Faithful reader and commenter Harry "Gipper" Morris asked the following...
I've recently procured a set of Lathe Turning Chisels and a set of Wood Carving Chisels. Now I'm wondering how to keep them sharp. Any suggestions?
Right off the bat, anytime you're working with tools, be sure you've read and understand all the pertinent manuals and that you're wearing eye protection...
Alrighty then... That out of the way, realize that entire books have been written on sharpening, and I obviously can't go into that sort of detail here, but at least I can offer some overview as to how I keep the shop going...
I guess there are two schools of thought concerning sharpening/honing: namely by power or by hand. Where you've bought turning tools (I assume a skew chisel is amongst them), I'd suggest that you consider the former and take a long look at the excruciatingly expensive Tormek or the more reasonable Work Sharp 3000. Then there are the traditionalists who prefer the latter (sans electricity), and that's fine too -- I used to be one of them. Today, for me, I ultimately use a mix of both... Take a look at this battered old chisel...
Ah, but a gem lies beneath... I use the goodies below to put a razor's edge on such things...
And those doohickeys are:
- Dual wheel grinder to establish the correct initial grinding and whetting edges... (more about this in a minute...)
- A roller guide that holds the chisel at the proper angle relative to the hand sharpening stones
- Natural stones and slips
- Diamond stones
- Dremel hand grinder for quick and dirty tune ups
- An angle gauge for checking bevel angles
- And of course the final strop
Concerning technique... First I use my bevel gauge to make sure that my coarse grinding wheel is set to about 25 degrees relative to the tool rest. Next I increase the bevel on the fine wheel to about 30 degrees. That takes care of the grinding and whetting edges
respectively. When working with a grinder, it is absolutely crucial to remember a couple of things... First, don't let the steel get too warm. (If it gets hot, you'll ruin the temper and therefore the tool.) Second, never
put even the slightest bevel on the back of the blade. When you're done with the grinder, the edge will look something like below as seen through a microscope...
Note the fine silver edge towards the top of the blade -- that's a "wire" or "burr" that has been formed by the grinding process. You can actually feel it as you sharpen. Onward... Next comes the fun part... Honing
Honing is as mundane as it is difficult. The trick is to alternate sharpening the exact whetting bevel (I use a roller guide) with flat-scrubbing the back of the chisel. Remember, you must not put a bevel on the back! The goal is to use finer and finer stones until the wire is gone and the edge is goofy sharp. A strop (piece of leather) will polish and end the exercise.
Voila! When done properly, you'll end up with something that will literally shave hair...
Obviously, the Web (as well as the marketplace) is packed with info, jigs, and accessories for sharpening gouges, planer blades, scissors, etc., etc., etc... If I had to boil the process down, I'd say that there really are only five objectives...
- Be safe
- Don't burn the steel
- Don't put a bevel on the back
- Make and keep the right bevel by gosh or by golly -- the more uniform, the better
- Don't sacrifice "plenty good enough" in the hunt for perfection... When getting ready for a new project, I'll sharpen 20 -- 30 tools in a relaxed afternoon.
Harry... Hope this helps!
P.S. If you want to see something really different, take a look at "scary sharp" or plate glass sharpening......
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