Drive shaft taper

Cartravel

Senior Member
I have to shorten a Model A driveshaft. I plan to cut at the taper end and have the taper, keyway and threads remachined. The driveshaft I have shows some trauma in the center part of the taper. Based on the unworn ends I measure a taper of 0.121 in/in. I read 9:1 taper (0.111 in/in) in an earlier post. What is correct?


Also, at the roller bearing end, what is the original and acceptable worn diameter?
Thanks
 
I have an NOS never installed Model A drive shaft. These are the measurements I got from it.

Overall length 54.125"
Taper length with thread 3.884"
Taper length 3.200"
Spline length from cir clip 3.235"
Shaft diameter 1.113"
Taper mid point diameter 0.922"
Taper end diameter 0.740"

This works out to a taper of .116 - .117

Warren

taper.jpg
spline.jpg
 
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Thanks for the response. I assumed Ford would have published this spec. I measured mine at 1/2 intervals. I get 0.747 (+ or - maybe 0.005) at the small end. I get 0.919 at 1.6 (your midpoint). These numbers are close to yours. However, the diameter in the midarea appeared to be somewhat less, which I assumed to be wear. I wonder how critical this is?
 

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I shortened my driveshaft 7" by removing material 6" ahead of the thread. It is dead straight and keeping the seam just ahead of the rear end, there is no vibration. Did it at a local machine shop. Took about an hour and cost $75.00
Warren
 
You can buy a quality shaft made here in America very reasonably. I have installed one in rebuilding my differential, and was pleased with all dimensional and quality aspects of it.

https://www.snydersantiqueauto.com/product.htm?pid=978236&cat=41627

I assume that you are shortening the shaft to repair a damaged region? If so then you will need to add what you took away to maintain the stock length. For all this trouble the new shaft would be the way to go I would think...
 
Most tapers are measured in degrees. Taper turning attachments are set up that way. Some shafts are heat treated after machining so keep that in mind as well.
 
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