CBN pre-Purchase Questions

[Mike Goetzke]

Today I pick up a commercial grade Dayton grinder. It's in great shape and starts the matrix wheels in I'd say 2 seconds, very quiet, and no vibration. Quite a step over my 1/4 horse Craftsman. I want to install probably two CBN wheels on this beast.

I see a majority of turners choose 80/180 grit combo if purchasing two CBN wheels (if there are others that chose different combo please comment advantages/disadvantages).

Looks like most purchase from D-Way or Woodturnerswonders and the latter supplier offers a 4 in 1 wheel. For those that have it is it worth the extra cash?

I would like to possibly use both halves of the wheel cover for dust control. I realize depending which jig system I use this may not work. But looking for ideas and suggestions from others how this would best be done.

My grinder has a 5/8" shaft with a step. As received there was a bushing with a flange that slid over the larger diameter step with flange facing outward. When I slide on this bushing it seems to stop at the inner race of the bearing and the face of the flange is proud of the step on the shaft. Then there is a cupped large diameter washer that stops against the bushing flange and has a small keyway that seems to be driven by the small roll pin in the 5/8" shaft. Next the wheel goes on then a large cupped washer and nut.

I'm wondering why the fanged bushing is used? Seems like the inside cupped washer could be stopped by the step on the shaft and still driven/guided by the roll pin????

http://img.photobucket.com/albums/v212/mbg/Wood%20Turning/Grinder/IMG_1269_zpswxnmsupi.jpg (http://smg.photobucket.com/user/mbg/media/Wood%20Turning/Grinder/IMG_1269_zpswxnmsupi.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Wood%20Turning/Grinder/IMG_1270_zpstssiirpb.jpg (http://smg.photobucket.com/user/mbg/media/Wood%20Turning/Grinder/IMG_1270_zpstssiirpb.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Wood%20Turning/Grinder/IMG_1275_zps4rkzovyt.jpg (http://smg.photobucket.com/user/mbg/media/Wood%20Turning/Grinder/IMG_1275_zps4rkzovyt.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Wood%20Turning/Grinder/IMG_1273_zpsmjb6vzfp.jpg (http://smg.photobucket.com/user/mbg/media/Wood%20Turning/Grinder/IMG_1273_zpsmjb6vzfp.jpg.html)
http://img.photobucket.com/albums/v212/mbg/Wood%20Turning/Grinder/IMG_1271_zpsssu3caot.jpg (http://smg.photobucket.com/user/mbg/media/Wood%20Turning/Grinder/IMG_1271_zpsssu3caot.jpg.html)



To me looks like I need to get rid of the roll pin and add about a 1/8" thick washer against the step on the shaft (or apply that flanged bushing and the washer stops against it), CBN wheel, washer (maybe spherical assembly), and nut. This would allow space to use the outside wheel cover. Or am I looking at this wrong and need to apply some other hardware?

Do I need the roll pin and inner cupped large washer with keyway? Or can I get rid of the roll pin and use friction to spin/drive the wheels? Doesn't look like other grinders use a key or pin to drive the CBN wheels that I have seen on youtube or suppliers web sites.


(Reed Gray has helped me a quite a bit with my questions by PM but thought my questions could help others in the future by posting here)


Thanks,

Mike

[Ralph Lindberg]

I only have a 180 CBN and if I only had one grinder, I would recommend only one wheel. I have a white (regular) 120 grit on the other side and I used that for about an hour today, grinding "mild steel". Something you really don't want to do on a CBN.

I have D-Way wheels (also what I recommend) and I didn't use the cupped washers, actually wouldn't have had the shaft length to use them

I do have rare-earth magnets around the CBN to catch the "fines" from grinding.

[Reed Gray]

The flange bushings are for flat wheels, and will not work on the CBN wheels because they are turned down and have a small hub, then the hollow. I have been trying to decide if I need a 600 grit wheel for essentially honing a burr onto my scrapers..... Curiosity is dangerous to the pocket book....

You could send your photos to either maker, and they can help you out for what will fit your grinder. No idea if you will need a custom hub or not.

robo hippy

[Mike Goetzke]

Ralph - thanks, guess I will keep my smaller grinder for mild steel.

Reed - great idea! I just cut/pasted/edited my post and e-mailed it to the vendors.


Thanks,

Mike

[John K Jordan]

Ralph - thanks, guess I will keep my smaller grinder for mild steel.

