One of the things I needed was an attachment for my garden tractor that would create V-shaped furrows so I could plant seeds like squash, potatoes, etc.
While making the furrower, I needed a U-Bolt that would hold a 1" diameter cultivator shank. The local hardware store--Dallas Green Farm Supply, had them, but they were only 1/4" diameter material and I didn't think that would be strong enough.
The store also had slightly larger U-bolts made with 5/16" material. That was more like I wanted, but you want to have as much of the bolt touching the shank as possible to grip it better.
So, how could I make the U-bolt smaller?
In the past, I've put the closed end of the bolt in a vise and tightened it down. This makes it smaller, but also causes the open end of the bolt to push in towards each other. You're then faced with the problem of opening the bolt up again, and generally end up with something like an oversize Bobby-pin (do people even know what a Bobby-pin is these days???) You also risk damaging the threads so you can't screw the nut back on the bolt.
As often happens when I'm pondering a problem, I had a sudden flash of inspiration--when I squeezed the bolt together, if I put a spacer at the open end of the desired width, it would hold it open.
The U-bolts come with a metal plate with elongated holes. The original width was 1 3/8", but the slots in the plate were 1 1/8" at the narrow side.
I screwed the nuts on to each side of the U-Bolt down to the end of the threads. This serves two purposes--First, if the threads become damaged, you can screw the nut off and straighten them out; and Second, you can actually grip the bolt on the nuts. Gripping on the rounded U-bolt shanks themselves can result in them twisting and flying out of the vise when you squeeze it down.
Next I put the plate on, then another nut to hold the plate in place. I ended up with something like this:
I then tightened the vise, checked the inside dimension, and tightened and checked until it was where I wanted it--in this case 1 1/8".
If you need a different size than the plate allows, drill your own out of bar stock or some other piece of metal. I would recommend at least 1/8" thick material, and make the holes at least 1/16" larger diameter than the bolt thread diameter.
Obviously this will only work on smaller U-bolts--up to about 3/8" diameter thread.
You could also use this a technique and a hammer if you don't have a vise handy. Use a pair of Vise-Grip pliers to hold the bolt, or you can crush some fingers.
FWIW,
Smitty
I use Bobby pins all the time
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