Recommended grinder speed

[Thomas Kila]

I keep hearing that a slower grinder speed is recommended for turning tools. However, while checking out Oneway's site, they recommend grinders with 3425 rpm. What do you all say?

I've been using a WoodCraft 1725 rpm 8" grinder for the past few years. I paid around $80 for it. The wheels are badly out of balance and I've already decided on "going-for-broke" 🙂eek) and purchasing a Baldor 8" grinder.

If I purchased the 3600 rpm 8" Baldor, I could save $100 in shipping costs, as the company here already has that model in stock. But if I want the 1800 rpm grinder, then I would have to pay about $1 per pound for shipping. (The unit weighs around 99 lbs.)

Any suggestions will be greatly appreciated.

 

[Jim Stoppleworth]

I'll be no help given you've already made your decision, but if it were me I'd be buying new wheels for the slow speed woodcraft you have.
You'll find as many people grind at 3450 as grind at 1750. Other than the obivious that you'll take more off quicker at the higher speed I don't see much difference. I have both speeds in my shop. The Wolverine jigs for most of the tuning tools are on the slower speed grinder. I use the higher speed for reshaping a tools profile and sharpen on the slower speed. YMMV.

Jim

 

[Ed_McDonnell]

Thomas - Most people will recommend what they use as the best solution. While it may be the best solution for them, it might or might not be the best for you. Here's what I've observed:

In my opinion, either speed grinder is capable of producing a sharp edge and the desired profile in the hands of a skilled sharpener. Someone who is still learning how to sharpen may find the slower speed a little easier to develop skills on because things don't happen as fast. The slower speed may also help the less experience sharpener avoid bluing any carbon steel tools they have.

If I was facing the same decision, only used M2 (or better), and considered myself a proficient sharpener (particularly if I sharpened free hand) I would save the $100 and go 3600rpm. Otherwise I would go with the 1800rpm.

But that's just the way I look at it.

Ed

 

[LHauch]

The president of our woodturning club recently purchased the one-way wheel balancing kit for his 8" grinder. Like your description, he was thinking about getting yet another grinder (he has three already) but decided to give the balancing kit a try. Since it worked so well, he's ordered at least one more kit, since the vibration went away completely.

Cheers,

 

[MichaelMouse]

Assuming you do a bit of other woodworking with carbon steel, like chisels, gouges, plane irons, the slow speed, a more forgiving option, makes excellent sense. It will also do the harder alloy steel in your turning tools. You can't grind metal away as quickly, but you love your tools, and you want to sharpen them with minimum metal removal anyway, so that's no factor.

Couple other points to ponder. If you have a bit of imbalance due to stone or mount, higher speed is going to react a lot more, just like an out-of-balance piece on the lathe. Energy does equal mass (or difference in mass) times the square of velocity, right? Means compared to a high speed setup, it's easier to keep that low-speed stone behaving properly.

Not that you'll ever experience it, but chip or break that stone while working, it'll pop you four times as hard, too!

 

[Malcolm Smith]

Couple of points. The stones that come on all the grinders I'm familiar with should be thrown away. I assume they are there because the grinders need to have something mounted on them when they are sold.

The stones should be frequently cleaned with a diamond tool.

I would highly recommend the Oneway balancing system. I mounted mine with an expectation that there would be an improvement in how the wheels ran, being familiar with Oneway. I have a Oneway lathe. The improvement was very noticeable.

As for the different speeds, carelessly used, either will do damage to the steel you are working with.

Malcolm Smith.

 

[Richard Baker]

Another vote for what Jim Stoppleworth said. Are your wheels NOT out of round, just out of balance? If the tool bounces on the wheel when sharpening, the wheel is out of round. If so, may be due to wheel dressing technique. Not saying that you are doing anything wrong, but I know from experience that improper dressing technique can actually "turn" a wheel out of round. Just something to consider before parting with all those $$ for a Baldor.

