Developing a Tool Set for a Wood Carver long
William R. Duffield, on the Cohansey
>Back before the Holidays, I mentioned that I was working on a carving �vise� for my son, Ross, who has recently become interested in wood carving. For starters, I turned him a carving mallet from cocobolo. There was no disguising his pleasure with this present. After Christmas, he went home with a few other carving tools, and some "firewood" that we scrounged from the Lox Toolworks. We have to watch SWMBO really close, what with Global Warming, as she really likes the fireplace, to be sure that only BTU-grade scrap is carried out of the shop.
I have made some progress on developing a carving system for Ross. It needs to be compact, because he doesn�t have room in his small apartment for a full size bench and a patternmaker�s vise.
Everything I'm presenting in this post is "prototype." That means it is a bunch of half-baked experimental kludges that are not guaranteed to work for either your application or mine, or Ross's. But maybe, we can develop some more ideas from it.
The design for the carving platform is derived from plans I found in a carving e-zine, Carving World. I built the platform, attached a benchhook type fence to the front and made some movable fences to set in place at the back and sides.
These fences are somewhat "beyond stock." Features include moveable round dogs and two different sets of dog spacings, to allow the fences to be set at either 90� or 45� to the edges of the table. I will find out whether the extra holes in the sides get in the way. I suspect they will, and a separate set of 45� fences will work better.
I have not yet built Woodcarving.com's "pipe dream" base for the table, because of my son�s space limitations, so I cannot comment on how well it might work. I did build their equiangular spiral cam clamp, using an angle of 80�. I found that it didn�t hold, so I built another one with a shallower angle of 82�. It wouldn�t hold either, so I decided I was wasting time and materials. That design has its shortcomings -- It seems it would only work in a much larger size and an even shallower angle. We can discuss this topic later if anyone is interested.
I looked at the other clamp promoted in the article, the one operated with a large eye-bolt, and decided it was not going to suit me either, because I�m spoiled by my patternmaker�s vise with adjustable jaw angles, and replaceable jaw inserts, which can accommodate a wider range of grip geometries. Woodcarving.com�s clamp just didn�t seem to have enough flexibility. So, I considered the designs of wooden hand screws, both with wooden threads and metal threads, and the workings of the holddowns that I built a while back (an adaptation of someone else's design). I show a new application of one of these holddowns to this new design in the last section of this post.
The first two photos show the assembled clamp in operation. The fences and jaws of this version are made from 11/2" square stock, and are therefore too high for the at-hand carved work-in-progress saw handle I used for the illustration. This is not a serious issue, since everything is made from scrap and simple, cheap hardware, whose dimensions can be modified at will. The modularity of the system allows the stationary and movable appurtenances: fences, 3/4" dowel dogs and clamp jaws, etc., to be adapted to the needs of any particular carving project.
There are three assemblies. First is the monolithic, replacable jaw. The face can be cut, sawn or carved to any shape needed to hold the work. The two screws are identical. The threaded rod is glued securely into the handles. The center block is a threaded nut attached to a dowel that drops into the table. The threaded rod rotates freely in the knuckle joint, and the knuckle joint rotates freely in the jaw.
The following photos show materials and constuction details.
I used a 11/2" Forstner bit to drill the sockets in the jaw for the knuckle joints. This poplar jaw may well prove to not be strong enough, since the knuckle walls are only 1/4" thick, and I may have to build a sturdier one. The holes are on 41/2" centers.
The screws are built from four subassemblies, the rod, handle, nut and knuckle.
The handle is turned hardwood, with a brass ferrule, and a deep hole the same diameter as the threaded rod. I have described my methods for making handles elsewhere.
The rod is a length of all-thread with two nuts jammed onto one end. With a hacksaw, cut the threaded rod to length. Smooth the ends of the threads with a triangular or cantsaw file. I also run a die all the way down the rod, to make sure it operates freely on the nut. Thread two nuts on one end, and with a pair of wrenches, tighten them against each other. You don't want them to ever work loose.
The knuckle is turned from a length of hard wood. It must turn freely in the holes drilled in the jaw. Make the jaw first, and use it as a gauge when turning the knuckles. Cut the knuckles to length. You'll need a V-block for your drill press to get accurately centered holes. Drill a pilot hole all the way through, centered on the length. From one side, drill a hole the nominal diameter of the threaded rod (5/16" diameter). From the other side, drill another hole, about 3/4" of the way through the knuckle, that allows the jammed nuts to turn freely (use a 5/8" bit for 1/2" nuts). Insert the rod, drop in a washer that will act as a bearing against the end of the nuts, and glue in a wooden (5/8" diameter) plug. allowing enough room inside the joint for the rod and nuts to move freely. After the sparingly applied glue has dried, trim the end of the plug flush with the outside diameter of the knuckle. I use a block plane and sand paper.
The nut is assembled from a length of dowel, a square block of hardwood and a piece of threaded rod connector. For 5/16" allthread, these are about 17/8" long. I made two nuts from one connector, by cutting it in two with a hacksaw. Alternately, you can use T-nuts. Drill a 3/4" diameter hole in the end of the block, most of the way through, and glue in the 3/4" diameter dowel for the dog. After the glue has dried, drill another 5/16" hole through the side to fit the all-thread. Centered on this hole, drill a 1/2" diameter to the depth of the half of the connector you made. To fit the connector into this hole without splitting the block, you will need to do a little carving with a veiner (V-groove tool). Center the end of the connector on the hole, and tap it with a mallet to indicate where the corners need to be carved. After cutting shallow slots all the way to the bottom of the hole, use the mallet to drive the connector into the hole.
Thread the rod and knuckle into the nut. The connector should face the knuckle, not the handle.
Finally, glue the rod into the handle. Epoxy, polyurethane, or PVA works. Alternately, Jorgensen uses a rivet in a hole drilled through the wooden handle and through the steel threaded rod.
Sometimes, it is more convenient to clamp the work down onto the table, instead of sideways between jaws. My original plan was to embed a matrix of threaded inserts into the top of the table so I could use my holddowns. Then I had an inspiration. One threaded insert could be embedded in the end of a dowel and the dowel inserted from the bottom of the table, if it had a head so it wouldn't pull through. I already had one that I could adapt.
Some dimensions of the one I built, provided as a benchmark for adaptation to your needs:
The table is 2" thick, glued up from three sheets of plywood, and framed in hardwood scraps. The bottom fence is screwed and glued to the bottom. A single piece of wood would have worked for the front face and fence, but that would have made it a bit more difficult to drill the dog holes. The 8 x 9 matrix of dog holes are 3/4" in diameter, on 11/2" centers. The round dogs are cut from 3/4" diameter dowel, 31/2" long. The fences are 11/2" square. The threaded rod, nuts, threaded rod connectors and threaded inserts are 5/16"-18 NC. The threaded rods are 9" long. The holes in the handles are 3" deep x 5/16" diameter. The knuckle joints are 11/2" in diameter. The clamp jaw is 11/2" x 11/2" x 61/2".
Let me know what you think about this design. I'm always looking for improvements.
