Bench grinder help

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athenstrestle

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Hi everyone,

I recently bought a Ryobi 8" bench grinder and am having some mean vibration and wobbling when running it. I'm pretty sure the shaft if bent slightly. I tried the masking tape trick (taping around the shaft after removing wheel, touching a sharpie to spinning shaft to see if line is drawn continuously around shaft) and got a non-continuous line. When spinning the wheel freehand there is NOTICEABLE side to side wobble. I've taken the following pictures, NOTE that the skew chisel was held in the same place and the only difference between the 2 pictures is that the wheel was handspun 1/2 a turn or so. Notice there's about 1/8th gap - would this be due to a bent shaft?

Would anyone know whether this type of problem is common with cheaper grinders? I really would have liked a Baldor or similar quality unit, but couldn't justify the cost difference until I figure out how much I'll use it. Before buying I did an internet search and the Ryobi's generally had pretty positive reviews, which makes me think this might just be a one-off dud (although upon returning to the store and giving the floor-model a handspin it also seemed to have some wobble)?

I guess the decision I have to make is whether to bother exchanging and trying again with a cheapo unit, or investing a bit more in something else. Thanks everyone for any input.

Happy turning!

Cory
 

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Have you dressed the wheel with a diamond dresser? If so, and the wheel is true front to back, then I think you're ok. That is unless you plan to use the side of the wheel. I recently bought the slow speed 8" grinder from woodcraft. It has some vibration, but after dressing the wheels, the wheel seems to spin true. There might be some side to side motion, but I don't intend to use the side of the wheel. And it does a more than adequate job of sharpening.

I wonder if a wheel that hasn't been dressed would cause enough vibration for the sharpie test to fail. Did you take both wheels off to do your test? And I wonder what the tolerances are for grinders. I know I'm not giving you much help, I'm just telling you my experience so far. And while my experience with my grinder has been good to this point, it's not vast experience by any means.

Here's a link to a video I watched that helped me a little getting started. And it talks about wheel vibration a little. I think it's in the 1st 10 minutes or so. The video is over an hour.

http://www.podcast.tv/video-episodes/podcast-%2337-turning-tools-%E2%80%94-sharpen-your-skills-with-sharp-tools-4563243.html
 
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I could agree more joefyffe. Do you have any recommendations on some reputable alternative grinders? I can't really afford the Baldor at the moment, but from what I understand they are the Cadillac and there are probably lots of solid options at only double what I paid for the Ryobi. Thanks for both the fast replies!
 
BSea, thanks for the link, I'll have a look. As for the sharpie test, I did take both wheels off so I only had a spinning shaft - so something there is out.
 
I bought one of these several years ago when a new Home Depot opened in my area. Special grand opening sale! Unbeleivable vibration! I tried everything I could think of to true the wheels. Finally, I gave up and stashed it in a corner...... About a year later, I saw some grinding wheels at Lowes and bought two new ones just for the heck of it. Problem solved! Wasn't such a good buy when all was said and done.
 
Wheels that come on grinders are mostly junk. Even wheels sold at most box stores are not high quality. Quality wheels will make your grinding much more enjoyable...but they aren't cheap...but worth the $$$. New wheels may or may not solve your vibration problem. Take it back. You paid hard earned money and should not have to put up with problems. We should not have to spend more $$ and lots of time to "fix" problems with new tools.

Personally, I have the Harbor Freight 12" disk sander and I'm very happy with it even though others would not even consider HF tools. I love my HF bandsaw and drill press also.

Do a good turn daily!
Don
 
It sounds to me that the wheels are unbalanced, not the shaft. I have a Woodcraft slow grinder that I got on sale for under $100 and I found that taking the wheels off and cleaning the shaft and then slowly turning the wheel by hand as I tightened the nut helped to eliminate any vibration. Sometimes things just need to be tuned up so they are balanced and run well. I tune my bandsaw monthly and it runs great, I also do the same thing to my lathe and drill press. A little dust can make things run poorly and parts wear out quickly and unevenly. I also clean all the metal surfaces and so have no rust, even though I often wet sand and cut wet wood.
 
navycop said:
What is a good speed and horsepower to have as a grinder for sharping lathe chisels?
Click to expand...

I'm not an expert but... slow speed of 1725 RPM will create less heat and remove less steel so it is generally prefered. If you are using a regular grinder of 3450 RPM use the lighter touch so you are not overheating the tool and removing a lot of steel.

Speed of the grinder really doesn't have anything to do with how sharp you will get your tools. It is the type of wheel you use, grit, your technique and if you use jigs or not for consistency.

I took a free class through the local turning club on sharpening that was hands on instruction. Although they explained about RPM and types of wheels the class was really about how to properly use jigs for various tools, technique and what kind of profile to put on different tools. Those are the things that make the difference, not RPM.
 
Oops, for got to mention, I don't think horse power really matters. you are putting very little resistance on it when sharpening.

I also should have mentioned that dressing the wheel occassionally is important. It keeps it round (balanced especially the first time when it is new), it will remove the concave center you will get becuase you sharpen in the center of the wheel not on the very edge and, very importantly, remove any steel from your tool that has built up on the wheel. That build up will not allow the wheel to sharpen as well and will also cause more heat build up.
 
I'll put in my 2 cents worth!! In the past I have used Baldor and it gave excellent service. No wobble, no viberation, in fact after turning on unit it was hard to tell it was running. Recently I got a new Delta, JUNK JUNK JUNK returned it to Delta for a new unit and it was just as bad. It would viberate off the workbench if not bolted down. I did not return the 2nd unit, just put in in the garbarge can and marked it off as a lesson learned. I then bought a Jet and it is good, not as nice as the Baldor, but also not as expensive. The Jet satisfies my needs and I'm happy with it.

Ben
 
Grinder lessons I learned

Agreed about big box grinding wheels, buy the grinder and donate the grey wheels to Goodwill for someone to sharpen lawn mower blades. I think a majority of the vibrations issues are the grinder wheels and the bushings.

I bought two blue grinding wheels from Woodcraft and went through six to get two that were balanced.

I tried the Woodcraft slow speed grinder and returned it. Poor quality grinder all around IMHO. The bearings sounded like they had sand in them.

I also replaced the the nylon bushings that came with the grinding wheels with steel drill bushings 1" OD -- 5/8" ID. That reduced vibration and the wheels run true. The bushings are about $10 ea

I bought the Porter Cable 8" grinder at Lowe's. The stock tool rests were discarded and replaced by a Wolverine jig.
 
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