I need to buy another one. It is for flat head cap screws. The hole is already there, just needs to be counter sunk. It will be used in a drill press with no coolant.

What would be the best type to get w/o spending $60 on one?

I've been using one of those with one big round hole in it like this.

It worked well but did not last as long as I would like. I have to countersink an ass load of holes. There are about 20 different styles and materials available. Single flute, 3 flute, four flute, six flute, HSS, cobalt, carbide.....

Also, what speed should I run it?

Thanks,
Jim

I've used the same bit in plastic fab shop. They don't last on metal. I would just use a larger bit with the right angle. That way you won't spend a bundle on countersinks. As for the speed I've always used a slow speed and just peck away at it. But thats a lot easier to do on mill. Hope that helps.

How slow will your drill press go? I have found the slower the better, as well as hooking up coolant of some type is well worth it if you do a lot of drilling.
My drill press is a big old 600V 3 phase thing. Has auto feed and a bunch of other cool things on it. I run the spindle speed at it's slowest (about 275 RPM) and find at times I wish it was slower. Especially for countersinks.
I made up a coolant pump using an old battery, 12V windshield washer pump, and an old steel laundry tub. In the beginning I was just running water mixed with Dextron. Now I am running the shit you mis with water 30:1. Drilling goes faster, and the bits last a long time before needing sharpening. I have less than $10 into the cooling system, and it has saved me big time on sharpening.
If you run cooling, even the cheap countersinks will last quite awhile longer.

I've been using a 5-flute 87* counter sink bit on steel. It has stayed sharp for quite a while.

don't buy a pilotless for steel you won't like it belive me i know, by a 6 or 5 flute chaterless countersink they are much better and will last 10 times longer.

Maybe try here:

http://www.discount-tools.com/countersinksindexmain1.htm

I'd go with a 6 flute solid carbide:

http://www.discount-tools.com/images/main/1835.jpg

more flutes means less load on each surface, so it should last longer, 5 or 6 is cool and carbide is always good poop.

I found a six flute carbide on sale a J&L for $40. Gonna give that a try. Thank for the info guys.

Jim

www.jlindustrial.com
thay sell one made by M.A.Ford you want the 82* one ...
there about all I use in the shop and I well run up to 5,000+ holes a day with them.... the constant of 110 surface feet per min for mild steel and times it by 4 and then divide it by the size of the hole at the big end... and thats the RPM you need

tool steel speeds

110 for mild steel
400 for alum
30 for stanless

( 110 times 4 ) = 440
440 divided by .500 = 880 RPM

I would not try using carbide on a small drill press,,, it well crack the edge most of the time.

I just ran some parts last week that had 17 countersunk holes in 12L14 steel and after 1,600 parts ,,, 27,200 holes the high speed cutter was still sharp.


































































































































































































































































:eek: :eek: :eek:

Originally posted by Shrock
It will be used in a drill press with no coolant....
It worked well but did not last as long as I would like.

I like the pilotless b/c they're easily sharpened, but regardless of the style that you use they all need some form of lubrication to work well and last long. Even if you just use cheapie aerosol spray lube (liquid wrench w/teflon), that's ten times better than running 'em dry.
Yeah, I preach this alot, but try it; you'll see.



Quote:
Damn, I'm cold. C'monnnnn global warming