I hope I'm not re-inventing the wheel with this. I have been trying to glue cleats to the inside of a long side crack. I wanted to use HHG, but there was no way that that I could get the Teeter clamps in place and wound up in the time available. Mulling over different approaches, I finally came up with this one.
These clamps are available for $1.99 at Harbor Freight. The top image shows how they come in the store, but they have a wing nut that allows you to reverse the action, so that they push apart rather than clamp. Bottom image shows that configuration. Harbor Freight sells two similar clamps, but the one that works the best has a grey release button. A 1/16 hole is drilled through each of the pads.
I made up some string clamps out of 1/4 inch hexagonal brass rod. The rod is drilled and tapped for a screw (I used 8-32), and then a 1/16 inch hole drilled through the side. Guitar 2nd strings with 0.016 diameter have worked well.
Where the crack comes together, I have been using a hand drill with a #74 drill (0.0225), thread the guitar string through that hole from the outside, and then add the cleat, the caul, and the brass string clamp.
The outside part of the guitar string is threaded through the Harbor Freight clamp, and another brass string clamp. I don't tighten that clamp yet, but use clothespin type of clamp to keep it from sliding off.
I have been able to put the HHG on, pull it into place, slide everything up, tighten the brass string clamp, and expand the HF clamp in under a minute. There is much better control of the amount of pressure applied. Plucking the string between the two pads also lets you know how tight it is.
Hope this makes somebody's life easier.
I wonder if something like Mapes Music Wire might work. It seems their .008" wire has a tensile strength of 380,000 psi. I say seems because their page gives a range for their different wires with 380K as a minimum and I'm assuming the thinnest wire will have the lowest psi.
I have no info on a similar sized guitar string for comparison.
Thanks for your comments. Try one of the clamps first, before cutting it. The picture does seem to show some angling down of the bar, but it was actually much less pronounced. The shorter screws would be easier, but I just used what I had on hand. I'm having trouble visualizing the pre-threaded aluminum spacer. Could you explain, or better yet provide a picture? Nothing better than improvements that make things easier.
I calculated the the cross sectional area of the 0.008 wire, divided it into 1 square inch, and then divided that into the 380,000 psi. I got a number of 19.07 lbs. That should be enough to hold a cleat on. But you may have trouble drilling a hole that smallGeorge
Good one, I've used a peice of pipe with a cap on it threaded a hole through the cap, put a bolt through it with a heavy fishing line swivel attached to the end. But I like this a lot better. I like to put the cleats on after the crack is glued, I feel like the cleat is insurance then and not part of the structure of the repair. But that's choice not a recommendation.
When you pull strings through holes like that, you may find that the hole gets a bit enlarged, or made oval by the tension and angle of the pull. That, and it's difficult to get a small enough hole drilled. I often used a clipped piece of the same guitar string to poke the hole rather than drill it, so I could keep the hole as small as possible. All in all, I like your clamp adaptation - I bet it makes for a longer string and better control, in addition to quick action.
But because of the external visibility of the holes, we've pretty much abandoned the use of pulling except in the most dire circumstances. Magnetic clamping techniques replaced the old technique over 20 years ago when those high strength neodymium magnets became affordable. I honestly can't recall the last time I used a string pulling clamp.
Thanks Frank! I have a bunch of magnets set up as per your technique. On this particular guitar, I had so much hardware in place trying to keep the sides of the split in alignment, that there wasn't room for the magnets. When there was room, it seemed as though the magnets were grabbing on to everything in the near vicinity. The clamp adaptation was born out of desperation.