Using a bench grinder as a polisher - overheating problems ?

[Khay]

Hi everyone,

Just a few days ago I got a bench grinder for my hobby use and my idea was to use it mostly as a bench polisher - got to thank Badger & Blade for an excuse to get yet another tool

The thing is, although it seems to be nice model (a Femi 33n, rated at 550W, 8" wheels, 2800rpm, weighs around 29lbs), I was using it with 6" stitched cloth wheels polishing an old straight I've been working on and after about 30 mins I noticed the machine's cast iron body was quite hot to touch - I could touch it, but I couldn't let my hand stay there for more than 1 second. Is this normal behaviour ? I know this machine is supposedly a "hobby grinder", not an industrial one, but I've noticed many people here do polishing work with bench grinders - and the manual doesn't say anything about a maximum continuous operating time.

So, am I doing something wrong by working with this thing for 30mins straight, anyone here ever felt they needed a fan pointed at their bench grinder for continued work, or am I expecting too much from a machine like this and it's normal for them to heat like that even if you're just polishing and not really overloading the motor ?

Thanks for your help!

[paco664]

they get hot... my grinder at work will heat up like that when i am doing a bunch of stuff... just aim a fan at it if your worried.... but them things are tough... let it run...

[Pkrankow]

I lapped a Black Surgical Arkensas on my Delta wet sharpener today, pretty toasty when I was done. All grinder bodies heat up. (Thanks Paco, finally got around to power lapping that thing, now to finish by hand)

Phil

[paco664]

I lapped a Black Surgical Arkensas on my Delta wet sharpener today, pretty toasty when I was done. All grinder bodies heat up. (Thanks Paco, finally got around to power lapping that thing, now to finish by hand)

Phil

those things are monsters to lap.... i consider it a punishment...

[Khay]

they get hot... my grinder at work will heat up like that when i am doing a bunch of stuff... just aim a fan at it if your worried.... but them things are tough... let it run...

Thanks Paco. I'll probably get some fan eventually and point it at the thing...

BTW, you are also one of the reasons I got the bench grinder - after seeing that video of yours grinding a kamisori :)

[ladykate]

Hi everyone,

Just a few days ago I got a bench grinder for my hobby use and my idea was to use it mostly as a bench polisher - got to thank Badger & Blade for an excuse to get yet another tool

The thing is, although it seems to be nice model (a Femi 33n, rated at 550W, 8" wheels, 2800rpm, weighs around 29lbs), I was using it with 6" stitched cloth wheels polishing an old straight I've been working on and after about 30 mins I noticed the machine's cast iron body was quite hot to touch - I could touch it, but I couldn't let my hand stay there for more than 1 second. Is this normal behaviour ? I know this machine is supposedly a "hobby grinder", not an industrial one, but I've noticed many people here do polishing work with bench grinders - and the manual doesn't say anything about a maximum continuous operating time.

So, am I doing something wrong by working with this thing for 30mins straight, anyone here ever felt they needed a fan pointed at their bench grinder for continued work, or am I expecting too much from a machine like this and it's normal for them to heat like that even if you're just polishing and not really overloading the motor ?

Thanks for your help!

Paco is the pro at the grinder.

FWIW - both my polisher ( a cheapo HF one) and my grinders (not so cheap) will warm up quite a bit. The polisher gets very toasty at times and if it gets too warm to touch, I let it cool. It's usually not a bad idea for me, anyway. Makes me reflect on what I'm doing.

My acid test with cheaper motors is if it smells hot, then it is. On other tasks, I've been known to burn out new Milwaukee impact drills (big ones) in the first 15 minutes of use. Drilling through concrete and brick is murder on anything I can afford. Did it twice in a row once. Those I figured out how to time - if there was a slight smell of plastic burning, then I had to give it a break. Thank goodness for warranties.

[SliceOfLife]

those things are monsters to lap.... i consider it a punishment...

Frictionite 00.

I'd lap A HUNDRED arkansas before I'd touch one of those beasts again. They are not of this world.

[paco664]

Frictionite 00.

I'd lap A HUNDRED arkansas before I'd touch one of those beasts again. They are not of this world.

i dunno.. that surgical black is just..... resilient...

[Pkrankow]

IDK, Black Surgical Arkansas cut rather well on the 1000 ish grit horizontal red wheel on my Delta wet grinder. I lapped both sides in about an hour, probably less. It has swirl marks so I need to lap it on paper next. How fine should I go?

Phil

[SliceOfLife]

I've done a few blacks. A couple vintage trans blacks. I've never seen one that was dished. I suppose gouges would be the only thing that would require a lot of material removal from one. You will never believe me on how hard a 00 is until you've lapped a warped one yourself. Trust me. I thought arks were the worst thing out there too... till I picked that monster up. It was inhuman. Lapping it with a 1200watt 4x24 belt sander with 60grit belts was like trying to scrape your windshield after a blizzard with a toothpick. Not even the same dimension of difficulty. It was more lapping the belts with the 00 than vice versa. I think eventually it got bored of entertaining me and just pretended to be flat so I'd stop wasting its time. It was literally a process that took me a couple months. An hour or two here. Another hour or two there. When I ran out of belts I went to my Coarse DMT, until I could go get more.

[Wetshavemike]

Nothing to worry about. All motors get hot, and a bench grinder has no holes to vent the motor and/so it doesn't need any. Grind/buff/polish away!