im trying to fit a towel rail bumper on to super bumper brackets. i need to have square holes for the bumper bolts.
any ideas on where to buy square drill bits?:duh
or how to make square holes in the bumper, they will be re chromed in the future, so im not to fussed about heat marks etc.

Drill a small hole and get cracking with a small die grinder?

I think you will find they were punched from the factory. Unless you have a substantial hydraulic press and a good square punch the die grinder will be your best bet.

Or use a drill bit slightly smaller than the width of the square and file the rest out with a square file.

you can buy square hole punches.

Drill hole - put bolt through - do up and it "pulls" a square cutting bit through into a "block" on the other side.

Use to use them when i made switchboards

Mate.. I found that number for the chroming..
Modern Plating, Oakleigh Vic, 03 9568 4588 ask for Jimmy or Harry.. Very good work
Rob

Square file the way to go! Pre-drill first.

Dare I ask what your up to?

thanks stenguns.
what sort of places would sell those pullthrough punch's?
andy, im going hybrid 50's to 70's

You'll have to post some pics when done

they will go in members rides under "akean1's on its way"
http://www.aussieveedubbers.com/forum/viewthread.php?tid=34468 

Or alot of engineering or sheet metal places have large hole punch machines,
They usually have all sorts of dies..where I used to work years ago we had a machine for doing such things...amazing the thickness of sheet the can pinch through.
Obviously this will cost folding stuff.

Break out the file