Advice on drilling through hardened steel?

[ThetaDot]

anybody?
We're afraid we will burn out our drills / ruin bits.

We have to lose weight!!

[Jones571]

i would do it on a drill press or bridgeport and depending on the hardness i recomend a Carbide tiped drill and it shouldnt have a problem good luck on makeing weight

[Cory]

Are you using large or small bits? crank the speed way down for a large one (This applies for any sort of drilling, regardless of material) Use tons of coolant, and try to use bits that arent pieces of junk. I think Titanium oxide (Nitride? I know it's titanium something) coated drill bits last much longer and drill better than regular bits. make sure you dont go so slow that you're just letting material get packed into the bit, as you'll dull it quickly, but make sure you arent drilling so fast that it dulls the bit, or snaps it.

Cory

[edit] Dont try to drill any large diameter holes with a hand drill. If the bit gets caught, you could jerk your arm pretty badly, and it sure wouldnt feel good for a few days.

[ThetaDot]

Yeah we just ripped them off and currently have the drill presses going.
Thanks though.
Quick response time.

[Rickertsen2]

Originally Posted by ThetaDot

Yeah we just ripped them off and currently have the drill presses going.
Thanks though.
Quick response time.

Just how hardened? We tried drilling through rh68(i think) shafts and ended up going through quite a few bits and shattering a shaft before giving up on that one. We attemptign to use ordinary black home depot stule bits. I have been told that even with carbide drill bits, alot of hardened can be rather difficult and you are really supposed to use some sort of grinder i think. Just curious. Where do you have large amounts of hardened steel on your robot?

[Rickertsen2]

[quote=Cory]I think Titanium oxide (Nitride? I know it's titanium something) coated drill bits last QUOTE]
There are actually 3 types of titanium coatings:
titanium nitride (TiN)
titanium carbonitride (TiCN)
Aluminum titanium nitride (AlTiN)

The only one you will likely ever see in your local hardware store is TiN. It is easily identified by its goldish color. TiCN is sometimes found on higher end stuff, and AlCn is still somewhat new from what i understand.

[tenfour]

I would use some oil and use a high quality bit. Go thru with a small bit at a high rmp (like 900 for a 1/4") and then go thru with a larger one (like 400 for 1") Just keep ur balls and u'll be fine.

[Kevin Sevcik]

do you need all the strength that comes with the hardness? I mean. if you don't actually need the extra strength, then just hit it with a torch until it's cherry red, hold it there for a few minutes, and then let it air cool. That should kill the heat treatment of most steels unless it's one of the air quenching varieties.

[IndyStef]

Dependes on how hard hard is.
Properly hardened high carbon streel, like tool steel for punches and dies - forget it, you won't even sratch it with a regular HSS bit, no matter what coating. And hard metal bits, or carbide bits won't help you much, either.
Surface hardened by carbonizing, or induction treated - with a hard metal tipped bit, or carbide, you might be lucky. Once you are through the surface, things get better.
Tempered steel - depends on the treatment it got, but generally coated HSS or carbide will do the trick - just a lot slower than on Al or mild steel.
Unfortunately, the use of the word 'hardened' is a bit blury in the English language - so you might just talk about a high tensile alloy, or a tough stainless steel. In that case: coolant is the answer. Increases the life of your drill bit a lot. Also - drill presses are not used in the same way as hole punches! Apply force, but not so much that the machine twists and bends. And keep the bits sharp by re-grinding them.

Hope that helps ... some rambling of a German toolmaker and mech. eng. .....

Stef

[Greg Perkins]

are yuor drive shafts out of hardened steel?

[maclaren]

It's all about the carbide drill bits. To do the drilling correctly you first must figure out exactly what you are drilling. Then you look in your machinists handbook(noshop is complete without one) for speeds and feeds. Then use a milling machine or high quality drill press. Use flood coolant. The coolant type is important for a good finish and keeping the drill bit cool. You can also find what type of coolant to use in your machinists handbook. If your bit heats up then it loses it hardness which makes it dull extremely quickly. Drilling is a battle of hardness and sharpness the hardest and the sharpest wins. You want the drill bit to win . You can purchase carbide drill bits at Enco or from MSC industrial supply co.

The moral of the story try and put hole in hardened steel before it's hard the harden it. Because there is no way to BS machining hardened steel.