Knowing there are a lot of ways to skin a cat Ive been trying to find the best/safest way to mount a spring behind the axle to split bones. To that end Ive collected these eaxmples from the many threads on here and elsewhere. Thanks also to the members Ive sent PMs to have provided input. Im still not 100 percent sure which way to go but have a bit of time as I collect parts. There seems to be 3 main types of mounts, brackets, perches through the bones and perch mounts welded onto the bones but one commonality I hadnt considered was that any of the ways need to account for the angle of the bones relative to the spring as it wont be inline with the spring. Thanks to all whose photos I have used, been doing a bit of copy/save. 1. Brackets welded to the wishbone. Can be one or two. I notice RJays sells brackets but as has been pointed out his website clearly states those are for mock up. 2. Then there are options for perches bolted through the bones. Some appear to be through the solid part of the front of the bone. On 1st pass that seems like a good idea? Another variation on that theme is on the outside of the bones although not sure how that works both functionally and aesthetically. With perch pins through the bones Ive seen images of that including a sleeve. Im pretty sure Gary from Cornhusker @krylon32 made these sleeves with the taper to match an OEM perch pin. Seems like a very good idea. Then there is another option where the actual perch is welded to the bones. Not all done well. Whilst it looks like these have been pie cut it sure looks sketchy. The fourth way involves using bat wings and hairpins which is not really what Im after as focussed on split bones but will include here to be somewhat comprehensive. I know this isnt a full comprehensive list of all the ways to do that so feel free to add other examples please. Also very interested on everyones view on the best way to approach this. My initial feeling is a sleeve with tapered end to suit a OEM perch pin welded into the bones then welding the perch pin to that at both ends, trimming the excess but very much open to input. Thanks. Please ignore the small pic below, its for a shock mount I think.
Keeping the taper and pulling it tight into the taper in the wishbone bung is what gives it it's strength. I've heard of guys machining off the taper but that creates a shear point that is prone to break. I also never weld the perch solid to the wishbone. After it takes a set and is aligned with the spring we use a slotted nut tighten the perch tight and pin it with a cotter key. I did a bones style chassis for my friend Dennis Saum and his deuce 3 window and he has over 50K hard road miles on it with no problems.. One other thing the less shackle angle you have the better it is for the bones. On the spring behind the axle setup I like the shackles to hang almost straight down which takes most of the side thrust off the bones. Spring still works as it was intended. Check hopupmagazine.com and scroll down to Dennis Saum Out Takes to see the finished product. Gary at Cornhusker Rod And Custom
Used Model A perch bolts welded into the bones a couple times. You do have to figure out the rear mount on the bones first so you can drill the 11/16" holes for the perch bolts at the right angle. Need a custom width spring too unless you are using a '37-'41 axle in which case a Model A spring will fit.
I like garys @krylon32 tapered crush tube idea. The double bracket one looks very solid , while the sketchy one looks like you will be in the dirt in no time. !!! I don’t think hanging off the batwing is a great idea with the forces involved and the twisting action on the bat wing,
I've built several spring behind set-ups with hairpins and the spring mounted to batwings I made from Ford axle yokes. Never found a problem with them. The batwings in the picture were fresh out of my jig and not finish welded.
Thanks all, my intent here was to try and gather all the options in one thread as there is a lot of great info spread across many many threads.
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