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Posted: 1/28/2006 6:34:40 PM EDT
I can't seem to come up with anything other than the basics with google:



Steel Bits— inexpensive and work well for boring in softwood. However, steel bits dull quickly in hardwood.


High-Speed Steel Bits (HSS)— harder than steel blades and stay sharper longer.


Titanium Coated Bits— cost slightly more than HSS bits, but their titanium coating is tougher and stays sharp longer than HSS or steel bits.


Carbide-Tipped Bits— more expensive than other bits, but they stay sharp much longer than steel, high-speed steel or titanium bits.


Cobalt Bits— extremely hard and dissipate heat quickly, they are most commonly used for boring in stainless steel and other metals.



I need bits to drill (drill press) aluminum and steel. I've seen the Titanium Coated Bits at Home Depot and was going to get a set for the aluminum and the occasional wood.

I am working on a gun project and will need to drill into steel. For example, I need to drill out the rear tang on a Suomi.



What would be a good bit for this?
Link Posted: 1/28/2006 6:37:53 PM EDT

I have had good luck with both the Carbide and Titanium bits . Use a cutting oil to protect your investment .
Link Posted: 1/28/2006 6:38:52 PM EDT
lower speeds too.
Link Posted: 1/28/2006 6:45:33 PM EDT

Originally Posted By HillBillySasquatch:
lower speeds too.



What range for something like the Suomi?
Link Posted: 1/28/2006 6:47:13 PM EDT
400-500 RPM should be about right.
Link Posted: 1/28/2006 6:50:38 PM EDT
I've worked as a machinist and currently do QA and engineering work in a large bus shop. HSS drill bits will work fine for general metal working and certainly for wood. Titanium Nitride coated bits are a notch up from HSS. Carbide drill bits are only used for very difficult-to-machine materials, also very brittle. Carbide tipped blades and router bits are excellent in woodworking.
Link Posted: 1/28/2006 6:51:23 PM EDT
Use a quality bit, either TiN (titanium nitride, not titanium) coated.

The coated bits have a slight advantage in hard material. Judge the proper speed by the color of the chips...blue chips=too fast. About 500 RPM in steel is usually OK for up to 3/8" bit.

A drill press is better than a hand drill, mainly because you can apply proper pressure. You have to keep the bit cutting or it will dull quickly. Hope that helps.

Cheers,
Bob Ash
Link Posted: 1/28/2006 7:01:07 PM EDT
I worked in a hardware store for 10 years, here's my advice.



Buy a cobalt bit.



That simple.

I sold a cobalt bit by chucking it into a cordless drill and going out to the persons rig where their "undrillable" piece of metal was and drilled one of the holes for them. A machine shop told them they could drill the holes, but they would need to order in a $50.00 drill bit and it would cost them another $200 in labor. The shop would have came in and a bought a $5 bit from us.



Normal use the cobalt will last way longer than the others.


The problem with Titanium Coated Bits is their just coated.



Link Posted: 1/28/2006 7:01:16 PM EDT
[Last Edit: 1/28/2006 7:06:13 PM EDT by GAU5-A-A]
Well,

In repairing aircraft, where tiny mistakes can cost $10,000 and more,

I use HSS double-margin, split-point, step drills for doing work similar to yours.

They wont "walk" across your work piece, and give you a perfertly circular hole, to within .004".

Using a little liquid Boelube keeps them sharp for a long, long time.

Expensive as hell retail, but usually available very cheap on ebay.

Link Posted: 1/28/2006 7:24:38 PM EDT
Thanks for the info so far. Keep it coming.
Link Posted: 1/28/2006 7:47:23 PM EDT

You have to grind a completely different angle on your bits for aluminum.
Link Posted: 1/28/2006 7:50:55 PM EDT

Originally Posted By Waldo:
You have to grind a completely different angle on your bits for aluminum.



Will it say at the hardware store what specific material the bit can cut?
Link Posted: 1/28/2006 7:54:47 PM EDT
For no more then your doing with it, steel or HSS. While the higher end bits are better and nicer to own, you really dont need a bit of that caliber unless you want an ego boost every time you chuck it up.
Link Posted: 1/28/2006 8:17:39 PM EDT
I machine metal for a living.... but take this for whatever you will.


For your use just buy quality HSS drills. Black oxide or bright finish doesn't matter. 118 degree (read normal) points will do fine. You don't need coated drills unless you are going to drill many holes in tough material.

