Bench Grinders, Wheels Sizes And Shapes

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BillWood

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Hey,

Would I really notice a huge difference if I upgraded my 20 year old el cheapo 6" ryobi 1/3HP grinder for a 6" grinder with bigger stronger motor ?

How about 8" grinders - are they really worth it - for starters the wheels seem far more expensive.

I think the white wheels are great compared to the grey wheels I got with the grinder.

Do many people use those fancy recessed or the fancy flared cup grinders ? Seems to me that they would make life much easier for getting straight grinds on known angles for metal lathe toolbits but I get the impression that very few people use them.

I also get the impression that lots of people grind on the flat side of conventional wheels despite manufacturers warnings.

Saw this the other day ............. http://www.nortonindustrial.com//uploadedFiles/SGindnortonabrasives/Documents/Safety-SideGrindingForPrecisionApplications-Norton(1).pdf

Off down the shops now to ask the same questions.

Bill
 
8" grinders are generally more powerful, Bill. You can put a 6" wheel on an 8" grinder which would increase the power at the wheel, but the grinding rest will have to be extended. Or you can modify a 6" grinder shroud to fit the 8" grinder motor.

Youd need to check to see that your 6" wheel has a 5/8" hole. Some 6" grinders have 1/2" shafts.

I think the cupped wheels have a larger (1" I think) hole. They would require a special bushing to fit on a regular bench grinder. Not a difficult thing to make if you have a metal lathe.
 
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I just replaced my Ryobi 6" grinder (also 20-25 yrs old) with a Jet 6". It makes a huge difference! My Ryobi would bog down if a approached it with a tool to grind, let alone actually touch the wheel. And the more substantial base and housing seems to make for a far smoother running machine. My only complaint is the tool rests. They were rough castings that required some machining to make useable.

Cheers,
Tom
 
I use my disk grinder almost exclusively. If you are looking at spending money, I'd look into that instead of buying a new bench grinder. A lot safer than using the side of the wheel.
 
Thanks for the replies.

Have googled disc grinder to find out more about them, but all I get is variations of angle grinders - what should I use in my google search ?

Bill
 
Although the OP didn't specifically state it, my impression is that he's mostly concerned with sharpening and shaping cutting tools ... ??

We all know that grinding on the side of the wheel is very bad ju-ju but we do it often - shame on us ! This can be avoided however by first roughing the project using the bench grinder coarse and fine wheels and then transferring to a disc sander for finishing. Just a thought -

If fab work is being done, big wheels and big horsepower are suggested IMO. However when I do welding work, I've managed to get by with just a body grinder equipped with an 80 grit wheel + sanding disc with finer grit paper for finer work.

A little practice with a body grinder makes it fairly easy to contour welds, chamfer/radius rough edges and even do some cutting. Not to mention that it's easier to move the tool than the work if large fabrications are concerned, LOL.

OK, this is probably completely off topic, LOL, the OP didn't even mention welding or large work.

For HSM "normal" applications, one can get by with a 6 inch 1/3 HP grinder equipped with coarse and fine aluminum oxide wheels + a green wheel available for carbide. More horse power would be desirable, I suppose, but not necessarily a larger wheel IMO.

This is all dependent on one's application, of course and long distance advice is worth exactly what you pay for it :)
 
BillWood said:
Thanks for the replies.

Have googled disc grinder to find out more about them, but all I get is variations of angle grinders - what should I use in my google search ?

Bill
Click to expand...

Try ''disk sander''
 
Thanks for the tips.

RandyC .................... Yes I am primarily interested in sharpening HSS cutting tools

I tried using my disc sander today and was pleasantly surprised by the results. Puzzled about how to get the top rake without using a wheel though.

Is there a best possible sandpaper type to use on the disc sander and on the belt sander ?

I had a go at this method today ( http://www.mechanicalphilosopher.com/kbsharpening.pdf ) but I wasnt very succesful - will have another go tomorrow I thinks its only for a final sharpen after the shape has been rough ground.

I bought an el cheapo grinder / belt sander combo and will have a try with that as well.

Being as I cannot slow down or stall my 6" grinder when I use it am wondering about why bigger wheels and more powerful motors are necessary - maybe I am responding to clever advertising ?

Bill
 
For genereal use I have an 8" H Frt pedestal buffer/grinder. The 8" grey wheel will power through and not blink. Great for roughing. But it is a pain to balance with the cheap HF grey wheels which can suffer from poor arbor centering and hole dia . Until solved the pedestal will walk which is aggravating. I used the poor man's fix which is to drill small holes at one radius on inner and outer retaining washer . Then move the washers around until you find the sweet spot.
 
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