Best practices for eliminating wobble and dressing a wheel.

[George Pagliarulo]

When eliminating wobble on a two wheel grinder, does it matter if both wheels are mounted. Should you eliminatet the wobble on one and then mount the other? It seems they should be independent but just checking.
Same question for dressing one of the wheels.
For wobble, what is considered acceptable? Is zero wobble possible? I'm at 0.05 now and still playing with it.
Thanks.

 

[hockenbery]

Here is an excellent method.

https://maakplek.nl/wiki/lib/exe/fetch.php?media=130412_tuning_up_a_grinder_with_photos.pdf

 

[George Pagliarulo]

Thanks Hockenbery. I have been using a dial indicator to try and measure the wobble but getting consistent results because of the friction between the wheel and the indicator probe moving the dial indicator.
This method is exactly what I need!

 

[robo hippy]

Well, best method would to go to the CBN wheels, which come spin and bubble balanced. Other things that can cause wobble include the standard nuts which are not precision machined. Not sure if you can put them in your chuck and flatten them out or not, but M2 HSS will cut most of the softer metals. You can also go to Woodturner's Wonders, and they have Helical nuts, one is concave and the other is convex, so they seat dead flat and true every time. The inserts for the centers of the wheels can be problematic. In general the plastic ones are junk, and should be replaced. Metal ones are far more accurate. You can true up the wheels without having to go to fancy truing systems. I used a platform, and would ease the dressing stick into the wheel as it is spinning. You can develop a 'feel' for nibbling off the high spots. The same can be done to the sides of the wheel, however care must be taken because the standard friable wheel is not built or designed for lateral pressure. You also need to mark the spot on the wheel and the axle of the grinder so it mounts in the exact same spot if you ever take it off, or if the wheel spins a bit as you are sharpening. The axles on most grinders do not run perfectly true. Oneway also had a wheel balancing system some years ago, but I never used one. I would expect that it would be necessary to check to make sure the balance does not change every time you trued up the wheel. The standard friable wheels are not always balanced.

robo hippy

 

[Leo Van Der Loo]

Here is the Oneway balancing kit on HOW TO
https://oneway.ca/pdf/balance_kit_old.pdf

And here is the kit that gives you the wobble free and balanced grinding wheels.

https://oneway.ca/pdf/Balance Kit Vers 5.1 Dec 2010.pdf

Oneway Quality and price go hand in hand, (it works)

 

[John Grace]

In all fairness...get rid of the stone wheels and simply get CBNs. They'll last virtually forever, they never need dressing, and you'll never need to incrementally move your jigs into the correct position. Arguably the single best purchase I never made with respect to my sharpening set-up.

 

[George Pagliarulo]

I was able to get back to getting my wheels wobble free today. I had great success on one wheel (haven't done the other) and then moved to dressing the wheel. Before dressing the wheel would rotate until the same spot was at the bottom. I thought this would go away after the wheel was dressed and round. It didn't seem to be changing so with a Sharpie I drew a line across the face of the wheel at the low point and drew another 180 degrees opposite. I dressed the wheel until both lines were gone. When the low line was gone, the opposite was still there so I continued dressing until it was also gone.
The wheel still rotates until the same spot is at the bottom. I thought maybe the cause was the opposite wheel that wasn't dressed yet so I took it off. It didn't make a difference.
I was expecting that once the wheel was round the rotation would stop and the wheel would stay still at all points of rotation. Am I wrong? If not, any idea what might cause it to still rotate?

 

[Steve Tiedman]

Hi George. I think you are right in your process, but it sounds like the wheel itself may have a dense spot, or a light spot, in the make-up of the wheel. I don't know how grinding wheels are made, but I imagine something similar to casting concrete... maybe? And how a dense or light spot (air bubbles?) could form, I'm not sure.

(I just typed out, then deleted before sending, an idea to counteract the out-of-balance weight issue, but then thought better of it in case the idea got someone hurt.)

There are wheel weight balancing systems out there, Oneway's comes to mind. Best of luck!

 

[Brian Gustin]

I was expecting that once the wheel was round the rotation would stop and the wheel would stay still at all points of rotation. Am I wrong? If not, any idea what might cause it to still rotate?

