3M 1.5HP Air Grinder - The Rolls Royce of air grinders

[Oscar]

I just got this baby today. Holeee Schikes! It is a bad piece of equipment! It's the biggest air-hog I own. It's pretty much a "dead short" to the compressor, aka it's like just opening a 1/2" air hose wide-open, no restriction. It brought my 10HP Polar Air 35 CFM air compressor to it's knees fast!







Highly recommended!

[ronsii]

I just got this baby today. Holeee Schikes! It is a bad piece of equipment! It's the biggest air-hog I own. It's pretty much a "dead short" to the compressor, aka it's like just opening a 1/2" air hose wide-open, no restriction. It brought my 10HP Polar Air 35 CFM air compressor to it's knees fast!







Highly recommended!

Nice!!!!!!!!!!!!!!


I always like to have at least one tool in a group that has *really* good power I'll have to look into that one

[Stick-man]

WOW! That is a piece of artwork!!! First, on something like that I would have a whip so the connection isnt rigid for such length. I have those same Milton connectors on my 1/2" air hoses too. Next, I have a cheapo air grinder I used to run off my tow behind diesel compressor, for smoothing out concrete when needed. I could spray water without worry. But I wouldn't think to use one for metal fab, over electric. Why did you get this one?

Also, if you don't mind, where did you purchase and how much?

[Oscar]

WOW! That is a piece of artwork!!! First, on something like that I would have a whip so the connection isnt rigid for such length. I have those same Milton connectors on my 1/2" air hoses too. Next, I have a cheapo air grinder I used to run off my tow behind diesel compressor, for smoothing out concrete when needed. I could spray water without worry. But I wouldn't think to use one for metal fab, over electric. Why did you get this one?

Oh it's a bad motherclucker alright! I'm highly considering an alternative to the Milton connectors, but who knows. For now I just ordered the same Milton fitting with a 1/2" NPT thread so I don't have to use that ½" → ⅜" reducer that is on there at the moment. I am also considering getting a Flexzilla 1/2" whip x 6ft long that has a swivel on one end (for the grinder end). That way that Milton coupler junction can be resting on the floor, or whatever. Another thing I was thinking was perhaps those Dixon style air fittings that twist together and interlock, with the R-clip. I'd still need to use a whip I suppose, but they seem pretty compact; and I'd have to add a ball-valve somewhere close by, for locking/unlocking the fittings. For now I'm gonna run with what I have.

My friend used to work for 3M and would rave about these grinders, so I just bought it for the hell of it to see if he was full of chit; which he usually is, but not about these.

[ronsii]

Did you look at the CP grinders? like the 3650 or 3850.... they got a bit more rated power than the 28824 3M but then again they would probably suck the life right outta your polar at 69CFM

[Oscar]

Did you look at the CP grinders? like the 3650 or 3850.... they got a bit more rated power than the 28824 3M but then again they would probably suck the life right outta your polar at 69CFM

The handle on mine is way better, so it's even.

[Lis2323]

Wow. That's a beauty.

Stickman beat me to the "whip hose".


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[whtbaron]

I wonder how it would compare to the lesser brands if you had to throttle it back for a 3HP compressor? Do you think it would still have the advantage, or would that just decrease the performance to the other brands? I had a Blue Point for years that I liked, but when I had to get it rebuilt by SnapOn it basically came back as a gutless air hog. Wish I'd put the money into a new one now. I think they charged me $350 for the rebuild. I need to take it apart some day and see what's going on. Either there is excess wear on the housing, or maybe it's something simple like stuck impellers that are too tight.

[Lis2323]

Not nearly as pretty as Oscar's but here's my old Nitto Kohki. Probably only around 1.1 HP.




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[whtbaron]

I couldn't find his on Amazon.Ca.... closest I found was a 1 HP extended body version for $470 Cdn.

https://www.amazon.ca/3M-Grinder-Ext...tionAndDetails

[ronsii]

I couldn't find his on Amazon.Ca.... closest I found was a 1 HP extended body version for $470 Cdn.

https://www.amazon.ca/3M-Grinder-Ext...tionAndDetails

https://www.ebay.com/itm/3M-4-1-2-He...IAAOSw-ktf3n-V

Says they ship to CA

[whtbaron]

Yep, they do .... and that puts me just shy of $700 Cdn.

[Lis2323]

Yep, they do .... and that puts me just shy of $700 Cdn.

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[filetobeef]

i like air tools but never really understood why the fanfare. noisy,needs compressor so even more noise,air hose gets in the way,not efficient and they stall more brutally than electrics.

understand out in the field where no electricity is available but in a shop? idk!

[ronsii]

Yep, they do .... and that puts me just shy of $700 Cdn.

Well then consider yourself lucky that these guys don't ship to CA


https://www.ebay.com/itm/3M-Grinder-...eE8~T#shpCntId

[ronsii]

i like air tools but never really understood why the fanfare. noisy,needs compressor so even more noise,air hose gets in the way,not efficient and they stall more brutally than electrics.

understand out in the field where no electricity is available but in a shop? idk!

