Qtr Elliptic Spring Perch mystery like Lochness

I know. Dont beat me real bad. I searched and found the "text" to the archived threads that could have been interesting but the pics were deleted photobuckets.
I wake up and go to bed at night worrying about the same damn thing.

• How come swivel leaf spring bushings are the size of a football.
• How come we can go to Mars but we only have limited choices of Perch's that go thru the axle.
• There are no Thrust Washers the work for a swivel perch mounts.
• How come Speedway Motors shows a 1/2-20 thread short perch going thru a axle in a shear position in their catalog for model Ts.

My brothers car may hit the road soon and I have tried to feel safe but cant. I bought the big ones from posies. I bought the off road 4x4 types. I bought Speedways big 4-link "eye" and its seems too weak.
I came up with just a simple bracket that "seats" inside the web of the axle and extends out to the shackle bolt which to me eliminates perch rotation. Who agrees?

 

Someone here had that POS perch from Speedway break a few weeks ago.

The parting lines in the pic made it look like a casting.

 

Leaf spring CAN twist, so pivoting perches should not be a big problem.

I would be more concerned about the size of the shank going through the axle.
Make sure there are no sharp inside corners to act as stress risers.

 

Make your own.
I think the shackle bushings are 3/4" od.

Find a source for 3/4 ID DOM, or just turn them from a solid.
Weld a bolt on the side, done.

 

I was concerned about this when I built mine, so, I used two heim joints with 5/8" shanks on either side of each spring, if nothing else I've at least got two attachment points for each spring.

 

Kinda like this, only heavier, and not chrome plated :

 

Might not be a bad idea.

I would run a spacer between them.

 

http://www.jalopyjournal.com/forum/showthread.php?t=304871&highlight=speedway+broken

 

yes a spacer would be needed if you were using them with a shackle. my setup didn't have a shackle, so the spring was between the heims. the heims also worked good on mine because springs pointed inward along with the frame rail, by having one heim stick out of the axle a little farther it compensated for the angle of the spring.

 

yes, 4 heims total, 2 for each spring. not sure on weight, its a 34 chevy pickup, fenderless , sbc, 700r4. I'll try to dig up some pics.

 

Its funny this thread should pop up because I've spent the last 3 days searching (here and elsewhere) for better beefier perches to no avail. I plan to run quarter elliptical springs on my front off of a model a axle, with shackles, and came up with these two designs, the first one is a weld on, my worries on this is that the welding would distort and weaken the somewhat thin axle. The second is basically a beefier version of whats already available but with the necessary spacer built on and of course the right amount of unthreaded bolt shank so no threads are in shear. Let me know if you have any input or improvements to either design...

 

Any reason not to use #1 and drill and tap it to take a bolt?

Tim D.

 

I like that idea, for some reason that never p***ed through my head.

 

probably not much help to go thru the axle because the threads are too short but Model t Rear spring perches are mounted in shear, would be good for the spring behind on bat-wings set-up as long as you plan on the offset for a raise or drop. geasable and tough Henry stuff.

 

I'm picturing something like this:



Two different variations, one with a drilled and tapped hole and one with a boss that is then drilled and tapped. The bossed version might be hard to machine though. There might even be enough room for 2 holes, eliminating the rotation issue.

Tim D.

 

Not able to make them myself...well, maybe, but every one would be a one-off. I do have a line on somebody who might be able to CNC them though.

Just thought I'd toss my idea out there, in case somebody wants to run with it.

Tim D.

 

Thats what I figured, I saw a pic of your set up on the 4-link thread. Not much help for you directly, sorry. Indirectly however, who knows what can happen with this place.

I am by no means an expert on early front ends or a formaly trained engineer, but that has caused me to study Henry's design as well as others.

Perhaps this is common knowledge and I just have not found it in print yet, but I often wondered why the ford axle has a sweeping curve vs some of the other OE manufactures. (ground clearance) The arc of the axle is opposite the arc of the transverse spring, The forces on the axle are actualy out/horizontaly towards the spindles and accros the arc tring to revese the arc and not directly vertical. The perch has over 3 inches of leveage thru the axle and bones to spead the load thru the curve and is really in shear in a sence but not directly. More of a rotation but not really. The other straight axles that use/see completly downward/vertical force applied all seem to have a completely different design to the axle it self besides the obvious curve or arc and mountings and are not seen often drilled. This is why the Henry axle actually gets stronger when it is drilled because the suface area is greatly increased in the direction of the force. The tension on the arc also will greatly increase the torional strenth of the axle and the curve actually de-flecting any linear loads the axle may see.
I would think that a drilled axle loaded directly linearly down/vertically would fail and fold the spindle toward the center close to the loading point.
It certainly is in conflict with Henrys design and intended purpose. Because the axle is only as srong in that plain by the metal left from the bottom of the hole to the bottom of the axle. Much less than 50% i would think.

Again I am not an expert, but a student. and these things have been done for longer than I have been alive and I sure would like to know .

 

I like the ideas shown here, both the folded and welded version along with the solid, machined versions. My only thought is you'd need to build in the slightest angle adjustment into your design to account for the smile in any axle. Otherwise you will build-in a bind right from the start.

 

thats what I was thinking,
then I thought that wouldn't work right either, One side of the shakel longer than the other should work for stattic alignment of the spring to the mount, start moving it one side up and one side down and thats not going to matter either. Soggy bushings wont be nice but would let it move enough but too much movement front to back.

I'm watching to see what you come up with

 

Thats cool !!! Make a bunch a them mofos

 

That does look sweet! I would forego the "no drilling" option though. Drill one alignment hole with a pin of some sort through the axle. That way the perch can't move side to side.

Tim D.

 

You could also compensate for the angle or smile by using a spherical bearing where the shackle connects...

 

A spherical bearing would add to the cost, a 3/4" bore, teflon lined uniball with a radial load of 31920 lbs is about $15.00. You'd also have to get snap rings to hold the ball in and purchase/ machine misalignment spacers to get down to the bolt size and spring width. I think if you bought a few set-ups you could get all the hardware for under $30.00 a piece. I might make a rough mock up this weekend and see how it works.

 

What is the OD on a 3/4" Uniball ?

 

1.375"

There are some 3/4" heims that have a 7/8" shank, I know this isn't as good as stopping the swivel issue goes but you could tap the axle and use lock nuts on either side. I also found that most of the misalignment spacers from 3/4" to 9/16" are conveniently 1 3/4" wide. (most of the shackle bolts are 9/16" right?) This would be a no fab/ machining alternative.

 

Don't just sit back and watch man! Your finned design in cast aluminum with that bearing just might work!

Anyone have any thoughts on using cast aluminum for these? Can't take much more of a beating than a bolt-on cast aluminum radius rod mount, right?

Tim D.

 

I'm confused here... why are we trying to remove the swivel action from a standard bolt through design???? I come from the rock crawling world where people are designing swivel shackels for their 1/4 elip leafs so the leaf pack doesn't twist when flexing. I know we're not worried about articulation here, but if you allow a leaf spring to move up and down without making it twist while it does it, your ride quality will improve. Why would you want to eliminate that???

 

This would be a great project for Leno's parts duplicator! Great thread, but you all are making me feel kinda stoopid...

Brian

 

That's what the mono-ball is for. The way the quarter elliptic perch is normally attached to a Ford I-beam, the twist is working against the nut holding it in place.

Tim D.

 

ahhh, gotcha. So I suppose you gotta keep checking the nut/bolt to ensure it's still tight? Would a lock washer help out? Or not do anything?