Brake cross shaft hangers and riveting rivets

[Urgent Austin]

Hello All,
 
The 1932 chassis I'm using as the basis for a special had a very loose cross shaft when I got it.  It turned out the zinc bushes had seized round the shaft and the spherical bearings had turned in their housings, wearing to a very loose fit.  Following suggestions on the old forum,  I removed the whole assembly from the chassis (ground off the rivet heads), "adjusted" the housings with the aid of a large hammer, got hold of some better bearings and re-did the bushes with some sheet zinc. 
 
However, when I came to put it all back on the chassis, i tried using bsf nuts and set screws to fit them.  For a reason I couldn't fathom at the time, if I tried to do the (necessarily quite small) nuts up properly tight, they would always strip their threads.  I finally worked out this was because, as the pressed steel flange of the hanger was tightened down onto the chassis rail, the resulting sandwich was not of perfectly uniform thickness - I was tightening down onto a slight wedge, and this caused the threads to try to cross and ultimately strip.
 
I did end up putting the hangers on the chassis using this method and nyloc nuts, not tightening them to quite the torque I would have liked.  Having had time to ponder this arrangement, and noting the safety significance of the component, I am not happy with this, and want to re-do it.  But how?
 
I've been researching rivets.  I assume that no pop rivet will do the job and I would have to use a solid steel rivet.  Has anyone tried riveting cold, using the set/snap method?  It works for garden spades, but I want to be absolutely sure the final fixing will be strong enough. I can't really justify investing in specialist hot riveting equipment (although it does look fun to do!).  I would be very pleased to hear from anyone who has successfully tackled this job.


Thanks!

Urgent 

[John Cornforth]

Hello Urgent

I once removed the cross shaft rivets on my 1936 Pearl (horrible job chiselling upside down) in order to overhaul the cross shaft bearings on the bench.

I replaced the assembly using bolts and Nyloc nuts, with plain washers under the nuts, and had no trouble tightening up to a torque appropriate to the thread size.  It has now stayed put for about 8 years.

I wonder if you need to source better quality fasteners ?  Some of the items on sale are of dubious strength and thread size tolerance.

Re-riveting seems to me to be asking for a world of pain !

Cheers

John

[bob46320]

Riveting that size with restricted access won't be easy. Good quality (Not B&Q) bolts will be the way to go especially if the brackets are not quite square. Socket head cap screws have smaller heads than bolts if head size is a problem

[Chris KC]

Agree with above, solid rivets are hard work even if quite small. Good quality, self-locking fasteners, and try to set up a good flat joint for them to clamp.

[Zetomagneto]

Agree with above,  solid rivets are hard work even if quite small. Good quality, self-locking fasteners, and try to set up a good flat joint for them to clamp.

Capheads with “K” nuts would do it nicely

[Urgent Austin]

hello again!
thanks for your replies. On that basis, I think i'll forget the riveting! My recollection is that I got the nuts and set screws from a specialist fastener seller on eBay. I think they were sold as 'high tensile'. Should I be looking for a more specific specification? I'll investigate the suggested options - thank you all.

[Chris KC]

I wonder how tight you are trying to do up those screws Urgent? They can only be quite small...

[Urgent Austin]

I wonder how tight you are trying to do up those screws Urgent? They can only be quite small...

Hello Chris.  Indeed they are quite small, based on the size of the vacated rivet holes.  I was only using a little spanner!  I always thought a bolt of any size was meant to snap or shear before it stripped its thread?  That's why I came to the conclusion that it was an alignment/evenness problem (although, accepted, if the steel wasn't the right stuff that would do it too).  I would dearly love to simply leave it where it is, Nylocs and all under three coats of paint, but given the shaft is largely hidden away, and is the most fundamental bit of the braking system, I just don't trust it I'm afraid.

[David.H]

If using Unified threaded bolts "R" are similar to Metric 4.8 and are often called "high tensile" by the unscrupulous
"S" quality are close to metric 8.8
"U" are rare & similar to metric 12.9 and are often seen as cap screws, but again "gang warily" ...look for genuine Unbrako or similar "proper" brands.
You can check the manufacturer of reputable threaded fasteners by looking up the head marking letters (bit of a faff, but the magic of the internet comes to your aid. They should have proper international quality assurance even if based in strange countries!

[Derek Sheldon]

I used 8mm setscrews on the Rosengart ( well it’s a metric car ain’t it). Plenty strong enough