Cutting large holes in plate

[Wozzaaah]

Hi all, as the title suggests I sometimes find myself drilling large (up to 25mm) holes in 10mm plate. I use my drill press and a blacksmith's bit at the moment but it puts such a strain on the motor that it's only a matter of time before I ruin the drill press. My current project involves drilling 88 holes @ 22mm plus 22 @ 25mm, all in 10mm plate. Would I be better off using hole saws rather than the blacksmith's bit and if so, can anyone recommend a brand which will last me? I like the idea of a mag drill/broaching bit but I'm not sure whether I can justify the cost of one as it's not very often a job like this comes up.

 

[rtbcomp]

I've used holesaws but not at this thickness! I suppose if you buy them from a proper engineer's supplier rather than Netto you can't go wrong. Really the thickness of metal shouldn't be a problem as the teeth have a set - just consider drilling 10mm the same as drilling 10 seperate 1mm thicknesses.

A couple of tips - use plenty of cutting fluid, I've used Rocal in the past which is good and apply plenty of downward pressure so the teeth cut into the metal rather than skid accross it, that's what blunts them. Also make sure the drill speed is correct, the holesaws should come with instructions recommending a suitable speed.

 

[akdaka]

Having used hole saws for that size hole in 6mm plate and have found no problems. Holes are not as clean as drilling, but lubrication and a slow speed are essential to keep the cutter from bluntening. Can recommend Starret or Morse as suppliers of good cutters.

Hope this helps

 

[morph]

For that many holes you will kill no end of hole saws no matter how good quality. Don' even think of it!

You could hire a mag drill but most places make you buy the cutters so you're looking at a total cost of over £50.I've got a mag drill but don't bother drilling that many holes. Much cheaper and easier to take the marked plates to somewhere with a press and let them press the lot put in under 10 minutes! Give them £30 and they'll be happy!

 

[Hitch]

Get it punched, or get yourself a rotabroach. (mag drill)
Cutter for mag drills go from 12 to about 60, a small single speed mag drill will cope upto about 30, much larger and you need a variable of at least 2 speed model.

One cutter will happily drill 250+ holes before reshapenening usually. Plenty of cutting oil is required.

I notice your in Wilts (if your close to Wincanton) i could punch them out for you if you bring it round to me, one eve. Send me a pm if your interested.

 

[morph]

When i was younger and didn't really know what a press was i made 3 large sheds with a evolution mag drill. I only bought 2 18mm bits- the first one broke after about 10 holes but the second did about 4000 holes in atleast 6mm but mainly 12mm plate. The drill came with a lube system feeding cutting oil(not that white stuff) whichn is probably why the broach lasted so well. Oh how my back knew about that for days after!!

 

[Hitch]

Long series cutters can be a pain, they break a lot easier when drilling thick plates.

 

[morph]

yeah very true only ever bought one and it drilled those 10 holes!!! 25mil all the way!

 

[Weldingartisan]

Wozzaaah,
If your drill press has a morse taper spindle, you could make an adaptor (from a morse taper blank) to take mag drill broach bits. I made one for smaller brackets etc that fit in a machine vise. W/A

 

[Wozzaaah]

It is a clarke CPD351 which has an MT2 taper. I'm taking Hitachimad up on his offer to punch the holes for me but I may consider your suggestion as well. I've seen mt blanks for around £5 so I assume I'd just need to get it bored out to suit the broach?

 

[Hitch]

Dont forget you have a spring loaded centre in a rotabroach holder, to help align and to eject the slug.

 

[nickk]

holes.

Hi all, as the title suggests I sometimes find myself drilling large (up to 25mm) holes in 10mm plate. I use my drill press and a blacksmith's bit at the moment but it puts such a strain on the motor that it's only a matter of time before I ruin the drill press. My current project involves drilling 88 holes @ 22mm plus 22 @ 25mm, all in 10mm plate. Would I be better off using hole saws rather than the blacksmith's bit and if so, can anyone recommend a brand which will last me? I like the idea of a mag drill/broaching bit but I'm not sure whether I can justify the cost of one as it's not very often a job like this comes up.

why not hire one,if your not in a remote area,most hire shops,stock them.

 

[Wozzaaah]

Thanks for the advice but I sorted it....4 years ago.
Hitch punched some for me then I bought a mag drill.

 

[Welderpaul]

Thanks for the advice but I sorted it....4 years ago.
Hitch punched some for me then I bought a mag drill.

What was the job Woz?

 

[Hitch]

I was just reading this, thinking it sounded like the ones i punched..... blimey, that were some time ago.

 

[Wozzaaah]

It was some setting tables for a roof truss manufacturer.