Cobalt would be fine also, just will cost you a little more. If you use them properly they may give you longer life in steels. Any drill will be toast if you let it spin in the material without cutting, don't use lubricant, or don't clear chips properly.

About the only advantage of carbide for drill press or hand drill use is if you are drilling abrasive materials. You can't achieve the consistant chipload and speed to realize any gain from carbide on a drill press. You will most likely end up with a chipped up drill that doesn't cut for crap.

Link Posted: 1/28/2006 8:26:49 PM EDT
Hey drill bit experts. We killed (9) 1/8" generic drill bits drilling 5 holes in a new steam table through the stainless steel body at a Panera Bread restaurant. I pushed as hard as I could and drilled SUPER slow, as not to overheat the bit, and they still sucked. What do I need that will drill me lots of holes in around 18-20 guage stainless steel. Remember, I am the one buying the bits, so I would like quality AND a good price.

AC
Link Posted: 1/28/2006 8:30:53 PM EDT
Just HSS bits, they sharpen easy. Just make sure you have the RPM's low when you are drilling, and use oil to keep the heat build-up down

Carbides are great bits, but they break easy
Link Posted: 1/28/2006 9:02:25 PM EDT

Originally Posted By AC_Doctor:
Hey drill bit experts. We killed (9) 1/8" generic drill bits drilling 5 holes in a new steam table through the stainless steel body at a Panera Bread restaurant. I pushed as hard as I could and drilled SUPER slow, as not to overheat the bit, and they still sucked. What do I need that will drill me lots of holes in around 18-20 guage stainless steel. Remember, I am the one buying the bits, so I would like quality AND a good price.

AC



You drill bits were crap. Use put a HSS bit in turn the drill on and push. Don't let it sit and spin without taking a chip or your job will be harder (literally)
Link Posted: 1/28/2006 9:09:45 PM EDT

Originally Posted By Waldo:
You have to grind a completely different angle on your bits for aluminum.



No, angles are the same but you do need a different cutting fluid. Kerosene works well for exclusive work in aluminum. Heavier oils or coolants are required for steel. Invest in a mister if you are doing a lot of work. It is a great investment but you have to have shop air available.
Link Posted: 1/28/2006 9:14:42 PM EDT

Originally Posted By OSUBeaver:

Originally Posted By AC_Doctor:
Hey drill bit experts. We killed (9) 1/8" generic drill bits drilling 5 holes in a new steam table through the stainless steel body at a Panera Bread restaurant. I pushed as hard as I could and drilled SUPER slow, as not to overheat the bit, and they still sucked. What do I need that will drill me lots of holes in around 18-20 guage stainless steel. Remember, I am the one buying the bits, so I would like quality AND a good price.

AC



You drill bits were crap. Use put a HSS bit in turn the drill on and push. Don't let it sit and spin without taking a chip or your job will be harder (literally)



You can also get a wax type lubricant that is easy to use in the field. Just stuff the bit into it every couple of holes to keep the bit lubed. And slow means really slow. If SS is trying to work harden on you you may have to go as slow as the drill will go until you can hear the chips popping one after the other like a "tick, tick, tick" every revolution. Heavy gage SS sheet is a bugger to drill.
Link Posted: 1/28/2006 9:17:33 PM EDT

Originally Posted By AC_Doctor:
Hey drill bit experts. We killed (9) 1/8" generic drill bits drilling 5 holes in a new steam table through the stainless steel body at a Panera Bread restaurant. I pushed as hard as I could and drilled SUPER slow, as not to overheat the bit, and they still sucked. What do I need that will drill me lots of holes in around 18-20 guage stainless steel. Remember, I am the one buying the bits, so I would like quality AND a good price.

AC



I think I've found your problem.
Link Posted: 1/28/2006 10:31:31 PM EDT
Go here for a very good overview of different drill bits, coatings, etc. click here


For your intended use, a coated HSS bit will be just fine and last a long time provided you use slow speeds and lubricant.
Link Posted: 1/28/2006 10:50:06 PM EDT
One of the best investments I ever made was a drill bit sharpener. While not perfect for a lot of uses, the resharpened bits work well for most everyday tasks.
Link Posted: 1/28/2006 11:12:22 PM EDT
Split Points HSS
For the work your doing that will be fine
If your going to drill wood buy something cheap (HSS) cause no matter what heat build up is going to kill anything you get other than carbide pretty fast
Split points work great espescially if your not using a spot or center drill first
Link Posted: 1/29/2006 4:36:09 AM EDT
Thanks again guys for all the answers.
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