I did that too, more or less. I put a conventional wheel plus a metal polishing wheel on a 1/2 hp grinder, two CBN wheels on a 3/4 hp grinder, an 80 grit and a wire brush on the big Metabo, and a 600 grit CBN on a Tormek. This lets me grind about anything the way I want it.

[Harold Walsh]

I ordered mine from Woodturners Wonders before Christmas. I purchased the 80 and 350 grit which was recommended by the owner who is also a woodturner.Both are quality products and love the finish the 350 provides on the gouges.

[hu lowery]

Woodturners Wonders took good care of me when I purchased a 220? grit wheel and a 350 grit wheel. The coarser grit one is the four in one wheel while the 350 grit is the flat wheel with sides radiused. The four in one is handy any time you want a flat on tool steel. I sharpened a skew or two flat instead of hollow ground, the relief of the hollow grind makes it much easier to cut an outside radius in my opinion. Would have to learn to swing a good bit more for the flat grind, plus it needs to be a sharper angle too since the hollow grind just measured at the top and bottom gives a false reading of the true edge bevel angle.

I have sharpened my cabinet scrapers on the 220 grit wheel with no obvious loading up, can't say it won't. Reed probably already knows but the burr from the 220 grit wheel would probably let me turn a bowl! Mounds of wide incredibly light and soft shavings.

I was a little concerned that the 350 grit wheel would be too fine. I find it very easy to do minor reshaping on it so I'd say no complaints on that score. The four in one wheel is excellent for sharpening pencils. No indication of any issues and the graphite should make a little lubricant! :D A minor issue I have, One edge hasn't seen enough use to be broken in and the wheel seems slightly unlevel across the face. I think this will disappear once it is broken in completely, a matter of not using that wheel near as much as the 350 grit which is what I do almost all of my touch up on. I didn't take time to remount my Wolverine bases a little further out so they are no longer quite centered under the wheels making me use one side of both a little more than the other.

While another grinder or swapping wheels would be needed for grinding mild steel or many other metals I am very happy with my choice of wheels even on a very lightweight grinder. It comes up to speed in maybe ten seconds or less, best I remember it takes a little over six minutes to stop from full speed and this grinder doesn't have high dollar bearings in it like yours probably does.

Reed, run out and buy the 600 grit, we need a good report! I'm pretty sure I would be happy with it in place of my 350 although I am pleased with the 350 too. Hmmm, tool sale day at my local club this month. Wonder what I could get for a lightly used 350 grit wheel? The six hundred grit is calling, calling, calling my name . . .

Hu

[Peter Blair]

I too have a cheaper grinder for other work but I have two 180 grit CBN wheels. One side is the wolverine system while the other uses a Robo Rest thus the two same grit wheels. I use the Wolverine for gouges and skews and the Robo rest for all the rest. It really excels for me when I need to sharpen small 1/8 in high speed steel tips etc.

[Mike Goetzke]

Thanks for all the comments. Especially I was confused as to get 4-in-1 wheels or radius one and see I could get one or each.

I reached out to the two suppliers as recommended and received emails from both but actually got a phone call from Ken at Woodturners Wonders on Sunday afternoon. He took the time to go over the pictures of my grinder configuration determining what spacers etc. we're required and somehow I ended up purchasing the wheels before I knew it. I've heard nothing but good things out of D-Way but Ken at WW was unbelievably helpful.


Mike

[John K Jordan]

Reed, run out and buy the 600 grit, we need a good report!

I'm not Reed, but I have been using a 10" 600 grit wheel from Rizza on my Tormek for several months now. It is not very useful for shaping, which I do on a coarser CBN wheel, but it is good for restoring a sharp edge. Use consistent settings in a jig and it takes about 3 seconds to sharpen and removes very little material. Gouges should last a lifetime.

It does not make as smooth an edge as the Tormek water wheel but it cuts fine. I'd like to try one of the 1000 or 1200 grit wheels on the Tormek.

JKJ

[John K Jordan]

confused as to get 4-in-1 wheels or radius one

Mike, I have a radius-edged wheel and a square edge wheel, both with grit down the flat sides for about an inch. I just got the square edged one a few days ago but already like it better than the radiused wheel. The radius would be better for sharpening the very small scraper cutters often used in hollowing systems, IF they are permanently fastened to long handles. That's the only use I see for the radius. I don't do much hollowing and I can always sharpen them the traditional way. The square edged wheel does give you a wider face and wider sides since the flat surfaces are shortened by the radius.

