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Thread: Bench Grinder Extension
10-07-2006, 01:16 AM #1
I've been busy setting up a new shop and when I needed to brush some old paint off some steel plate I am using it took me over an hour to chamge my grinder to a wire wheel. It's an old grinder and several things came up including rust that I would not tolerate.
Anyway, I got to thinking. I only have one grinder and it has a coarse and fine wheel and then I went and bought a wire wheel. So changeing is a fact of use. But what if I mounted the wire wheel on a shaft extension. I could maching a 3 or 4 inch extension that attached via the spindle threads in place of one of the nuts and mount the wire wheel on that. Of course, I would have to extend the safety guard on that side.
But I wonder if this would be a good idea? Would it be safe? I do plan to bolt the grinder down with a loose fit on the screws so it will stay put but the rubber feet will still absorb much of the vibration. So it will not be in danger of coming off the stand. But are there any hidden dangers here?
On the new shop, I will post pictures when it is done.
10-07-2006, 02:15 AM #2
Paul, a couple of ideas -- your extension shaft is not a bad idea at all, but with 4" of extension it would be much safer to run an outboard bearing.
Another idea is to make a pulley that runs in place of the nut, and run the wire wheel on a bearing-supported shaft on a plate extending to the rear of the grinder. To use, just slip on the belt and turn the grinder around. It would spin the "wrong" way, but if you're aware of that, it shouldn't be much of a problem.
Last idea, a dedicated wire wheel on a motor. I have a box of salvaged appliance motors for just such occasions. A light switch, weld or bolt up a frame, turn up an adaptor, and voila! It doesn't need to be elegant.
10-07-2006, 08:00 AM #3
Surely 'Chinese' 6" DE grinders are available for perhaps $15. At that price you can have a bank of the things to do a multitude of tasks including wire brushing.
10-07-2006, 08:28 AM #4
I have five grinders. Sure beats changing and truing wheels all the time.
10-07-2006, 09:23 AM #5
I've been going through this as well trying a few different things. You have the wrong tool. Bench grinders with the guard around the wheels have lots of limitations. The guard is going to prevent you from using most of the wheel. For small stuff you're good. For larger stuff like wire wheeling a flat surface, the bench grinder will come up short.
Also truing a stone after it's remounted is a pain.
A few options I've used.
1) Drill press. Mount wire wheel on an arbor and chuck it up in the drill press. I've had great success using this approach. Also works very good with buffing wheels.
2) If you do this type of work frequenty, you may want to consider setting up a buffer with a wire wheel. Buffer is just like a grinder but with no guards and longer arbors. I've set one buffer up with Scotch Bright wheels and working on another for a wire wheel.
10-07-2006, 10:41 AM #6
If you are wire brushing a flat plate the best way is to use a 4" body grinder with a wire wheel on it. It's easier to hold the grinder than the big plate. Many times they are better than a bench grinder.
10-08-2006, 12:53 AM #7
Yes, I certainly thought about just buying another grinder but my present shop is a bit limited on space. I have not had the luxury of having a wheel available for instant use in the past so I do not really know how much I would use it for so I am a bit hesitant to loose the space that another grinder or buffer would take up. But I suspect it would be handy for a bunch of tasks. It sure is handy for removing old paint and prepairing for painting. I suspect it will be nice for fast deburring also.
And yes, the guards do limit the use of the wheels. That's one reason why I was considering the outboard mounting of the wire wheel. A somewhat skimpy guard would allow better access. As for big plates, I try to keep my projects small. But if I was cleaning up a big part, I would use a hand held wheel for sure.
I really wanted to see if anyone had any horror stories about a rig like that.
10-08-2006, 03:10 AM #8
"I really wanted to see if anyone had any horror stories about a rig like that."
My horror stories are usually about things that seemed like good ideas.
Get a bolt with the same thread as the grinder shaft. Put a bearing on the shank of the bolt, then a spacer, a washer, the wire wheel, another washer, and a long nut.
The other end of the long nut threads onto the shaft threads sticking through the nut that holds the stone on. Put a rubber plug inside the long nut to keep the shaft and bolt from jamming together.
