Epoxy and machining Slow Speed Grinder Flange?

[Brad Pittman]

After many years of struggling with a wildly vibrating 6" grinder, I decided to purchase an 8" from WoodCraft. However, the more I read on the subject, the more I realize I'm going to be disappointed with the WC grinder performance as well. I will be doing some upgrades including machined washers, steel bushings, and diamond truing (I'm going to make a diamond cutter like the Geiger).

The only thing I haven't figured out yet is how to better the arbor flange. I've read as many threads on the subject as I can find and no one offers the solution I think will be best (other than trying to find some machined flanges that will fit).

I've fixed several arbor flanges on other machines (namely table saws) using a carbide bit, a mock tool rest, and a steady hand. It has worked very well. The only issue I see with doing this on the new grinder is that (at least from the grinders I've used) the flange is not fixed to the motor shaft.

My idea is to epoxy the flange to the motor shaft (as perpendicular as possible), and then turn the flange true once the epoxy sets.

Anyone else attempted something like this (and/or has other tips?)?

[Roger Chandler]

I think what you are proposing to do is overkill, and not neccessary as far as the flange. I know many turners who have the WC 8" slow speed grinder and have super good results with it. Yes, you might have to true the wheel, and I would recommend the drill bushing from McMaster Carr, and you should be good for a while.

If you are going to use a frangible wheel, the Norton 3X blue ones are about as good as they come, but if you really want to make a grinder perform for turning tools, then you cannot beat a CBN wheel.

[Brad Pittman]

Would you get the bushing from McMaster that has the Head/flange on once side? Seems like it would make sense, but I haven't heard anyone doing that

[Reed Gray]

Dave at D Way can make you a machined bushing and flange for your wheels. The plastic bushings that come standard with most wheels are junk. A machined bushing will take care of a lot of run out. Best bet is to get CBN wheels. They are spin and bubble balanced and run true right out of the box. No need to balance, true up, or clean, ever. They are sold with a bushing. A machined washer won't do any good if you are riding on a plastic bushing.

robo hippy

[Brad Pittman]

I plan to replace the plastic bushing with a machined bushing. I was just inquiring, primarily about the arbor flange.

I'd love to have a CBN, but can't justify the cost.

[Roger Chandler]

Brad, when I got my bushing I got the headless one. I don't see why one with a head would not work, provided that you have enough arbor to allow the threads to take on the nut and tighten down good.

[Brad Pittman]

Does anyone have a good idea how long the CBN wheels last?

[Jeffrey J Smith]

Does anyone have a good idea how long the CBN wheels last?
Dave at D-Way also sells turning tools - gouges and scrapers - all are shipped sharp. He uses his CBN wheels for all production sharpening and has been using the same wheels for well over four years. I don't know how many gouges and scrapers have been sharpened on those wheels (from initial profiling to final sharpening), but I'd figure it's got to be the equivalent of several lifetimes of my going to the grinder to touch up an edge.
I've never heard of anyone wearing one out in normal turning use.

[Brad Pittman]

Oh man, now I really want the CBN. Everything I've seen and read. Awesome stuff.

[Mike Cruz]

Brad, I couldn't justify the cost, either. Until I got one. Loved it so much, I got a second one for the other side of the grinder. They really are THAT awesome.

[Reed Gray]

Like Mike said, once you get one, you will understand. They are worth every penny. They will outlast by far any comparable dollar amount of any wheel available. Add in the safety factor of there being no risk of them ever blowing up, if you have the money get a 180 grit first.

robo hippy

[Thom Sturgill]

The OneWay balancing rig includes flanges and arbor bushing. However, at $70 that is a major portion of the cost of the CBN wheel. Add in the cost of a Geiger or OneWay dresser and a Norton 3x wheel and you have paid for a CBN wheel.

