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Radius arm clearance in axle end.

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Radius arm clearance in axle end.
Nick Lettington Offline
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#1
04-07-2023, 02:28 PM
I need to make up some new spacers for a Bowdenex IFS front axle to fit between the two steel plates that connect the springs to the flame cut axle ends... there are five each side, four for the clamping bolts and one where the radius arm passes through. Thinking about the connection between the radius arm and the standard axle, this appears to be a transition fit (not loose like a clearance fit or tight like an interference fit). Does the radius arm actually rotate at all at the outboard end, or just pivot on the chassis ball? I'm trying to decide whether the spacers need to be carefully bored/ reamed to a fine tolerance or can just be tube with a more comfortable clearance, as the plates will provide locational restraint and the contact area between the plates and spacer may prove relatively small to stop it rotating if it really wanted to.
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Chris KC Offline
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#2
04-07-2023, 03:17 PM
I'm not sure what the design intent was Nick, but if the "early" radius arms had any freedom to rotate, the "Ruby" type with a second fixing bolt certainly did not.
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Nick Lettington Offline
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#3
04-07-2023, 03:23 PM
(04-07-2023, 03:17 PM)Chris KC Wrote: I'm not sure what the design intent was Nick, but if the "early" radius arms had any freedom to rotate, the "Ruby" type with a second fixing bolt certainly did not.

That's a very good point Chris!
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Archivist Offline
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#4
04-07-2023, 04:05 PM
Nick - are these what you mean and do these drawings help? They were kindly re-drawn from the original scribbles by Gordon England who, of course, has recently become Archivist and I am just an echo of the past...


.pdf   115-003 IssA Radius arm hole bush.pdf (Size: 465.06 KB / Downloads: 39)
.pdf   115-005 IssA Side plate.pdf (Size: 468.75 KB / Downloads: 37)
.pdf   Assembly.pdf (Size: 406.79 KB / Downloads: 43)

As you can see, these were drawn up a while ago and are yet to be published, along with the others that go to make up the set..
https://archive.a7ca.org/
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Nick Lettington Offline
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#5
04-07-2023, 04:34 PM
(04-07-2023, 04:05 PM)Archivist Wrote: Nick - are these what you mean and do these drawings help? They were kindly re-drawn from the original scribbles by Gordon England who, of course, has recently become Archivist and I am just an echo of the past...



As you can see, these were drawn up a while ago and are yet to be published, along with the others that go to make up the set..

Thanks Hugh, that's brilliant. 

They almost added to the confusion, but I think I have worked it out... I'm reasonably certain that the end of the radius arm is 3/4" diameter, the corresponding hole in the end plate is 25/32 which suggests 1/32" clearance, but the bush dimensions on that drawing indicate 3/4" OD and a 1/2" hole through the centre. This must be a bush to put in the end of a sawn off Austin axle in the hole the radius rod was originally pushed into... the flame cut end has a half inch hole in the equivalent place for a securing bolt. 

Do you happen to have a drawing showing the hole diameter in a standard axle Hugh?
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Chris KC Offline
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#6
04-07-2023, 04:46 PM
Allow me...
   
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Stuart Giles Offline
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#7
04-07-2023, 05:23 PM
It's a very long time since I worked on a Bowdenex setup, but IIRC, they used a special nut that had a machined rebate on the Bowdenex supplied radius arm nuts. the rebate was a close fit in the hole in the front sandwich plate leaving the hexagon on the outside. This was necessary because the two plate sandwich increased the thickness such that a factory nut couldn't pull up on the radius arm thread. ISTR the thread is 5/8 x 16 WF, as per the halfshafts.
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Archivist Offline
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#8
04-07-2023, 05:30 PM
The additional drawing Nick has requested...


.pdf   115-002 IssA Radius arm distance collar.pdf (Size: 469.46 KB / Downloads: 33)
https://archive.a7ca.org/
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Nick Lettington Offline
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#9
04-07-2023, 11:03 PM
(04-07-2023, 05:23 PM)Stuart Giles Wrote: It's a very long time since I worked on a Bowdenex setup, but IIRC, they used a special nut that had a machined rebate on the Bowdenex supplied radius arm nuts. the rebate was a close fit in the hole in the front sandwich plate leaving the hexagon on the outside. This was necessary because the two plate sandwich increased the thickness such that a factory nut couldn't pull up on the radius arm thread. ISTR the thread is 5/8 x 16 WF, as per the halfshafts.

Thanks Stuart

I knew I had a couple somewhere... mixed up with some Speedex wheel nuts... Hugh also sent me a drawing showing the original nut design. Definitely another victory for the Archive! 


.jpg   Screenshot_20230704-225458_Gallery.jpg (Size: 131.81 KB / Downloads: 100)
   
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