ned
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| posted on 9/2/06 at 09:23 AM |
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panhard rod end bolt
I have a gts dedion tube, trailing arms and panhard rod.
The dedion tube's boss for the panhard rod has an m12 thread and the rose joint used at the axle end of the panhard is 1/2".
I've had it all done up for a while, but not tweeked/torqued right up for the final time, but there seems to be some lateral/sideways movement
in the axle which I'm putting down to the 0.5mm or so different between a 12mm bolt shank and a 1/2" rod end hole.
Has anyone else noticed similar problems, or am I worrying over nothing?
I know 0.5mm isn't much, but when you're on the road and it could change your rear axles squareness or toe I'd be concerned.
cheers,
Ned.
beware, I've got yellow skin
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DIY Si
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| posted on 9/2/06 at 09:33 AM |
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Is the movement there if you just push sideways, or only if you lift the axle up/down? The shouldn't be much sideways action, but will always be
some due to using a Panhard rod as opposed to a Watts linkage. May sound silly, but have you checked all the other bolts?
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ned
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| posted on 9/2/06 at 09:44 AM |
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Maybe I'm jumping the gun a bit. Will check/torque all the bolts up tonight and see if anything improves.
cheers,
Ned.
beware, I've got yellow skin
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flak monkey
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| posted on 9/2/06 at 09:58 AM |
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Engineering wise, yes all the bolts should really be 1/2". However with a 0.7mm difference, equating to 0.35mm movement in any given driection,
and no movement if the bolts done up properly! (The rose joint is clamped tight to the axle) Then it shouldnt be a problem.
David
Sera
http://www.motosera.com
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BKLOCO
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| posted on 9/2/06 at 10:08 AM |
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For what it's worth I had exactly the same concerns.
I wrapped a piece of shim steel round the shank of a 12mm bolt before fitting it.
Works a treat
Experience is what you get when you don't get what you want!!! 
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NS Dev
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| posted on 9/2/06 at 11:09 AM |
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You don't want to run M12 bolts on 1/2" holes. As was said, the clamp on the joint should in theory keep it tight, but in my experience,
they nearly always come loose and start knocking.
Wrapping with a shim is one answer, another would be to go down to M10 bolts (which are still much more than strong enough, well OTT) and make up some
top hat spacers stepped to sit through the 1/2" bracket holes. I'd do the latter, and oyu can glue the spacers in so you don't need
3 hands when installing the joint.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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BKLOCO
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| posted on 9/2/06 at 11:16 AM |
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You can't reduce to 10mm... The Rose joint is bolted into a pre tapped 12mm bush welded onto the DeDion tube.
Experience is what you get when you don't get what you want!!!
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ned
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| posted on 9/2/06 at 12:02 PM |
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what do you mean by wrapping with a shim? Where can I find such a wafer thin piece of metal to try and cut and wrap around the bolt shank?
cheers,
Ned.
beware, I've got yellow skin
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Mix
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| posted on 9/2/06 at 12:18 PM |
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Feeler gauges?? 
Mick
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Gav
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| posted on 9/2/06 at 12:18 PM |
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Foil?
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Avoneer
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| posted on 9/2/06 at 12:19 PM |
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Coke can...
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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britishtrident
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| posted on 9/2/06 at 12:22 PM |
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A drop of Locitite Bearing Fit --- hmm in the right place
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BKLOCO
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| posted on 9/2/06 at 12:29 PM |
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Ned U2U sent
Experience is what you get when you don't get what you want!!!
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ned
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| posted on 9/2/06 at 12:34 PM |
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u2u replied, thanks very much BKLOCO.
Ned.
beware, I've got yellow skin
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Nick Skidmore
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| posted on 9/2/06 at 03:24 PM |
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I do get worried when I hear things like this.
You should even think twice about using a 1/2" bolt directly in a 1/2" rod end as most commercial fasteners are 8 to 10 thou down on their
nominal size and the amount of fretting that this gives cause to premature failure.
As detailed earlier you shoud use a larger rod end in this case, probably a 16mm one with 'top hat' reducers in the bore and then drill
the holes in these 11.9mm to take the 12mm bolt.
If you wish to use bolts directly in rod ends use NAS bolts which are 1 to 2 thou down on their nominal size.
I know it's been mentioned on this site before but a read of caroll smith's nut, bolts and fastener handbook or prepare to win would give
you lads who are really into doing a job right all the pointers on this sort of thing.