 

[john lucas]

I agree with pretty much everything that's been said. 3450 is fine I use slower simply because it feels safer, doesn't heat up the tool as much, and removes the metal slower.
I use the Woodcraft slow speed grinder and did have to spend some time trueing up the wheels to make them run smooth but when I got it they keep running true with just a little cleaning. I've been using them for about 2 years now and still good.
The Baldor is a great grinder. I've used them and lust for one but since the current machine I have works really well I just can't justify one.

 

[John Jordan]

A Baldor 1800 rpm with good wheels is as good as it gets, smooth, quiet and easy to use. Having said that, your grinder is probably fine. Take the wheels off your grinder and turn it on. If it runs smoothly, buy a couple of good (60 grit)wheels and TURN bushings to fit. Wobble from side to side is not the same as out of balance. Tighten/loosen/tighten/tap with your hand lightly, tighten/loosen etc. until the wheels don't wobble side to side. It CAN be done, be patient. Dress any out of roundness with a good diamond dresser.

If one has a grinder that runs smoothly without the wheels, and one buys good wheels, you won't NEED a balancer-a waste of money. This is based on having used literally hundreds of grinder setups. I have all of the above mentioned here in my shop. It's almost always wheel wobble or wheels out of balance.

FWIW, if ten turners tried otherwise identical, well set up 1800 and 3600 Baldor grinders, I would bet that 9 out of 10 would pick the 1800, but probably 8 out of 10 would say it really didn't make very much difference. 😀

John

 

[rsser]

If you plan on making some of your own tools out of HSS blanks then go for the high speed grinder IMO. Shaping is quicker.

 

[MichaelMouse]

If you plan on making some of your own tools out of HSS blanks then go for the high speed grinder IMO. Shaping is quicker.

Belt sander. Abrasives are cheaper.

 

[Odie]

FWIW, if ten turners tried otherwise identical, well set up 1800 and 3600 Baldor grinders, I would bet that 9 out of 10 would pick the 1800, but probably 8 out of 10 would say it really didn't make very much difference. 😀

John

I tend to think John is right about this. For most practical purposes, either speed will get the job done, and do it well.

I'm one of the 2 out of 10 that has used both extensively, and think there is a difference. For my way of looking at it, there is a BIG difference, and choose the 1725rpm as the better option.

The reason for this is simply.......heat!.....(The 3450rpm will build heat quicker than a 1725rpm wheel......duh!)

If one learns to sweep the tool faster over the 3450rpm wheel, the adverse effects can be minimized. For skews and gouges, where the angle is more acute, and thus a thinner cutting edge, the importance is greater than the larger angle on scrapers.

Because I don't have to sweep the tool over the wheel as fast as I used to with the 3450 wheel, I HAVE GREATER CONTROL of what I'm doing.

ooc

I have used both:

 

[John Jordan]

Here's a picture of a smooth running grinder. No, they aren't glued on.🙂 NO balancer!

 

[Jerry Hall]

I have an older Woodcraft grinder

and was in the same fix as you. Bought the Oneway wheel balancers and a 120 and 80 Norton 3x set of wheels and it is sweet. No reason to change.

 

[Thomas Kila]

Thanks to all that have responded!

I really appreciate the sage advice I've received on this. I'm sure others with a similar question will also benefit from this thread. Mahalo!

 

[Odie]

Here's a picture of a smooth running grinder. No, they aren't glued on.🙂 NO balancer!

I am really impressed by the photograph showing your Baldor grinder with the nickels balanced, John......

I decided to do a little test, using my Delta 1825 rpm grinder. At first, the nickels would not balance........but, I tried your advice about repositioning the wheels by "trial and error" method, and managed to get my grinder running more smoothly.....thanks for inspiring me to do this. 😀

I do not own the Oneway balancer kit. I've thought about getting it, but just never have done it. After taking John Jordan's advice about balancing wheels, I'm not so sure the balancing kit is necessary.......just a little patience! :cool2:

OOC

Below is the "after balancing" photograph showing nickels on my own Delta grinder balanced while grinding a bowl gouge. I've heard a lot about how good the Baldor is.......but, I'm not so sure it's how much money you spend on the grinder itself......but, how well your wheels are balanced. This may not apply to the really cheapo grinders, but obviously does apply to the upper echelon group of grinders........

