Thread: Anyone use Rotabroach style hole boring

Have you thought about a super drill? I have used one and they work surprisingly well...

I really should make one.. The cutters are just square HSS ground to suit..

PracTool | Super Drill

lol A guy at Toowoomba was selling them, fairly rough on your drill but a good idea

Originally Posted by Pete F

My largest drill is 13 mm and I quite often find myself wanting to open up larger holes, either just in itself, or before boring. Rather than drill bits, does anyone use Rotabroach style cutters? Is there any special equipment used with the generic versions of these of can they also be turned in conventional jacobs style chucks?

Pete

7Pcs (18MM-28MM) HSS ROTA BROACH ANNULAR CUTTER SET MT2 - $199.00 : HandY Imports, Tools and Machinery

If you're talking about these things, I've got a set from that bloke - different size range though, I think my biggest is 38mm. Make beautiful long ribbons as they cut into the steel, work very well (IMO, anyway). The really good thing about them is you can cut off the edge of something, to make a semi circular hole (or you could use the offcut for a key to hold something on a shaft too, I guess).

I hold them in a 19mm collet on the Bridgeport (copy), I wouldn't be game to try using them in a hand drill of any sort - probably break your hand and the cutter... No reason you couldn't use them in a drill chuck on a drill press or mill though, they're just a 19mm straight shaft.

Incidentally, another name often used for them is annular cutters, if you go on the hunt...

Ok thanks for that, I've never seen them used, but seems like a better idea for larger holes than a twist drill. No I'd never consider trying to hand hold a cutter that size, however I think 19 mm would be beyond the capacity of many Jacobs style drill chucks.

Pete

Originally Posted by Pete F

Ok thanks for that, I've never seen them used, but seems like a better idea for larger holes than a twist drill. No I'd never consider trying to hand hold a cutter that size, however I think 19 mm would be beyond the capacity of many Jacobs style drill chucks.

Pete

Agreed. I have a JT3 chuck that takes up to 20mm, but it's certainly not a common size. Probably worth mentioning that there is actually a proper arbour to hold Rotabroachs (allows use of the ejector pin too), which if I remember correctly is MT2? Rotabroachs seem to have been designed for use in Mag Drills, so whatever taper they have is the one the arbour should have. If it's the same as ones drill press, could be another option - either make or buy.