Now all you need is a support for the outboard bearing.
The "extension" can be installed and removed easily without affecting the position of the stone.
10-08-2006, 06:37 AM #9
If you are short of floor or bench space for a grinder/wire wheel unit, mount it to a piece of 3/4 plywood and then mount the plywood directly to the wall. So the unit sort of "sticks" out from the wall. This can be a very strong mount, and creates some floor space.
10-08-2006, 10:33 AM #10
Since you are short on floor space, I would suggest better utilizing any existing equipment you may already have. The extended arbors is a good idea but not without some techical challenges. As I stated earlier, a wire wheel mounted on a mandrel in a drill press also works very good. [img]smile.gif[/img]
When I mentioned limited access with the guards and working with flat plate I wasn't really talking about large sheets. It obviously makes more sense to mount the wheels on a hand held device and keep the work stationary. I mounted a couple of scotch bright wheels on standard pedestal grinder. I quickly grew frustrated on what I could not reach due to presence of guards. Stone wheels definitely need guards for safety purposes. Sotch bright and wire wheels are not in the same category.
10-08-2006, 12:36 PM #11
Please correct me where I'm wrong, (of that I have no great fear) but doesn't the imaginary safety of a guard for insurance against exploding wheels do the opposite? Per force, you are standing at the only, (OK, one of two if collection shute is provided) discharge point of the guard assembly. Kind of like the scroll on a pump or blower, assuring the medium being concentrated at the outlet, INTO YOUR FACE! Ooh, forgot about that indestructable little piece of plastic between you and the barrel of that shotgun. You do ustilize that while working on a large workpiece don't you?
I believe that the "guard" on a grinding wheel was one of those things that seemed like a good idea to contain explosion at the time and without rational thought, was accepted into the lore of humanity as a "safety first" imutable truth, makes us all feel as though we are engaged in proactive defence of life and limb.
As politicians are fond of saying, "perception IS reality", then they smile as if that bit of nonsence even approaches truth. Interpreted, it means, "sheep will always follow bull."
Yes, the guards are in place on my grinders but other than being useful at containing loose abrasive/glowing iron, I won't lie to myself regarding their safety value. OK, the guard will aid in insuring that the pile of errata stacked about your grinder won't be engaged and launched by that spinning wheel but there are other solutions to that.
If in a heavily staffed setting and in an open area, (not against a wall) it will help to insure that the operator alone will get the concentrated blast and that innocent bystanders don't share in dispersed, lower velocity, (by virtue of distance) bits.
I must place my trust in quality manufacture of the wheels, or quiver under my bed in abject cowardice. [img]smile.gif[/img]
Seems to me that in a one man shop, an offset motor, (back or down), driving a small pulley, (less intrusion into the workspace than the larger diameter motor) on a long, well supported arbor, sans guard, is the most useful way to mount a stationary wire wheel. A good face shield will deflect errant little chunks of wire.
Personally, I utilize a large 6" Milwaukee grinder, regular up to 10" or cup type wire wheels, no steenking guard, small pieces held in vise and am prudent enough to not place the wheel against any part of my body while spinning, jeez, why would you?
A lot less dangerous than rock climbing or sky diving and useful to boot.
Two eyed, ten fingered old rabble rousin' Bob
10-08-2006, 01:52 PM #12
Carl Darnell had the right answer--a 4" body grinder. They're cheap at Harbor Freight and work fine for this application. Mount a wire wheel on it. This is perfect anything large enough you can get at it with the grinder. Essential is you do much welding, for example. For anything small, it's still nice to have a mounted wheel. You'll have to work that out with the space you've got. I can only say that if you search around for workshops used by guys that make knives, they manage to cram a lot of grinding into a very small space. Meanwhile, the body grinder with wire wheel can go in a drawer when not in use.
10-08-2006, 06:58 PM #13
I was fortunate enough to pick up a 1/2" drive, 4 foot flex shaft at an employee only auction. I made a mount for the "hand piece" that fits the end of my mill and then just put the other end in the mill's spindle. Just like that I have a 2 horsepower wire wheel with a 1000lb base!!