 

[john lucas]

Odie That's what I've been recommending for years. I have never needed the Oneway system although it might make it quicker. By using paper shims to make the wheels run true left to right and rotating the wheel I have been able to get several grinders running perfectly true.

 

[Odie]

Odie That's what I've been recommending for years. I have never needed the Oneway system although it might make it quicker. By using paper shims to make the wheels run true left to right and rotating the wheel I have been able to get several grinders running perfectly true.

Hello John.......

Would you mind going over, in a more detailed way, your method of using the paper shims to true the wheels.

I'm not so sure this is something that has a significant practical benefit, as long as the balance is good, but if there is something I'm missing, I would welcome you "cluing me in"! 😀

So far, I'm not seeing a marked improvement in my sharpening, over the lesser balanced wheels I was using before, but it would stand to reason that any improvement in the smoothness of the sharpening operation has got to be a benefit in some way. Just how measurable that benefit will be, remains to be seen at this time.

One's technique in sharpening may overcome some small amount of detrimental effects of a slightly out of balance condition. I reserve the right to change my mind, but at this point, I'm not seeing much difference in the quality of my edge. Since I am using the grinder in conjunction with a wet grinder for everything but scrapers, it would stand to reason that if there is any real difference, it will likely be more apparent with the scrapers.

Need more time to form final opinions/analysis of the results I'm getting .......

OOC

 

[Richard Jones]

I bought the Oneway balancing system to use with my slow speed Woodcraft grinder. Wouldn't work, since the Oneway requires a 1" grinder shaft to operate.............

I AM going to try the make-your-own-bushings, as that may very well be the cure to a problem. Something else that I did was to make a jig to true the wheels with my T-dresser and that made a HUGE difference. Very smooth running now, and I run 120 grit 32-A's on both sides.

That said, IMO you simply can't go wrong with the Baldor.

Rich

 

[john lucas]

Then I do the same thing for the front surface. I hold a pencil on the tool rest and rotate the wheel by hand so it leaves a mark on the high spot. I loosen the nut and rotate the wheel on the shaft and repeat. This can take a while but it's worth it in the end. That trues up the front to back vibration of the wheel.

now there may be some wobble left and right. I rotated the wheels by hand and marked the spot where it move the furthest to the side. Then I loosened the nut and put a thickness of paper (brass or copper shim stock would work better) between the wheel and the inboard washer. This moved the wheel more in line. It took a few try's and several thickness's to get it right.
Once you have these as close as you can you can true up the wheel using a diamond hone. Before I started using this method my stones vibrated a little. I thought everything was OK and it didn't matter. Boy was I wrong. A smooth running stone with no vibration makes sharpening so much easier. You have so much better control of the tool. Especially if you sharpen without a jig. I have several tools that I grind for a specific cut and they must be done by hand. The tool just sits on the stone and runs very smooth so it's a very simple matter to just rotate it in a smooth arc and get the grind you want.
I haven't tried balancing nickles but my $89 Woodcraft grinder and cheap white wheels work perfectly with no noticeable vibration. I'll try the Nickel thing this morning. I'm having about 20 or more turners over today and I usually do a sharpening demo.

