Board logo

Shock bolt in single shear?
ceebmoj - 7/6/13 at 08:22 PM

I am in the process of converting my live axle locost to dijon. The live axle that I have has the uses a longer than book rear shock using the 1/2" top trailing arm bolt to mount the rear shock with a bracket so the bolt is in double shear. However the Dijon tube is set up to use a shorted shock. Will it be OK to cut the bracket of and ues the bolt in single shear to mount the shock?

blakep82 - 7/6/13 at 08:31 PM

Mmm mustard axle

Xtreme Kermit - 7/6/13 at 08:34 PM

quote:
Originally posted by blakep82
Mmm mustard axle


Lol

ceebmoj - 7/6/13 at 08:50 PM

I apologise for the spelling of de dion. Any thoughts on using the bolt in single shear?

blakep82 - 7/6/13 at 09:05 PM

Shocks always in double imo

Dingz - 7/6/13 at 09:52 PM

Its been done before but the bolt will need to be rigidly held so there is no movement imo.

ceebmoj - 7/6/13 at 09:56 PM

quote:
Originally posted by Dingz
Its been done before but the bolt will need to be rigidly held so there is no movement imo.


i.e. done up tight? if not what do you mean?

craig1410 - 7/6/13 at 10:05 PM

I wouldn't be comfortable with my shockers mounted in single shear to be honest. On my de-dion axle I even went to some lengths to mount my panhard rod in double shear.

I'm in the process of migrating my old build diary over to a new web service but I have some pictures of the double shear panhard mount here. It might give you some ideas for your own build.

http://meerkats.uk.com/meerkat-rv8-build/2003/5/18/more-may-progress

Images are now high-res on my site so just click to zoom in.

Cheers,
Craig.

britishtrident - 7/6/13 at 10:07 PM

Loads of tintop including Jag XJ6 and Daimler DS420 rear coil overs and Rover 75 self levelling unit mounting bolts are loaded single shear but the bolt dia is considerably larger and mounts are beefed up to take the bending moment.

E type rear



[Edited on 7/6/13 by britishtrident]

britishtrident - 7/6/13 at 10:24 PM

quote:
Originally posted by ceebmoj
quote:
Originally posted by Dingz
Its been done before but the bolt will need to be rigidly held so there is no movement imo.


i.e. done up tight? if not what do you mean?


It is the bending moment that has to be allowed for, not so much on the bolt alone .but the bracket.

ceebmoj - 7/6/13 at 10:25 PM

I have been looking at a lot of pictures and it looks like a number of people have done it both ways.


http://www.locostbuilders.co.uk/viewthread.php?tid=78935

craig1410 - 7/6/13 at 10:31 PM

Seeing that picture looks better than what I had pictured in my mind. I was picturing a setup like mine but with an L shaped bracket instead of a U shaped bracket and my concern was that the bracket would fatigue. If the bolt is M12 or 1/2" and of good grade and quality then yeah it might be okay. I would try hard to get a bolt though and not a set screw and ensure that the unthreaded part of the bolt is supporting the shocker. I wouldn't want the threaded section to be in bending load.

snapper - 8/6/13 at 06:55 AM

All the single shear I have seen have the bolt supported in a U bracket or threaded with the shock hanging off
I don't think a so goe mount plate would last long as the bracket would flex, bend and fail

britishtrident - 8/6/13 at 10:13 AM

quote:
Originally posted by ceebmoj
I have been looking at a lot of pictures and it looks like a number of people have done it both ways.


http://www.locostbuilders.co.uk/viewthread.php?tid=78935


More that stiff enough.

Also you do realise on the rear the damper body can be turned through 90 degrees so the bolt is aligned fore-aft.
If anything this will generate less torque on the mounting as the axle moves.


[Edited on 8/6/13 by britishtrident]

ceebmoj - 8/6/13 at 11:31 AM

quote:
Originally posted by britishtrident
quote:
Originally posted by ceebmoj
I have been looking at a lot of pictures and it looks like a number of people have done it both ways.


http://www.locostbuilders.co.uk/viewthread.php?tid=78935


More that stiff enough.

Also you do realise on the rear the damper body can be turned through 90 degrees so the bolt is aligned fore-aft.
If anything this will generate less torque on the mounting as the axle moves.


[Edited on 8/6/13 by britishtrident]


great that is what I was planning on doing.

I had considered turning the shock mount through 90 on the axle however with the longer shocks that I have it would make getting to the trailing arm bolt hard also I would need to turn the bracket on the car through 90. so that the top and bottom of the shock where in the same orientation.

procomp - 8/6/13 at 11:47 AM

Hi

Westfield have been doing it for the last 25-30 years on the live axle cars. I have never seen one bend a 7/16 bolt in normal usage.

Cheers Matt

HowardB - 8/6/13 at 12:05 PM

quote:
Originally posted by procomp
Hi

Westfield have been doing it for the last 25-30 years on the live axle cars. I have never seen one bend a 7/16 bolt in normal usage.

Cheers Matt


The point is that is bending, it would be very difficult to ensure single shearas opposed to bending in this application. Therefore the comments about rigidity and fatigue are more significant. WeII designed, single shear, double shear or bending should all be ok.

Just my thoughts on the matter.

britishtrident - 8/6/13 at 01:21 PM

As the dampers are long the trailing arm and the damper could share a single through bolt.