Note that Ken can order almost any type of wheel with any grit you can think of, it just takes a few weeks. Maybe all the dealers can do the same, I don't know. He now carries flat 2-siided CBN honing plates too, any grits. They are like the common diamond sharpening plates except wider than any I've seen.

At the risk of sounding like a salesman for Ken, I must report that I also like the LED lights he carries. An extra long gooseneck, strong magnet, very bright.

And yes, what a helpful guy!! My last order came in in the middle of last week and instead of shipping it he brought it to me at the TAW symposium and handed me cash to refund the shipping cost.

JKJ

[Tom Albrecht]

I have a new 8" Dayton VS. I have the Woodturner Wonders set of wheels and I leave both the inner and the outer guards off the machine. You won't be getting dust and grit from CBN wheels, and they won't blow up in your face either.

I kept my old HS Jet grinder for general shop grinding of softer steels.

[hu lowery]

I'm not Reed, but I have been using a 10" 600 grit wheel from Rizza on my Tormek for several months now. It is not very useful for shaping, which I do on a coarser CBN wheel, but it is good for restoring a sharp edge. Use consistent settings in a jig and it takes about 3 seconds to sharpen and removes very little material. Gouges should last a lifetime.

It does not make as smooth an edge as the Tormek water wheel but it cuts fine. I'd like to try one of the 1000 or 1200 grit wheels on the Tormek.

JKJ


Thanks a bunch! Judging by how my wheels work now my next one, assuming a next one, will be above the 350, finer grit. The 350 is fine but I get the impression I could go to a finer grit for just sharpening. Sure is nice to see that new metal shine edge to edge after just touching the gouge to the wheel for a second or two.

Hu

[Reed Gray]

Okay, it is all of your peoples fault, I have a 600 grit on the way... Yes, I am familiar with the old song line, 'The Devil made me do it the first time. The second time I did it on my own... (Black Rose, Waylon Jennings does a version of it, song about a woman)' I did a shear scraping demo for our club last week, and of most interesting note was a piece of highly figured maple baseball bat/rolling pin blank. Tear out with skew and yes that could be my skew skills, tear out with continental style roughing gouge and regular roughing gouge, almost no tear out with 180 grit wheel scraper burr, no tear out with burnished burr scraper. I have always figured that the CBN wheels in particular kind of burnish a burr when sharpening. A honed burr is a bit finer than a regular wheel burr, so, it remains to be seen.

I do have a couple of his magnetic lights. Pretty good actually, but for my bowl turning, they are more of a spot light, so I love them at the bandsaw for following scribed circle lines, and at the drill press for drilling out the centers of my bowl blanks for the forstner bit expansion holes. They just don't broadcast enough light to see the whole thing without having to stop and move it.

Tom, the metal dust drifts every where, just like wood dust. One turner had a magnet set up 10 feet away, and it collected metal dust. I found some inside a box around a magnetic base...

Report in a week or 4.

robo hippy

[Mike Goetzke]

Oh boy, the flat hobby was bad enough but this round stuff has really turned me into a toolaholic. My new CBN wheels from Woodturners Wonders came in these beautiful bluish/purple boxes that aren't suited for a tool but expensive jewelry. But after I pulled one of the wheel out I thought - this looks like a fine piece of jewelry! So I go out into the shop and put one wheel on the old bargain Dayton grinder I bought (to save a few dollars) and didn't have the heart to put the second one on last night. So this afternoon I rushed off the WC to pick up one of those new Rikon slow speed 1HP grinders. Now my wheels will have a much better home.

Mike

[Alan Heffernan]

Oh boy, the flat hobby was bad enough but this round stuff has really turned me into a toolaholic. My new CBN wheels from Woodturners Wonders came in these beautiful bluish/purple boxes that aren't suited for a tool but expensive jewelry. But after I pulled one of the wheel out I thought - this looks like a fine piece of jewelry! So I go out into the shop and put one wheel on the old bargain Dayton grinder I bought (to save a few dollars) and didn't have the heart to put the second one on last night. So this afternoon I rushed off the WC to pick up one of those new Rikon slow speed 1HP grinders. Now my wheels will have a much better home.

Mike
Keep us posted on their installation of the new Rikon. I have one I bought in December and it's equipped with Norton discs at the moment and hoping to swap them out real soon to CBN. I for one will be very interested in how this works out on the Rikon.

