self larnin' goin' on--narrowing rear axle

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67Dart273

67Dart273

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So today I dragged home a Ferd 9" out of a 78 Mark. Worthless gears, but factory rear disc!! brakes. So I'm gonna try my hand at larning to narrow the housing.

Now I have a lathe and can do basic stuff, so I intend to build a jig. I'm confident I can build the bushings to fit the bearing journals, and two more for the bearing recesses.

My QUESTION concerns the "big bar" through the middle. Why in heck can't I use a big chunk 'o heavy wall tube? Seems to me that would be plenty strong enough to line things up, and..-----if so, what technical term do I want to use to ASK for appropriate tube? That is, STRAIGHT?
 
If you attempt to use tubing you would need to put it on V blocks and use a dial indicator to check if it's true (even on a normal alignment bar it's good to check this). You want it to be true to under ".004. I'm not sure tubing will give you that accuracy though, the slightest bit of flex in the tubing could spell disaster as well. There's a reason those alignment bars cost $100+.
 
you Could ask for some tubing as thick a wall as possible. Of course it should be straight.
(sounds nasty dont it..) Look at it first b4 u buy it. If it slightly bent it can be straightened. (Axles get straightened and so do cranks.) Solid round bar is way expensive; yes a solid round bar that is wide enough to do both sides at one time would prolly be more accurate, depends on how much U wanna spend and if u can get the steel cheap, like from a scrap yard. If you go with new, tell em what ur doin and they can steer u in the right direction as far as tubing. A 5' length of thick wall tubing is not going to be bent that much unless it has taken some serious abuse. If it did they prolly wouldnt be able to sell it.
 
My worry is when they manufacture the tubing that the tolerances are not near as strict as an alignment bar's.
 
hey, if you got a lathe....(your drive shaft is tubing, it does not bend unless u abuse it, and it is not thick wall at all) I'd use some thicker wall tubing, largest diam you can get away with and machine the ends for the "pucks". use a line to check for straightness or a laser. (various types nowadays) solid bar is nice but is overkill but if you insist will prolly cost you about $175 US. (plus shipping) for a 5 ft piece. (thats for 2" round 304 stainless).
 
Thanks for the thoughts. I was hoping someone knew specifically what kind of tube is likely to be better. Seems to me I remember some with a name like "Shelby tubing."

last night I was googlin' around and someone had commented on another discussion that ya might look for a rod out of a defunct hydraulic cylinder. Of course one that long would be expensive, and worth overhauling, so that might be a stretch.
 
Why waste your time and money machining a bar unless the base stock is free.

Get a turned ground and polished 1045 bar in the diameter you want. It's not that expensive if you get one that's under 48". Shipping goes up a bunch with lengths over 48".

http://www.speedymetals.com/c-8232-turned-grnd-polished.aspx

Pick your OD, bore your pucks and you have an alignment jig. I use a 1.25" TGP bar that is 48" long, about $50 delivered, IIRC. Do one side at a time for most rears.
 
What do you guys make your pucks out of? Aluminum or steel?

Thanks
 
Red383 said:
What do you guys make your pucks out of? Aluminum or steel?

Thanks
Click to expand...

Aluminum... that's what my mandrels/pucks are made out of.

Grease up the puck (inner & outer) and bar before sliding it through to prevent galling. The bearing ends are much easier to remove if you grease up the housing end/outer of puck. The two materials steel/aluminum don't always play well together.

Chamfer the end of the rod too...
 
crackedback said:
Aluminum... that's what my mandrels/pucks are made out of.

Grease up the puck (inner & outer) and bar before sliding it through to prevent galling. The bearing ends are much easier to remove if you grease up the housing end/outer of puck. The two materials steel/aluminum don't always play well together.

Chamfer the end of the rod too...
Click to expand...

What he said. :toothy10:
 
And... when you go to weld the ends, spot them at four places, and weld as you would on sheetmetal, dont try to run a contenuous bead at one time!! alternate as you go!! After you are done, the bar should slide out pretty easy. If the housing warps slightly, you can heat and quench the tube to straighten it, to a small degree... Taking your time, really pays off here!!
 
damnimcooltom said:
67Dart273 - Did you check to see if they had what you need over at CDA metals on Wilbur?
Click to expand...

Haven't yet. The way the weather --and my arthritis-- has been doing, it may "be awhile."

Another little setback I may have encountered, and I haven't even checked it yet----that damn Lincoln axle I bought JUST MIGHT have the larger bolt pattern Lincoln used on some of 'em, so I STILL would have to redrill the axles and rotors for the BP Mopar/ Ford bolt circle.
 
Yeah, measure the pattern. Some Lincolns used the 5 on 5 pattern. Also check into the price of the disc parts. One site I was reading said they only used thats setup for four years, and the parts are getting pricey. And if the axles need drilled, will the rotors have enough meat in them to allow drilling without weakening them too much.

I drive right by CDA Metals all of the time. If I knew exactly what to ask, I could stop in and bug them.
 
Bevel it so the wire has some place to fill.

housingend02.jpg
 
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