Bench Grinder ??

My no name Woodcraft grinder (10 year old 3/4 hp) has developed a vibration. I did accidently "wreck" when sharpening a bowl gouge with the wolverine varigrind jig. I have one 8" steel CBN wheel and the wolverine system. I use the friable white wheel for shaping on the other side. Don't know If something is bent or what. It seems the Rikon would be the best choice, but open to ideas. never had a problem with the 3/4 hp motor and was wondering if the 1/2 hp Rikon would work or if the 1 hp is required. About $60 difference in price.

Edit: is it necessary to stay with slow speed or is 3450 rpm ok?

My old Dayton built C'man 1/2 hp has done everything I've thrown at it. 7" as well, and 3450 rpm. No probs with the higher speed as long as I don't get too aggressive.
Bill

I had one of the old blue no name grinders from Woodcraft years ago. It was 3/4 hp also. Comparing it to my 3/4 hp Baldor, the blue had much less power even though it had higher amp draw. I haven't used the 1/2 hp Rikon. It should be able to handle 1 steel CBN wheel. To me, it is still a bit under powered. I did get a 1 hp Rikon, and it has plenty of power to push 2 steel CBN wheels. I do prefer things to be over built... I did take the rubber feet off to bolt it down to some plywood for taking it to demos. I had to grind off about 1/8 inch on one foot to get it to sit flat though. It has about the same power as the Baldor. Not as good of a grinder, but for the price, a good tool.

robo hippy

I have the Woodcraft 8 inch slow speed grinder with a wolverine set-up and it works far better for sharpening chisels than my old No name 6 inch 3450 speed grinder. The 8" makes for a lesser hollow grind on the chisels when sharpening than the 6 inch 3450 speed grinder. My 8" slow speed grinder also has more power than my smaller one and it also, I think, causes less heat on the chisels when sharpening. Good luck on getting a new, better grinder for your shop.
Tim. :cool:

Before you give up on the old grinder take off the wheels and see if there is any vibration. If you have an indicator see if the shaft has been bent. If no vibration without wheels put the CBN back on and see what it does. If still no vibration take it off and mount the white wheel. If it vibrates then dress it until it is round again. That should tell you where the vibration came from. Now if you really want a new grinder skip the troubleshooting and go directly to the store. :)

I have the 1/2 hp Rikon and like it fine with one cbn wheel. But if you can swing the extra $60, why not grab more HP? It's like cars - a little more horepower than you think you need is never a bad thing (unless there's a gas shortage).

I use one of the old off-white Woodcraft no-name bench grinders, a Rikon 1/2 hp and a Rikon 1 hp, all half speed. The 1/2 hp is a bit under powered. I use an aluminum CBN wheel and a metal polishing wheel on it and it spins up OK. I've heard that someone with two steel CBN wheels had to give his some help by hand to get it started.

Before I gave up on the old grinder, I'd check the shaft with a dial indicator as someone mentioned, or a dial test indicator. If you don't have one you can rig a pointer indicator: rest something like a yardstick or longer on the top and near the end of the shaft, hold the end of the stick firmly against something to make a pivot point a few inches behind the shaft, then have someone rotate the shaft by hand while watching the end of the stick. Any runout on the shaft will be amplified and visible on the far end of the stick.

Also, check for side-to side runout on the both wheels. Perhaps a wheel was rotated some and the washer is not perfect. (I like to use the inexpensive spherical washers from Woodturners Wonders when mounting CBN) You might try mounting a different stone wheel if you have one.

I assume the vibration is not from something as obvious as a chunk of wheel missing after the crash. Does it run smooth with just one wheel at a time?

If the shaft is bent it might be repairable.

As for speed, I think the lower speed is best for hardened high-carbon steel tools to help prevent overheating. HSS and 10V tools can take the heat. However, I like the feel of sharpening with the 1/2 speed.



JKJ

Ok followed advice and the grinder is ok. Shaft runout is 0.002-0.003" that I would expect from the no name (white) grinder. The CBN wheel is a steel wheel with a insert. I did not see any damage to the wheel. When I measured at the inside rim runout was 0.025". The runout is in the insert. After rotating wheel/bushing the best I can get is 0.012". When I set everything up originally I used wood screws to secure the grinder to the plywood and also for the square arrachment assemblies. I redid all the plywood with new and used bolts through the table and longer wood screws for the square assemblies. Everything seem to be fairly decent now.