As Steve mentioned, possibly a density issue (grinder will vibrate when running due to out of balance) - if the center hole of the wheel is not a snug slip fit on the motor shaft, allowing wheel to sit off-center, then your wheel would of course be out of round in relation to the center hole, changing the distribution of mass of the wheel around the motor shaft once the outside of the wheel has been trued up.....

Or it could be the motor itself - some motors may have a tendency to return to a favored spot (Its a magnetism thing - residual magnetism/voltages - You know, you can actually generate a voltage back through the power cord on a brushed motor when spun by hand, *sometimes*... that principle is reason for a trick many techs will use to "fix" a generator that won't put out power... called re-flashing the windings...) If it is just a magnetism issue in the motor, your grinder might run/spin almost smooth as glass (can barely tell it is running - another reason I put bright colored tape on the sides of CBN wheel - a visual indicator it is running, since I can't hear motor running.)

if it's a balance issue, you'll find vibration in the grinder - and it'd get worse the more out of balance it gets.. but if the grinder and wheels are in balance and grinder runs smooth and it still favors one spot when coming to rest, it'd likely be a magnetism issue. (which really is a non-issue)

 

[Leo Van Der Loo]

I was able to get back to getting my wheels wobble free today. I had great success on one wheel (haven't done the other) and then moved to dressing the wheel. Before dressing the wheel would rotate until the same spot was at the bottom. I thought this would go away after the wheel was dressed and round. It didn't seem to be changing so with a Sharpie I drew a line across the face of the wheel at the low point and drew another 180 degrees opposite. I dressed the wheel until both lines were gone. When the low line was gone, the opposite was still there so I continued dressing until it was also gone.
The wheel still rotates until the same spot is at the bottom. I thought maybe the cause was the opposite wheel that wasn't dressed yet so I took it off. It didn't make a difference.
I was expecting that once the wheel was round the rotation would stop and the wheel would stay still at all points of rotation. Am I wrong? If not, any idea what might cause it to still rotate?

George I would take both wheels off, and then proceed to balance one wheel, after that I'd do the next wheel.

Now grinder wheels are not always evenly made, round and thickness, and then the grinder makers use low cost washers, just stamped really, and those are a PITA when trying to balance and straighten the wheels.

If the wheels have harder or denser spots (it happens) you can not get the job done by straighten and dressing the wheels.

That is why this was made available, and yes CBN does do away with the problems (expensive).

Also costly and you're wheel has to have at least a one inch opening to get it installed in the wheel, but it does make for a precision balanced and wobble free wheel.

 

[Timothy White]

The answer to this question:
It depends, do you want to spend your shop time working on an inferior archaic grinding system buying balancing systems and etc.
Or do you want to spend your shop time turning?

 

[Terry Brown]

Vibration can be caused by an imbalanced wheel. Wobble alone does not cause vibration. If it did, we would not be able to use wobble dado heads on table saws. A dressed stone with minor wobble does not affect the grinding process.

 

[Steve Tiedman]

Some other methods for tweaking the grinding wheels, from... whoa, 22 years ago. I'm getting old(er). See pages 3 thru 5.

https://www.mnwoodturners.com/cms-files/2002-08-newsletter.pdf

 

[Bob Vaughan]

Some of the Asian-made grinder substitutes I've run across were great for mixing paint. I first tried to balance the wheels on a few with no luck. I removed the rotors (armatures) and found the shafts had a slight arc in them and would never balance. The wobbly sheet metal flanges and minimal indexing shoulder didn't help. I've never had a wheel balance problem with a Baldor or equivalent USA-made bench grinder. My point is that the wheel may well not be the problem.

 

[Steve Tiedman]

Some of the Asian-made grinder substitutes I've run across were great for mixing paint. I first tried to balance the wheels on a few with no luck. I removed the rotors (armatures) and found the shafts had a slight arc in them and would never balance. The wobbly sheet metal flanges and minimal indexing shoulder didn't help. I've never had a wheel balance problem with a Baldor or equivalent USA-made bench grinder. My point is that the wheel may well not be the problem.

