GMF 6'' Junior bench grinder

[jack620]

My dad gave me this grinder yesterday. It runs very smoothly, but even with the wheels fitted it comes to a stop within about 10 seconds, which seems very quick. Maybe the bearings are shot?

As you can see it has no guards, nor does it have any obvious way of mounting guards. Does anyone know if they were made without guards?

It has a 5/8'' arbor and looks like it is made to take 1/2'' wide wheels. You could squeeze a 3/4'' wheel on, but the outer flange would be riding on the thread which sounds a bit dodgy. This little fella may not be able to drive a 3/4'' wheel anyway.

I'm thinking of stripping off the old paint and hitting it with a spray can of blue/green hammer finish paint.

Any tips, tricks, warnings appreciated.

Jack

[pipeclay]

I have no idea at all but seeing there is no guarding or tool rests is it possable that this particular model would of been suited to buffing rather than grinding.

[jack620]

Could be. It doesn't have a HP rating stamped on it, but is rated at 2A. I guess that makes it about 1/2HP. Would 1/2HP be enough to do buffing with? Don't buffing wheels fit on a tapered spindle?

[pipeclay]

Most do but I have seen types of wheels that fit with use of flanges.
1/2 should be ok depending on how much load you were to put on it.

[neksmerj]

Good pick-up.

If there are drilled and tapped holes in the bosses at each end of the body, chances are it did have guards, now long gone. The tool rests would have been fitted to the guards.

Stopping in around 10 seconds might be normal without the momentum of grinding wheels fitted.

New bearings and a lick of paint wouldn't go astray providing you mask off the name plate.

Ken

[jack620]

Hi Ken,

the 10 seconds was with the wheels fitted. It's cold here today, and the grinder also labours when starting, even without the wheels. I think I know why. I removed one of the pressed steel cups from the side of the machine. Under the cup is a roller bearing which is packed with a very thick brown grease (it looks like Vegemite). The bearings are retained by circlips. I'll remove the bearings, clean & re-lube (or replace) them. Is grease the appropriate lube for grinder bearings?

There are 4 tapped holes in the ends of the castings, so it looks like the covers are long-gone as you suggest.

Jack

[new_guy90]

Bearings that have no grease run forever once the motor stops because they have no load from the grease, I would guess the excessive grease you mentioned may help stop it and its only a small grinder so the wheels wont have as much energy as say a 12" wheel

If it runs good then why play around with the bearings? why would it stopping fast be a problem :?

[Dave J]

I would pull it apart and clean the bearing out and anything else in there from sitting for so long.
6 inch grinders are cheap these days ($25-$50) so I would just buy one and use this to power something else or as a buff as said above.

Dave

[keltrader]

eBay purchase with guards attached with bolts to tapped holes on main body. Takes 50 seconds to stop spinning. Hope this helps. http://tapatalk.com/mu/c0947551-647e-ba8d.jpg

[steran50]

HI:) jack620,
Here is some Information that I found on Your Grinder http://www.titaniumstudios.com/tooljunkie/paper/MC1966-Grinding.pdf . Keltrader's Grinder looks liike it might have 3/4" Wheels on it - Hard to tell from the photo. If it does have 3/4" Wheels this could explain why it takes a while to stop. Bigger Wheels more momentum, so a longer time to get going and slow down or stop. I have a Chinese 6" Grinder (1.0 Amp) that takes about a 1 Minute to stop (had to count no watch) it has 20mm Wheels on it.
Grease is fine for the Bearings. I would certainly clean out the Old Grease and Relube them as the old Grease has probably gone a bit hard with age. Good luck with Your Grinder.

[jack620]

Keltrader,
thanks for the pic & info. So mine is definitely missing the guards.

Yours looks very nice. Did you buy it like that or spruce it up yourself? It looks like a 3/4'' aluminium oxide wheel on the right and a 1/2'' or 3/4'' carbide on the left. Is that right?

