# Bench disc grinder from 8" bench grinder



## Dutch (May 28, 2011)

Paid $50 for a new 8" 3/4 hp bench grinder from HF.




Replicated the spindle of a 5/8-11 angle grinder:







I eventually put a new 8" wire wheel on the other end as I end up using a lot of salvaged (rusty) steel so it's used quite abit both ways. The disc size is 7 1/2". It will also take 4 1/2" grinding wheels for angle grinders. It's very practical for grinding radius on steel in weldments. Nothing precision just for ornamental esoterica.

Dutch


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## Old Iron (May 28, 2011)

Where theres a will theres always a way great idea!!

Paul


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## HMF (May 29, 2011)

Folks,

My sincere apologies to everyone for the comments by one poster in this thread that were less than kind or diplomatic - the comments and responses to them were removed to keep the thread informative and non-confrontational.

While my philosphy is not to meddle, or impose myself on the members here, I don't have any intention of watching any of you get "roughed up" the way other forums permit. We can disagree, without being disagreeable. Some machinists feel that every lesson must be delivered at the end of a boot. I disagree.
Patience accomplishes the same thing without the sting.

Thank you for your patience.


Best,


Nelson


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## Tony Wells (May 29, 2011)

My only concern is as I stated earlier: Bearing life. The type of wheels used on angle grinders are extremely tough, and take tons of abuse when used as designed, on the end of a hand held grinder. If they can take that, then surely they would be no more dangerous in this configuration. I suppose if you concentrated enough in one spot to wear a groove in the disc, a ring would be flung off, but Darwin's rules make that ok, right? 

Norman's only point to be considered should be the lack of guards. I would tend to agree that guards are a good idea in general. Not that I've never ditched them when I needed to get a little more use out of a grinder. But I've also seen the results of the lack of them. And felt it. Fortunately, not in any serious accidents on my part, but I have seen others that were serious. 

And wire wheels are inherently dangerous by their very construction, guard or no. Then common sense has to be observed, stay out of the line of fire, and no loose clothing or anything that would grab. That's not pleasant.

Anyway....let's let Norman drop out quietly. It's better that way.


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## Dutch (May 30, 2011)

A guard over the top of the wheel wouldn't do much. The left side of the wheel is the side used. This can result in a ricochet effect off the table. Safety glasses are mandatory. 

The relative safety of such a power tool rests not in any state-mandated guards but in the actions of the operator. You need not work around fast RPM abrasive machines very long before you learn how dangerous they can be. I use this disc sander to round edges like the table itself and the angle iron base. All those rounded corners were done on this disc sander. 

While building this disc sander I was de-rusting the 3/8" plate using an angle grinder fitted with a standard cup wire wheel. I was wearing my regular denum shop apron. Leaning over for all this caused the shop apron to hang a little too far forward and it got caught in the 11,000 rpm wire wheel of the angle grinder. Happened real fast and ripped that apron right off me. It stalled the grinder right now. (notice there's a guard on the angle grinder... for all the good it did)








Bearing life: Harbor Freight bench grinder $50. What would the replacement cost of the bearings be? If it was over $20 it'd be more prudent to just replace the grinder. However, bearings are relatively inexpensive. I'm 60. If I get 5 years of use out of this disc sander it will have been a good cost return. My lathe tool grinder is a Craftsman 1/4 hp I bought when I was 19. The bearings are about shot and it'll be replaced very soon with a bigger hp unit. Forty years out of a $20 Craftsman grinder ain't too shabby considering the hard use it's had. 

I appreciate concerns over safety. I worked 23 years in a diesel maintainece garage for Los Angeles County Metro, 10 of those as a leadman. Some accidents result in death in such a place. I was pretty hardcore when it came to looking out for the people on my crew, sometimes to the utter contempt of ~management~. I never lost an argument over safety because I knew the job better than anybody else and I took responsibility every time I said 'no' to a supervisor. 

I don't mind someone raising an issue of safety. But you better do it in plain English without hyperbole. You'll find I'm a capable communicator but I won't suffer fools.

This disc sander was built in July, 2009 so it's had almost 2 years of use. It's been an excellent addition to my shop. 

Dutch


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## Tony Wells (May 30, 2011)

I've had a wire wheel grab my apron and jump out of my hands only to climb up into my chin about the time it stalled out. Glad the trigger lock was not engaged. I've spent a few hours (ha!) on an angle grinder, and been bit more than once. Doesn't seem to help all the time to have guards and such, but I suppose there are times when they have prevented a skinned knuckle or two for me. 

Recently, I've been using an adapter to spin Radiac cutoff wheels on an angle grinder. Once they are two small for use on a 14" saw, there is still some life in them used carefully on a grinder. They make pretty good hand finishing grinders.


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## Nikon Ron (Mar 31, 2013)

*Re: Bench disc grinder from 8" bench grinder*

I like this idea Dutch. I just happen to have a spare motor lying around for a project like this. I agree with other posts that basic guards would be a good idea. Of course, it isn't as if I need any more ideas for working in my shop. Thanks for the picture.


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