Hi Bob. I tend to agree about the possibilities of the low-cost grinders being less-than-perfect. (Sometimes they are perfect out of the box but without its wheels.) 20-some years ago when I bought my Baldor, they were still just on the high end of affordable. Now they are really quite expensive (as all things are nowadays), approaching or exceeding 4-digit prices. Although Rikon seems to be the market leader (by what I've noticed) on the "affordable" end, if a turner, or anyone using a grinder regularly, can stretch for a Baldor, I'd still suggest trying for it. I think Jet may still make industrial-quality grinders, probably priced between the mass consumer grinders and Baldor.

My Baldor is as smooth as glass. If at anytime it was not, the wheels were the culprit.

If a budget grinder is the only way to go, I'd suggest removing the wheels and flanges when new and running the motor by itself to make sure it is running smooth and free of unusual vibrations. Then follow all the various tips offered to get the wheels to behave as much as possible.

 

[Bob Vaughan]

I just checked the prices. New Baldor 8": $1400.00. New Rikon 8": $140.00. The quality difference is there but maybe that difference may not equate to an advantage to someone just grinding lathe tools. I guess one trick in reducing vibration risk would be to avoid a 3600 RPM Chinese-made grinder.
Of course there's always the option of getting a used Baldor or equal grinder and fixing it up but that isn't for everyone.

 

[odie]

In all fairness...get rid of the stone wheels and simply get CBNs. They'll last virtually forever, they never need dressing, and you'll never need to incrementally move your jigs into the correct position. Arguably the single best purchase I never made with respect to my sharpening set-up.

If you want the best results you can possibly have on your lathe....then you'll forget about cbn wheels, and quit trying to get a cutting edge directly from the grinder.

The only purpose of a grinder should be to remove metal and shaping....that's all. By hand honing those edges, it is simply one element in the total equation......and with that in mind, is the pathway to perfection.

Hone those edges much more often than you ever thought you would, should, or had to......and, your cutting edges will perform like you're in turning heaven! Relying on edges direct from the grinder, along with hybrid steels, is the ticket to having an edge that is almost as sharp as it could be....for extended periods of time.......but, it's for sure you won't have to return to the grinder very often......it's a choice, and there are no simple or easy solutions.

-o-

.

 

[Bob Vaughan]

That pretty much says it all.

Retailers want to keep that a secret. Once the customer achieves his goal, the retailer is no longer necessary.
For many, a tool's edge right off the CBN grinding wheel is the best they've ever had but that edge is not going to be as sharp as it can be without a little honing and burr removal.

 

[Chris Hoehle]

I'll have to say that the Oneway wheel balancing kit made very little difference in my opinion, quite disappointing after all the fiddling it took. What did work great however, was their diamond dresser that gets held in the Wolverine jig and gives the dressing point a fixed frame of reference to true the wheel (and I imagine the Geiger jig would be the same in this regard). One of those plus the upgraded bushings from CSUSA makes a good amount of difference.

Raptor R3X Grinding Wheel Bushing 2 Piece Set

The Raptor R3X Grinding Wheel Bushing Kit is a precision wheel bushing system specifically designed for use with Norton 3X Grinding Wheels. Our experience has shown that knockout bushings and stock wheel washers almost always result in run-out that’s difficult or impossible to eliminate.Our R3X...

woodturnerscatalog.com

Oneway Wolverine Diamond Dressing Jig

Easily dress grinding wheels with the Oneway® Wolverine™ Diamond Dressing Jig. Grinding wheels must be free from metal particles or other debris and must be flat across the face if the wheel is to perform sharpening tasks quickly, accurately and without "burning" tool edges. Diamond dressers are...

woodturnerscatalog.com

Using Geiger's Tru N Dress

Using Geiger's Tru N Dress

www.geigerssolutions.com

 

[Bob Vaughan]

Note: A diamond dresser makes a big difference in truing up the wheel's surface. I've been using them for decades. The kicker that retailers won't tell you is that a diamond dresser knocks off the sharp rocks in the wheel and makes it incredibly dull. Now the wheel needs to be sharpened and that's where the star dresser comes in. I'll use the star dresser often on my wheels to expose sharper rocks (aggregate). I recommend the Desmond Huntington size 0. Its cheap enough and the replacement wheels are equally inexpensive. It will last for decades. Any time my wheels seem to not be cutting as quick as I want, three to five seconds of push with the dresser exposes a new sharp surface.

