Thursday, May 24, 2012

Got dem bevel grindin' blues

*insert likely Blues lyrics informing you I woke up this morning (yes, I woke up this morning), ain't got no money (no, ain't got a cent) and so forth*

So, do we have any Pelmanists in the house? Because I'm going to ask the reader to perform a feat of memory and cast your mind back again. Good news though; this time it's merely a little over a year since I succumbed to the power of suggestion, the Oh Look It's Got 10% Off Effect (infinitely more dangerous than the Schwarz Effect), and plain old curiosity, and purchased one of them thar fancy blue Norton 3X grinding wheels. And now I've finally got round to fitting it on my beloved "Mole".

That, gentle reader, is an awesome combination right there. The "Mole", the ever-useful grinder tool rest by you-know-who (which would only be improved if it wasn't aluminium that clings to the grit like a mother with her new-born - but then I couldn't afford it at all, so...), and this powder blue thing. Turns out my previous Norton wheel was both harder and finer than I had thought, which did the baby blue new boy some extra favours in making me go "Wow", but even so. It does, as they claim, cut fast, and thus run very cool indeed.

As I was playing, er.. I mean as I had my nose to the grindstone, I thought I might mention a few things that occasionally come up on the matter.

First, why grind? Some folks seem to actively see it as a matter of pride that their preferred sharpening regime means they don't use a grinder. To me that's like prepping stock from the rough with nothing coarser than a jointer plane; you can do it, but it's not terribly efficient. Grinding is the jack plane of my sharpening; it's allows me to quickly get rid of material that's in the way of the finished edge I want, and starts me on the road to that edge. And as nothing of the grinding will actually end up in the finished edge, I can grind coarse, and thus fast and cool. I suspect some woodworkers get thrown a loop by all the wheels aimed at the roundy-spinny turning brigade, who, of course, often do use a grinder to get their finished edge.

A hand grinder-specific problem is that of bushings. Norton thoughtfully provide them down to 5/8" - but ye olde hand-grinder manufactures often made their shafts smaller than that. That's kinda worrying if you're new to purchasing such a grinder, but it's worth remembering the arbor isn't what's holding the wheel. Nope, it's the washers bearing on the side of the wheel (and the paper washers thereon) that are doing the work. Allow me to direct you to Mr Hand Grinder, Tom Thornton's Old Tools List post on how to work with an oversized bushing and an undersized shaft.

Having said which, it's a lot easier - if you have a lathe about your person - to turn up a bushing smaller still, to fit. Which I did some years ago, and which is just as good now as when I made it. Arguably that isn't saying much, but it does the job.

The other hand-cranked grinder worry is Pat Head Rub Stomach Syndrome, and the concern that one won't be able to do it. I certainly wondered. The Veritas rest, or similar designs that have a blade holder, do give one some confidence in that respect. Set the grinding victim up in the holder and just slide it back and forth across the wheel. It's how I started, but it is a bit limiting. You should have some slack in the slot so you can pull the edge away from the wheel, but unless you set up very carefully you can find you can't push the steel into the wheel far enough once you've already ground some off. Also I found it depressingly easy to cack-handedly drive the edge hard into the wheel as I was trying to manoeuvre the blade holder into the slot.

So I ended up losing the blade holder and going freehand. Because of the limitations of where I could set up the grinder at the time, I ended up learning all this with my left hand whilst I cranked with my right, despite being very right-handed as a normal rule. The key thing is to retain control over the tool (surprise), and there are a couple of ways I do it.

Firstly you can act like the blade holder and use the slot (if available) as your guide. The first finger is providing the down force on the tool rest - with the bonus of being able to tell if the steel is starting to heat up.  The thumb and middle finger are providing the side support, with the middle finger also acting as the "clutch". I'll explain about that in moment. Personally I don't find it the ideal set up, but it's handy for the narrower and shorter things, such as combi cutters,

My preferred grip ignores the slot and I find offers more control on the majority of chisels and plane irons. First and middle fingers go on the top to provide down force.

The thumb and third finger provide side support, with the third finger also acting as the "clutch" in this case.

And yep, I do have the top fingers that close to the edge. It's almost certainly just a psychological thing, but I feel a lot happier doing this with a hand grinder than I would a tailed grinder. In practice these things have plenty of momentum and the wheel will go round a fair bit after I stop cranking, but somehow it feels safer knowing I'm at least not going to be keeping on cranking as my fingers are ground into a bloody mush. An electric motor knows no such mercy.

So what do I mean by the "clutch" finger? That's the one that controls the forward/back movement of the edge into and out of the wheel, kinda like a clutch pedal I thought. I find the straight rear edge of the Veritas provides the ideal edge to just guide that finger along. Push the finger towards the wheel and you disengage the edge from the grind; curl it back, and you're grinding again. I reckon 90% of grinding happiness is letting the wheel do its job, so a delicate touch of steel to wheel is essential. So many people seem to favour jabbing the edge into the wheel like they're trying to use the tool as a brake, and then they're surprised that losing temper is a problem. Let the wheel cut, don't let the tool heat up beyond warm at all, and grinding is a lot less stressful process. If I have to plunge the tool into water to cool down, I consider myself a dumb klutz.