Did you buy the spherical washers? I saw a pair of these on a cheaper grinder recently and one was wobbling very badly. I assume it was the installers fault. I did not have the heart to point it out or ask.

I have been considering these or D-ways. By the way, I sprung for a Robo Rest already.

[Mike Goetzke]

Keep us posted on their installation of the new Rikon. I have one I bought in December and it's equipped with Norton discs at the moment and hoping to swap them out real soon to CBN. I for one will be very interested in how this works out on the Rikon.

Did you buy the spherical washers? I saw a pair of these on a cheaper grinder recently and one was wobbling very badly. I assume it was the installers fault. I did not have the heart to point it out or ask.

I have been considering these or D-ways. By the way, I sprung for a Robo Rest already.

There are a few that have this grinder - do a search (at least Reed Gray and David Delo have it).

Yes - I bought the spherical washer set. The ID is a little big so that's why you saw the wobble but I doubt it hurts anything. Ken at Woodturners Wonders has a video on their application.

Mike

[John K Jordan]

he ID is a little big so that's why you saw the wobble but I doubt it hurts anything.

When I asked, Ken told me the ID is oversized on purpose so they will be able to move to adjust as necessary. The holes do seem larger than needed to me but they seem to work fine. I can't see that they introduce any vibration into my grinder even when not centered exactly. I suspect the hole in the flat washer could be made to fit the arbor. Maybe it's a "one size fits all" thing for different arbor diameters.

JKJ

[Alan Heffernan]

Yes the wobble in the washers is quite evident in his video. They are not concentric in the video and obviously have oversized holes. The description on the website tells you why.

Are the holes in the wheels themselves oversized?

In my earlier post I was actually talking about wheel wobble. My acquaintance's setup has a large wobble in the wheel itself. Not sure if it is grinder runout, wheel itself, poor installation or what.

[John K Jordan]

In my earlier post I was actually talking about wheel wobble. My acquaintance's setup has a large wobble in the wheel itself. Not sure if it is grinder runout, wheel itself, poor installation or what.

Wheel wobble: When I installed my first CBN wheel, I actually found out the flat washer that came in the set of adjustment washers was the problem. This is the non-curved washer that's supposed to go behind the wheel.

My wheel went from wobble to smooth instantly when I ditched that washer and substituted a precision ground washer that came with the Oneway balancing system. I didn't write down the numbers, but I tested with a dial indicator and the final runout was insignificant.

When I installed a second CBN wheel I didn't even try the washer in the kit but just kept the precision Oneway washer on the shaft. Perfect. Perhaps Oneway sells these washers separately.

I did not examine the washers careful to determine the problem. I might put them on a surface plate and check them with a dial test indicator to see if there is any variation in the thickness. Perhaps there is a slight burr or edge distortion. If so, it could probably be flattened with some fine wet/dry sandpaper or stone. It might also be easy to simply machine a new washer but I didn't try that yet.

I did have more runout when I put a CBN wheel on my Tormek but that was not surprising due to the design of the shaft and bushings. Fortunately, the Tormek runs at such a slow speed the issue may not be as critical. However, I wanted it to run true and I did get it that was with a few tries - I tried some different washers and kept rotating both the washers and the wheel and shaft until I found a position that gave almost no runout when the nut was tightened.

JKJ

[Reed Gray]

Well, a couple of things... I did get my 600 grit wheel, and have to mount it and give it a test run. I am getting ready to do a 'Shear Scraping' video, and have been testing out different burrs on my scrapers, so I will see how the 600 grit burr compares to the 80 and 180, and honed, and burnished burrs...... No end to things I have to experiment with..

The arbor holes are always ground slightly over sized. If you have a 5/8 arbor and drill a 5/8 hole in the wheel, you have to pound it on, so they are just a hair over sized, which I will guess is in the thousandths of an inch range. Stock washers are way out of the 'perfect' range that you need to keep run out to a minimum. I stacked 3 or 4 up on my Baldor to space the wheel away from the grinder. The wheels had noticeable run out, till they came up to speed. Once there, the mass of the wheel seemed to even out the run out. I got machined 5/8 inch thick washers for the grinder, and there was no noticeable run out. I don't have a thing to measure it, but I could keep a tool on the side grind with no problem. If the washer has a larger bore than the wheel, as long as the surfaces it goes against are true, then the wheel will still run true.

robo hippy