I suspect that the reason retailers and Youtubers don't mention a star dresser is sales of wheels. With a star dresser, one doesn't need to buy a new wheel when the surface gets dull. That fact isn't good for their business plan.

 

[Bob Vaughan]

As a side note, the grinder was a used one that I bought and fixed up. Very similar to one I did shown in the American Woodturner, Spring 1999, Vol 14, #1, page 22.
Smooth and whisper quiet at 3450 rpm.

 

[Russell Nugent]

Note: A diamond dresser makes a big difference in truing up the wheel's surface. I've been using them for decades. The kicker that retailers won't tell you is that a diamond dresser knocks off the sharp rocks in the wheel and makes it incredibly dull. Now the wheel needs to be sharpened and that's where the star dresser comes in. I'll use the star dresser often on my wheels to expose sharper rocks (aggregate). I recommend the Desmond Huntington size 0. Its cheap enough and the replacement wheels are equally inexpensive. It will last for decades. Any time my wheels seem to not be cutting as quick as I want, three to five seconds of push with the dresser exposes a new sharp surface.

I suspect that the reason retailers and Youtubers don't mention a star dresser is sales of wheels. With a star dresser, one doesn't need to buy a new wheel when the surface gets dull. That fact isn't good for their business plan.

View attachment 61464 View attachment 61465

I've never heard of anyone buying new grinder wheels because they got dull.

 

[Bob Vaughan]

I've never heard of anyone buying new grinder wheels because they got dull.

I sure have. I've been given wonderful wheels because of that.

 

[odie]

That pretty much says it all.

Retailers want to keep that a secret. Once the customer achieves his goal, the retailer is no longer necessary.
For many, a tool's edge right off the CBN grinding wheel is the best they've ever had but that edge is not going to be as sharp as it can be without a little honing and burr removal.

I suspect that quite a few turners have a great deal of $$$ invested in their exotic steel tools and CBN grinding wheels......therefore, it's going to be a hard sell to convince them of anything they would tend to consider as "old school" methods of obtaining and keeping a sharp edge.

Bob.....you're right that many of the new generation of turners, as well as quite a few old hands, are experiencing a level of sharpness they they've never experienced before with the CBN wheels. With the old hands, I suspect they've never even tried hand honing.....or if they have, they've never refined it to the point of getting the best cutting edge that can be had.

There is one strong principle that results in the noted differences between an edge created from a spinning wheel vs an edge that is formed by honing by hand. That is.....the edge created by the wheel is done in a single direction, whereas the edge formed by hand honing can be created by honing from multiple directions.....and THAT is one difference that is directly related to how well the very tip of the cutting edge can be formed.

-o-

.

 

[Steve Tiedman]

I don't disagree with anything you said, Odie, and I can confirm both the notion and experience. Heck, in another recent thread I showed photo proof of the hand-honed edge being superior to a 180 grit CBN. I think the challenge with hand sharpening/honing, for me, is keeping the stone perfectly registered against both the edge and the heel of the grinding wheel created hollow-ground bevel while stroking the stone and following the curvature of the tool (such as a gouge). I am much better at it with skew chisels, but it takes a good amount of dedicated hand-eye practice to develop the action for gouges. It is all too easy to lose contact at the heel which instantly creates a different edge micro bevel angle (different from the edge angle right next to that new angle) resulting in a spot on the edge sweep that needs to engage the wood at a different tool presentation angle (and without realizing this, it feels like a dull spot on the tool). If the stone is lifted from the edge and hones the bevel heel only without realizing it, now you have an unsharpened point on the edge.

A final challenge is making sure your handheld stone strokes don't create multiple flat facets at the edge (which you alude to in your message), which are easy to create when stroking perpendicular to the edge and heel rather than stroking with smooth, curved strokes following the curvature of the tool.

Now, admittedly all of these shortcoming can be overcome with... continuous practice over time, but unless you are a daily turner spending many hours a day at your lathe, you may not be able to practice the skill enough to become proficient at it. Enter the tool holding jigs and grinding wheels which provide the consistent single facet flowing curved bevel resulting in a servicable cutting edge.

