Best way to put neat holes AR550 steel

[Cannonmn]

Friend needs to put a bunch of 1/2 in. Holes in 1/2 in. Thick AR550 steel. Asked me, but I’ve never even seen the stuff. What technique/tooling would you recommend? He has small shop with Bridgeport, drillpress, and a few other things.

 

[cmccull166]

This would be the 'neatest" way .
Actual hole time would be in milliseconds range saving shop capacity
dramatically.

Machine and setup costs would work out to
be insignificant to buying an actual machine tool also.

WALL DESTROYER Sniper Rifle !!! US .50 CAL Barrett M82 - YouTube
If they would like to sub this job out please contact me.

 

[Archer120x]

Friend needs to put a bunch of 1/2 in. Holes in 1/2 in. Thick AR550 steel. Asked me, but I’ve never even seen the stuff. What technique/tooling would you recommend? He has small shop with Bridgeport, drillpress, and a few other things.

Send it to me. Its what I do every day.

 

[52 Ford]

Get chu some black tip .50 BMG.

Or maybe some APIT. If you need some serious cool factor, get some SLAP or SLAP-T rounds. Best to load your own if you use SLAP. Pull the bullets and put in fresh powder.


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[gbent]

SLAP would be great, but would only give a .30 hole. He needs 1/2".

I'm a wimp. There is a low limit on the number of holes I want to poke.

 

[Yankee Metallic]

Plasma cutter.
Maybe burn holes with an arc welding electrode.
If the holes are just for mounting hangers, they don't have to be precise.

 

[52 Ford]

All kidding aside - an indexable carbide insert drill would be a good choice.

The pilot hole could probably be done with something small like a .338 Lapua Magnum AP round.

Or maybe a solid carbide twist drill.

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[52 Ford]

Plasma cutter.
Maybe burn holes with an arc welding electrode.
If the holes are just for mounting hangers, they don't have to be precise.

If I was making target plates and wanted holes, I'd peirce the plate with the stick welder, then cut the holes with the plasma cutter.

What I have done in the past with good luck is to weld rebar hooks onto 1/2" AR500. No drilling or cutting.

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[Cole2534]

Laser would be my first inclination.

Programmed via Mazatrol

 

[D Nelson]

Waterjet them
Don


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[52 Ford]

Laser would be my first inclination.

Programmed via Mazatrol

Right. I'm guessing the guy wants to keep the hole poking in-house, though.

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[52 Ford]

Waterjet them
Don


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Hard to water jet with a Bridgeport.

The abrasive is REALLY rough on the sump pump.

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[Spruewell]

Put it in the Bridgeport with a good short screw machine length HSS drill bit running around 200rpm. Don’t let it get hot and don’t let the drill get dull. Replace it or regrind the drill often

 

[52 Ford]

Put it in the Bridgeport with a good short screw machine length HSS drill bit running around 200rpm. Don’t let it get hot and don’t let the drill get dull. Replace it or regrind the drill often

I'd get at least a Cobalt twist drill. McMaster Carr - Stub Length Cobalt Twist Drills

I wonder if the TiN coated twist drill would be worth it in this case.

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[52 Ford]

Probably want to buy a whole box of those 1/2" twist drills. Not just one at a time. Hard steel is... well, hard.

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[Scottl]

He could try using a brand new carbide rock bit such as those made by Bosch with the mill in back gear. It needs lots of pressure feed so the quill has to be up and locked and the feed put on by the knee, preferably with a power feed.

Basically a motorized version of doing the same thing with a Cole Drill.

The rock bits are sharper than the run of the mill masonry bits.

 

[D Nelson]

Hard to water jet with a Bridgeport.

The abrasive is REALLY rough on the sump pump.

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Sometimes a smart man knows when it’s time for some help. So you don’t tear up your good stuff just to help someone out who doesn’t give a shit about your stuff. Make him pay
Don


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[boslab]

I’ve done hardox 500, just a drill bit and ( or “drill”) a drilling machine, though the rotobroach puma made short work of it, the drilling machines were an archdale radial, and an abroga gear head drilling machine, cleavdon morse taper drill, centre drilled, 8 mmm pilot for the 1” holes, I think I ground 135 on the 1”, either way it didn’t resist machining half as bad as I imagined.
Mark

 

[HappyWyo]

Friend needs to put a bunch of 1/2 in. Holes in 1/2 in. Thick AR550 steel. Asked me, but I’ve never even seen the stuff. What technique/tooling would you recommend? He has small shop with Bridgeport, drillpress, and a few other things.

Spade drill or insert drill. Carbide or ceramic. Here is a video of a hardened rod being cut with ceramic. It will give you an idea of you are up against.

https://youtu.be/GtjVX3amr4c

 

[52 Ford]

He could try using a brand new carbide rock bit such as those made by Bosch with the mill in back gear. It needs lots of pressure feed so the quill has to be up and locked and the feed put on by the knee, preferably with a power feed.

Basically a motorized version of doing the same thing with a Cole Drill.

The rock bits are sharper than the run of the mill masonry bits.

I've drilled some stainless that was 59 RHC with a carbide masonry drill. It worked there isn't much support behind the carbide, though. It cracked the carbide as it broke through the backside of the material. Maybe best to grind the carbide down to get it closer to the steel? If I had to do that again, I'd back the part with another piece of hard steel.

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