Wheel grinder technique, safety
forestgirl
| Posted in Power Tools and Machinery on
What can you guys tell me about using a bench grinder safely. I’ve only used mine a little bit — it has all the guards and such. But I was cleaning off the end of a just-cut thin metal bar the other day and didn’t feel like I was doing it right. With the wheel spinning down seems like catching is a likely event. Need general “how to use it” stuff here, thanks!
forestgirl — you can take the girl out of the forest, but you can’t take the forest out of the girl 😉
Replies
If you feel it catching move the tool rest closer to the wheel .You have a lathe, same idea.If the metal is really thin clamp it with visegrips to a piece of 1/8 bar stock and keep the rest close .If it still feels bad use a file.Make sure that the stone is dressed round and use a light touch
Jako's right on the money. I keep the tool rest as close to the wheel as possible (about 1/8" away) and hold my workpiece flat on the rest. I always hold small parts with a pair of Vice Grips, but have found that small screws or bolts are best done safely by hand. For grinding wheels, you want the wheel moving downwards when viewed from the front. For buffing / stropping, you want the wheel spinning upwards.
Chris @ flairwoodworks
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
My grinders go down. On a never-sharpening machine with a leather strop, the wheels go up. At a large golf company I was at where they did all the final buffing with huge wheels, they also went down. Whats the rational for the buffing pad on a grinder going up? How do you set up the grinder? Do you stand on opposite side or reverse polarity?
I would think having the wheels go up would drive most of the flyoff back into your face. No?John
Edited 2/13/2008 11:08 am by boilerbay
John, I'm looking forward to the information you asked about (especially how to get the "up" arrangement), but his post isn't the first where I've seen that precaution urged.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
To get the wheels to spin upwards, the simplest is to remove the gaurds and, as Jako mentioned, stand behind the grinder. This, however, puts the machine between you and the switch. You could mount another switch on the other side if you so desired.
There is another way, though. If you look under the base of your angle grinder, you will likely find a bolt which secures the motor/arbor assembly to the base. If you loosen this bolt, you can turn the motor/arbor assembly around so that it faces the opposite direction. All that's left to do is to remount the guards, should you choose to do so. The only drawback is that if you use one grinding wheel on one side and one stropping wheel on the other, you constantly need to turn the motor around.Chris @ flairwoodworks
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
Thanks everyone for all the tips! Re: this business of having the wheels run up instead of down, we have like 3 or 4 (or maybe even 5) ginders (did I mention my husband is a pack-rat?), so I can just take one of those and rig it up for buffing. Cool, eh? Thanks, Chris, for the tip above.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 2/13/2008 11:55 pm by forestgirl
John,
Couple of thoughts, 1. might not work though.
1. Stand on your head.
2. Make a cradle/fixture with perhaps its own tool rest and flip the grinder upside down.
Sorry forestgirl!
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 2/13/2008 11:05 am ET by KiddervilleAcres
If I stood on my head, with lack of hair, it would roll a lot. Give everything a camber. Maybe sell the technique to LV? Model 4.
John
John,
Nyuk, Nyuk, Nyuk that was funny. Can I at least get a bit for the idea?
I wasn't exactly joking about #2 though. I did that and it works rather well. Gives the grinder a bit more flexibility and utility, and might just save a buck or three.
When you want to use it in normal mode, just flip it back over out of the cradle.fixture.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
You stand behind the grinder with the guard rotated so the opening is at the top.So buffing is done on the top with the felt rotating away from you
John,
Stropping is normally done on a soft surface covered with honing compound. If the wheel is rotating down (towards the edge), it is almost inevitable that the tool will dig into the wheel. Not good. If it rotates upwards (away from the edge) this is impossible.Chris @ flairwoodworks
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
"Stropping is normally done on a soft surface covered with honing compound."
The stropping, I am use to. As I said, I have one rig (with a leather stropping wheel) that rotates in that direction - up. It is the buffing comment that presents the problem. Even if standing behind and moving the guard, the wheel will still be going toward you, into your face, but standing to the front of a grinder equipped with buffing wheels, the wheels, unless running backwards will still be going down and away from you. Much safer.
As I said before, I have been to factories than had their buffers running down. I doubt that OSHA would allow it any other way.
I get great results on wood and metals running the buffing wheels down.
To each his own. JohnEdited 2/14/2008 12:01 am by boilerbay
Edited 2/14/2008 12:05 am by boilerbay
Bench grinders of any reasonable quality are handed i.e there is a left hand thread on the left side and a right hand thread on the right so that when the wheels are spinning downwards, as designed , so that the tool rests can do their job, those nuts tend to be tightened due to the direction of rotation .
I don't think it is a good plan to mix grinding and buffing or stropping on a bench grinder-it is designed for grinding really.Philip Marcou
Philip I don't get you. If you modify the grinder as I suggested ,what's the problem?only the inconvienence of being able to access both sides (Mine swings up on a bracket t the end of a bench so access is easy.I do appreciate that the switch is inaccessable when buffing on the felt wheel
Jako,
No problem if one does as you suggest: stand on the opposite side and rotate the guards. I was just pointing out that if one reverses the rotation of the wheels either by swapping end for end or by spindle reversal the nuts can loosen.Philip Marcou
1. As other have stated, keep the tool support as close to the wheel as possible but also try to keep it at or above the center of the wheel as viewed from the end. This will help avoid the tendancy for the part to be drawn between the wheel and the support. When the time comes (and it will) when the tool support cannot be used, get it WAY out of the way or better yet remove it altogether for that job.
2. Use goggles or better yet a full face shield (but you knew that).
3. Clamping small parts with a vice grips is pretty good but even better is something I discovered only a few years ago called a "hand vice". Little gadget that looks like a tiny vice but held in the hand. It's infinitely more secure that vice grips IMHO. Got mine on E-bay for around $6 IIRC.
