Help drilling holes for recovery swivels

I'm struggling with drilling the required 36mm holes in my Mantec winch bumper!! I've tried a hole saw which made a circular mark but wasn't man enough to go through. I bought a cone cutter but it's not big enough and I've been advised against trying it.

Basically I'm after giving someone local some beer vouchers if they have the right tool and are able to drill two holes in the flat face of my bumper for me either side of the winch. One side already has a small pilot hole and a circular scratch.

I'm just south of Leighton Buzzard, but would be happy to travel 15-20 miles or so if anyone can help?

James

Use a trepanning cutter

I'll look that up, not heard of one before. Thanks for the tip.

failing that get a milling machine cutter and fit it in a pillar drill or a router. and use lots of coolant

How about hiring a mag drill

I had to do the same on my ex disco, just used a hole saw and it cut fine through about 6mm of steel....

cant remember the brand though...

All you need is a decent HSS holesaw, I have used them for years for cutting through all different thicknesses of steel and not had any problems. I don't know how thick your Mantec bumper is (it's not over 4mm is it?) but just in case I suggest buying a couple (they are only about a fiver each) should you dull the edge. I would have thought the biggest problem was how powerful your drill is, your average pistol drill will get pretty hot as a holesaw can really drag so don't let it overheat.

Screwfix sell bi metal hole cutters that would do it. Although id recommend doing it with a pillar drill rather than a hand held drill. And whilst drilling, keep dabbing in some 3 in 1 oil. It will squeal and a bit of smoke, but it will cut the hole.

Failing that, you could get a pair of those series bumper gavanized bolt on towing loops.

As someone said use a new HSS one from screwfix keep putting oil on the cut but also put the drill in 1st gear and take your time or it will burn the holesaw out before you get through.
Follow these rules and the holesaw will last ages. I use them at work a lot you see.

Rich

Same as above, at work we cut through 10mm steel with a hole saws 46mm in diameter. Just plenty of coolant. A tip when you get 1-2mm in, put some of the swarf into the cutting groove as this seems to make them cut better.

I'm sure I replied to this thread but my post seems to have disappeared!

Fantastic, top tips! I'm off today so will try to hunt down the correct hole saw. Cheers all!

redhand said:

failing that get a milling machine cutter and fit it in a pillar drill or a router. and use lots of coolant

Click to expand...

Sounds a good way to damage the work and maybe hurt yourself

good quality holesaw is easiest, closest to above would be to use a rotabroach cutter in a very rigid drill or a mill assuming you can clamp correctly and true to the cutting axis