[mark yundt]

Has your attention ever drifted off for a second while carving and you sliced your finger? Has by lack of attention your shirt or something get caught in a power tool ?Has anyone ever heard of some sort of disaster occuring in or around sharp spinning blades in notoriously dangerous shops and power tools? I can say yes to at least all of these.
When I walk up to a power tool in my or anyone elses shop I expect it to run directionally as it habitually does. I have several bench grinders and when I or a friend turn them on,,they go the same direction,towards you and down. These are what I use as a power strop. Even knowing which way they turn I occasionally have brain farts,,the tool gets caught ,and like a bullet shoots at the floor before I realize or could react to what happened.
The last thought I want to go through my brain,,following the chisel implanted there is "$hit,I forgot,,this one spins the other way"Too late pal.
Even if I remembered every time which way a bench grinder spins,,I'd rather have a chisel shoot at the floor,,or stick in my foot,,than have to remove it from my eye,,neck or some other spot in my head.I would be mortified if that should happen to a friend using my shop,,and I didn't tell him or he didn't realize ( out of habit) that the tool is spinning over 3,000 RPM in the direction opposite of what you normally expect. This isn't a manually powered knife resuting in a nasty cut,,this is propelling a chisel like a bolt out of a crossbow!
Now I'm not saying you shouldn't ( though I really am) or that you can't reverse the direction of bench grinders.I'm merely suggesting that you might be inviting a distaster to happen to yourself or a friend.It only takes that one split second of inattention ( you should see the gouges in my felt wheel) to watch the poop hit the wheel. Let the chisel end up sticking in the ground,,not your forehead.Every shop I visit,,and those that visit me,know what to expect from our tools,and it's no problem for any of us to buff using a grinder spinning in the "right" direction.And when it's left running you can't really see which way it's going. A surprise of reversing directions would be the worst kind of surprise to allow to happen.
BE careful,,err on the side of caution.

[chuckt]

Hmm - interesting and critical thoughts Mark. I have heard it argued in both directions as to what the "right" direction is.

I suppose then that from your perspective there is a long history of grinders spinning "towards" the worker at the top of a vertical wheel and away at the bottom. I assume also this means that there is likewise a long history of folks knowing how to address the tool to the wheel with this orientation in mind (i.e. NOT from the top of the wheel - but the front or the bottom?) such that if the tool catches it is thrown down to the ground.

Is this correct?

Becuse I have seen some well respected carvers, sharpeners, and tool makers who seem to orient their grinders the opposite. I presume this is in order to allow the tool to be applied to the TOP of a vertically oriented wheel, rather than the front or bottom with the wheel's surface spinning AWAY from the edge - which seems to me to be "right".

So I guess this direction of rotation question depends on whether the tools edge should be applied to the wheel with the wheel spinning INTO the tool's edge - or AWAY from the tools edge. No? The answer to THAT question and whether you want to approach the wheel from the TOP versus the bottom - determines which direction is the SAFE (right) direction. No?

This is difficult to describe so I hope this makes sense.

The problem as you point out - is when we assume (through repetition and learned carelessness) that ALL others will approach it the same way. The other problem seems to be getting everyone to AGREE on a standard approach and therefore "right" direction for the wheel to turn.

Am I missing something? Because I have NO practical experience in this, only observational and "book" learning. Please clear this up for me.

Thanks!
ChuckT

[Thomp]

Tool safety:
most of us know the rules, hardly any of us obey them every time we turn on a motor! if you were to think back to the last 10 times you got hurt you wasent as safe as you could have been,
yes there is a few times where it couldnt be avoided at that moment,. but you can think back how you might not have been injured if you would have thought of the possibility of that accident from happening in that way,
with experiance comes the knowledge of safety.

certinly you cant don all the safety equipment osha requires every time you go out into the shop, IE: if your carving you dont need a face mask and hearing protection steel toed boots and breathing appritus, but we do need the essentials. in this heat you would have a stroke...

Mark has made some great points of unexpected hazards around any shop,

any tool that can cut grind or gnaw up wood can do that to your hide, loose clothing, jewelry, long flowing hair, for a few items.. dont have a place in a shop, wear your safety equipment and if your distracted put the job off till you can concentrate on the task at hand,

-snip-

power tools are a great advantage and take the drudgery out of lots of work, they can hog off unwanted stock in a hurry, or shine up a dull tool, but will eat fingers as well.

I like the idea of a apron and full face mask when working on sharp things, and bits can be flying into the air,
no gloves becuse they can get intangled in blades and wheels,
the worst problem i have with the current little shop syndrome is clutter.

Kenny,
another thing to look into for power sharpeners is the wheel chair motors,
most places that make them buy the ones back from familys no longer needing them, and rebuild the chairs with new motors so they can garentee them, and toss the old motors, some are really good and are some are still 12vdc, they turn slow or set on a reostat so you can use them at a veriable speed..

