Accurate Chisel Sharpening with a Belt Grinder

[adam breuer]

I would like to do a high quality sharpening job chisels and straight gouges on a belt grinder. I have two of these Burr King 760's in the shop:

http://i935.photobucket.com/albums/ad200/Dartmouthmtb/ff2d1c50-735c-4458-b5c8-81d861823dc8_zps08532ba0.jpg (http://s935.photobucket.com/user/Dartmouthmtb/media/ff2d1c50-735c-4458-b5c8-81d861823dc8_zps08532ba0.jpg.html)

After quite a bit of searching, I have found many posts detailing how to do a 'quick and dirty' sharpening job with a woodworking belt sander, but no info on how to do a first rate sharpening job on a metalworking belt grinder. However, I have knifemaker friends who use these belt grinders to do extremely accurate, fine sharpening on knives. So, who here uses a belt grinder on their nice chisels?

I have access to a full machine shop to machine a jig to accurately hold chisels/gouges if necessary, and would love to hear any thoughts re:jig usefulness and design as well.

[Chris Parks]

Derek Cohen used or uses a horizontal belt grinder and I believe he has the details on his site.

[ian maybury]

Robert Sorby in the UK do a belt based sharpening system - there's quite a lot of information on method there: www.robert-sorby.co.uk (http://www.robert-sorby.co.uk/proedge.htm) One key point is that their system runs a relatively slow and narrow 700ft/min x 2in wide belt (meaning it should work well on chisels, but may be slow/not well suited to wide and thick e.g. plane blades), and they offer a very wide range of belt grits. Even at that the likelihood is that finish honing on waterstones or whatever is required if you need a truly sharp edge - and that the waterstones would handle resharpening until such time as the bevel needed grinding back again.

There's various videos about on YouTube that show sharpening chisels on sanding belts, but (as the thread in the Neanderthal section) i think a lot depends on what you mean by 'sharpening'. My own experience so far suggests that a typical high speed linishing belt is likely to be very aggressive for use on e.g. narrow chisels - that hand fed it would bring a high risk of burning and unnecessary metal removal. Against that a faster belt can be very good for removing larger volumes of metal from wide blades/reshaping bevels with reasonable speed - but with lots of care needed to avoid burning as the edge thins.

I've a sneaking feeling that an optimised and more universal belt sharpening system would combine variable speed, availability of a range of belt grit grades and types, a flat platen and smooth belts, and a comprehensive system of jigs so that angles can be accurately held while using very light feed pressures. Which if bought ready made a la Sorby rapidly runs into very high costs: www.hartvilletool.com (http://www.hartvilletool.com/category/robert-sorby-proedge-system/1)

DIY is no doubt an option, but might entail quite a lot of parts sourcing and set up to get it properly optimised?

[Jim Matthews]

The stability and adjustment range of the platen are really important for accuracy.

Because of the speeds, lower grits than you might use by hand are advisable.
Keep something to quench the steel, and keep the temper of your blade.

I use the version sold by Lee Valley,
but only on blades that need extensive grinding.

I intend to experiment with purpose made leather strops
for the machine, as that holds real promise for fine work.

If you have two, you could keep one belt for coarse
and one belt for fine compounds.

http://www.southern-tool.com/store/Burr-King-grinding-belts.php