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Musings from the Workbench: Got dem bevel grindin' blues
This (from ms UK Alf) is the best article on grinding I've read in a long time.
I put some freaky multi-facets on chisels when I first tried ... probably for a year :) ... but it was brilliant the first time I managed to get a nice even bevel off the grinder :)
A cheap after-market tool-rest from Carbatec was a huge help first off - also acts as a heat sink I think.
Cheers,
Paul
Brilliant! I've been trying to find a way to mount my Norton wheel to my hand grinder for ages!
Hand grinding works great, and it's really not hard with the Veritas tool rest. Couldn't do it otherwise though.
Hi Snafuspyramid,
Is this the Veritas grinder tool rest you use?
Buy Veritas Grinder Tool Rest at Woodcraft
Am I right in saying that, for grinding, the following equipment is sufficient:
1) Grinder
2) Grinding Wheel
3) Tool rest
4) Work Bench
Cheers.
Yup. No need to buy the additional straight grinding jig IMO.Quote:
Originally Posted by Russell Cook
To your list I would add -
Safety glasses!
Angle-checking jig (adequate one is supplied with the Veritas).
Jar of water with a little bleach to stop it going nasty. Use this to dunk the tool when you are making it hot by grinding quickly - otherwise it is unnecessary. Some maintain that dunking hot tools causes harmful micro-fractures, or something. If that sounds plausible to you, just eschew the water and grind a little slower.
Cheap diamond wheel dresser. Mine cost $10. These are useful for removing any clogging in the wheel and for getting a new wheel to spin true. You don't really need this that urgently though, because low grit white wheels are so friable they don't clog often. A wheel that's slightly out-of-true isn't a big deal either on a hand grinder - the tools themselves will knock it into shape (eventually). Still, if you can afford one, definitely do buy one.
Lastly - dustpan and brush for all the nasty grinding dust!
I need to point out that I'm really not an expert here - I am relatively new to this hobby, while there are a good number of members here who have been engaged in the hobby (or profession) for considerably longer than I've been alive.
A quick word about grinding wheels. You asked earlier about what sort of wheel to look for in case the "white wheel" we've been talking about earlier isn't available locally.
For tool steel, the best wheel is one with a course grit and a relatively loose binder. The abrasive used for tool steel is usually aluminum oxide, not silicon carbide, and the binder is usually ceramic not resin.
Within that description there is likely to be a large difference between the performance of different products. A quality wheel will have evenly spaced abrasive particles of high quality, which will not dull too quickly. The binder will be formulated to ensure that it wears and releases fresh abrasive at a rate that corresponds to the speed with which the abrasive dulls. The binder matrix will also be uniform, so that pore size and distribution is about the same (to avoid localized clogging or differential wear).
How exactly you can find a wheel that fits that description without using a well-known brand (Norton or 3M make great stuff) I'm not sure... My suggestion would be to find a local store person or manufacturer that really knows what they are talking about, and rely on their recommendation.
As far as the size of the wheel, a little wider isn't a big deal, except that it can increase weight and theoretically bend the spindle. I'm not sure that this is an issue with a hand grinder because the speed and forces are so much smaller, but I defer to other more experienced forum members.
The diameter of the wheel is important, however. The wheel creates a corresponding hollow in the tool (hence 'hollow grind') which if too deep - as would be caused by a small wheel - can provide inadequate support for a cutting edge. Again this is a bit hypothetical for me, as I've never seen an edge fail like this, but I'd still recommend six inches minimum.
Cheers, Snafuspyramid.
Here in Shanghai, I've found lots of places that sell 6 inch white aluminium oxide grinding wheels, and also a hand cranked grinder that can hold them. All the shops seem to carry the same brand wheel, so that makes the choice easier!
What grit wheel do you use? Derek recommended a 46 to me, but the coarsest I could find was 60. Do you think that would be a suitable substitute?
Cheers.