Stewart,
thanks for the link. I'll repack the bearings with grease if they aren't stuffed. How's the fishing at Malacoota these days? I need to get back there with the boat soon. It's the only place that I can consistently catch fish! First trip was 34 years ago as a kid. Last trip was 2 years ago with my own kids.

[keltrader]

Gave it a paint job. Mounted on base that has suction caps for portability and stability. 3/4 on right 1/2 on left. It's a general workhorse as I have four other dedicated grinders. Regards Kel.

[matthew_g]

Gave it a paint job. Mounted on base that has suction caps for portability and stability. 3/4 on right 1/2 on left. It's a general workhorse as I have four other dedicated grinders. Regards Kel.
Your as bad as me, I have 5 bench grinders all mounted with different wheels for different jobs...It's a pain trying to explain to people why I need so many

[steran50]

Your as bad as me, I have 5 bench grinders all mounted with different wheels for different jobs...It's a pain trying to explain to people why I need so many

HI:),
If You had another Two Grinders then You could Say that one is for Monday and That one is for Tuesday and so on.

[steran50]

Keltrader,
Stewart,
thanks for the link. I'll repack the bearings with grease if they aren't stuffed. How's the fishing at Malacoota these days? I need to get back there with the boat soon. It's the only place that I can consistently catch fish! First trip was 34 years ago as a kid. Last trip was 2 years ago with my own kids.

HI:),
The Fishing has been Good. The Tourists and Locals alike have been Catching plenty of Bream. The Flathead are off the Bite though until it warms up again. The Gummies were good over the Summer, but some had trouble getting onto the Ocean Flathead. They were getting Big Salmon (Salmon only good for Fish Patties I Say) near the Entrance area so I am told. We have had a lot of Rain lately and still more to come. The Water in the Lake has been up and the Water is a bit dirty now, because of the Rain up in areas like Bombala River Flowing down Stream into the Mallacoota Lake. I never seem to find the Time Myself nowdays to Go Fishing, I always seem to be to Busy.

[Dave J]

HI:),
If You had another Two Grinders then You could Say that one is for Monday and That one is for Tuesday and so on.

I have seven, 6 x 6 inch, and one 8 inch but a mate has been hounding my to buy one so I just sold it to him today. Does this mean I get a day off a week now.

Dave

[jack620]

Well I pulled it to bits, cleaned and re-greased the bearings and painted the casing. It now looks and runs great. Now I need some 150x13mm grinding wheels to mount on it.

As I'll be mostly grinding HSS lathe cutters and the odd chisel, I was thinking of going for a white alum oxide wheel. Norton make some fancy blue and pink wheels, but from what I've read about them they probably need some serious power to drive them given the aggressive grinding rate they give.

Anorak Bob posted a scan of a Norton brochure recently and it looks like Norton don't make a 150x13mm wheel in white alum oxide. They do make the pink, blue and off-white wheels in that size though:

http://www.woodworkforums.com/f65/norton-grinding-wheels-another-scan-135153/

Can anyone suggest which type & grit should I fit to each end of the grinder taking into account the 1/2hp rating and intended usage?

[Dave J]

Hi Jack,
H&F's have these ones
https://www.machineryhouse.com.au/Products?stockCode=G169

https://www.machineryhouse.com.au/Products?stockCode=G168

You could make a bush to bring it down to you spindle size, they may even come with one or sell them separately.

If not I am sure someone on here close to you could spin a couple up for cheap or nothing. I would do them if you where closer, but if you get stuck it will only cost you postage from me.

Dave

[jack620]

Hi Dave,
I saw those, but unfortunately they are 25mm wide. My little grinder only takes 1/2" wide wheels. Any wider and the outer flange is riding on the threaded part of the spindle.
Jack

[Dave J]

You can buy depressed centre wheels that can be used to grind on the side of the wheel as well. It would be the best of both worlds then as you could make up a tool rest on the front and one for the side.

Dave

[jack620]

Thanks Dave,
I've been searching for depressed centre wheels. Haven't found one in 150mm yet, but I'll keep looking.