Cutting large holes in 2mm steel

[ndg]

Hi All,

I'm helping a buddy out with his hot rod build at the minute ('33 ford if you're interested). One of the jobs we need to do is to recreate the diagonal reinforcements in the chassis. These are fairly straightforward 2mm steel C sections. The originals have ~84mm holes punched in the to save weight and provide cable/pipe routing. It's not essential to replicate them at all and certainly not accurately, but it would be nice to do so. Plan B is to buy a hole saw and get cutting, but can anyone recommend a punch tool that can deal with material this thick? I have a 10T hydraulic press and the rails will fit through it fine if that helps?

If it goes well on the reinforcements we'll probably go for the same technique on the chassis boxing plates.

Thanks

 

[winchman]

I have seen punches on Aliexpress I think? But Starratt do tungsten tipped hole saws I feel would easily cut it with lube on.
You could just buy one then sell after if its only used for one job?

VEVOR 15 Ton Hydraulic Knockout Punch Driver Kit Hole Tool 1/2"-4" with 10 Dies | eBay

VEVOR Hydraulic Knockout Punch Driver Kit Hole Tool 4 Die 1/2", 3/4", 1", 1-1/4". VEVOR 10T Hydraulic Knockout Hole Punch Driver Tool Set Kit Hand Pump 22-62mm. Comfort at its finest: Punch with ease and comfort using our user-friendly knockout set!

www.ebay.co.uk

 

[Agroshield]

84 mm is an odd size so how flexible can you be? 89mm is 3" so would be easier to find.

Qmax cutters, which are the standard for this type of work, seem to top out at 80mm:

Q Max Sheet Metal Hole Punch Metric | Hole Punches

Buy Q Max Sheet Metal Hole Punch Metric and other Q Max Hole Punches at MyToolShed.co.uk. Fast Delivery.

www.mytoolshed.co.uk

Maybe if you found their own website, instead of one of their dealers, you would see if they actually make anythign bigger.

You would also need to check if they are good for 2mm thick.

How many holes do you need to cut?

If you go for a holesaw, this style will be rounder than the hacksaw-in-a-circle type:

https://www.amazon.co.uk/Mollom-Carbide-Cutter-Stainless-Plastic/dp/B0B3XM5WSH

 

[Kram]

Easiest may be plasma with a template to guide the torch.
The knockout punches are on there advertised thickness limit.

Holesaws of that size will requite a slow speed, high torque drill, far too many teeth for the cutting diameter in my opinion, one of two teeth would work better. If you have a lathe it'd be fairly simple to turn a tube, cut a clearance gullet and braze a carbide or two on the end.

 

[Pete.]

84mm in 2mm steel is a lot of hole to punch. I'd go for a trepan.

 

[nickk]

89mm is 3.5”
Q- max wouldn’t cope with 2 mm,I’ve several of those up to 1.25”, they struggle with 1.5mm.

 

[fizzy]

Are the holes just holes? Sometimes, when they punch them out, they make a lip as well to add strength. Having said that, in 2mm it should be fine.
Which Ford is it?
Mate of mine had a Ford Mercury pickup from the 50s which he used in dragster events. Had a Chevvy V8 in there with straight through exhausts. Lovely job

 

[Ton-up]

A holesaw will do that no bother in a pillar drill, I cut 14 off 108mm dia holes in 3mm steel two weeks ago without trouble.

Standard holes on a 33 K member are like a elongated hole with a return.

 

[bricol]

I've hole-sawed a 5" hole in vertical 6mm stainless, in a pit, in a non-airconditioned building in an LA summer with a dewalt battery drill and a Starritt holesaw. Admittedly, the trigger unit failed soon after (Grainger supplied another trigger assembly cheap enough), but 80 ish mm in 2mm mild steel in much nicer conditions should be pretty easy.

 

[hotponyshoes]

Limiting factor with a q-max style punch us the bolt.
You can make things easier with a thrust bearing and lube on the threads.

If you just used the bolt as an alignment guide I'd expect a punch that size to do 2mm steel sheet in a hydraulic press easily enough.

I've done 3" in 3mm aluminium just with a thrust bearing and a driver.

If it struggles (and you have loads to do) make up a jig for drilling the center hole plus 2× small holes where the punch ends start.

And use lube.

