hand crank grinder wheel?

Re: hand crank grinder wheel?

Peter Evans

>You can easily blue a blade on a hand cranked grinder. Go for a 46 grit open wheel at biggest diameter possible. Something equivalent to a Norton 38A46JVBE. The important codes are "46" for grit, remember you are grinding, not honing and the coarser the frit the cooler the cutting, and the quicker; and "J" for hardness - you want a relatively soft wheel in the range "I" to "K". Lower than "I" wears quickly, harder than "K" heats up the blade quickly, and cuts slower. One reason the wheels on grinders you buy these days have a hardness rating of "M" is because they are cheaper (more bond, less abrasive).

The Blue Norton wheels are even better; there are articles on this site that go into a lot of detail on wheel selection, browse through those.

Cheers Peter in Sydney

Re: hand crank grinder wheel?

KenI

>Thanks. I knew about the information on the site, I just didn't know I should treat a hand crank grinder like a tailed one.

Ken

more information and some dissention

Bill Tindal, E.TN

>At slow speed there will be less force to break the abrasive particles which renews the sharp cutting surfaces. So I would speculate that a softer than normal wheel would be preferred as well as an extremely friable abrasive particle. Also, in my hands, the grits make a coarser scratch at slower speed.

I have a 3 phase grinder running off a VFD drive and I run it at about 200 rpm for fine work on tool edges. I use a 120 grit wheel, H bond and a highly friable pink or white abrasive. I get no burning at any speed with a light touch, but the slow speed gives me more control at the tool edge.

Unless you are shaping tools, in which case a power grinder would make more sense, 46 grit is way more coarse than I would recommend. The blue (seeded gel abrasives, or the blue zirconia abrasives) are designed for high pressure grinding (sturdy particle) and I would think they would be a poor choice for your application. You will never wear a wheel out grinding chisels, so don't fret about wheel life with a soft wheel.

Re: more information and some dissention

Paul Kierstead

>So you find 120 grit white wheel OK for doing a full bevel grind on A2 or O1 metals? I am about to buy a wheel for my hand-cranked grinder myself and am kind of stuck as to which wheel to buy....(I never do harder then A2).

yet more information

Bill Tindal, E.TN

>I do full bevel hollow grinds on chisels and plane irons- O1, A2 and CPM 3V. The slower speed and finer particle size is not necessary to aid edge refinement in the following steps. With a variety of next steps, they all remove even 60 grit scratches during refinement of the edge after hollow grinding. (I happen to use 1 micron diamond as the next and final step.) Nor does the grit size have a practical affect burning if one has a light touch, and the wheel is properly dressed and of proper construction. Yes, one can remove material faster at 46 grit without burning, but I can't remove material that fast and maintain control at the edge so it is of no practical importance. It is a different story if one is altering the shape of a too rather than removing a dull edge. I own a 46 grit wheel for this case and use it at 3600 rpm.

The only benefit I see to finer particle size is to slow the rate of material removal to aid control. It is way bad! to wind up with a not straight edge across the tool edge because the next step will then take forever to reestablish a straight line. What is optimum for wheel grit will depend on your skill level, the abrasion resistance of the metal, and temperament (that is your temperament not the steel's).

There is little doubt that I could not control material removal with a 46 grit wheel, while other's might. But I have used 60,80.100, 120 grit wheels successfully. Remember, that he slower they turn the deeper the scratches they will make. Wheels are cheap. Get an 80 or 100 and try it and then go from there if you feel the need to improve a little. The bottom line is that wheel speed and construction is way more important for good control and minimum heating, than grit size in the range of 120 to 60 (at least in my hands).

How does one person grind with a hand powered grinder? It seems a 3 handed job to me?

Re: yet more information

Paul Kierstead

>How does one person grind with a hand powered grinder? It seems a 3 handed job to me?

Good question! I have no idea, but am interesting in spending some time figuring it out. I expect developing a 'feel' for it, plus perhaps relaxing the urge to be excessively anal retentive. But, in theory, you should be able to feel it some. I think. Heh. I am going to start out on a scrub plane with good sized nicks, so if I don't do a perfect job, it's ok.

I will be shaping irons with this down the road, but will be on unhardened steel, so even then I expect it will be ok.

Re: hand crank grinder wheel?

