Cup Head Bolts Spinning

[Garves]

Does anyone have any tricks to stop cup head bolts spining inside the timber when turning the nut on? I am using M12 to connect bearers to post.

[ozwinner]

Drill the hole slightly undersize.

Al

[Garves]

Thanks Al, thats a good idea but i have already drilled the holes any. Any other ideas

[ozwinner]

Thanks Al, thats a good idea but i have already drilled the holes any. Any other ideas

Buy bigger bolts?
How many bolts are there?

Al

[Groggy]

You want the bolt to be pulled and not twisted as you tighten it.

a. Try a spring washer under the head.

b. Put a tiny dab of oil between the nut and the washer (not the thread) - you ARE using a washer, aren't you?

c. As a last resort, put a slot in the head with a hacksaw and hold it with a screwdriver.

[outback]

Use hex head bolts.

get some smaller holes and fill the big ones in a bit with them.

[Ashore]

Isn't there a square section under the head so when you drive the bolt home with a hammer the square section drives into the wood and is enough to allow tighterning.
If you have drilled the holes too largefor this to happen then you proberly need to use the next size up bolts

You could also try cutting some round toothpicks in half and pushing them into the hole with the bolt head , might be enough to stop it turning while tightening


Are you using Gal bolts and nuts if so run the nuts down the thread on the bolts first to clean away any little lumps of gal but do not run a tap or die over the threads as you will remove the protective gal coating.


Rgds

[BobL]

If you have already put the nuts on the bolts none of the above will help much.

If you want to take the bolts off and the bolt is long enough (ie threaded bit sticks out far enough) you can lock two nuts together on the threaded end and unscrew the inner most nut to a point where you push the bolt back and can grab hold of the square part of the base.

If you are trying to tighten the bolts you can drill a hole at an angle across and through the bolt head and put a nail through it into the timber. If you cut the nail head off just before you drive it home you will hardly see the nail - at least until it rusts. This method will only work up to a point, if you really want to tighten a bolt and the nail is too thin you may end up shearing it in half.

[Clinton1]

Are the cup heads countersunk or flush with the surface?
If its not flush make a spanner out of the thinnest sheet metal you have so you can hold it while doing up the nuts.

[Andy Mac]

I have this problem often on easels I service at work...the timber wears away from use and the square lug no longer bites into the timber. My fix is pure butchery: I take out the bolt and weld big dollops of (weld) metal onto two opposite points of the square then replace the bolt with a decent hammer blow to bite into the wood. Job fixed! Mybe not the best for galv bolts outdoors though...

Cheers,

[BobL]

I have this problem often on easels I service at work...the timber wears away from use and the square lug no longer bites into the timber. My fix is pure butchery: I take out the bolt and weld big dollops of (weld) metal onto two opposite points of the square then replace the bolt with a decent hammer blow to bite into the wood. Job fixed! Mybe not the best for galv bolts outdoors though...

Cheers,

Andy, if your fix is butchery mine must surely rate as savagery?

[DavidG]

Pull the bolt back a bit and fill the hole between bolt and timber with liquid nails.
Hammer bolt back in, clean up excess and let set.
Should hold if you tighten carefully.

[journeyman Mick]

Will the bolt heads be visible? I've had success driving a flooring punch down next to the head to jam the shank in the hole. Other alternatives all used at various stages as up here every rafter gets a tie down bolt through it/next to it on the outer wall/pole plate/verandah beam are:
Drive a 3" nail through the timber at 90deg to the bolt to jam the shank in the hole.
Drive a roofing screw or batten screw as above (these are 14 gauge very heavy screws)
Smack a ding in the rim of the cup head with a cold chisel and drive the chisel into the timber to hook in the ding.

None of them are pretty, but they work and they utilise the tools that are slung in the nail bag or hang off the rafters somewhere close by.

Just read the above and it sounds like we do this all the time. When you use about a hundred or so cup head bolts on the one job you do get a few difficult ones so over the years they add up. Usually though the combination of snug fit and squared shank section do their job.

Mick

[Garves]

Thanks to everyone for there input im sure i will be able to sort it out with one of those methods.

Great forum