# holes thru steel



## SE18 (Feb 21, 2008)

like strap iron

how?

I've been breaking drills and dulling spring loaded punches

I've also pounded nails but it distorts the area around the steel 


any ideas appreciated


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## Dave F (Jan 2, 2008)

50 cal armor piercing rounds?


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## Totalwrecker (Feb 26, 2009)

cutting oil 
High sulfur oil will help save your bits and make a cleaner hole, keep it off your fingers and clothers 
I got mine from Ace, but should be widely available. 

Make sure your bit is sharp, if you don't know how to sharpen one correctly, buy a new bit and always use the cutting oil and it can last a long time. 

Comes in a can as Cutting Oil 

John


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## SE18 (Feb 21, 2008)

thanks; I've snapped a number of 1/16" (sizes smaller and slightly bigger) bits. I'll check around for that oil 

also, should the bit be carbide or tungsten or high grade steel? I doubt if I'll drill thru anything thicker than strap iron, although I may later use heavier gauge steel to bolt together a bridge (a welding kit will have to wait) 

(I've also got a 6-ton shop press; the danger there is that something could go flying out (like a nail).) 

(50cal brings back some memories)


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## Totalwrecker (Feb 26, 2009)

It's not the thickness, that relates to the time it takes, it's the kind of steel you're cutting. Strap iron should be soft, but if it's dulling your punch, I'd suspect something harder. Makes sense to cut with a metal harder than the stock. HSS should cut iron like butter, sooo..methinks you are cutting steel and need to go the next step up. 

Use a steady pressure and back out often to clear chips, more oil in the hole and resume. Experience will show you how much, sometimes I'll dip the bit in oil and that's enough. Start with a medium light pressure and adjust as you go, the bits shouldn't bend too much. The smaller the bit the slower the spin, until you get a feel. Can't explain reflexes! lol 

If you are drilling micro holes (#61-80) in brass, beeswax makes a great lube. It sticks to the bit and melts at low temp to flush the chips out. 

Punching holes is out of my league, maybe Les can help with your press. Pop rivets might work for your bridge until you get a wire welder.... not as bulky. 

John


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## Totalwrecker (Feb 26, 2009)

Your nail attempt will always distort the metal, it has to go somewhere....


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## SE18 (Feb 21, 2008)

thanks


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## RimfireJim (Mar 25, 2009)

If you are snapping (breaking) bits, it's probably because you are bending them. A 1/16" bit has very little strength in bending. Bending can be caused by applying too much force with the least amount of of-axis angle - usually with a hand-held drill. Less of a problem, typically, in a drill press, because the press maintains the alignment. So, be careful to push as square to the work as you can, and only as much as needed to make the bit cut properly.


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## Dwight Ennis (Jan 2, 2008)

The speed of the drill bit is also important - high speed for small bits, slower speeds as drill size gets bigger.


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## denray (Jan 5, 2008)

The above advise is all correct, one thing I would add is only buy good USA made bits. Particulary when they are small bits. Be sure to use the lubrication.
Dennis


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## armorsmith (Jun 1, 2008)

Please clarify what you are calling 'strap iron'. Based on the tone of the conversation, this material is the banding steel used on shipping crates. If so, this material has a hardness/spring nature to the material. Standard mild steel in that thin a section should be able to bend 180 degrees with out breaking. Banding steel strap will snap every time. You can anneal the strap by heating it to bright cherry red and letting it cool. This will soften it sufficient to drill it. 

Bob C.


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## Gary Armitstead (Jan 2, 2008)

From an old tool and die maker: you don't have to push on the drill to get it through. If the drill is sharp and you are using cutting oil, it will cut and go through. If you have to push to force the drill, then it WILL bend and break. I have drilled flushing holes in copper electrodes for EDM and they have been as small as .010 in diameter. It can be done.


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## SE18 (Feb 21, 2008)

Posted By armorsmith on 12 Oct 2009 07:49 PM 
Please clarify what you are calling 'strap iron'. Based on the tone of the conversation, this material is the banding steel used on shipping crates. If so, this material has a hardness/spring nature to the material. Standard mild steel in that thin a section should be able to bend 180 degrees with out breaking. Banding steel strap will snap every time. You can anneal the strap by heating it to bright cherry red and letting it cool. This will soften it sufficient to drill it. 

Bob C. 

OK,

so banding steel is harder to drill thru


BTW, I'm using a drill press, but mention was made of higher speed; I'm probably going too slow.

Also, I'm dulling spring punches on the strap iron (used for banding RR ties and building lumber). Maybe I should use different material!

I also am probably applying too much pressure.

All your comments extremely helpful!


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## SE18 (Feb 21, 2008)

also, mention was made of sharp bit. 

Can I sharpen a bit using a hand-held grind stone (like I would a knife); I have a bench grinder, but I'm thinking for tiny bits it might overkill


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## Les (Feb 11, 2008)

Sounds like you've got some cold-rolled steel. That stuff's brittle and hard. Try cold bending a piece, if it breaks, it's coldroll. Generally. See below.

Drilling with small bits is tricky because one tends to put too much pressure on the down-handle on the drill press.

All the other advice is good, the fact you're dulling the punch while displacing some metal makes me think you've got coldrolled or possbily strapping steel if it's --well, if it looks like strapping steel. That stuff comes in different grades, however, I have a roll that's pretty soft and has a future in my RR as brackets and whatnot. It's colored a dull gray, come to think of it.

Don't, oh I plead on bended knee, use your press for a power punch. Maybe for soft brass and the like, but be prepared for a hillock on the other side.

Blacksmiths used cold punches at times, but they also had a striker wielding a 3# maul to get 'er done. And the metal was thin.

I'm not real sure there's any actual 'strap iron' left anymore. True, it can be special ordered, but it is a high carbon steel and tends to be unforgiving.

What you want, I think, is mild steel that has some of the hardness drawn after rolling. That stuff's not too hard to find.

The biggest problem is, almost all the general steel we have is made from recycled steel, and the workability can vary all over the place.

One last trick you can do: hold a piece of steel against your grinder and note the color and quantity of the sparks, and the spray pattern. It won't mean anything at first, until you connect the fact that certain colors of sparks, etc, from a piece of metal show up in its workability. By the same token, you can slide a mill ******* file across a piece and depending on whether it wants to 'skid' or 'bite', you'll know a little something of the mallability of the steel.

Les


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## SE18 (Feb 21, 2008)

thanks!


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## unimog (Apr 21, 2008)

So Les, 
You probably have the Machinery's Handbook-12th edition... 
Ti


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## Les (Feb 11, 2008)

Ti,

I dunno what the name is. Anyway, I have two, a very old one and mine. I can look, if you're interested.









Les


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## unimog (Apr 21, 2008)

Les,
Family owned a machine shop when I was a kid. Became a challange in the family to see who could aquire the earliest edition. 
Ti


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