Narrowing my own 8.75. Questions.

[pishta]

I saw a pic of a bottle jack and some chain used to pull in a shorter axle shaft into an 8.8 cast iron carrier. Iirc the steel 3" tube are just held into the cast case with friction and a plug weld in a hole.

 

[pishta]

Here is a guy's post :
It is important that the cuts be made very precisely (including the width of the saw blade itself) and edges beveled and lined up "just so". You want to weld it solid and straight if you cut. I used four lengths of 1" angle iron strapped tightly around the pumpkin end of the tube and slid the newly cut outer end into that, with the axle too for added insurance. The axle should want to slide perfectly in. Double check the length is correct and tack good between the gaps in the angle irons. Then weld away..

He used 4 angle irons as parallel rails to slide the fly end of the tube into place and the axle to verify straightness, just like I did. Even beveled the edges to give the weld bead plenty of seat. Grind down the bead flush, sand and paint.

 

[33IMP]

You are doing this at a college machine shop etc.
Then machine the pucks for the center section and the axle ends you want to use, find a straight steel bar (an inch dia?) and do it right. When your done, if you do it this way, you can narrow other guys rears, and make some money.

 

[pishta]

^^ huge liability..make sure you are comfortable taking peoples money for that service.

 

[CudaFactHackJob]

Weld the ends on after the support is welded to the housing, The housing will warp, but you can weld the ends onto it in the proper location. When I narrow 8.8s I put the axle end over the shaft an slide in strips of aluminum can between the bearing and axle to make sure they're parallel, Then rock the end all differet ways to test where the centerline is; based on the side gears.

 

[nckennyb]

Shortened these axles that came out of a 69 Fury for use in an A body.

 

[Col_Steve]

Shortened these axles that came out of a 69 Fury for use in an A body.View attachment 1715871508

Am I looking at cut and welded axles?

 

[TT5.9mag]

Shortened these axles that came out of a 69 Fury for use in an A body.View attachment 1715871508

What? What? What?

 

[72Duster440]

Am I looking at cut and welded axles?

Sure is what it looks like. Hopefully he's running a /6 or they won't last, still might not.

 

[nckennyb]

Got a set just like it in my wife's car with 340 and 4 speed for 20 years now. 245/60-15 tires on back. Don't hate until you try it.

 

[Col_Steve]

Got a set just like it in my wife's car with 340 and 4 speed for 20 years now. 245/60-15 tires on back. Don't hate until you try it.

No hate here, but no I wouldn't try it. Axle shafts are very specially heat treated which welding negates. I really like to keep it in my own lane, a powerful car turns very fast when an axle snaps under full throttle. Other folks lives are at risk too you know. Cbody and truck axles can be cut and re-splined to Abody length without tossing a very questionable variable into the equation. Aftermarket axles are cheap too and even stronger than factory.

 

[mopar head]

Got a set just like it in my wife's car with 340 and 4 speed for 20 years now. 245/60-15 tires on back. Don't hate until you try it.

Probably no worse than my welded steering arm

 

[nckennyb]

No hate here, but no I wouldn't try it. Axle shafts are very specially heat treated which welding negates. I really like to keep it in my own lane, a powerful car turns very fast when an axle snaps under full throttle. Other folks lives are at risk too you know. Cbody and truck axles can be cut and re-splined to Abody length without tossing a very questionable variable into the equation. Aftermarket axles are cheap too and even stronger than factory.

If you had a spool in the rear, I would agree with the statement about changing lanes but not with a sure grip or open differential. I've snapped axles-that weren't welded on by the way-while drag racing running slicks on a Duster with a sure grip and it just couldn't transfer enough torque to the unbroken axle to make the car turn. The engine reved and that's about it. I was able to drive it home from the track with one good axle by taking it nice and easy on the sure grip.

 

[Col_Steve]

If you had a spool in the rear, I would agree with the statement about changing lanes but not with a sure grip or open differential. I've snapped axles-that weren't welded on by the way-while drag racing running slicks on a Duster with a sure grip and it just couldn't transfer enough torque to the unbroken axle to make the car turn. The engine reved and that's about it. I was able to drive it home from the track with one good axle by taking it nice and easy on the sure grip.

That would be true with the '70 and up Auburn spring loaded cone type not so Sure?-Grip (cheap) that even when new only transfers 25-40 lb. ft. of torque to the tire with traction. The sought after Dana Powr-Lok Mopar Sure-Grip used through '69 when properly clutched for drag racing transfers at least 200 lb.ft. to the tire with traction. At about a hundred miles an hour (the 2/3 or 3/4 shift) that is enough diagonal thrust to significantly upset the stance of the car at a time when the front end is high from acceleration and has big air flow under the car, thus down force on the front tires is very low making steering response weak. This sudden upset is unexpected by the driver who senses the instantaneous drift and quickly steers into it to keep the car straight and then reactively gets out of the gas. Getting off the gas reverses all the previous forces because now the tire with a good axle acts as a brake on one side. Now all of the steering inputs the driver has applied to correct the full throttle drift are suddenly no where near what he needs now and the back of the car wags out. He is then either into the wall or across the other lane. The entire event takes less than 2 seconds. Narrow low friction front drag tires allow it to happen even quicker. 4 speed cars with great traction are the usual victims, automatics not very often. Those of us who watch a lot of drag racing have seen it many times, most without knowing what they are seeing. After a great launch a car looks to have a perfect run in progress when at a gear change the car suddenly goes sideways walls up or rolls over or both. Watching the sad event in slo-mo we can see the suspension didn't break, the tires are all inflated and there isn't any oil on the track. It looks to us like the driver intentionally turned into the wall or other lane. Sometimes a good driver -or a driver that has been there before- knows to ease out of the gas, and after a lot of white knuckle gymnastics saves the car. The broken axle is discovered back at the garage at a later date. The audience never gets to know why.
Steve