I will remove these today and give them some shape but I NEED advice on the best approach to use in welding them on to the tubes. I had a HORRIBLE experience with my last set of cast perches that I had welded to 35/36 axle tubes, they warped bad and I had to start over with new tubes and new perches. I know this has been done thousands of times but what is the best approach to avoid problems.
well---The closer you are to the end of the tube, the less apt it is to warp. Generally when I weld anything to an axle tube, I make it out of a full 360 degree plate. I split the plate so I can put it in place around the axle without having to take the axle flange off, then tack it back together, then weld ALL THE WAY AROUND THE AXLE. That way, at least the same amount of heat is distributed fully around the axle, so warping is minimized. Since you already have the weld on brackets, and they are not a 360 degree type, good luck---
My friend whom did the welding on the last set was trying to get me to use a 360 degree set of perches that he uses all the time but I was insistant on the cast pieces. The new perches are store bought Pete/Jakes that I pinched to fit the smaller diameter axle housings. My new spring eye centre is 47-1/16in as opposed to the stock 49-1/4in
I welded a set on a while back. If I recall, I just jumped around a bit and switched from one end to the other. The perches were also chamfered down to a point. I haven't noticed any warpage.
I bought a rough set of cast weld on perches here on the board that needed all the machine work done. After they where machined and welded I took the housings to have the machine work done for the new bearing races and the tubes where warped on the ends, kind of like a spaghetti noodle chucked up in a lathe.
I used the "cast" perches from Sacramento Vintage Ford and would no personally use the steel ones because of their size. I heavily chamfered the cast ones and ground them to my 3" tubing. I used a TIG and stared slow and continued to build up as I went out. I kept switching back and forth. The runout on the ends before I welded was around .004, and when I finished was round .006/.007. I did the same with my ladder bars..................had no problem. IMHO
Id go with a new set of 360 degrees.....but if you want to stick with what you have you could create some matching heat around the remaining area with a torch...the problem would be how much heat to equal the welded perch, tricky but can work.......Bert
The cast pieces look like they would take a lot of heat to get a properly fused weld, yet they are going onto a relatively thin wall on the axle tube. ---Yes, with a tig which has a very small "heat affected zone" you can probably get away with it, but with stick or mig, by the time you get enough heat in there to properly weld the heavy castings, the axle tube will pretzel on you. When you heat any steel up to the point of good metal fusion, it expands, then when it cools it never quite contracts by the same amount, in a uniform manner. Thats why welding on one side only of an axle tube can deform them so badly. I much prefer to see a spring hanger made of a lighter (as in 3/16" to 1/4" material, a full 360 degree design, with a triangular gusset to stop any side deflection of the bracket (if the hanger is cantilevered out from the axle tube).
Thank you all for your input. In the B/T AV8 book they just weld on cast perches and it all sounds very simple. The pic shows the sharpie lines on the bearing race where the problem area is. How much runout is acceptable on these?
So what would be wrong with putting a bead all the way around the tube, even though it's not a 360 degree perch?
Hypotheticaly speaking, if you were to use a 180 degree bracket, perch or whatever, could you heat the tube opposite of the welds first with a torch to counteract the warpage from the welding?
Or after. Weld your perches on (carefully and slowly, avoiding heating the **** out of it) Then, pop it up in a lathe and heat the opposite side until it's strait again.
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