How do I stop this bolt from spinning? (Steel bolt, Aluminum Housing)

[zipzit]

I've got an odd problem. This bolt is a tight fit, but not really tight enough. When mounted, the head of the bolt is no longer visible. When I torque on the nut on the other end of the bolt, this end spins. Note, its not a whole lot of torque.. I'm guessing in the range up to 20 ft lbs? Not much more than that.



I want to use my mediocre TIG skills to add a few dabs of aluminum to build up enough in the base to preclude the head of the bolt from spinning. I want the bolt to be easily removable, just not spin freely when seated.

I thought I'd just clean up the both the aluminum casting and a sacrificial bolt (without die chromate finish on it...) and just try to add a few dabs of aluminum filler and see where this goes. Initially I thought I'd add dabs of filler against two of the bolt flats.

Is this possible? What happens when molten aluminum hits up against the steel bolt head? Anybody tried this? Any advice or suggestions? Other tricks and hints?

[Mac's Crew]

I would say a drop of super glue would help.

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[ronsii]

I'd mig the head of the bolt with a nub that fits into the corner... no sense in ruining the aluminum casting with mediocre skilzz.

[Bistineau]

Place a small weld bead on the body of the bolt perpendicular to it's length then make a small groove in the side of the hole for the weld to slip into. Just a tack weld would do it with a notch cut in the side of the hole for it to fit into. Or you could build up a weld on 2 opposite flats of the bolt head to just touch the sides of the square hole it's sitting in. A thin shim on 2 sides tacked in place would work.

[CAVEMANN]

Weld a small key on one of the flats so when the bolt tries to turn it will rotate into the wall of the pocket.

[BD1]

Tack ears on the bolt. Maybe 1/4" square?
Depending on size, set a larger nut over the head and tack


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[Bls repair]

Weld a small rod across the top to lock into corners

[ronsii]

Or..... pour some JBWeld in there after smearing some grease on the casting and grinding a couple grooves in the bolt head for the JB to bite into.

[Bistineau]

Or..... pour some JBWeld in there after smearing some grease on the casting and grinding a couple grooves in the bolt head for the JB to bite into.

Yeah, but then he wouldn't get to use some of his mediocre TIG skills.

[mimac]

If you can get at the other end of the bolt hit the center of the end a good smack with a heavy pointed punch right in the middle of the bolt. It should spread the end of the bolt enough to tighten the threads to the tapped sides and still be removable.

[Sandy]

Internal star lock washer. One size under whatever the bolt is will usually barely fits plus won't show outside the bounds of the bolt head.

[farmshop]

I would find a piece of bar stock to wedge in there than it just needs a tack

[M J D]

Star washer or a serrated flange head bolt. Another option would be a thin flat washer bent around the bolt head and trimmed to fit on the one side.

[davec]

One more vote for a lock washer, like a star style. Easy peasy, fast and cheap. What's not to love?

[ronsii]

This thread needs a poll

[zipzit]

Wow, lots of responses here. Thanks for the ideas...

I'm very familiar with my ability to weld an antispin device on top of the bolt. reference...

Unfortunately, that bolt that is actually used is an aircraft spec bolt, high-strength type 4037 or 8740 alloy steel. The bolts are centerless ground and threaded after heat treatment. Minimum tensile strength 125,000 PSI. Cadmium plated per specification QQ-P-416A, Type II, Class 3. If that bolt breaks, human blood immediately ensues. Not necessarily death, but certainly pain. Not good. No go on adding heat there. Sorry I didn't include that in the description. And that bolt actually used is not the sacrificial bolt shown in the picture.

The star lock washer is a great idea. Obviously it's easy to give that a try.

The idea of a thin flat washer bent around the bolt head and trimmed to fit on the one side is really a great idea. I'll see what material I have... .

I know the grease / JB weld is an option , but where is the fun in that?

What I really want to know is... what will happen if I try to do a corner joint weld between the head of the bolt and the casting, obviously focusing most of the heat on the aluminum?

Anybody ever tried that before, or is it just a really bad idea?

I'm thinking of just going for it, and if I fail, then my die grinder is my buddy.

Again, thanks for all the ideas.

[OPUS FERRO]

zipzit

I've got an odd problem . . .

I want to use my mediocre TIG skills to add a few dabs
of aluminum to build up enough in the base to preclude
the head of the bolt from spinning . . .

I want the bolt to be easily removable, just not spin freely
when seated.

I know you want to weld, but - 'Get it done, and get the check' - welding
the box is backwards . . .

"I want the bolt to be easily removable" - this dictates what you do . . .

Measure: the width & depth of the bolt head gap - and the length of the
bolt facit.

Go to your Cold-Rolled cache: select size - and cut 'to bolt facit length'
[scrape acceptable] . . . size with play [slop] . . .

This is an Open-Face Fillet Joint - tack/weld across the ends only - any
where else is excessive. Fuse/.035 filler - easy to fix/adjust [correction]?

If this was a Solution Timed Event - It would be done in less than 10 Min.
with coffee and NPR . . .

hth


Opus



ps - See post #12 . . .





.

[farmersammm]

Bolt holding rub blocks on a 3pt hitch.









Probably a 10 minute job. Forget about all the crap they tell ya about bolt coatings...…….just weld over it (with stick at least, maybe not TIG)

[BD1]

You never said that.
Make a washer that holds one edge of bolt and bend washer to stop at aluminium. No welding on bolt. Making a washer to do both.


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[farmersammm]

So, what has me interested...…………….How come ya got a 125K bolt running through an aluminum casting. Seems sorta counter intuitive.

[zipzit]

Bolt holding rub blocks on a 3pt hitch.









Probably a 10 minute job. Forget about all the crap they tell ya about bolt coatings...…….just weld over it (with stick at least, maybe not TIG)

FarmerSamm... I like it.. but I'm way nervous about touching the heat treat of the bolt. I'm allergic to pain, and blood. And yeah, these bolts do break.

[farmersammm]

Hell, it's pretty doggone same as a Grade 8 bolt. https://www.boltdepot.com/fastener-i...ade-Chart.aspx

[farmersammm]

I guess I can understand your worry about applying heat.

If you have access to a milling machine, it would just be a matter of taking a piece of metal, and slotting it so that it will cradle the bolt. Like a washer underneath the bolt, but simply a "track" with a hole in it. The sides of the track engage the casting.

[zipzit]

So, what has me interested...…………….How come ya got a 125K bolt running through an aluminum casting. Seems sorta counter intuitive.

Yeah... so its an old guy skateboard thing.. It called Long Distance Pumping. You can go ten miles without every taking your feet off the board. It's a weird twisting perpetual motion kind of thing. It's weird to watch, cause you think it will never work.

The bolt is the kingpin on the bottom of the skateboard truck, and it gets a whole lot of repeated oddly oriented loading. There is a huge amount of stress on that bolt. When that bolt breaks there is absolutely no warning. Down you go, have a nice day.



With that said, wearing a helmet is mandatory for us old guys...

[farmersammm]