Carriage Bolts.

[stuckmotor]

Carriage bolts and I seldom get along. They go in well enough when new but, after rough treatment and exposure to the elements the square part of the shank tends to slip in the hole or slot that's supposed to hold it still. Since they have a sloped cap, it's even a fight to get locking pliers to hold them still.
This mini-rant comes because I spent a good part of the afternoon trying to make one good hay ring from two and the carriage bolts wouldn't cooperate. I've got to remember to change all of them out for hex bolts before the next round.

 

[Fuddy1952]

An impact or drill if possible usually works better because it spins nut fast.

 

[4570Man]

If they’re really bad a torch is the best option. An impact usually works pretty good. The worst bolts to deal with IMO are stamped head bolts usually found in automotive. The hex area is tapered minimizing socket contact area.

 

[jaxs]

That's why hot wrenches were invented.:drink:

 

[bcp]

Carriage bolts should have a Torx socket in the head.

Bruce

 

[4570Man]

Carriage bolts should have a Torx socket in the head.

Bruce

Then you can just break the torx off.

 

[LouNY]

I've been known to weld a nut on the head before.:cool2:

 

[stuckmotor]

I hope I never assemble another hay ring with the carriage bolts that come with it. A big washer on either end of a sturdy hex head bolt and a lock washer under the nut prevents some problems. If the nut rusts to the bolt. I can usually wring the bolt in half and replace it.

 

[GaryM]

You need carriage bolt torque washers: Torque Washers for Carriage Bolts WCL Company

They lock onto the square shank and keep the bolt from rotating. Work great. I've used them on wood, but supposed to work on "ductile materials" as well.

 

[goeduck]

I am not a fan of carriage bolts either. I thought the comment about having a female Torx slot was a good idea. It still would leave a rounded head which is impoartant on many things, but would allow extra grip. I do not see bolt makers doing it though.