[mark yundt]

You're right,,we all do take our fair share of risks,,Lord know's I have and for the most part have been lucky.Experience helps,,but I know many woodworkers with their share of missing body parts and really nasty looking scars and fingers that don't work quite right.After an accident don't we all say,,"I always wear my carving glove.." "I knew which way it was spinning but,," "I only looked away for a second and..." "This was the last cut and figured I could just..." Isn't that the way it happens?
Pretty much every bench grinder I have seen and used spins towards you and down. My wet wheel goes the same way,,same for the grinder on it's side. A stone on a grinder won't catch a chisel the same way a felt or cloth wheel will.Also with a stone,,the sparks fly down,,( no,,you're not grinding a chisel with sparks like this) and should anything get caught which way will it travel? Same if you have a wire wheel in there. Otherwise everything will spray directly up into your face.I understand the rationale for having it spin the other direction,,you can lay the chisel on the top of the wheel and better see the angle and such.But are you using a high speed bench grinder to sharpen your chisels??? Probably not ,,just buff and strop.It certainly will work,,but don't ever get that chisel touching the wheel any where near horizontal or below it,,or you'll see it close up real quick.
like I said,,even with how I use mine,,primarily for buffing and polishing,,and I don't have to think how they spin,,occasionally It does get caught. I'd rather pick a chipped chisel off the floor than out of my head.
Just thinking of what would happen if mine spun the other way,,whatever the reason for it doing that,,and I had as I said a brain fart,,only just the smallest moment of inattention,,,the only direction is up.I may not be much to look at,,but a chisel sticking out of my head won't help much.
Gives me the creeps just imagining it,,like watching an episode of that show Scarred,,,

[chuckt]

Thanks Mark -

So let me see if I am understanding this correctly. No matter what speed the tool is turning (500rpm, 1750rmp, or 3450rpm etc.), the manufacturers ALL make them to spin towards you and down at the top of the wheel.

So therefore we should get into the habit of ALWAYS addressing the wheel with the tool at the BOTTOM of the wheel with the blade edge facing DOWN/AWAY (handle up in the case of a gouge). So the wheel is removing metal AWAY from the tool edge (i.e. DOWN the bevel) - right?

So even though it may be more difficult to gauge the correct angle in this position (I assume) this is the safest approach. I just want to be sure I am getting this right.

I agree with Thomp that the direction of rotation should always be clearly marked just as a reminder.

Thanks for the words of wisdom to us grinder/sharpening NEWBIES and veterans alike.

!
ChuckT
(who pales at the thought of a sharpened gouge being launched at his chest/face like a bullet)

[Thomp]

Chuck at the risk of over staiting the method,

with a wheel grinder it is usually sent from the factory with the direction of rotation so that it will throw sparks and mis braced tools at the floor, your foot or legs,


i dont sharpen my tools on a grinder i use a belt sander touch and dip method to keep the tool temper cool...

edited for content,,,

[chuckt]

Understood Thomp. By turning the grinder around you are effectively "reversing" the rotation of tool by approaching from the back. But it sounds like Mark is saying this is a dangerous way to approach the tool - IF - you are used to working the OTHER way or are not cognizant, because you could more easily address the tool to the wheel incorrectly and have it embedded in your head.

My point in my first post addressing Mark - was that whether a tool flys AT you depends not just on the direction of the rotation but also on how you address the tool to the grinder/wheel from the TOP or BOTTOM.

His argument seems to be that because this is way ALL grinders/buffers are designed and manufactured, that is the way MOST users will expect a wheel to turn, and therefore the danger with reversing that is that an unsuspecting user will approach the wheel with tool from the opposite direction and have a tool thrown at them. Therefore, this is a bad idea given THE NORM.

You seem to have mitigated this problem by using your tools in a consistent way (not switching between the two types - an assumption on my part) and marking the direction of rotation clearly.

So Mark - am I getting this right?

ChuckT

[chuckt]

The otehr factor here that I was trying to get at - is there some scientific sharpening advantage or disadvantage from having the metal of the knife edge or gouge edge address the wheel into the rotation as opposed to away from the rotation? (ie - metal pulled away from the bevel vs into the bevel)

Thoughts?
ChuckT

[mark yundt]

Yup,,you got it right.
And no,,I don't think there is any metallurgical reason as to how the metal is taken off. BUT this doesn't mean you are facing the chisel into the direction of rotation regardless how you spin the grinder. I used to make custom knives as well as straight razor knives and I used the grinder in the traditional way. I preferred being able to use my body weight to press the steel into the wheel and be able to lock my arms against my body for leverage.Just as you see metal polishers do when prepping for chroming and such.Also the books I had seen on building knives did it this way as well.For me anyway it was a more controllable and powerful way to grind steel.I have used two grinders put back to back with the wheels almost touching and laying the steel between the two spinning wheels. Almost perfect hollow grinds were made this way,,but it's an unusual situation.
I had worked with a harpsichord builder,,he used a really long belt sander type set up with an idler wheel on the wall. Here ,naturally ,the belt HAS to run away from you . Belts did occasionally let loose but it wasn't a big deal. No real threat to life or limb.
Same with the 16 ft by 12 inch belts for a surface sander I used to use. And here you had to put your hand inbetween the belts and press one down to sand the surface you were working on.They ripped, took off and no real big deal even with your hand in between them.
You or anyone can use a grinder any way you see fit.Apparently it's done by many. I ,,nor any of the dozen or so shops I frequent ,up to major production shops,,have anything set up like this and somehow I learned to manage with hundreds of chisels and thousands of carvings.But the choice is yours.If it works for you ,,go for it.
Personally ,,seeing what damage I have already done with something I already know,,I just couldn't trust myself.Not too much scares me in a shop. Pushing little pieces by hand though a 12 inch jointer,,small,,odd pieces through a table saw,,,holding tiny pieces by hand using a router ,cut off or band saw. But for some reason,,maybe it's just me,,and seeing how many times a stupid little grinder has sent a chisel ,knife,,bolt flying ,,that's the one thing that bothers me.Seems silly I know considering how dangerous a shop is,,but it catches me more often than anything. Guess that's why I had to say something.

[mark yundt]

Come to think of it. How does a baseball pitching machine work?A ball basically gets snagged on a spinning wheel and shoots at you at 90 MPH. What if that were a steel shank .Spin the grinder any way you like,,just don't EVER make a mistake like I occasionally do.Slow speed with a stone,,no real threat,,3750 rpm with a cloth or felt wheel,,that's a different story.