Grinding Wheels questions

Re: Grinding Wheels questions

hu lowery

Jorge,

I do remove the rubber feet since the Wolverine system is mounted to the base under the grinder. I want all of that to move as one unit or not move at all.

My grinder has two flats on the ends of the arbor so you can hold the arbor while tightening the wheel. If you don't hold the arbor in some manner it is pretty much impossible to tighten both wheels properly. You should have those flats on your grinder or some other manner provided to hold the shaft while you tighten the wheels.

Hu

Inertia?

John K Jordan

I fastened my woodturning grinder to a piece of thick plywood so I could mount fixtures and things to the plywood (Tormek support, Wolverine.) No rubber feet needed - there is no vibration with a Oneway balancer.

That grinder has no means to hold the shaft while tightening. I can get it tight enough on each side by taking advantage of inertia - snug with the wrench then hold the opposite wheel while gently jerking or bumping the wrench with the palm of my hand or a chunk of wood. The mass of the wheels and motor rotor keep things from moving for an instant. A few bumps does it.

A socket on a torque wrench would do this easily but at the risk of overtightening and cracking the wheel (which then might take your face off some day!)

I have considered using a Dremel to cut a big screwdriver slot on one end of the shaft but haven't gotten to it yet. I used to do that to remove stripped phillips screws a half-century ago in my motocross days.

JKJ

Re: Grinding Wheels questions

Jorge

Thanks hu

alas, my grinder has not such provision. I will try John suggestion.

new question

Jorge

Thank you John

This grinder is like that, no provision to hold the shaft, I will take to a machine shop and have them to cut the slots.

It is an 11 year old 1/2 hp Ryobi, very cheap, after it developed a serious shaking lately, I took the wheels off and figured out it had a shot wheel bearing. Had a shop replace both bearings and now that motor ha no vibration!

A new question: I bought a 1hp Rikon thinking of giving it CBN wheels.

The idea of rebuilding the Ryobi was to have one with grinding wheels and the other with the CBNs, so now that the Ryobi runs smooth, which grinder would you used for the grinding wheels and which for the CBNs?

Re: Grinding Wheels questions

robo hippy

A bunch of things to address here. First, especially for standard matrix wheels, you can over tighten them and crack them so that when you turn the grinder on, the wheel explodes like a bowl does when you have a really nasty catch. I hold the wheel I am tightening in my fingers, and tighten the nut up till the shaft starts to spin. If you add a slot or flat for additional tightening, again, you run the risk of cracking the wheel. If you have the CBN wheels, they are all on metal hubs and solid metal wheels, so no over tightening problems until you want to take them off.

I put up a review here a week or two ago about the new Rikon 1 HP slow speed grinder. First thing I do with it or any other grinder I use for my lathe tools is to take off the rubber feet. I want it attached firmly to the work bench. The feet on the cast base were 1/8 inch out of level, or if 3 legs were on the bench, the 4th was 1/8 inch up in the air. I ground it off so it would sit flat. I had to raise the Wolverine platform up off the bench top by 1 piece of 3/4 inch plywood under it. With most of the other grinders, you have to raise the grinder.

For power, most 3/4 hp grinders are sufficient for running CBN wheels. My 3/4 hp Baldor is a lot stronger then my 3/4 hp blue no name grinder that I got from Woodcraft many hears ago. Rikon does have a 1/2 hp grinder which is popular because of the cost, but I would worry that with heavy use, the CBN wheels would be too much for it.

robo hippy

Thank you Reed!

Jorge

You always have good advice.

Re: new question

John K Jordan

I just recently set up with my first two CBN wheels (one on the grinder and one on the Tormek) so I don't have much experience with this. I replaced the fine wheel on the slow-speed grinder wit a 250 grit CBN, thinking that I could use the coarse grinding stone for rough shaping. The 250 grit CBN wheel is so aggressive i could rough shape with it now, bot I understand it will tone down a lot after break-in so I'll wait and see before ordering another wheel. Reed Grey mentioned on his web site it took a month of use to break-in his wheel properly.

If one grinder is lower speed I might try that with a CBN first, assuming both have the same diameter shaft. I have read that some lower power grinders have trouble spinning up some CBN wheels due to the greater mass, so if that was a problem the more powerful motor might be best.

In recently studying VFD inverters to replace the failed one on my JET 1642 and at a suggestion from Harvey Meyer, I am on the lookout for a used 3-phase industrial grinder. Since setting up a VFD is no longer a mystery, I hope to set up a variable-speed grinder, milling machine, and possibly a drill press. Such a grinder would be amazing!

BTW, if you have a Dremel you can easily cut a screwdriver slot is a steel shaft yourseld with one of the small metal cuttoff wheels that Dremel sells. This should only take a few minutes. I use these a LOT, for everything from cutting ro shaping to sharpening bandsaw blades. (Wear safety glasses since they can break if overstressed.)

Re: new question

Jorge

Thank you John,

Yes, I will use the bigger slow grinder 1hp for the CBN.

Since I lost the grip on my right hand I shy away from using tools like the dremel , the foredom and the hand grinder. Lately I find myself using more and more all the old carving tools, I work with both hands on them, so is less likely I will hurt myself. Slowly training my left hand while keeping my right active.

I admire your getting into the VFD, I fear I will make things worse, then again, I have not put any time to study that.

Tonight I did put together the Ryoba again, much, much better that it was before, it is time to replace the wheels, they are worn down to 6 3/4" from 8"

Re: Thank you Reed!

Jorge

Reed,

I reassembled the Ryobi tonight, managed to do it just with my hands as you said. Hope it holds.

Much, much better that it was, the new ball bearings made a difference.

It needs new wheels, the old Norton's are down to 6 3/4".

Thank you!