Thread: Need to make large holes in steel

I need to make 25 mm holes in 2 bits of 5 mm plate. The biggest drill bit I have is a 16 mm bit. Anyone know of a way to make these holes and they don't have to be perfectly circular with your basic run of the mill items found in a typical workshop? I am considering using a file to make the hole larger but that will be slow. Other option is to buy a bigger drill bit but it would only be used for a one-off job.

Buy a bigger drill = dollars from your pocket
File it bigger = time from your life
What can you best afford

Have you thought of using a Hole Saw. Even though they will cost a few dollars you would probably find a use for them doing other jobs.

Originally Posted by Tiger

they don't have to be perfectly circular .

assuming you have a drill press, what about drilling a series of smaller holes around the circumference of a scribed circle

regards david

superdrill??? I have seen one in action and they do work well..

http://www.practool.com/super-drill.html

Originally Posted by robbygard

assuming you have a drill press, what about drilling a series of smaller holes around the circumference of a scribed circle

regards david

That's what I do now, one day I'll get a metal cutting holesaw.

p.s. big drill bits in a normal 16mm drill press are a pita

I faced the same problem while running electrical wires around the workshop just recently..

The quickest option I found was a "step" drill. I ended up buying one and doing all of the holes I needed.

They can be expensive, depending on the step size you want, or conversly contact a garage installer and see if they will lend/hire you one of theirs for a few hours.

look here : http://www.irwin.com/irwin/consumer/...rwinProd100146

you could use an arc welder to blow the holes in the plate. I know I can do it easy enough and unfortunately all to frequently, so doing it on purpose would be a nice change

Originally Posted by Matty5700

you could use an arc welder to blow the holes in the plate. I know I can do it easy enough and unfortunately all to frequently, so doing it on purpose would be a nice change

lol ... i'd thought of suggesting oxy but figured that it wouldn't be in the average shed

regards david

Thanks guys for your ideas. I haven't had to use the drill press for anything over 13 mm and I agree with Bob, what a PITA and that was for the 16 mm bit that I had. The machine struggled no matter what lubricant I used or what speed I used. Thought that the bit was blunt but even after sharpenings it still was slow and I got the triangle hole. I will investigate the hole saws.

Hate to say this but if you got a triangular hole then the drill wasn't sharpened properly

Yeah just buy one of those el cheapo hole saw kits you see at places like Bunnings & other cheap shops.

Last time i bought a kit it was $14.00 or something,cut 3 holes through engine bay sheet metal for a turbo kit & still looks like it would cut plenty more.Only thing i had to do was drill a good pilot hole.

If it goes blunt after a few cuts who cares its cheap lol.

Cheap holesaws are useless on steel, you need a hss blade

Walk in to an engineering shop with your two plates and a slab. Job done.

Tools

If you're up for a short drive, I have bits in that size here if you want to bring them here and drill them