Tightening a nut without causing the bolt head to just spin freely. How?!

Do the bolts have a square shank similar to a carriage bolt? If they do you should be able to pull on the nut as you tighten and the bolt will hold into the wood. If this has been taken apart a few times and the holes are worn you might need to dowel pin the holes and re-drill. Then you tap the bolt into the clean hole so that it grabs. They also sell a small metal item called (screw-mate I think) that will help hold the bolt in the hole.

 

Why don't you just try wrapping a little masking tape or something similar around the bolt head? See if that does the trick before you go gluing it together.

 

It won't cost much to try it. But you still won't be able to torque it much. Epoxy or urethane glue might be a better choice, but messier.

You could shop for larger bolts or a better solution.

 

I would do the earlier suggestion of a dowel and re-drill. That's the right way to do it.

 

Damnable hard to drill a square hole.
I'd jam a few 3/32" double terminated white birch dowels (that's what you call them if you're charging for them; otherwise, they're toothpicks) in there to hold the square on the bolt.

 

Got a pic? not sure if I'm getting at the problem, but..
For a good grip you need the right tool. Knipex Cobra won't let go.
against marring, use a strip of rubber tubing or leather.

 

Drill out and shoulder with a chisel.

 

.....

 

I think I dont understand, but can't you just put a star washer under the nut or under the bolt head? Whichever you cant hold...

 

If the bolts have the little square shank under the head like a carriage bolt, do the following:

Measure the diameter of the hole the bolt is in. Get a hardwood dowel that matches or is just a wee bit larger than the diameter.

Cut a 1/2" length off the dowel and use a file to add a small chamfer to one end (this helps it go in), like this:




Use a Qtip to run a drop or two of wood glue around the inside of the hole. Place the little dowel plug in the hole, chamfer-end down, and tap it in so the plug is flush with the surface.

Allow the glue to set up for about 30 minutes, and then drill a hole through the center of the plug so the threaded portion of the bolt just barely slips through. The hole you drill will be too small for the square shank to slip in, but when you install the washer and nut at the other end, tightening the nut will draw the square shank into the plug, preventing the bolt from rotating.

If the bolts are just long enough to accept the nut but the square shank prevents the threads from protruding and you can't start the nut on the bolt, you can use (1) a mallet or (2) a block of wood on the bolt head and a hammer to tap the head of the bolt to seat it so the square shank forms a matching recess in the plug.

This repair will be completely invisible.

If the nuts go onto the threads with a lot of effort, you can "chase" the threads on the bolt with the appropriate (diameter and TPI) thread-cutting die to restore them for smooth assembly.

 

Not sure if this would work or not but, how about a shoe lace pulled tightly around the space between the bolt head and the wood, holding the bolt with enough pressure to keep it from spinning? Then you can crank it down, perhaps, and squish the shoe lace (or leather strip?), and cut off the excess with a razor or knife once it's tight? Just throwing out an idea in my head. Good luck!

 

Are any of the threads exposed beyond (outside) the nut? Enough to get a pair of Vise-Grips in them? Not optimum, it would mess up the exposed threads, but hey...

Or could you shoot a whole bunch of superglue around the carriage bolt head (don’t let it get close to the nut or you’re going to be totally stuck) and thus glue it to the wood, enough to let you tighten the nut until the clamping force holds the bolt to the wood. Caution though: have some acetone (also found in some fingernail polish remover) handy in case you glue your fingers to the bolt or table.

Lastly, can you unscrew the nut? Then clean off the threads to the bolt, and maybe get a new nut if necessary, to be able to run the nut all the way down. Also make sure the nut hasn’t run out of threads and is up against the shank of the bolt (adding a washer or two could help).