Melting/Dulled drill bits? Bad press?

Robert_Phelps

Robert_Phelps

Joined
Nov 29, 2005
Messages
475
I have an old-ish drill press I use, and I've used a couple different types of bits that claim to be alright for metal drilling. I line up the bit with my planned hole, and start to drill, but the bit starts this nails-on-a-chalkboard squealing, smokes, then either comes out completely dulled, or melted. Is there something wrong with my press? Could it be set too fast? I'm drilling 1/8" 1095, with an 1/8" bit. I've tried to pace the drilling process, drilling a little at a time, but it doesn't really help.
 
if your drill press uses a belt system then move it to the slowest setting. if its a dial then turn it down to a few hundred rpms. when drilling steel you cant have it going to fast or you burn the metal and the bit. on the right setting you should be able to drill the whole thing in one pass. if i learned anything from metalshop in middle school and from working with my grandpa growing up its that you dont use a high speed on drilling metal. causes too much friction which causes alot of heat and will melt the bit. hope that helps.
 
Could be several things.
The above post is correct.

Is the 1095 hardened, normal or annealed, must know this unless you want tp buy a carbide bit and just be done with it.

What kind of bits are you using, high speed, cobalt
Are you using a coolent
You may have work hardened the spot you are trying to drill, if so you will have to soften the metal or use a carbide bit.

If you plan on soing much work with knife steels, you will be way ahead by investing in carbide bits. I have found good buys on ebay searching for carbide drills. Do not attempt to use them by hand, they are very brittle and require that you use a drill press or lathe. Be sure to reduce your cuttin speeds and feed rate. A mist sprayer with water is fine for a coolent, use lots of it. If the metal chips are brown blue black, you need to keep it cooler. Do not use dull drills as they will just create heat which may just harden your work piece.

Leon
 
Slow down. I seldom drill steel faster than 600 rpm. Use a tooling fluid, a few drops of tap-matic will work. Use light pressure, let the tool do the work as long as you are making chips the tool is cutting. You will get some squeal just before the bit punches through. Don't use the plain carbon steel bits for drilling steel they are for wood working.

The lowest grade of bits for drilling steel is HSS or High Speed Steel. HSS bits are made from M2 steel. The TiN coated bits (Gold colored coating) are a gimmick. The TiN coating wears off the cutting edge on the first few seconds of cutting steel. TiN will make it easy to clean stuff like pitch off your bits when drilling pine and it will keep bits from rusting, But aside from that nada. What do you suppose happens to the TiN coating when you sharpen the bits?

After HSS the next step up is Cobalt alloy drills. They aren't appreciably more expensive than HSS and are supposed to cut harder steel.

For hardened steel your only choices are Solid Carbide and Diamond. Carbide are about 10X more $$$ than HSS but handy to have around. They are nice to have around when you want to drill a hole after the steel is heat treated.

Diamond bits aren't common and don't really cut, They make holes by abrasion. They must be flooded with tooling fluid.
 
if your afraid of the metal rusting with the water coolant i learned a trick from Johnny Stout. use windex to cool it down. windex is also good when wet sanding a blade. it wont make the blade rust.
 
Lots of good advice here. I would also recommend that you get a starrett speeds and feeds quick reference chart next time you are in a store that sells starrett. It will give you accurate rpms for what size drill you are using and what material you are drilling.
 
Wow, thanks. That was like, an advice-splosion. :cool:
I'll take a look and see how to fix the belts. I saw where it had some sticker with belt and speed info. I'll also try the windex.

The steel was straight from Admiral. I'm pretty sure it was annealed, I've been cutting, etc, on it.
 
Just another small tidbit of advice while we're on a roll.
Make sure your drill bit isn't sticking too far out of the chuck. The longer it is, the more it will flex. If it flexes, your hole will be off, and it can bind up and break.

Only expose enough bit to get through the material and a little excess.
 
Very often 1095 is not fully annealed, even though it may listed as such. 1095 from Admiral is generally too hard to drill with HS bits. I have had it come in so hard that cobalt would not drill it. The hardest 1095 I ever got came from Koval as "annealed". I ruined two cobalt bits on it, then annealed it myself. Drilled easy then.
 
You should not have any problems with rust other than minimal surface stuff.
Do not use water as a coolant, use cutting fluid that is an oil/water mix that is white in colour.
If your drills are melting you are either way off on speed or your drill bits are rubbish.
You will see them go blue with over heating before you get close to melting them, you can smell burnt metal easily enough, just stand around a Grinder.
Most people do not know how to sharpen a Drill bit properly it is a skill worth learning.
 
Note the comment on work harding your piece. Some metals are really bad about this many stainlesses and titianium are real bad about it. If you attempt to work it with a dull tool or with to much presure or speed on milling machine, drill press or lathe and you get it hot it will self harden and add to you misery.
 
Are you using Hot rolled steel? Make sure its Annealed steel and not just hot rolled. Most of the HR steel ive used isnt actually annealed and much of it is somewhat hardened, sometimes in the center of the bar, which results in getting 1/3 way through, then hearing the horrid screech.
 
After being told for years that I could use them cement drill bits to cut holes in the tang, I tried it last week, and it did work.
 
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