They're great if you have big air.... you can't burn them up by stalling or overusing the motor you can use then while water is draining all over you from a tank you're working on without worrying about getting fried you can drive on the air hoses without worrying about shorting them or arcing then to something you can use then under a cat with dirt flying all over the place without dirtying up the motor and ruining it air has lots of plusses.... has some downsides too.... IF you're not set up for it

[Lis2323]

They're great if you have big air.... you can't burn them up by stalling or overusing the motor you can use then while water is draining all over you from a tank you're working on without worrying about getting fried you can drive on the air hoses without worrying about shorting them or arcing then to something you can use then under a cat with dirt flying all over the place without dirtying up the motor and ruining it air has lots of plusses.... has some downsides too.... IF you're not set up for it

I was gonna reply but you beat me to it. (plus you had a half dozen points I hadn’t thought of ). LOL


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[ronsii]

I was gonna reply but you beat me to it. (plus you had a half dozen points I hadn’t thought of ). LOL


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Oh Shoot!! I didn't mean to stop you from posting


And.. they're also handy for keeping your hands cool when it's hot out and the rest of you if it's got a rear exhaust

[Oscar]

I wonder how it would compare to the lesser brands if you had to throttle it back for a 3HP compressor? Do you think it would still have the advantage, or would that just decrease the performance to the other brands? I had a Blue Point for years that I liked, but when I had to get it rebuilt by SnapOn it basically came back as a gutless air hog. Wish I'd put the money into a new one now. I think they charged me $350 for the rebuild. I need to take it apart some day and see what's going on. Either there is excess wear on the housing, or maybe it's something simple like stuck impellers that are too tight.

It's all about the airflow. It would bring a 3HP compressor to it's knees pretty much instantly, unless said 3HP compressor is hooked up to a VERY large tank AND has time to adequately recover. Imagine hooking up a 1/2" or 3/4" air hose to said 3HP compressor and then using a ball-valve to open it out into the atmosphere with no restriction. How long until the pressure falls below say 80psi? I bet it would be pretty darn fast! that's what this grinder does, essentially. So technically the performance of the 3M would not decrease, for the few seconds it would have adequate air supply. It's like getting into the ring with Mike Tyson (in his prime). Sure you could last 30 seconds in the ring with Iron Mike if you run around, but when he does catch you.....you goin' down sucka!

[whtbaron]

Probably not where I'd go anyway... for the money your Optrel hood was a lot more tempting. I have the 9" corded DeWalt for big jobs and I don't use it much. You did shame me into checking out my Blue Point though. Sadly it doesn't look like there's going to be an easy solution. The vanes all seem to be free and working as intended, and any attempts to re-align the ports didn't seem to make any difference. It really should have went straight back to SnapOn when I had it rebuilt, but I'm about 6 yrs late for that now. I did check out the big CP grinder in my GS-2 catalogue and it's coming in at $600 Cdn. so not a lot cheaper.

[whtbaron]

i like air tools but never really understood why the fanfare. noisy,needs compressor so even more noise,air hose gets in the way,not efficient and they stall more brutally than electrics.

understand out in the field where no electricity is available but in a shop? idk!

My Blue Point is a light duty compared to Oscar's, but when I was working around autobody it was a lot more forgiving when things went south. Back then everyone was using those heavy old electrics and I saw more then one open faced disc get stuck into a cinderblock wall. My 9" DeWalt isn't much lighter to work with either, comparing technologies over 40 yrs. My DeWalt is also rated for 6,000 rpm, only half of Oscar's 12,000.

[whtbaron]

It's all about the airflow. It would bring a 3HP compressor to it's knees pretty much instantly, unless said 3HP compressor is hooked up to a VERY large tank AND has time to adequately recover. Imagine hooking up a 1/2" or 3/4" air hose to said 3HP compressor and then using a ball-valve to open it out into the atmosphere with no restriction. How long until the pressure falls below say 80psi? I bet it would be pretty darn fast! that's what this grinder does, essentially. So technically the performance of the 3M would not decrease, for the few seconds it would have adequate air supply. It's like getting into the ring with Mike Tyson (in his prime). Sure you could last 30 seconds in the ring with Iron Mike if you run around, but when he does catch you.....you goin' down sucka!

I'd still be curious to see how it would perform if you restricted the air flow to the point that the compressor could keep up. I suspect you might still have a superior grinder than the one built to run at those CFM's. but nowhere near the HP you have now. I was looking at my discs and they are only rated for 8500 so my discs wouldn't even work at your 12,000 rpm. Think I saw somewhere where they recommended a specific 3-M disc.

[farmersammm]

I have rear exhaust...........HOW COME IT DOESN'T KEEP ME COOL???????????????????????????????

[ronsii]

I have rear exhaust...........HOW COME IT DOESN'T KEEP ME COOL???????????????????????????????

I think we all know what.... oh nevermind you almost suckered me into that one

[Oscar]

I'd still be curious to see how it would perform if you restricted the air flow to the point that the compressor could keep up. I suspect you might still have a superior grinder than the one built to run at those CFM's. but nowhere near the HP you have now. I was looking at my discs and they are only rated for 8500 so my discs wouldn't even work at your 12,000 rpm. Think I saw somewhere where they recommended a specific 3-M disc.

Technically it should still work, but I suspect that if throttled-down it won't spin at 12,000 RPMs, which is what 4.5" discs/wheels should be ran at. So it might even be less effective than a less powerful grinder that is running 11,000-12,000 RPMs. And yes 3M's Cubitron II's excel in any grinder. You should try them. They're out of this world.

So you have 4.5" discs rated at only 8,500 RPMs??