Best way to drill a 7/8" hole into 1/4" steel.

[Eddo Rogue]

I need to drill a 7/8" hole into a 2"x2"x1/4" hot rolled mild steel plate.

I started with a pilot hole and worked my way up to 9/16" before getting stuck.

So far my step and large drill bits have brought me no luck. They are of HF brand.

I ordered a good set of drill hog step bits hoping this will help.

I cant seem to find a quality large drill bit, but would rather not buy one anyways.

I remember @Dirtman mentioned a good cutting fluid in a recent post, hopefully he sees this. I need to tap some 3/4" threads as well.

Any other tips, tricks or suggestions I say thanks in advance-Eddo

 

[Dirtman]

Are you using a hand drill or a drill press?

 

[MikeG]

Your first problem is buying drill bits from Horrible Freight.

Second problem is not using cutting fluid. Surprised you didn't burn up a few bits, already.

Buy a decent set of "Silvery and Demming" bits (reduced shank) and make sure they are COATED. The yellow-ish coat is Titanimum Nitride or something similar. Go up one step at a time.

Hopefully your horrible freight drill bits did not work-harden the steel to where a regular drill bit won't touch it. What are you using for a drill? Please tell me you have an actual drill press, with the work properly secured to the table! Larger drill bits have a LOT of leverage on the work, and it is surprisingly easy to fling the workpiece into some part of your body that will HURT on impact with a sharp piece of metal. Ask me how I know this.....

If all else fails, get a GOOD hole saw (and I hope I don't have to tell you where to NOT buy it from). Again - drill press, work properly secured, etc. DO NOT under ANY circumstances try to use a hole saw without the correct sized pilot unless the work is WELL SECURED to the drill press table. AND you need cutting oil for the hole saw, if you go that route.

Don't drill metal without cutting fluid!!!!!!!! (except cast iron) You can pick up cutting fluid for steel at any hardware store. For aluminum, that's more of a specialty item, but ATF works reasonably well. Even the slightest drop of motor oil is FAR better than no cutting fluid at all.

 

[fastpakr]

Harbor Freight does sell some decent bits (titanium coated), but the brand name escapes me at the moment.

Cutting oil for sure. Go slow too.

 

[PetroleumJunkie412]

These work really, really well:

Hunting Energy Services | PerfECTA® Charges

www.hunting-intl.com

 

[ericbphoto]

If you’re already up to 9/16”, then you’re going to have trouble with the pilot bit for the hole saw. Step bits are not made fir material that thick. If you’re using a drill press, the hole saw can work even without the pilot bit. It is best if the work piece is perfectly perpendicular to the hole saw so that the saw contacts the work evenly all the way around. Uneven contact will make it try to walk around or grab and fling stuff around. Feed the hole saw into the work slowly.

correcting this with a handheld drill at this point is extremely difficult and even dangerous unless you can fill your existing hole so that the pilot bit has something to work with.

 

[Eddo Rogue]

Are you using a hand drill or a drill press?

Sorry forgot to mention I am using a drill press, set on the slowest speed. I think its 320 rpm.

I have an old can of cutting fluid that I think might be something else. looking at the tapmagic varieties on ebay, might stop by the Ace hardware...

 

[Dirtman]

If you have a drill press just use a 4 flute end mill and lots of oil.

 

[ericbphoto]

This would be a good time for a cutting torch or plasma cutter.

 

[Eddo Rogue]

If you’re already up to 9/16”, then you’re going to have trouble with the pilot bit for the hole saw. Step bits are not made fir material that thick. If you’re using a drill press, the hole saw can work even without the pilot bit. It is best if the work piece is perfectly perpendicular to the hole saw so that the saw contacts the work evenly all the way around. Uneven contact will make it try to walk around or grab and fling stuff around. Feed the hole saw into the work slowly.

correcting this with a handheld drill at this point is extremely difficult and even dangerous unless you can fill your existing hole so that the pilot bit has something to work with.

I didn't even thing of a hole saw. I intended to use drill or step bits. I have plenty of material to start over. That might work.

 

[ericbphoto]

If you have a drill press just use a 4 flute end mill and lots of oil.

He probably doesnt have a way to chuck up a 7/8” end mill.

 

[Eddo Rogue]

This would be a good time for a cutting torch or plasma cutter.

I have both, but too messy, too much setup, they are crammed away and scattered about.

 

[Dirtman]

He probably doesnt have a way to chuck up a 7/8” end mill.

Use a reduced shank duh...

 

[Eddo Rogue]

He probably doesnt have a way to chuck up a 7/8” end mill.

I didnt think of end mill either. I might have a chuck, and my buddy neighbor might have the bit. I might just use his press. Y

Your first problem is buying drill bits from Horrible Freight.

Second problem is not using cutting fluid. Surprised you didn't burn up a few bits, already.

Buy a decent set of "Silvery and Demming" bits (reduced shank) and make sure they are COATED. The yellow-ish coat is Titanimum Nitride or something similar. Go up one step at a time.

Hopefully your horrible freight drill bits did not work-harden the steel to where a regular drill bit won't touch it. What are you using for a drill? Please tell me you have an actual drill press, with the work properly secured to the table! Larger drill bits have a LOT of leverage on the work, and it is surprisingly easy to fling the workpiece into some part of your body that will HURT on impact with a sharp piece of metal. Ask me how I know this.....

If all else fails, get a GOOD hole saw (and I hope I don't have to tell you where to NOT buy it from). Again - drill press, work properly secured, etc. DO NOT under ANY circumstances try to use a hole saw without the correct sized pilot unless the work is WELL SECURED to the drill press table. AND you need cutting oil for the hole saw, if you go that route.

Don't drill metal without cutting fluid!!!!!!!! (except cast iron) You can pick up cutting fluid for steel at any hardware store. For aluminum, that's more of a specialty item, but ATF works reasonably well. Even the slightest drop of motor oil is FAR better than no cutting fluid at all.

Yep its that silver demming set. Not sure what that means but sounds light duty. Anyways that was my only option at the time for large bits, but now I have found some better ones on ebay I may upgrade to.

 

[Eddo Rogue]

By the way these will be caps for table legs so that the casters can be threaded up and down for height adjustment. I will weld a nut to the plate before capping the leg with it, nut side in, and weld the bolt to the caster plate. Right now I have the caster plates tacked directly onto the bottom of the legs, but scored some huge nuts and bolts.