rpm speed for cutting

[greystoke]

ok guys,

I'm basically new to working with sheet metal. This morning I was cutting down a panel to fit, I had a cutoff wheel mounted on a makita peanut angle grinder. This thing spins at 11,000rpm and just ate up the cutoff wheel I was using. It was also difficult to control. So my question is what are you guys using? Variable speed? if so what speed setting? Are all cutoff discs created equal? What are the best? Thanks for any help you can give.

[crushermechanic]

all wheels are not equal. you get what you pay for. the dewalt stainless cutting wheels are the best i have found at a store. i use sait or kronaflex brand that can be found at a welding supply house. be ready to pay for the good ones but they last 3-4 times as long. run the grinder wide open and get a wheel rated at a higher rpm than your grinder.

[chris mc bride]

probaly the wheel. I agree sometimes cheap is just that. As for rpm usually only a issue when cutting with metal blades and its not a one answer thing. the type metal your cutting and what your cutting with.example ss require less speed than a piece of mild steel.
Look for a metal working book or fabrication at any good book store.

[cableguy0]

I always use the 3?inch 3m cutoff on air powered cut off tools. After the first cheapie shatters and implants pieces of disk into your hand you learn quick to stick with quality brands. I have always had great luck with the 3m disks though. http://multimedia.3m.com/mws/mediawe...6EVs6E666666-- . I have a cheapie harbor freight air cut off tool and it works great especially for the 8 bucks it cost. If you kill one or two a year who cares its dirt cheap.

[donut]

Be aware, your discs "should" have a speed rating on them, personally I prefer a higher speed rating than the tool your using. IIRC, this goes for any grinding "rocks"

Like with a skillsaw blade, you only want to cut through (shallow), not plunge the wheel to full depth. Don't throw your extra wheels into the bottom of your toolbox, toss wrenches on them, and not expect them to be damaged.

[GRX]

I'd wager it's your technique as well. Are you cutting all the way through straight off? Best method is to cut a shallow channel along your cut line first. Then make progressively deeper cuts until you are through the sheet.

[mbgmike]

yEAH YOU GET WHAT YOU PAY FOR. WE USE NORTON MOST OF THE TIME WITH VARIABLE SPEED.BUT MOST OF THE TIME WE KEEP IT THE SAME HIGH RPM'S. SAFETY IS ALWAYS A FACTOR THATS WHY WE DON'T GO CHEAP

[greystoke]

i got some 3M cutting discs, they work decent. I was also checking out some video's of those air recip saws, those are pretty cool. Just depends and what your cutting. I'm just learning and made a large cut on top of my cab, one side got off a little because I'm short couldn't get a good view of my cutline. Next time I'll learn to put down some bluetape so it's easy to follow. It will turn out fine since i'm using panel bond rather than welding. I'll post pics of the whole repair on my build thread. Thanks a lot for chiming in gentlemen.

[cableguy0]

The other thing is dont push. Let the wheel cut at its own pace. you will feel it slide right through if your moving at the right speed. Dont force it thats what breaks wheels and causes bad things to happen.