Problems sharpening chisels

[Richard Sterry]

Yes, I'm having problems sharpening my chisels to 30°. The basic problem seems to me to be that my sharpening stone is far far too fine. It's in perfect condition, but is probably quite a lot older than me and is marked "Bauxilite 479 Medium". Bauxilite is of course the abrasive material, I've managed to figure that one out, but the number is meaningless and "Medium" is a very subjective term. I have some brand new chisels to sharpen, already ground to 25° but blunt, and some old ones which due to years of horrible mistreatment really could do with regrinding to 25° before I grind them to

30°.

The last time I was taught how to sharpen a chisel, it was at school back in the early 1960's, and we had a motor-driven grinding wheel, using water as a lubricant, with a clamp so you could get just the right angle on the thing. I do not have such a thing at home, just a bench-mounted grinder with no means of clamping, plus the aforementioned sharpening stone.

I ought to mention that I have a little gizmo into which I can clamp a chisel or plane blade at just the right angle, and then roll it backwards and forwards over the sharpening stone. That seems to do what it is supposed to do, only it takes forever to grind the tiniest amount off the blade - Zzzzzzzzzzzz.

I once allowed one of these door-to-door chappies to regrind some chisels on his grinding wheel in his van, and he basically wrecked them! Never again...

Before I roam the local DIY and tools stores, any advice?

[mrcheerful]

Get a perfectly flat piece of board or thick glass, stick a sheet of emery paper (about 180 grit to start) to the board and use your rolling guide to bring the basic edge to visible, then use progressively smoother sheets till you have a "scary sharp" chisel. You can go to an absolute mirror, razor edge if like.

mrcheerful

[Michael Mcneil]

Get a belt sander. They are cheap enough these days. Just a cheapo will do, beware the price of replacement abrasives though.

[Toby]

Can you get wet n' dry belts? I've not seen anything finer than 120 grit for mine.

[Mark]

got one of these

to a perfect angle, then a quick hone on a fine stone for a perfect edge.

[Richard Sterry]

Simple, and cheap - I like it!

Rick

[Andy Hall]

Yep.

Treat yourself to a Tormek machine

These are a low speed, water cooled grindstone which can be graded as required for different operations.

Which is an excellent web site explaining how it all works.

You can sharpen virtually anything on one of these - chisels, gouges, plane blades, knives, scissors,.....

.andy

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[Badger]

I really must try our 8000 "grit" diamond polishing machine for final finishing....

Niel.

[Richard Sterry]

Looks a handy bit of kit. Presumably you need to clamp the power drill in some way - is this critical in any way, as I don't have any proper mount other than a vertical drillstand. Can I just clamp the thing in a a Workmate for example?

Rick

[Dave Plowman]

Martek stuff usually does. It's the pretty colours. Unfortunately, it doesn't live up to its looks.

I wouldn't bother. To sharpen anything accurately requires a rigid relationship angle wise between the work piece and stone, and on these plastic things this just doesn't happen.

[Richard Sterry]

Mmmmmm, looks a really nice bit of kit, but seems like we are talking close to £200 with a few jigs and by the time VAT and carriage are added on. I would find it hard to justify that sort of outlay - shame!

Thanks

Rick

[Andy Hall]

I know. I've built up quite a large collection of chisels over the years and several Lie-Nielsen planes. When I thought about the cost of these and tried out a Tormek, I was able to convince myself :-) It does the job pretty quickly as well......

.andy

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[Richard Sterry]

Keep talking. ;-)

Rick

[Howard Neil]

I have had a Tormek for six years now. I would not be without it and support what Andy has said. In addition, if you have a power planer or thicknesser, you can sharpen the blades and keep them in balance (mind you, the jig for this is expensive).

The cost? It has more than paid for itself (including every jig Tormek makes). It does such a good job that others bring me their blades to sharpen.

[jacob]

If the stone is too fine you need a coarser stone - seems obvious to me. For grinding I use either a belt sander with 60 grit, or an angle grinder with a grinding wheel not a cutting wheel. I then hone on a stone with bike oil thinned a bit with white spirit. The stone is 30 years or more old bought from Woolworths for 5 bob or something. I somtimes use a honing guide to get the angle perfect but then do it by eye for re-touching. The most important thing with an oil stone (after getting the grade right) is to wipe it clean immediately after using it and to put the lid back on. Then It will never clog up or need cleaning.

cheers

Jacob

[John]

Assuming you aren't yet in your dotage and just maybe you might still have some contact however tenuous with your old school perhaps you might be allowed to use the aforementioned grinding stone with water lube?

[OldScrawn]

As a rather casual woodworker I'd find the cost/space hard to justify, but Wickes and others do chinese bench grinders with a normal speed wheel at one end and a wide, geared down, water cooled one at the other. Around £30: surely a much better buy than the drill attachment thingy. I use the normal grinder as much as the whetstone, but the latter is OK for the 30 degree chisel cleanup and then I use the "stanley" guide tool for the final 25 degree hone on a normal stone.

[Richard Savage]

Screwfix sell a two-wheel grinder - one high speed wheel as normal, but the second wheel rotates considerably slower and has a water bath. Not too dear and seems to produce satisfactory results for me.*

I have (somewhere) one of the Martek gizmos. I screwed it to a bit of timber along with an otherwise redundant brown B+D drilling machine. Again the results were satisfactory - razor sharp edges but at a fixed angle. Also the wheel is too narrow for sharpening 1" chisels. This is overcome by rocking the chisel carrier back and forth across the rotating wheel, which seems to work. This may also allow the edge to cool as you are not holding the tool constantly against the wheel.

I also have a Martex drill sharpener which was surprisingly effective; it came with a series of wheels, collets to suit different drill sizes and, most impressive of all, collars which held the drill/collet assembly at the correct angle for different drill types.

Rgds Richard

• just looked at the current brochure and can't find my grinder - what does that tell us?? (But I think that I have seen it elsewhere B+Q??). However, they do have a 'wet stone grinder' for £90 17162-73

R

[Richard Sterry]

I think you got the angles the wrong way round, but I take your point.

It has become clear to me that the stone I was using was far too fine, so I nipped down to the DIY store this morning, and bought a double-sided Stanley one plus the guide. This is definitely a lot better, and I have managed to put a passable (nothing spectacular) edge on the smaller sized chisels in both sets. (I have a decent set purely for woodworking, and a grotty set for abusing.*) However, I still cannot get a decent edge on the larger widths - I am always left with a very neat but slightly blunt edge which is clearly being renewed all the time rather than me simply not grinding off enough metal. I am puzzled why this happens with the wider chisels and not the narrower ones.

• I ground off one particularly abused narrow chisel at 25°, followed by finishing off at 30°, and it's come up quite well.

Rick

[Andy Dingley]

OK for rough grinding, but they won't sharpen a chisel and their price is ridiculous. If you really want a powered wet cylinder, look at the much cheaper Record machines

I'd suggest "scary sharp" (Google for heaps of information). But use silicon carbide (wet and dry) rather than emery.