12mm in 1/2" hole gives at least 28 thou overall (more like 36 with commercial bolts) or 14 (18) side to side movement which in engineering
terms is a fecking mile out.
[Edited on 9/2/06 by Nick Skidmore]
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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BKLOCO
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| posted on 9/2/06 at 04:22 PM |
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It's in the post.
Experience is what you get when you don't get what you want!!!
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ned
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| posted on 9/2/06 at 04:31 PM |
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thanks again...
Ned.
beware, I've got yellow skin
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BKLOCO
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| posted on 9/2/06 at 04:49 PM |
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quote:
Originally posted by Nick Skidmore
I do get worried when I hear things like this.
You should even think twice about using a 1/2" bolt directly in a 1/2" rod end as most commercial fasteners are 8 to 10 thou down on their
nominal size and the amount of fretting that this gives cause to premature failure.
As detailed earlier you shoud use a larger rod end in this case, probably a 16mm one with 'top hat' reducers in the bore and then drill
the holes in these 11.9mm to take the 12mm bolt.
If you wish to use bolts directly in rod ends use NAS bolts which are 1 to 2 thou down on their nominal size.
I know it's been mentioned on this site before but a read of caroll smith's nut, bolts and fastener handbook or prepare to win would give
you lads who are really into doing a job right all the pointers on this sort of thing.
12mm in 1/2" hole gives at least 28 thou overall (more like 36 with commercial bolts) or 14 (18) side to side movement which in engineering
terms is a fecking mile out.
[Edited on 9/2/06 by Nick Skidmore]
All of the above is very subjective.
You cannot make generalisations about "commercial fastenings" like this.
If you use cap head socket screws or good quality bolts from a reputable manufacturer (Unbrako for example) then they are made to much closer
tollerances than you are suggesting. This is why books like Machinery's Handbook and Zeus give recommended clearance hole sizes? Generally 0.1mm
above nominal for the smaller sizes of bolt.
Obviously in the Ideal world we would make everything a precision clearance fit but we don't when it is not necessary.
In this application a 12mm bolt in a 1/2" clearance hole although wrong would in all probabillity present no problem at all if torqued to just
below its elastic limit. However to err on the side of caution a shim sleeve provides a belt and braces solution both cheeply and quickly.
Not everyone has access to a lathe to be able to turn a top hat bush. Therefore another solution has to be found, that although not as
"correct" in pure engineering terns, is perfectly acceptable.
There are as many different ways of solving most problems as there are engineers willing to give advice.
Another way would be to use a larger rose joint with a shoulder bolt.
Lets just keep it simple where we can eh.
Experience is what you get when you don't get what you want!!!
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NS Dev
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| posted on 10/2/06 at 10:46 AM |
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Missed the extra answers and looks like I'm a tad late now, but I would gladly spin up a top hat adaptor for anybody that needed one, as would
Nick.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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locoboy
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| posted on 12/2/06 at 12:09 PM |
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I have asked this question to Darren but have had no reply, I fitted my Dedion 2 weeks ago and was concerned about this play too.
Anyidea what it shold be torqued up to?
Anyone willing to offer a bit of shim steel???
ATB
Locoboy
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ned
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| posted on 12/2/06 at 01:39 PM |
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Locoboy, I have some that BKLOCO kindly sent through to me. If you're not in a rush I can send some onto you once I've done mine, there
should be plenty enough to do mine and yours.
cheers,
Ned.
beware, I've got yellow skin
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locoboy
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| posted on 12/2/06 at 03:55 PM |
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Would be much appreciated Ned, and BKLOCO
You have U2U Ned.
ATB
Locoboy
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ned
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| posted on 16/2/06 at 10:42 PM |
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Right, been busy in the garage, here's some pics of the problem and the solution:
problem of slop between 1/2" rod end and m12 bolt:
http://www.locostbuilders.co.uk/upload/IMG_1809b.jpg
http://www.locostbuilders.co.uk/upload/IMG_1810b.jpg
shim steel to pack out the girth of the bolt:
http://www.locostbuilders.co.uk/upload/IMG_1811b.jpg
http://www.locostbuilders.co.uk/upload/IMG_1812b.jpg
solution/shim steel in situ in rosejoint:
http://www.locostbuilders.co.uk/upload/IMG_1814b.jpg
http://www.locostbuilders.co.uk/upload/IMG_1815b.jpg
cheers,
Ned.
[Edited on 16/2/06 by ned]
beware, I've got yellow skin
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TimC
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| posted on 17/2/06 at 07:36 AM |
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Well played!
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