Lenghtening a 1934 propshaft :Tech

[Mr 42]

There been some discussions how to shorten/make a Propshaft.
This is how i lengthened mine since i had a 1934 Four cylinder propshaft.
But needed a V8 that is around 45mm longer.

Please This is how i did it it's maybe not the best way but it's my way.
And ive been driving 8000km plus without problem.
Just for the record I did the lenghtening at the rear axle end.

Maybe it can be of some help or give you ideas.

I used a water hose clamp, to get a straight cut.

Used a hacksaw to cut it going slowly.

Used a rotating file to clean up the inside a but since there was a bump after the tube was welded together.

Used a lathe to cut down the extension bit to the inside dia of the tube.

OK the thickness of the material was maybe overkill but it was what i had laying around.

Made this two holders using some skateboard bearings.

Welded the holders to a long pipe, so i could lay the propshaft on the bearing's and spinn it by hand, to check for roundness.

I had to stagger the bearings on the gearbox side because of the small diameter of that end.

Before i cut it i used this dial indicator, and then during and after i welded it back together, so i didnt get into trouble.


As i said in the beginning ive been driving 8000km plus, without any problem, i took it apart a couple of weeks ago since i goofed when welding the rear sprint, and it loosened, Everything else looked OK, So im happy.

 

[PeteVS]

Very informative thread! Did you have the parts chamfered to get a good deep penetration weld? Also, I like your rollers!

 

[Mr 42]

No i did not chamfer the joints since the part i stuck in the middle was smaller diameter than the pipe, leaving a lot of space for the weld to penetrate.

 

[Coupe35]

Great idea about using a hose clamp as a guide to get a straight cut. That's one of my mine concerns, getting a straight cut. And BTW, you cannot use a pipe cutter as it could egg shape the end of the tubing. Thanks mr 42. Using the dial indicator, how true was the shaft when you finished.

 

[Mr 42]

I did this three years ago, and i have hard time remembering the details.
But it was not out by much, max one tenth of a mm (sorry im a metric guy ).
But it was the same as before the cut, so i did not fiddle around with it.

I also drawed a line lenghtwise so i put it together in the same position (phase).

I have used a pipe cutter when i made propshafts from scratch, without any problem.
You just have to take it slow and nice. Did not have one this time.

 

[FlatheadTed]

I had a discussion with some one last weekend re this very subject ,but shortening .He said the 34 four banger shaft would fit behind a 32 with v8 with no cutting ,That makes a 32 with a 4, even shorter .

 

[Richard (EV8G)]

Don't think so... a late 32 driveshaft is about 9" shorter than a 33-4 V8 driveshaft. A 33-34 driveshaft for 4cyl is only about an inch and a half (whatever it is?) shorter than the 33-34 driveshaft for a V8.

The driveshaft for 1932 V8 and 4cyl are the same length, as the transmission
and mount are both against the K-member, unlike the 33-4 where the position
of the rear of the trans (and reversible mount) are in different locations V8 vs.
4cyl. (The driveshaft for an early 32 "B" rear is a different part than for the later 32 "18" straddle-mounted rear.)

The 33-34 4cyl driveshaft WOULD make a nice donor to convert a 33-34 rear to become a "late" 32 rear to fit a 32, but it would need to be shortened.