After bolting in Timbren, Steel tubing walls bent

[tony.latham]

your book has been the #1 resource for information...

Thanks for the shout!

Tony

[Squigie]

Ah, yea, .120 wall is never going to hold up to a clamp load like that.
That is what crush tubes are for.
External reinforcement can get you there, but I prefer crush tubes. (Yet I can't find a good photo of any that I've done - not even the oil cooler mount that was most recently built).

If the bolts ever loosen up with fish plates, it can waller out that thin wall really quickly. Takes much longer with crush tubes.

[gudmund]

GREAT video explanation!!!!

[working on it]

By strap do you mean a 1/4'' steel plate (cut to size to fit on the tubing) ...

Yep! :thumbs-up:

Tony

perfect, thank you.

btw, although I'm build a square drop, your book has been the #1 resource for information and I have learned so much from it. thank you!

I did something similar when I attached a new axle, springs, and hangers to my original frame. I used a 3/16" flat strap (to spread the load to prevent crushing the 11 gauge original frame), and 1/4" thick angle iron (2" legs) to weld & bolt-on the new hangers to it. No problems many years later. Not wanting to blow-through the thin steel of the old frame with extensive welding (my first time), I simply tacked on the 3/16" strap and used PL adhesive to secure it, before bolting thru with six 3/8"-16 Grade 8 bolts to hold everything together, with 50 lbs torque, to not further crush the already damaged frame. It hasn't moved a bit in 8+ years.

flat strap + angle iron over existing 11 gauge frame.jpg (311.05 KiB) Viewed 507 times

[Squigie]

Not my video.

I finally made it back to my work bench, where I have a clamp force chart posted.

According to this chart, a 1/2-13 bolt** with a 90 ft-lb torque is going to produce up to 11,000 lb of clamp force.


**Splitting the difference between 85 ft-lb Grade 5 and 95 ft-lb Grade 8 dry torque on the chart, and assuming Timbren's called out "1/2 UNC" is the usual 13 tpi; and that you're not lubing the threads.

[chopperwalker]

a 1/2-13 bolt** with a 90 ft-lb torque is going to produce up to 11,000 lb of clamp force

That is really impressive. It's much higher than I realized.

[twisted lines]

First Picture shows a plate on both sides the bolt goes through.
Says one is not included
90 lbs yes that will bend 1/8" with out spreading the load.

you are right, that is totally what I missed, dang. thanks for the help.

First Picture shows a plate on both sides the bolt goes through.
Says one is not included
90 lbs yes that will bend 1/8" with out spreading the load.

you know, thinking back and looking at the manual again, my plan was to do the 2nd option that is displayed in the picture which is to use a 2x2 as a cross-member. Its confusing because in the picture of that method, they do not use an extension plate.

I have a couple axleless stubs in boxes and I am learning as well.