Metal Drill Bits

SES Constructio

Does anyone have a set of drill bits they would recommend for drilling in hard metals? I haven't had the best of luck with drill bits. I have a decent set that i have been using but had to drill a bunch of holes into steel and burnt a couple up, not sure what the bits made out of but paid around 70 bucks for the set about 4 years ago from craftsman. I was looking at the craftsman site tonight and they cobalt and titaniam coated sets each 99 bucks. I read that the cobalt are nice but can shatter easily. Also has anyone had good luck with drill bit sharpeners like the drill doctor? Thanks for any advice on this.

thom

Find cobalt bits. Generally you can find these at an industrial supply house. Don't go the discount store route, you won't find what you're looking for.

Chris Johnson

Drilling hard steel is difficult to do properly with any bit on a regular drill. Depending on the number of holes or the amount of different times you need to do it look into a magnetic drill, although pricey ($ 1500.00 +/-) they do the best job and help the bits last longer since the drill is stationary, locked in and not moving, the only thing you control is the speed of depth you drill at.

Rental places may also have them available if you don't want to buy one.

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Chris

SES Constructio

Thanks guys. I don't do a ton of drilling in hard steel just the occasional job where i need some holes in steel or stainless or something like that. I am just looking for a good set of bits that will last. I like the cobalt bits but have been reading about them being fragile and shattering if not perfectly straight. Was told they are more for drill presses. Anyone ever use the drill doctor and have good experience with it? Thanks guys

chenley

Drill Doctors are only really good for wood bits. Good bit sharpeners are in the thousand's of dollars range for metal cutting bits (that's what I hear).

I have a drill doctor collecting dust in my shop and I'll take my bits to get professionally sharpened which is usually about a dime each.

Make sure you are using cutting oil while drilling the hole slowly and the bits should last quite awhile.

Dustball

Start with a pilot hole 1/3rd of the final size and that'll help with the drilling.

stp57

Great advice Chenley & Dustball.
Have you ever tried white grease (lithiuim) as a cutting oil? I thought about trying on my rotary hammer bit shanks. It cleans up great & it actually will remove other oils & grease.
Steve

CJKarl

I love my Drill Doctor. I'd say they come out better than factory. Once I started using it I was searching the barn for bits to sharpen. Maybe not for a machinist, but for most of us the Drill Dr. ROCKS!!

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Teetorbilt

For hand drilling, I've had really good results with B&D's Bullet bits. This is drilling 1/2" holes in Detroit Diesel engine mounts.

As said, high dollar bits like solid carbide take more control than you can provide manually. As suggested, a magnetic base drill press can help a lot and liberal use of a cutting oil can not be over-emphasized.

Most people drill too fast (RPM), this is terminal for drill bits. Machinist's use the term 'keep the heat in the chip' meaning keep the cutting edge in cool metal. If you're not getting a nice, clean spiral for a chip then something is wrong.

Change bits the moment that you see something wrong. 'Finishing that last hole' can temper the metal that you're drilling (making it harder for the next bit to finish) and anneal the drill bit making it useless to resharpen without cutting off the first 1/4-1/2".

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Aiken Colon

I've heard alot of good things about "Black & Golds". Apparently, they're made for hard to machine metals. I know a few guys who have been selling these for a while now. You have to make sure you get the ones made of "M-7 Nitro-Carborized" steel though. Here's a picture of what they look like. Pretty sure the inside of the twist is black and the outside of the twist is gold. Hence the name. Although, I've never seen 'em in a case like this. It says it's water-tight, but it dosen't look like it would take much of a beating. I've only seen them in an all metal box with tiers. Oh, and don't be fooled by the Irwin knock-offs. They're not the same thing.

Chris

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minorng

bad dog tools i saw the show guy drill a hammer

im still new here but heres video on youtube about it

youtube.com/watch?v=pDEcUTnMI9c

richard123

ye i never have any luck with them either, they always are god damm breaking!!!