[Leo Van Der Loo]

After many years of struggling with a wildly vibrating 6" grinder, I decided to purchase an 8" from WoodCraft. However, the more I read on the subject, the more I realize I'm going to be disappointed with the WC grinder performance as well. I will be doing some upgrades including machined washers, steel bushings, and diamond truing (I'm going to make a diamond cutter like the Geiger).The only thing I haven't figured out yet is how to better the arbor flange. I've read as many threads on the subject as I can find and no one offers the solution I think will be best (other than trying to find some machined flanges that will fit). I've fixed several arbor flanges on other machines (namely table saws) using a carbide bit, a mock tool rest, and a steady hand. It has worked very well. The only issue I see with doing this on the new grinder is that (at least from the grinders I've used) the flange is not fixed to the motor shaft. My idea is to epoxy the flange to the motor shaft (as perpendicular as possible), and then turn the flange true once the epoxy sets.Anyone else attempted something like this (and/or has other tips?)?Brad, new flanges or truing yours would be quite simple IF you had a metal lathe, or a good buddy had one, anyway, if you have a piece of machined tubing, steel or brass you could pinch the flange to the shoulder of the grinder shaft, and then true it up, mark both the flange and shaft so you can locate the exact place afterward.You also could get these flanges, though I don't know how accurate they would be, HTH.http://routerbitworld.com/Freud-SC-001-Saw-Blade-Stabilizers-With-5-8-Bore-p/freud%20sc-001.htm

[Brad Pittman]

Well, I tried to put new bushings in the wheel - disaster. I was under the impression the wheel had a 1" arbor hole. I tried to press in a 1" bushing from McMaster Carr and, against my better judgment (as I knew it seemed too tight), cracked the stone in half. Upon further examination, the wheel appears to be metric - with a 25mm arbor hole (which is just smaller than an inch). So mad!

[Dick Mahany]

The OneWay balancing rig includes flanges and arbor bushing. However, at $70 that is a major portion of the cost of the CBN wheel. Add in the cost of a Geiger or OneWay dresser and a Norton 3x wheel and you have paid for a CBN wheel.

Excellent point and I know this from experience :o. Now I have a CBN wheel and won't ever look back.

[Michael Poorman]

Am I the only one that didn't have any trouble with the WC grinder? I upgraded the platforms (which I would link to but might get in trouble...) and just used a diamond hone to true up the wheels. The grinder runs really true and smooth.

Now, would I get the CBN wheels if I felt like spending the money? Sure, but my friable wheels are working just fine. Maybe I'm lost in the dark here...

[James Cheever]

Plus 1 on getting the CBN wheels from Dave at D-Way. I got the radius edge ones. With arbors it was almost $500 but worth every penny. I have the WC low speed grinder and it runs like a top with the CBN wheels.

[Leo Van Der Loo]

Brad, What keeps the saw-blade straight on the saw, ??, no not the bushing, as I'm sure you know that, it is the flanges, the same thing counts for grinder wheels.

I've had enough experience in metal working shops to tell you that the bushings aren't the ones to do it.

Years ago the grinder wheels did get lead in the wheels to center the wheel on the grinder arbor, nowadays it is often plastic and some have several layers so you can fit them to different size grinder arbors, still these things are for just centering the wheel, not to keep them perpendicular to the shaft, if the flanges are not doing the work.

There were always machined flanges on the grinders, machined from thicker steel, they fit the arbor precisely and keep the wheel square on the arbor, but to make more profit this was stopped and replaced with stamped out steel washers, they just aren't able to keep the wheels properly aligned on the grinder.

If you buy the Oneway balancing set, it is made with machined flanges, just for that reason, and then also has a means to balance any weight difference there might be within the wheel, but it is the machined part that is the real reason the wheels run true.

I do not understand why anyone would spend $500.-- to grind some turning tools, though it is their money, my tools cut just fine sharpened with ordinary carborundum wheels, done that for some 60 years on all kinds of HSS machining tools.

There are steels that need different grinder wheels, but the HSS that are used for turning wood do not need these special wheels, and carbide would need diamond to do a nice job, oh well, I also still live in the dark I suppose :rolleyes: :D

[Brad Pittman]

Leo, that is the most informed post I've seen on the grinders yet. It's clear that the new (relatively cheap) grinders have had some corners cut on them. I agree that the flange should keep the wheel (blade, etc) perpendicular to the shaft. However, I still think the bushing should be a rather snug fit to help keep the wheel in place in relation to being centered on the shaft. The bushings that came on the WC grinder I bought had a ton of slop. Pitiful, really. I think I can true up the stamped steel flange just fine. I also bought some machined washers from an old radial arm saw to put on the outside of the wheels..

