Suggestion

[thedude5600]

So I've been tasked with having to increase the size of the hole through a 3/4" thick solid plate steel as seen in the picture attached.

I know I should use a strong drill bit like Cobalt and to take it slow while keeping the bit and steel lubricated to help reduce the heat friction. But for the drill itself I honestly don't know what the best type to use is. I was thinking of using a hammer drill but is there a different style that would work better for this application?

Thanks for any suggestions/advice

Mark

 

[sberry]

Not a hammer drill but it can be done with a common bit and battery drill. You can also clamp a washer over it to center a hole saw. I drilled 4 holes in these, 2 plates 1/2 thick for total of inch on each one. Used a little water and about 5 minutes a hole.
You may notch the hole a bit with a sabre saw to let the chips clear while drilling flat or drill from the bottom with holesaw. It may take 2 steps with a common bit.

 

[readhead]

If it isn't to much bigger I would suggest a reamer. Makes a lot of noise because you usually use an impact to drive it but you don't run the risk of the bit catching and breaking.

 

[NORTON'S SHOP]

If it's a nominal size that you need to go to, use a Unibit. Those things are great for enlarging holes. If the material is thicker than what the Unibit can handle, go from both sides. They can be kind of pricey for the larger sizes though.

 

[PugetDude]

So I've been tasked with having to increase the size of the hole through a 3/4" thick solid plate steel as seen in the picture attached.

I know I should use a strong drill bit like Cobalt and to take it slow while keeping the bit and steel lubricated to help reduce the heat friction. But for the drill itself I honestly don't know what the best type to use is. I was thinking of using a hammer drill but is there a different style that would work better for this application?

Thanks for any suggestions/advice

Mark

Current/desired diameter?

 

[dogdog]

drill progressively till final hole size in 1/16 or 1/8 steps. use cutting oil etc. I just remember any hole size larger than 1/2" is hard to drill straight in one shot unless it's a mag drill.... if it is harden stainless... good luck, I am still messing with my 1/8 thick key chain..

Not sure about hammering drills, with the hammer functions... it's not for drilling metal as far as I know...... low speed high torque drills with a handle for both hands would be ideal. Or a Mag Drill.

 

[theoldwizard1]

The biggest problem most people have when drilling medium to "large" holes in steel is using too much speed. It can over heat the bit and ruin the hardening.

 

[MoonRise]

Hammer drills are used for going through masonry, not steel.

 

[iajonesy]

BE CAREFUL. When enlarging a hole the drill will have a tendency to want to grab and you can easily break your wrist. Those look like 1/2" holes,now,what size are you going to? Can you get that piece to a drill press? If not,go slow and as straight as possible with a hand drill. Use lube to keep the drill cool.

Mike

 

[sberry]

Another pic. I do this all the time. One on right about 8 drops of oil. Those thick green ones above no oil, used water.

 

[vettex2]

BE CAREFUL. When enlarging a hole the drill will have a tendency to want to grab and you can easily break your wrist. Those look like 1/2" holes,now,what size are you going to? Can you get that piece to a drill press? If not,go slow and as straight as possible with a hand drill. Use lube to keep the drill cool.

Mike

break your wrist? yeah if you have severe osteoporosis
did you even read his post and look at the pics?

 

[sberry]

Battery drills are the best thing they ever invented for steel for safety.

 

[Bondo]

Ayuh,.... I use hole saws all the time for virgin holes, or a hole no bigger than the pilot bit,....

For expandin' a hole over 5/16", I use a high-speed tapered ream,....
Quick, 'n easy,... use plenty of oil,...
Got the 5/8", a 3/4", 'n a 1",....
I like the 3 sided shank, so it don't slip in the chuck,...

 

[dogdog]

Another pic. I do this all the time. One on right about 8 drops of oil. Those thick green ones above no oil, used water.

curious, since the op already have a fairly large hole (it seems, larger than 1/4" ), the hole saw you have only have maybe a 1/4" bit, how do you keep that hole saw centered while drilling without a sort of jig with a 1/4" hole and some clamps ?

 

[dbabicky]

Mag Drill, cutting oil, slow and steady !

 

[bulldogr6]

Mag drill , a 3/4 drill bit and lots of cutting oil.

Sent from my E6782 using Tapatalk

 

[sberry]

Once it gets started and in the grove it doesn't need the pilot. I don't have a pic but do this to fix egged holes too. Weld it up and stick a saw back thru to true it, next time I do one like a worn drawbar will take a picture.

 

[tarbellb]

^^^ Or you can clamp a wood block or metal plate with the correct size hole on top of the smaller hole- use as a guide.

Personally i would try a reamer, exactly wha they are made for. Or a step drill if possible.

18v cordless with the add-on handle... cuz wrist.

 

[ilovevocs]

I just use the clutch on my cordless on the highest setting when using the hole saw.

Here is the answer to hole sawing an existing oversize hole.

https://www.amazon.com/dp/B00023M8RS/?tag=atomicindus08-20

 

[Nor'Easter]

Tapered reamers exist for this purpose.

 

[Richard D]

This is why I love my mag drill!

 

[sberry]

The reason I am a hole saw and or bit fan is they are so common and this can be done in a few minutes with very little set up time. By the time guy would get a mag drill rigged in to this ******** spot would be done and getting a coffee.

 

[NORTON'S SHOP]

Tapered reamers exist for this purpose.

^^I've been a tool maker for over thirty five years and that's a new one!

 

[Willie Makeit]

Tapered reamers exist for this purpose.

someone has never used a tapered reamer

 

[34kw]

I use tapered reamers all the time on truck frames to enlarge holes from 1/2 to 5/8. I don't know why you couldn't use one to go 3/4". I like my old slow electric drill with a handle for this - but you have to hang on for sure.

 

[ovrrdrive]

The low speed 1/2" drill from HF is a beast... It does have enough torque to hurt you if you aren't careful. Then everything else you said is what I would do. Take your time and lots of lube.