4. Keep water handy, not only for quenching, but just in case some sparks land on something that starts to smolder.
5. Have good lighting at the grinder but rig up a cover for bulbs that are close. If there's an accident, you don't want it compounded by busted light bulbs.
6. If it doesn't spark, don't grind it!! Many materials will "fill up" the wheel and cause them to disintegrate in a very spectacular and dangerous fashion!
Regards,
Mack
"WISH IN ONE HAND, S--T IN THE OTHER AND SEE WHICH FILLS UP FIRST"
When using a wire wheel of cloth buffing wheel. ALWAYS ! use the lower 1/4th of the wheel, wheel should be going down and away. Better to have a piece pulled away from you than getting thrown at you. OOPS, Forgot to mention that the side I use for wire wheel and buffer has no guard.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
Edited 2/13/2008 10:26 pm ET by BruceS
Forest girl , use a vertical sanding machine like 1"x42" or even a disk sander instead of the grinder. Your're correct in being wary of grinding a thin piece of metal on a grinder.I do this several times a week on a grizzly 1"xmaybe 36" or 42", not sure which size. I've had this sander a couple of years and only changed the belt once.
mike
Thanks, Mike, I have a disc sander tucked away in the corner.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Hi Mike,
I've got a small 1" belt sander that I thought I'd like to use to sharpen/hone curved blades, i.e. carving gouges and curved turning tools. Have you ever used yours for these tools?
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 2/15/2008 7:24 am ET by KiddervilleAcres
No I haven't personally but a lot of people do with success. I have a friend who uses a homemade 2" wide stationary belt sander for almost all his sharpening. The only use the grinder gets is for metal lathe tools.He has the belt revolving upwards, a good feature that will prevent a tool from catching. Most of his sharpening is for wood lathe tools. His method works as he sharpens tools for a lot of his neighbors.
mike
Bob has got a mini belt grinder by the sound of it, and your friend with the home made 2 inch belt grinder has definitely seen the light.
There are many differences between a belt sander and a belt grinder, but if one keeps in mind that coated abrasives are far more efficient than vitrified wheels one is on the way to enlightenment.
At this stage it seems that the average home woodworm is yet to appreciate how much more useful one of these is when compared to a bench grinder. Possibly there is also the notion that it is a "factory" item or something only used by industry-I don't know.Philip Marcou
philip,
You're right I do have a 1" belt sander as Delta calls it. I take the backer off when sharpening and it seems to work very well for my carving chisels. I use a rather worn out 220 grit belt. The give on the belt without the backer lets me hone and not wory about taking off too much steel.
Could you elaborate a bit more on a belt grinder; perhaps a pic?
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Bob,
Typically a belt grinder moves at speeds of 4000 to 7000 sfpm (surface feet per minute), which is a lot faster than speeds for wood sanders. So not good for wood applications because of burning, but mighty useful for woodworkers who want alternative ways to sharpen and grind, make and shape cutters such as those for moulding planes and shapers and for general metal working that some woodworkers do, such as cleaning up plane irons and parts.
Coated abrasives are far more efficient than vitrified wheel grinders (bench grinders) and there is much less heat involved. Example: the rounded heel and toe of a plane- this is 8mm thick tool steel-I do this by hogging off the waste free hand then refining it with a disc sander, which is far quicker than band sawing then refining-and there is no problem with heat.
They are versatile because one can use a wide range of belt types (believe me there are hundreds) and different diameter contact wheels made of various materials. One can grind on the wheel, or on the flat, either vertical or horizontal, with or without a platten. One can use a tool post or merely freehand . Contact wheels can be soft or hard, smooth or grooved- this affects the rate of material removal and surface texture. One can also use a leather belt which is impregnated with abrasive paste-excellent for honing carving tools and lathe tools, whilst a course belt is good for shaping lathe tools.
The real thing is an expensive machine but I have seen many home made ones which are probably more versatile because they are purpose made. I made one basically for knife making, but also made sure it would take a range of belt lengths- I had acquired a large quantity of abrasive belts . I made sure it could take different diameter contact wheels and fitted it with plattens and a work table as well as a variable angle tool rest, and several spindle speeds.(One needs to speed up the spindle if a smaller contact wheel is used). I can also operate it with either two wheels or three wheels. It all looks very crude but it works well and has saved me a lot of time and frustration. (Obviously the thing is dear to my heart).
And on the other side of the spindle I have two Scotchbrite wheels- such as Steinmetz has described....Philip Marcou
Edited 2/17/2008 3:06 am by philip
Jamie, Thin (Sharp) metal on a grinding wheel can and do catch and usually cut you. I fabricate many parts with sheet metal. To de-burr or blunt any sharp edges, I use a smooth file ,but If you want to hold thin objects to the wheel, consider supporting the piece with a flat wooden shoe to keep from warping.
Best way is to use a medium Scotchbrite wheel as it not only removes material, but, it contours and polishes and removes scratches and pits.
The wheel is made of woven fiber impregnated with fine abrasive.
It won't shatter like a stone wheel or overheat and ruin cutting tools.
Grainger has them and they last forever. I use them to polish tools,brass,aluminum, copper, kitchen wear, jewelry,etc.
If you don't want to fit the Scotchbrite onto your bench grinder, attach it to an arbor and use it in your electric drill. Steinmetz.
Edited 2/17/2008 2:25 am ET by Steinmetz
Thanks, Stein, that info is very useful. This piece of metal was galvanized, about 1.25" wide, 4' long "strap" with holes for nails. Not super-thin, maybe 1/16"? Of course, it was awkward because of its length. Anywho, will use a file next time.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
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