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Top wishbone wall thickness
sebastiaan - 23/2/10 at 04:07 PM

Following the demise of the Wozsher wishbones (that I REALLY would've liked to have....), I am investigating alternatives. One could of course simply rosejoint the existing wishbones. Since the suspension uses M12 bolts to hold everything together, you'd also need to use M12 male rosejoints that screw into the wishbone tube. I know the outer diameter is 19mm, but what is the inner diameter? If it is 10mm (wall thickness 4,5mm?), you'd be able to cut M12x1,75 thread straight into the tube. If the inner diameter is larger (which I suspect it to be...), one would need to come up with an alternative solution.

Sooooo: Who knows the inside diameter of the standard round-tube MK wishbones before I cut mine up?


Ben_Copeland - 23/2/10 at 07:41 PM

I think your thinking about it a bit wrong... you wouldnt screw a rosejoint into the existing bush tube. You'd need to cut and weld in a new tube taped to the relavent size and welded in 90 degree to the bush tube......


Ben_Copeland - 23/2/10 at 07:45 PM

like this ....


http://www.locostbuilders.co.uk/viewthread.php?tid=130571


russbost - 23/2/10 at 07:51 PM

Ben, I think you've misunderstood, isn't he saying cut off the pivot tube & replace it with a rosejoint? At the inboard end - or have I got it wrong???

I would imagine the tube wall will be 1.5mm so 19mm OD will give 16mm ID, you can buy "tube nuts" which are used for joining lengths of stiudding with a standard m12 x 1.75 thread, these will drop straight into the tube after a kiss with a grinder - weld up & job done!

[Edited on 23/2/10 by russbost]


britishtrident - 23/2/10 at 07:59 PM

Rose joints and other brands of spherical rod end bearing used in mototorsport are traditionally used in in Imperial UNF thread sizes.

Hole ID and threaded shank OD don't need to be the same, usually they are but they can be bought with the shank nominal thread OD one size up from the hole ID.

Don't tap the tube it will be thinwall ---- top wishbones don't carry enormous loads, when they are loaded its is mainly in tension.

You can buy pre-threaded inserts to insert into tube see http://stores.shop.ebay.co.uk/McGill-Motorsports__W0QQ_armrsZ1

[Edited on 23/2/10 by britishtrident]


Ben_Copeland - 23/2/10 at 08:00 PM

I dunno.... confused now!

I dont like the idea of putting the rosejoint into the wishbone tubes. Surely the angle would be well out?


britishtrident - 23/2/10 at 08:06 PM

quote:
Originally posted by Ben_Copeland
I dunno.... confused now!

I dont like the idea of putting the rosejoint into the wishbone tubes. Surely the angle would be well out?


MK wishbones are very different from book wishbones.

see picture
http://www.smartsportscars.com/prices.html


sebastiaan - 24/2/10 at 07:48 PM

quote:
Originally posted by russbost
isn't he saying cut off the pivot tube & replace it with a rosejoint? At the inboard end - or have I got it wrong???

I would imagine the tube wall will be 1.5mm so 19mm OD will give 16mm ID, you can buy "tube nuts" which are used for joining lengths of stiudding with a standard m12 x 1.75 thread, these will drop straight into the tube after a kiss with a grinder - weld up & job done!

[Edited on 23/2/10 by russbost]


Yes, that is exactly what I mean. "Tube nuts" sound good, any examples / hints where to find these? If the ID of the tube is indeed 16mm, the wall thickness of a tube nut could thus be (16-12)/2=2mm. Maybe a bit thin, but a couple of holes drilled through the outer tube and puddle-welded up might do the trick.

Thanks!

-goes off to research tube nuts-