Brazenkane is correct, I have made a few of the Koehler-esque gouges, thanks for the plug Padraig!
I had the opportunity a while back to compare gouges and talk to Benedict a couple years back at the SoCal Tionel. I think mine are pretty close to Benedict's by direct comparison, and they work! Bill's description is indeed correct, a hardened blade of tool steel sandwiched between two pieces of wood, held on with rivets.
I use 1/16" thick tool steel (0-1 or W-1), about 1/2" width. You can order it in from ENCO - http://www.use-enco.com/CGI/INPDFF?PMPA ... PG=INLMK32
- I use oil hardening (0-1) because that is what I have on hand, but water hardening (W-1) might give you a harder edge that will last longer between sharpening.DSC03762
by Rev Joe Buck
, on FlickrDSC03761
by Rev Joe Buck
, on FlickrGouge bevel 2
by Rev Joe Buck
, on Flickr
jdevereux, I can give you a brief description of how I make them.
The tool steel comes annealed so it is easy to cut and shape with hack saw and files. Grinding annealed steel is NOT recommended, it gums up you grinding wheel really quickly and really doea not save you anytime. Basically, file the profile and the bevel as much as possible before hardening, and drill any holes for rivets too.Hardening
- heat with a propane torch (or better yet Oxy-Acetylene with excess of acetylene, reducing atmosphere) until red hot (a magnet will no longer stick to it). You can do this on some ground up charcoal brickettes, it helps retain heat if using a small propane torch. Heat as quick as possible, and dunk in some motor oil (oil hardening), or water (water hardening). You really don't need to heat the whole blade, just the 1" or so near the tip that will be sharpened. Once cool, it should be so hard that not even a file will leave a mark on it. It is too brittle in this state so you need to temper the hardness back a bit. You can do this the way blacksmiths have done it for centuries, remove the scale and heat in a dark space slowly and carefully and note the color change, then quickly quench in oil or water again. Extent of tempering can be determined with practice very accurately, a straw yellow will get you a very hard and durable edge (Rockwell ~53-55). Another way is to simply heat in the oven at 450 Fahrenheit for about two hours, quench in oil or water.Sharpening
- can be done on a good grinder (true and smooth wheel), paying close attention that you don't heat so much that you ruin the temper, which is very easy to do with such a thin blade. Have a can of water on hand and dip the blade often to cool. Go slowly and check your progress often. This is where getting the initial bevel really close to final shape before hardening really helps, you can even do the final shaping on sand paper on a flat surface. The bevel needs to be really acute with a long bevel (see photo above), and you will find that the edge will dull quickly with use. Sharpen on a series of good stones. I use Japanese water stones, they can't be beat! I finish by stropping the edge on leather impregnated with chromium oxide paste, puts a mirror finish on it and it is REALLY sharp. Actually, Rory's link to Veritas tools will take you to probably the best and most exhaustive treatise ever written on sharpening tools (written no less by the founder of Veritas tool, The Complete Guide to Sharpening by Leonard Lee - http://www.leevalley.com/us/wood/page.a ... 91&p=32991
). It also describes in detail how to sharpen scrapers!
You could use the blade as is I guess, but it is pretty easy to add a functional handle of wood. If interested PM me and I can walk you through the process.
Hope this helps