countersink for the armor screws

[steve-0]

i purchased a countersink today. the ones i was using became dull so i ordered a carbide one.
some info on them
82 degrees
the screw heads are 3/4" diameter so you will need one with a minimum 3/4" diameter
edit= dont order this one
part number 2923A26

http://www.mcmaster.com/#2923A26

[steve-0]

dont order the 6 flute carbide one listed above. it does not cut smooth and vibrates all over the place. i ordered a new one, i will let you know how it goes.

Single-Flute High-Speed Steel Countersink 82 Degree Angle, 3/4" Body Dia, 1/2" Shank Dia
part number 2846A34
http://www.mcmaster.com/#2846A34

[Outsider]

I've had good luck with the 6 flute ones. I just turn them slow and took my time (a little coolant doesn't hurt either). I had more trouble with a 3 flute I tried.

Steve

[col.halftrack]

 I am wanting to buy a magnetic drill press for countersinking / drilling track armor. Any suggestions? I noticed that all of Milwaukee's specify a steel surface of at least 1/2"-3/4". Since most halftrack steel is 1/4" I am not sure this will work?

[Outsider]

Mag drills all work better with thicker steel. What will happen is that the drill won't be stuck as good on a thinner surface, and because of that you won't be able to put as much "force" down with the handle on the bit to the surface. All you need to do to bypass this is either stack up some of the steel plates to get a thicker "plate" or my simple way is to just lean down on the drill to help hold it in place when exerting extra force on the bit.

BTW the mag drill I use is also a Milwaukee.

Steve

[steve-0]

i agree with outsider. you just can't crank down on them like you can with thicker steel.

i have a couple big mag drills and what i have found is that they are the best for drilling the holes in the bigger plates but for countersinking i like the mill or if you don't have one of those a drill press with an accurate stop.

[BombFarm]

I would like to add my $.02 if you are still pondering a mag drill purchase. I purchased a "Revo" brand mag drill when I first got into doing halftrack restoration. See it here (http://www.gjhalltools.com/revo.htm) It was much more affordable than most other brands. There have been times that I would prefer a variable speed control and definitely a built-in coolant dispenser would be great, but those are the things that drive the price up. As far as performance, I have drilled and countersunk well over 1,400 3/8" holes in 1/4" mild steel for reproduction armor without a single mishap related to holding pressure. Adding backing material definitely helps, but can be an unwelcome task as it to just another time consuming thing to do before drilling each hole. I am not trying to discount anybody else’s input, they are all right on; but I have had extensive personal experience drilling and countersinking 1/4" steel with a mag drill, and I will continue doing it that way on all large armor sections. The most important thing is to invest in, is high quality drill bits and countersinks. . . . Additionally: change them when they are dull, don't chance it! Another key to the success I’ve had is likely due to the style of countersink that I use. I would always suggest using a countersink with some type of pilot guide. The pilot makes centering dead on easy and eliminates off center drifting as well as that annoying chatter that can occur with other designs. Take a look at the picture in this link to see the particular type I use (http://toolinghouse.com/countersinkanddeburringset5piece.aspx)

Again, just my $.02

[steve-0]

thanks bombfarm
i didnt know they made a countersink like that, im going to have to try it.
the mag looks alot easier to handle than mine, i have one of the big milwaukee mags. i bet its at least twice as heavy.