 

[Odie]

Then I do the same thing for the front surface. I hold a pencil on the tool rest and rotate the wheel by hand so it leaves a mark on the high spot. I loosen the nut and rotate the wheel on the shaft and repeat. This can take a while but it's worth it in the end. That trues up the front to back vibration of the wheel.

now there may be some wobble left and right. I rotated the wheels by hand and marked the spot where it move the furthest to the side. Then I loosened the nut and put a thickness of paper (brass or copper shim stock would work better) between the wheel and the inboard washer. This moved the wheel more in line. It took a few try's and several thickness's to get it right.
Once you have these as close as you can you can true up the wheel using a diamond hone. Before I started using this method my stones vibrated a little. I thought everything was OK and it didn't matter. Boy was I wrong. A smooth running stone with no vibration makes sharpening so much easier. You have so much better control of the tool. Especially if you sharpen without a jig. I have several tools that I grind for a specific cut and they must be done by hand. The tool just sits on the stone and runs very smooth so it's a very simple matter to just rotate it in a smooth arc and get the grind you want.
I haven't tried balancing nickles but my $89 Woodcraft grinder and cheap white wheels work perfectly with no noticeable vibration. I'll try the Nickel thing this morning. I'm having about 20 or more turners over today and I usually do a sharpening demo.

Thanks John.......

As usual, I think you have some good information to impart......thanks for spending the effort with the rest of us. I believe I'll give that a try and see if I see some improvement that makes any significant difference in my sharpening.

I have one wheel that has no noticeable side to side wobble, but the other one does, but only very slightly. Judging from the balanced nickel photo, it's definitely running very smooth, as is......but, I'll see if truing that up with paper shims makes some, or any difference for me.........

OOC

 

[Odie]

OK, I played around with my grinder this afternoon......used some paper spacers to make the side to side wobble better, not perfect, but much better for sure.

I don't believe the balance was improved by this, but it might have....if anything, it was improved very slightly to the better. Hard to say about that, since the balance was extremely good to begin with......good enough to balance the nickels anyway.

One thing I did do differently is mark the shaft ends, the two grinding wheels themselves, and all four flange washers. This is so that in case I have a need to use another grinding wheel, I can do that and get either of these two wheels re-mounted exactly the same as before.

Thanks to John Jordan and John Lucas for giving me the inspiration to experiment and learn something I didn't know before. 😀

OOC

 

[John Jordan]

OK, I played around with my grinder this afternoon......used some paper spacers to make the side to side wobble better, not perfect, but much better for sure.

I don't believe the balance was improved by this, but it might have....if anything, it was improved very slightly to the better. Hard to say about that, since the balance was extremely good to begin with......good enough to balance the nickels anyway.

One thing I did do differently is mark the shaft ends, the two grinding wheels themselves, and all four flange washers. This is so that in case I have a need to use another grinding wheel, I can do that and get either of these two wheels re-mounted exactly the same as before.

Thanks to John Jordan and John Lucas for giving me the inspiration to experiment and learn something I didn't know before. 😀

OOC

We're mostly from the same gene pool in TN, don't you know.😀

John

 

[GLENN ROBERTS]

One thing that I have looked at, trying to get my grinder balanced, was how well the flange washers are made. Some of them are so flimsy. I placed some in my metal lathe and they needed facing. Somewhat the same problem you are overcoming with the spacers. I noticed the better quality grinders have much thicker flanges and are machined, not pressed metal. Something to look out for. You still need to 'play' around with getting the wheels to run true but it sure helps.

Glenn

 

[john lucas]

That's a scary thought being in the same gene pool as John J. Hope we both aren't related to Randy Trentham also, now that would be scary. 🙂

 

[Odie]

We're mostly from the same gene pool in TN, don't you know.😀

John

That's a scary thought being in the same gene pool as John J. Hope we both aren't related to Randy Trentham also, now that would be scary. 🙂

You guys don't play banjo and guitar duos there, do you?

😀 Ha!

OOC

 

[john lucas]

I play guitar and I'm a really good Archer. Used to do a bit of white water canoeing as well. 🙂

 

[Frank Townend]

Ah, I get it. Balance nickels on your grinder to make it run smoother. Thanks guys. 😀

 

[John Jordan]

You got a purty mouth, boy. Howdjou get out here?😱

John