Note: when I was at the symposium I signed up for Glenn Lucas"s newsletter. He provided a tip on the wolverine locking mechanisms. If you switch the cams from one side to the other it basically makes it like new again in respect to locking the arms in place. I did that and yes, it works.

I'm glad it's working. If the bushing is not steel maybe it was deformed and could be replaced. The CBN wheels I get from Ken Rizza are bored directly for the arbor shaft.

Quote:

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Note: when I was at the symposium I signed up for Glenn Lucas"s newsletter. He provided a tip on the wolverine locking mechanisms. If you switch the cams from one side to the other it basically makes it like new again in respect to locking the arms in place. I did that and yes, it works.

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Interesting idea. All I have still work like new but that is good to keep in mind

Another thing about these cams that may be useful to someone. When I wanted to position to grinders (already mounted on plywood bases) close together the locking handles interfered and only one could be locked at at a time. I took the cam out of one and turned it around. Now one handle locks by pushing the handle back and the adjacent one on the next grinder locks by pulling the handle forward - both coexist peacefully in the same space.



BTW, I saw a different locking base design in a WoodCraft ad. Is this a new design OneWay is supplying with the Wolverine now? Anyone have experience with it?

https://woodcraft-production-weblinc...g?c=1480921309 https://woodcraft-production-weblinc...g?c=1480921309

JKJ

Quote:

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Originally Posted by John K Jordan

I'm glad it's working. If the bushing is not steel maybe it was deformed and could be replaced. The CBN wheels I get from Ken Rizza are bored directly for the arbor shaft.



Interesting idea. All I have still work like new but that is good to keep in mind

Another thing about these cams that may be useful to someone. When I wanted to position to grinders (already mounted on plywood bases) close together the locking handles interfered and only one could be locked at at a time. I took the cam out of one and turned it around. Now one handle locks by pushing the handle back and the adjacent one on the next grinder locks by pulling the handle forward - both coexist peacefully in the same space.



BTW, I saw a different locking base design in a WoodCraft ad. Is this a new design OneWay is supplying with the Wolverine now? Anyone have experience with it?

https://woodcraft-production-weblinc...g?c=1480921309 https://woodcraft-production-weblinc...g?c=1480921309

JKJ

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its a steel bushing. I bought this wheel years ago and at the time I'm guessing Hurricane was the cheapest, but had the bushing. I suspect when I first installed it I got lucky and hit the min runout. When I wrecked it it must have moved. Not sure about that new design except it would be easier to mount.

Edit: I now need to remake all of the set blocks for my chisels.
Attachment 365416

It seems like they go out of their way to make crappy inserts.

Quote:

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Originally Posted by John K Jordan

I use one of the old off-white Woodcraft no-name bench grinders, a Rikon 1/2 hp and a Rikon 1 hp, all half speed. The 1/2 hp is a bit under powered. I use an aluminum CBN wheel and a metal polishing wheel on it and it spins up OK. I've heard that someone with two steel CBN wheels had to give his some help by hand to get it started.

Before I gave up on the old grinder, I'd check the shaft with a dial indicator as someone mentioned, or a dial test indicator. If you don't have one you can rig a pointer indicator: rest something like a yardstick or longer on the top and near the end of the shaft, hold the end of the stick firmly against something to make a pivot point a few inches behind the shaft, then have someone rotate the shaft by hand while watching the end of the stick. Any runout on the shaft will be amplified and visible on the far end of the stick.

Also, check for side-to side runout on the both wheels. Perhaps a wheel was rotated some and the washer is not perfect. (I like to use the inexpensive spherical washers from Woodturners Wonders when mounting CBN) You might try mounting a different stone wheel if you have one.

I assume the vibration is not from something as obvious as a chunk of wheel missing after the crash. Does it run smooth with just one wheel at a time?

If the shaft is bent it might be repairable.

As for speed, I think the lower speed is best for hardened high-carbon steel tools to help prevent overheating. HSS and 10V tools can take the heat. However, I like the feel of sharpening with the 1/2 speed.



JKJ

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Thank you for your valuable feedback. I will take it into consideration when purchasing a bench grinder.