Thread: 7" cold cut metal circ blade in 9" saw?

All comes down to how much the blade protrudes through the base.
Generally, as far as I know, the RPM is about the same.

Stay safe!

What exactly do you mean by cold cut?

This term used to imply saws similar to to Brobo with HSS blades, generally fine positive rake teeth and flooded with coolant. These things run 25 to 100 RPM via worm drive gearboxes.

More recently it has also been used to describe CS toothed metal cutting blades to distinguish them from the cut off wheel type abradive blades.

Provided that the saw and blade match purpose, have corect mounting boss and RPM limits, and allow sufficient depth of cut you should be OK. But don't try putting a small Brobo style onto a hand held saw.

Richard,

Just off-topic for a second, one of the issues you are up against (theoretically...) is the temperature of the swarf that is produced during the cutting, because it is hot enough to discolour the sheeting if it is able to settle on it. That's why the purpose built units like the over-$500 Makita and co. have a little collector built into the guard that catches the swarf...

The solution is to make sure that the underside of the colourbond is face-up when you are cutting it so (also helps to avoid visible scratches from the baseplate...), and also to plan your cuts in such a way that you end up with the cut edges concealed under flashing or overlaps, etc.

No reason at all apart from arbor size that you couldn't use the 7" blade in the 9". As a matter of fact, the purpose-designed 184mm Makita "Cold-Cutter" (sorry Malb, you're dead-set correct about the Brobo's, but I don't know what else to call the Mak!) runs at 3500rpm, so your 9"er is probably going to run the blade better than your 7"er anyway...

Try to lay the sheet on the ground on top of some ad-hoc battens, especially with one just each side of where you're cutting, and keep the blade up so that it's just getting through the sheeting and that's all (except for an allowance for sagging in the sheeting), because as the stuff gets cut, it sags differently on the way out and can get caught-up on the exit teeth.

Wear goggles.

Good Luck with it.
Batpig.

Originally Posted by malb

What exactly do you mean by cold cut?

This term used to imply saws similar to to Brobo with HSS blades, generally fine positive rake teeth and flooded with coolant. These things run 25 to 100 RPM via worm drive gearboxes.

More recently it has also been used to describe CS toothed metal cutting blades to distinguish them from the cut off wheel type abradive blades.

Provided that the saw and blade match purpose, have corect mounting boss and RPM limits, and allow sufficient depth of cut you should be OK. But don't try putting a small Brobo style onto a hand held saw.

Weird timing, but I was just shooting a video for my website today of Triton's metal cutting saw - cold cut, no lubricant or coolant, runs a TCT blade (designed for metal), 4000RPM, resulting cut is cool enough to touch immediately.

http://www.woodworkforums.ubeaut.com...=tearing+sheet

The blades an Irwin I think, I'll check.

I usually tear the sheets and I will probably use the cheese wire method to rip, cut I need perfectly straight tops and bottoms on this job, so the wavy edge you get with tearing isn't going to do.

Thanks, as always for the advice.

Cold cut blades dont need lube with thin materials like tin, they shouldn't discolour colourbond(unless there's no carbide left...)

Hint, they do not like plunge cutting into flat material at all, make sure the blade cuts completely through the thickness of the tin's flutes with a few cm's to spare, ie dont use a 4~5" blade for corro, it wont last one cut without damaging the teeth because it hits the bottom of the flutes.