George Makowski

>Ken, This is a bit OT, but before you bother to get a wheel for your old/new grinder, check the bearing of the wheel spindle to see if it runs true enough to allow consistent work. Many of these grinders have worn out bearings that wobble. That wobble is mutliplied at the edge of the stone and mean that you can't control your grinding with any certainty.

Good sharpening,

George in AL

Re: yet more information

ThomD

>I wouldn't buy the loose partical type of wheel. It's bad enough running those things when you can dive in for a quick cut while holding one's breath, let alone a slow moving hand powered one. I don't see any need to have such a thing on a hand crank wheel, mine is just the regular hard wheel. In fact, the whole dis on grinders electric and otherwise is mostly nonsense. Sure you can crank the thing fast enough, and stupid enough to draw the temper but it's so easy to avoid. There are lots of methods, this one is fool proof (though not really necesarry on a hand crank, but it might be confidence building). Dip your tool in water before you start to grind; start grinding; Keep grinding until the water start to dry off the edge; re-dip. The edge never gets above 150-200. No bad thing can happen.

Keep in mind that if you are grinding D2 or A2, HSS, you can't draw the temper, period. I would electrogrind those without a thought.

To some degree the fragible stones (I still have them on my bench grinder) are outmoded. If you need to grind hard it's sanding belt time, if you are just refreshing an edge they aren't necesarry.

grinding and "loosing" temper

Bill Tindal, E.TN

>Our steels are hardened and then heated to temper the hardness to some lower value, often around Rockwell60. The higher the tempering temperature the softer the steel will become. While grinding one must not get the steel above the temperature it was tempered at or it will become softer than it was.

O-1 (carbon steel), D2 and A2 will be tempered at similar temperatures, likely less than 500 degrees F. While grinding them it would be prudent to keep them equally cool. M2 and 3V on the other hand are "high speed steels" and they are tempered at 900F or higher . Clearly it will be unlikely that the tool will reach this temperature with normal grinding.

shedding heat during grinding, a discussion

Bill Tindal, E.TN

>The friction of the tool rubbing against the wheel, as well as the work done by the abrasive particle digging through the metal, generates heat. A sharp abrasive particle will remove a chip of metal and this chip will carry away a significant amount of heat (that shower of sparks one sees). A dull abrasive particle will plow through the metal and not remove a chip, so all the heat generated stays with the metal piece.

Hence, a wheel that continues to provide sharp abrasive particle edges will grind cooler than one that dulls and stays dull. Abrasive sharpness is enhanced by dressing the wheel, by a friable abrasive particle that breaks to expose a new edge, by a soft bond that ejects the dull particle and/or an engineered particle that microfractures (SG technology).

Re: hand crank grinder wheel?

Moses Yoder in White Pigeon, MI

>A 46 grit wheel is pretty coarse, but as mentioned should grind cooler than the 80 grit that I use. The hand cranked grinder for some reason is the galoot's secret. Even many galoots I know would not have one. I think people assume that it would be too difficult for them to grind with one hand and move the iron with the other hand. I like the hand cranked grinder because it is so easy to control. I use an 80 grit white friable wheel mostly because that is the grit that was in the box full of wheels I bought at the auction for $5. The 46 grit that was recommended will work fine.

Re: yet more information

Moses Yoder in White Pigeon, MI

> " How does one person grind with a hand powered grinder? It seems a 3 handed job to me?

I think you have just made the hand cranked grinder my favorite tool. I will think of you every time I use it ;) You crank with your right hand (if you are right handed) and control the tool with your left hand. You need a decent tool rest. In high school I went to a career center, where at the age of 17 or so I made the brilliant decision to take a course on small engine repair instead of electronics or computers. So much for the accuracy of iq tests. The teacher there showed me that the only thing you need to do is keep the sparks in the center of the wheel.

Re: hand crank grinder wheel?

ThomD

>Krenov wrote about it in his early books. I got one when I found it cheap at a tool barn. I'm living a little further down the road, but it could be useful.

Re: hand crank grinder wheel?

Phil Joines Krum,TX

>Where do you all get the wheels? I need a 4" and haven't found any smaller than 6.

where ever machine shop supplies are sold

Bill Tindal, E.TN

>MSC would be my first choice for mail order. Any local place that sells into the trade will order anything you need if you want to shop local.