Axle Taper

Henry/Kokomo

Henry/Kokomo

Well-known member
Can anyone give me the taper, in degrees, of the outer portion of Ford rear axles OR aim me at a source for that information? I have a couple of rear axle shafts with rough tapers. I also have a lathe with taper attachment and a toolpost grinder. It seems to me the repair should be straight forward providing I use the proper taper. Thanks in advance for any assistance.
 
Here is a drawing from the Benson Ford Research Center, BUT..........read the included thread in this link. The guys in the link "discuss" the possibility that the math just doesn't quite work-out. I have NOT tried to work the math. Click the link! DD

http://www.mtfca.com/discus/messages/29/26761.html?1175217029

26763.jpg
 
Henry,

Remember that removing metal on the taper will cause the drum to move in towards the axle housing. Note how much the drum moves out with an axle shim.

Charlie Stephens
 
V8COOPMAN said:
Here is a drawing from the Benson Ford Research Center, BUT..........read the included thread in this link. The guys in the link "discuss" the possibility that the math just doesn't quite work-out. I have NOT tried to work the math. Click the link! DD

http://www.mtfca.com/discus/messages/29/26761.html?1175217029

26763.jpg
Click to expand...
Since the drawing is from the Model T site I wonder if the taper is really the same as on the later axles? I will be the first to admit I don't know the answer.

Charlie Stephes
 
V8COOPMAN said:
Here is a drawing from the Benson Ford Research Center, BUT..........read the included thread in this link. The guys in the link "discuss" the possibility that the math just doesn't quite work-out. I have NOT tried to work the math. Click the link! DD

http://www.mtfca.com/discus/messages/29/26761.html?1175217029

26763.jpg
Click to expand...
Since the drawing is from the Model T site I wonder if the taper is really the same as used on the later axles? I will be the first to admit I don't know the answer.

Charlie Stephens
 
Henry, There is no math involved in the cleanup of rough axle tapers.
Remove the key and knock down the high burrs with a flat file.
Install a drum with grinding compound and a loose fitting axle nut. Adjust the nut as needed to turn the drum by hand.
 
A person would think that FoMoCo would use a Morse Taper or maybe Brown & Sharp for ease of tooling but I wouldn't be a bit surprised if Henry didn't make his own taper. They made a lot of their own tooling at Ford back in the day. It looks somewhere near a MT-5 if I had a guess at it.
 
I thought it was 7 degrees total or 3.5 per side. I am not sure why that sticks in my head, it could be an Indian crankpin taper????? But if you have a taper attachment I would blue the axle and start with that and see how it looks.
 
7 degrees is what initially came to my mind also, but I believe I got that from the taper on Ford tie rod holes. DD
 
Thanks guys! All good ideas. Charlie - Good point. My intention was to grind off the "humps" and leave the small "valleys" so as NOT to change the location of the drum.
ford38v8 - It may come to that. I just acquired a new (to me) toolroom lathe with taper attachment and I guess I was trying to justify the purchase. rotorwrench - you're right. WAY too easy. JonC - will try that first and see where I come out. V8COOPMAN - very possible. I was taught that anything less than 8* was a locking taper. Thanks again for all the replies. Much appreciated.
 
Removing the high spots will certainly move the hub toward the housing. A disaster when the end of the housing bottoms inside the hub.

Setting the taper attachment within a second or two would be a real challenge even if the correct taper numbers are in hand.
 
V8COOPMAN said:
7 degrees is what initially came to my mind also, but I believe I got that from the taper on Ford tie rod holes. DD
Click to expand...

Your right, thanks for the correction, I did make some adapters for hiem joints to fit into front spindles and now I remember the 7 degrees.
 
Old timers used to take an old hub that still had a good taper then put some lapping compound on the shaft and go to lapping. This would tell you where the high spots are anyway. Conical shims were also used but at some point you just have to pitch the stuff and find something in better condition.
 
I would chuck up the axle, then run the compound back and forth with a dial indicator on the taper,instead of trying to get it set correctly with the degree marks. That way regardless of what it's supposed to be, you will be tracking on what it is.
 
More often than not, axles with a damaged taper are cracked in the area of the keyway. Have them inspected, or Magna Fluxed before you use them. Losing an axle on the road is an invitation to disaster. Unless you have access to tapered shims, recutting the taper isn't going to work.The last time I saw shims was in a Joblot catalog as AS-4235.
 
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