The other thing, like so much hand tool use, is to look and see what's happening. Holding the tool freehand, it's very easy to take it off the rest, have a look at progress, then return it safely. I do it a lot. In this case I was taking the grinding angle on the 1" Veritas chisel down from 25° to 20° (told you I did many evil things to them), so I had an easy reference to check that I was grinding square i.e. The existing bevel. Sometimes a square and/or judicious use of a Sharpie might be required. Either way, it really helps if you can readily spot if you're not grinding evenly - an even bevel at this stage cuts down the work needed at the honing stage, after all.

The end result came out okay. Normally I wouldn't grind quite as close to the edge as this, but as things were staying so cool, I pushed the limits a little. By the end the chisel was starting to feel warm, but the temper was in no danger at all. Nice. Looking forward to see how the wheel copes with some less easy-going steel.

Anyway, there ya go, some of my thoughts on grinding. Whether you wanted them or not. :)


  1. Gounthar Frankfurt5/24/2012 03:29:00 pm

    Very nice, Alf, thanks a lot. I received my Veritas tool rest this morning, so I'm going to try it tonight with my hand cranked french grinder.
    I do have to grind sometimes, as with my NOS Coulaud chisels tonight (the bevel is just nonexistent on these).

  2. I take from your entry that you can only use one hand for each operation - one to hold the tool and the other to spin the wheel. You can't spin the wheel up and use two hands to grind with as the wheel coasts?
    If so, I assume that there is a bit of a learning curve getting the right and left parts of the brain to work together on this.
    Have you ever used a tormek? Curious to know how it compares.

  3. Ralph, yeah, one hand cranks and the other holds. The wheel soon slows down with the friction against the tool so you need to keep up the oomph. But it's not as tricky to get the knack as it may appear. Although I believe some people have hitched up simple foot pedals - or small children! :)

    Never used a Tormek, nope. I suspect I might find it a little slow as a grinder, and a little coarse as a sharpener, so not ever been tempted.

    Ah, a NOS chisel drive-by. Nicely played, Gounthar :)

  4. I agree completely with what you've said. I've never quite got on with the hand-cranked grinder, though, mostly because of the 'Pat Head Rub Stomach Syndrome'. I think this machine might excite you - not least because it's Cornish.

    It is a complete Rolls-Royce of a machine, and deserves a quality wheel. I can't resist making it spin every time I pass it.

  5. It looks like you have averything sorted out nicely but if someone lacks access to a lathe, I was able mount my oversized wheel without any bushing at all. I mounted the grinder horizontaly, put some slowish setting epoxy on the washers and then cranked it, nudging the stone this way and that until it was centered. It seems to be holding together well.

    I use that LV toolrest as well and find it works best with a simple holder that is basically a 3" x6" wide board with one batton underneath, to ride in the groove of the toolrest and another on top, perpendicular to that. You can rest one side of the plane blade against it to keep it square to the wheel face, but it's not clamped down. The batton on the bottom should be a bit narrower than the toolrest groove, seeing as it only needs to register to one side. I personally find that turning the toolrest around backwards gives you a wider, more stable brearing surface (never figured out the advantage of having the toolrest "surrounding" the edge of the wheel). Making the tool holder 2X wider than the toolrest gives you a more stable platform. You'll need to make a separate chisel holder along the same lines, or an insert that rides on top of this one.

    Paul Bouchard

  6. Gounthar Frankfurt5/24/2012 10:02:00 pm

    I plan using my foot pedal powered sewing machine to crank the grinder.
    I can't figure how to remove the handle though...

  7. Hi Alf,

    How do true the grinding wheel?

    All the best,


  8. @Harry: Oh yes, always fancied one of those horizontal, treadle ones. Didn't realise I could play the Cornish excuse, er, card on one though!

    @Paul: Ah, sounds like a refinement of Tom Thornton's method. D'you grease or otherwise guard against the epoxy sticking to the shaft, or just assume it'll need an application of heat if/when you want to remove it? The tool rest surrounding the wheel is handy when you want to utilise the corner of the wheel, but if you don't ever need to do that, then yeah, turning it round is not a bad idea.

    @Chris: I use a Diamond dressing block - pricy, but very effective. Having said which, on some older grey stones, I've actually found the unglamorous and old-fashioned Devil Stone more efficient.

  9. I just looked at it again and realize that I got it backwards. First I centred the stone, tightened the washers and then put 3 dabs of epoxy around the outside edges of the washers.

  10. Nice work Alf, I have followed you and purchased a second hand Mole hand grinder. I have just wondered, how did you get the wheel off. I was thinking of putting the old wheel in the vise and try to undo the bolt on the outside. Would be good to hear how it is removed.


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