.