It does make me wonder, though, if some turners spend too much time on the grinding wheel per sharpening session. I can read the conditions to know when my tool is dulling, and when I'm at the fine grinding wheel I apply no more pressure on the wheel than the natural weight of the tool leaning on the wheel (and a trued wheel is important here to keep the light tool pressure contact from bouncing on the wheel), and I take no more than 3, maybe 4 smooth, full radius strokes across the wheel. This take me less than 5 seconds. No heat is generated, and the tool and wheel life are preserved.

Now, if I could just discipline myself to practice and master hand sharpening more often between trips to the grinder...

 

[Kent Reisdorph]

I suspect that quite a few turners have a great deal of $$$ invested in their exotic steel tools and CBN grinding wheels......therefore, it's going to be a hard sell to convince them of anything they would tend to consider as "old school" methods of obtaining and keeping a sharp edge.

Bob.....you're right that many of the new generation of turners, as well as quite a few old hands, are experiencing a level of sharpness they they've never experienced before with the CBN wheels. With the old hands, I suspect they've never even tried hand honing.....or if they have, they've never refined it to the point of getting the best cutting edge that can be had.

There is one strong principle that results in the noted differences between an edge created from a spinning wheel vs an edge that is formed by honing by hand. That is.....the edge created by the wheel is done in a single direction, whereas the edge formed by hand honing can be created by honing from multiple directions.....and THAT is one difference that is directly related to how well the very tip of the cutting edge can be formed.

-o-

.

What do you use for honing? A 1,000 grit card or something else?

 

[Kent Reisdorph]

It does make me wonder, though, if some turners spend too much time on the grinding wheel per sharpening session. I can read the conditions to know when my tool is dulling, and when I'm at the fine grinding wheel I apply no more pressure on the wheel than the natural weight of the tool leaning on the wheel (and a trued wheel is important here to keep the light tool pressure contact from bouncing on the wheel), and I take no more than 3, maybe 4 smooth, full radius strokes across the wheel. This take me less than 5 seconds. No heat is generated, and the tool and wheel life are preserved.

Agreed. The sharpening jigs take a bit to set up, but once done you can sharpen in seconds.

 

[Steve Tiedman]

Hey Kent, I'd be interested in Odie's choice as well. When I choose to hand hone, I'll use a 600 or 1200-grit diamond plate, like the DMT "credit card" diamond plate. It can be used dry or lightly splashed with water. If I recall back eons ago to seminars with Alan Lacer, he once used a medium India slip stone that he kept in his apron chest pocket, but then moved on to diamond plates as well, something like a 2"x6" plate that is light and easy to keep nearby or in a pocket. For this type of purpose, I think the 600 or 1200 grit diamond is going to be well suited for turning tools. Hand carving or bench tools, even finer is better.

 

[hockenbery]

It does make me wonder, though, if some turners spend too much time on the grinding wheel per sharpening session.

I rarely take more than two passes on an edge. I watch the sparks breaking over the edge. Any gap in sparks requires a repeat.
In club workshops - students come with sharpening skills all,over the spectrum. Some Bette than mine to abysmal.

I also sharpen at set points in the process.
For a natural edge bowl. Before I mount the blank. Before I finish turn the outside. Before I cut the inside wall to thickness.
Often I’m sharpening an edge that’s cutting well but I want the sharpest to start these operations.
I hone a skew but not the gouges. I use the Tormek leather strop wheel on mt skews.

I use a jig for the bowl gouge. I use the platform for most other tools. Here is a quick view of the process from a club demo.
I prefer a flat or slightly convex bevel on the spindle gouge

Bowl gouge with Ellsworth jig. …..…. How I sharpen the spindle gouge …… getting a similar grind using the woulverine
. .

 

[odie]

Now, admittedly all of these shortcoming can be overcome with... continuous practice over time

Now, if I could just discipline myself to practice and master hand sharpening more often between trips to the grinder...

^^^^^ Well, there you go, Steve!

You've just said what needed to be said right there!