 

[qwakers]

I have hole sawn 68 mm holes in 15 mm steel before now in a pillar drill. A good quality tct hole saw will do it fine.

 

[jo1010]

Are the holes just holes? Sometimes, when they punch them out, they make a lip as well to add strength. Having said that, in 2mm it should be fine.
Which Ford is it?
Mate of mine had a Ford Mercury pickup from the 50s which he used in dragster events. Had a Chevvy V8 in there with straight through exhausts. Lovely job

...
And radiused lips would be a stronger finished job too - and need a lesser diameter than 84mm too

 

[ndg]

Lots of replies already - thanks!

89 mm would be fine in this application - it's a hot rod, not a concours resto! I'd looked at the Q-max style puches but they seemed a little underspeced for this job.,

I think a carbide hole saw similar to the one mentioned (https://www.amazon.co.uk/Mollom-Carbide-Cutter-Stainless-Plastic/dp/B0B3XM5WSH) along with the pillar drill is probably going to be the route forward - as mentioned fewer teeth may be better to ensure decent tool pressure. If we do just the braces there will be ~20holes to do; if we do the frame boxing too it will be triple that I expect. Someone mentioned the oval holes - there are two of these each side to do which I thought a punch would cope with better than a holesaw, but as long as it's clamped down it should be okay.

Regarding radiused edges, I was hoping to make up some dimple dies to match the hole we end up with, shouldn't be too much bother and will make it look 100% more finished.

 

[Morris]

I've used a 100mm hole saw before in a milling machine. I put a couple of 12mm holes on the inside of the radius to allow swarf to get out, helps prevent jamming I feel. Take your time and it should go ok.
Long time hot rodder so yes, a '33 is interesting

 

[Turbo]

Make up a jig with a 89mm hole in it to stop the hole saw wandering and get more accurate holes.

 

[Ton-up]

Lots of replies already - thanks!

89 mm would be fine in this application - it's a hot rod, not a concours resto! I'd looked at the Q-max style puches but they seemed a little underspeced for this job.,

I think a carbide hole saw similar to the one mentioned (https://www.amazon.co.uk/Mollom-Carbide-Cutter-Stainless-Plastic/dp/B0B3XM5WSH) along with the pillar drill is probably going to be the route forward - as mentioned fewer teeth may be better to ensure decent tool pressure. If we do just the braces there will be ~20holes to do; if we do the frame boxing too it will be triple that I expect. Someone mentioned the oval holes - there are two of these each side to do which I thought a punch would cope with better than a holesaw, but as long as it's clamped down it should be okay.

Regarding radiused edges, I was hoping to make up some dimple dies to match the hole we end up with, shouldn't be too much bother and will make it look 100% more finished.

IMO you don't need a carbide holesaw. A good hss saw is better. This is a Kennedy 152mm i have used in a pillar drill. About as big as I would want to go as it overpowers the arbour!!

 

[timgunn1962]

The cheap Carbide holesaws will do the job. You'll want them turning pretty slowly so a pillar drill is best. Failing that, a slow handheld drill.

There are a couple of things you can do to help keep the holes round and tidy if you use a handheld drill. One is to drill the pilot hole first and then to use the holesaw with a piece of rod installed in place of the pilot.

The other, and my preference, is to holesaw a hole in a piece of scrap, remove the pilot drill, clamp the scrap to the workpiece in the correct location and run the holesaw through the workpiece using the hole in the scrap as an external pilot. I first did this when I needed some discs without holes in the middle, using bimetal holesaws and scrap 1/2" mdf. The holes turned out rather tidier than usual for holesawed holes. With the one-piece Carbide holesaws, the holes are pretty close to perfect. It's worth mentioning that some of the carbide holesaws, notably the Starrett ones, have the cut depth limited by a step on the OD, which might limit the choice of scrap thickness.

 

[Agroshield]

Make up a jig with a 89mm hole in it...

Make up a jig with an 89mm hole in it so you stop the hole wandering when you make up the jig suggested above.

Chicken. Egg.

 

[fizzy]

I much prefer a rotorbroach but not cheap in that size

 

[ndg]

Thanks all. I've done 80mm odd holes in 12mm steel before, so happy with that process. Was hoping for a faster way with the press, but recon I'm we're going to have to just plug away at it.