[Leo Van Der Loo]

Brad the new wheel has to be dressed to round, and again as the wheel gets plugged up or glazed over, you will have to do this no matter how well the bushing fits.
The stamped steel washers just don't have enough thickness to do the job Brad, they still can wiggle or wobble on the shaft easily, that's just the problem with the sheet metal they are made out of, if they are thicker they sit right square on the shaft and up against the machined shoulder of the grinder shaft :).

[Brad Pittman]

The dressing will be addressed (I have the diamond bit in hand). I'll post when complete!

[Brad Pittman]

Ok, after spending more hours than most of you think are sane, I've finally got a grinder running very true. After removing the stamped steel POS flanges, I noticed the shoulders of the motor shaft they sit on to be fairly mangled (7 thousands run-out because of it on right side, not so much on left) . So, first things first, I strapped the grinder to my lathe bed, installed a carbide bit into my homemade Oland tool, turned the grinder on, and trued up the shoulders. Worked beautifully.

Next, I epoxied the flanges to the motor shaft using a machined washer, a machined bushings and a nut to hold it as square and tight to the shoulder as possible. Once that was set, I measured run-out on the flange to be about 7 thousands on both sides. Again, I mounted it to my lathe bed and went to work. The run-out now is less than 1 thousandth and the wheels run extremely true!

Next up, need to build a diamond dressing tool (mimic the Geiger), and dress the wheels to concentric.
279934279935279936279937279938279939

[Brad Pittman]

I also ordered new wheels that will accept the machined bushings I bought from McMaster Carr

[jack forsberg]

Leo is bang on the flange is what runs the stones true. And on grinders there fairly bad most of the time but can be tuned by hand to with in less than .001 run out. Use the nut with just a bushing to hold the flange on to dress the face of the flange.

here is how i did it


http://www.youtube.com/watch?v=JHr9M-87WJ8

http://www.youtube.com/watch?v=JUFPdYdqLsg
http://www.youtube.com/watch?v=E12I1sF_CDg
http://www.youtube.com/watch?v=YbJTLuDrv9Q
http://www.youtube.com/watch?v=pSwMrs4r3y4

[Reed Gray]

On the third clip, with the nickle on the table, when the grinder is turned off and slowing down, you can see that there is run out on the inside of the flange. The face is true. This interior run out will cause some vibration because while the flange face is true, it is not balanced. Advantage to CBN wheels, they are spin and bubble balanced. Any stamped washers or flanges are just about as bad as the plastic bushings. I put some on my grinder to space the wheels out a bit, and the wheels would have lateral run out till they were up to speed, but then ran pretty true. I had some machined washers made (5/8 inch thick for my Baldor grinders), and they ran true.

robo hippy

[jack forsberg]

that video was my balance video. i drilled a few more holes in the flange where i took less off until the nickel did not fall over. low teck but effective.




On the third clip, with the nickle on the table, when the grinder is turned off and slowing down, you can see that there is run out on the inside of the flange. The face is true. This interior run out will cause some vibration because while the flange face is true, it is not balanced. Advantage to CBN wheels, they are spin and bubble balanced. Any stamped washers or flanges are just about as bad as the plastic bushings. I put some on my grinder to space the wheels out a bit, and the wheels would have lateral run out till they were up to speed, but then ran pretty true. I had some machined washers made (5/8 inch thick for my Baldor grinders), and they ran true.

robo hippy

[Leo Van Der Loo]

Well done Brad, hat off to you for persevering, it is just not good enough that we have to do all this work, and companies can get away with this shoddy work, good luck and happy sharpening and turning :)

[Brad Pittman]

No doubt. It is shameful the product some of these companies are selling. I would have expected a premium product from Woodcraft. This grinder belongs at Harbor Freight! I feel like I should document my hours and costs and send WC a bill!