Hand honing is very quick, and isn't difficult at all, but any real progress can only be made through a personal knowledge base gained solely by practical application.....rather than someone like me preaching it's virtues!

What do you use for honing? A 1,000 grit card or something else?

600 gt diamond plate, both flat and cone works very well for me.

Keep in mind that honing from multiple directions produces a much more refined edge than the same grit from a single direction.....and, that honing on both sides is important to getting that refined edge.

-o-

.

 

[Kent Reisdorph]

Hey Kent, I'd be interested in Odie's choice as well. When I choose to hand hone, I'll use a 600 or 1200-grit diamond plate, like the DMT "credit card" diamond plate. It can be used dry or lightly splashed with water. If I recall back eons ago to seminars with Alan Lacer, he once used a medium India slip stone that he kept in his apron chest pocket, but then moved on to diamond plates as well, something like a 2"x6" plate that is light and easy to keep nearby or in a pocket. For this type of purpose, I think the 600 or 1200 grit diamond is going to be well suited for turning tools. Hand carving or bench tools, even finer is better.

I have a 1,000 grit card so I'll try it out.

 

[robo hippy]

I did try a star wheel dresser for the wheels, and didn't like it at all. The problem is that it rides the wheel as you refresh the surface. Main issue with that is that you are not able to take out any eccentricities if the wheel is not 'perfectly' round. That is the advantage of the T shaped dressers. On a steady platform, and gently ease it into the spinning wheel. You get to nibble down the high spots as you go rather than riding the dresser against a wheel that isn't round to begin with. That does make a considerable difference.

I have heard the pros and cons of the touching up the edge with diamond card for years. I don't bother. More of because it is faster to go to the grinder and touch it up there. I do all of my sharpening on the platform, which is a lot faster than the jigs. If I hadn't learned to use the platform maybe I would resort to the cards more often. I do like a card for the bevels of my coring tools. 220 card raises a better burr...

robo hippy

 

[hockenbery]

That is the advantage of the T shaped dressers.

I use a T dresser too.
I use a different process.
I start on a corner of the wheel. I move the dresser a couple light strokes with the diamonds at about 45 degrees to the wheel face.
This gets the corner true real quick. Then I use that true edge as a guide and move the dresser from the corner to the other corner with 5-8 strokes changing the angle with each stroke until ithe diamonds face the front of the wheel on the last stroke.

Each stroke takes off a bit more of the roughness until the last stroke which is all smooth.
The motions are a lot like thread chasing- cut a thread on the leading edge and use it to cut the next thread…

I like the one Packard sells. The thick matrix of diamonds is long lasting.

 

[Doug Rasmussen]

Note: A diamond dresser makes a big difference in truing up the wheel's surface. I've been using them for decades. The kicker that retailers won't tell you is that a diamond dresser knocks off the sharp rocks in the wheel and makes it incredibly dull. Now the wheel needs to be sharpened and that's where the star dresser comes in. I'll use the star dresser often on my wheels to expose sharper rocks (aggregate). I recommend the Desmond Huntington size 0. Its cheap enough and the replacement wheels are equally inexpensive. It will last for decades. Any time my wheels seem to not be cutting as quick as I want, three to five seconds of push with the dresser exposes a new sharp surface.

I suspect that the reason retailers and Youtubers don't mention a star dresser is sales of wheels. With a star dresser, one doesn't need to buy a new wheel when the surface gets dull. That fact isn't good for their business plan.

Wow...... It's hard to tell if this post is meant to be sarcastic or a joke.

In my business experience I've learned a bit about dressing grinding wheels. Having owned surface grinders, a cylindrical grinder. tool and cutter grinders, precision drill grinders, etc all capable of grinding parts to high precision, easily in the range of +/-.001" using a hand held star dresser would never have even been considered. All those machines came from the factory with a mount for a single point dressing diamond that was precisely guided across the grinding wheels faces. (not hand guided).

A star dresser or the diamond cluster type might be recommended for wheel dressing in crude snag grinding like when cleaning up rough castings or weld grinding.

 

[George Pagliarulo]

Finally got my grinder wheels running wobble free and true with no vibration. Used the Oneway balance system and dressing jig with good results. Now to finish sharpening the tools and get to turning!