For the amateur wishing to undertake their first repair of some old, hopefully expendable, violin, the cost of professional luthier tools may make the project seem prohibitively expensive. One area where costs can be minimized is that of clamps, if one is prepared to spend a little time creating one's own from simple materials. I have documented the making of spool clamps for holding the top to the body here. The creation of longer clamps to aid in the repair of cracks is similar in many ways.
Behold our simple materials.
A wooden broom handle could be made to serve, but that seemed somewhat less substantial than what I envisioned. I found this over-sized dowel type thing at Home Depot. It was there as well that I purchased the wing nuts and threaded rod. The cork I had on hand from another project.
I made marks every 12mm along the length of the large dowel for 4 disks, then 6mm for two smaller disks intended to fit in the f-hole.
Note, my inspiration for this project was from a posting on maestronet.com by DougP wherein the dimensions suggested were 1/4 inch threaded rod and half inch disks, but for non-Americans these measurements may be a challenge. The threaded rod I found was 10-24 (whatever that means) and as well the wing nuts. Anything in the ballpark will do, just be certain that the nuts fit the thread of the threaded rod. The dowel is a hard wood, I forget what at the moment, but if you were using a soft-wood, you might want to increase the thickness somewhat. Nuts and rod don't have to be brass, I just like the look.
I clamped the dowel into my yellow plastic miracle jig, and cut on the marks.
Here are our disks
I tried slipping one of the narrow disks into an f-hole, and it fit, but barely. It would be a squeeze with the cork facing. I could have sanded a millimetre or two from it, but at what point does one begin to worry about the strength?
It occurred to me that for this smaller clamp perhaps a couple of big buttons would do.
I found these in the bargain bin of a local fabric store -- 45 cents for the two of them including tax.
For extra strength and to give them a flatter surface, I filled the concave face of the buttons with some green stuff, a two part putty that hardens into a kind of plastic (the shadow in the image belongs to the shop cat who likes to be involved with whatever is going on.)
The next step was to cut out cork circles for the four wooden disks. The material probably doesn't matter that much, so long as it is firm, yet softer than the wood to be clamped. You could probably cut out circles from plastic containers. Something to remember is that on violins we only use hide glue, and hide glue 'grabs' as it dries. Clamping hard won't make the hide glue grab any harder, and may do damage to the violin. Consequently, you have some latitude with regard to what you face the disk with. Likewise, good form might dictate using a washer between the wing nut and the disk, but I don't think it's really necessary given the minimal clamping force I will use.
While hide glue is the glue for violins, it is a bit of a pain to prepare, so I glued the cork on with white glue. This can benefit from some force in the clamping.
After gluing, the next step was to trim overhanging cork, as I cut the circle a little larger than the diameter of the disk.
That done, the step after that was to drill holes. I started with a smaller diameter bit to drill the initial hole, then finished up with a 13/64th bit (old bit set, pre-everything being metric at the hardware store). Later I discovered this hole to be a bit too tight, as to move the disk, I had to rotate it on the rod, essentially screwing it into place. This is suboptimal, so I made the hole bigger with the 7/32 bit. That made it a little bit looser than I would like (do they make a 27/128 bit?). The ideal is snug, but not so that you can't move it easily simply by turning the nut.
I holed the filled buttons (I also put a bit of green stuff on the back), and then cut the rod with a hack saw (300mm, 450mm, and the button clamp got what was left of the rod, about 160mm), then assembled the clamps.
Here they are applied to a violin top (well, most of a violin top).
Note, you can get commercially made crack clamps from China on ebay for about sixty bucks, roughly six times what I paid for materials, which feature screw down feet for pressing down one side of the crack or the other or both in order to have both sides of the crack even with one another, but you can achieve the same effect with these by using little wedges. It's not clear from the picture, but the rod is curved and not touching the surface of the top, so there's room for wedging if required.
Note, this diagonally clamped image is just for show. I do want to move in the lower left bout rib a bit prior to regluing, but I would do this from the other side clamping against the back at the top, and against a shaped piece of wood next to the rib at the bottom.
I still have a full rod and four wing nuts left, plus plenty of cork and dowel. Rather go into mass production mode, I'll simply have the materials on hand, and make clamps as needed to the specifications required -- another advantage over shelling out for a set of commercially made clamps, some of which one might not use.
With a little ingenuity, time, and some affordable materials, bringing an old fiddle back from the dead need not cost as much as buying a brand new violin. Read widely, be patient, and do the best you can with what you can afford.
Notes from the real world
I'm using these clamps in a repair which I am documenting here.
Two notes: One, I haven't gotten the wedge thing to work, though must admit I haven't tried very hard. The angle of my wedges may be too steep. They slip out.
Two, if you're not using a wedge, consider using a bit of cloth to protect the surface of the violin from being marred by the rod.
Here I've adapted my littlest crack clamp to serve as a end pin hole clamp by adding a cork lined block of wood. This is handy for gluing ribs back to the violin's bottom block.
