Can anyone give me the dimensional differences (diameters) for the tapered area of the A drive shaft compared to the AA drive shaft. Also, what is the included angle of the tapers of each. I am assuming at this time that the taper angle is the same on both. Any help would be appreciated. Thanks. Don/WI
Drive axle dimensions for A & AA
- Thread starter Don/WI
- Start date
SeaSlugs
Well-known member
those are both worm drive AA drive shafts, i thnk you mean axle shafts, tapered part with the keyway for the drum to slip on correct?
a bad aa axle shaft
a good axle shaft pokin out.
i can get measurements tommorow if you would like.
just curious myself but are you doing research or just curious?
SeaSlugs quote "i can get measurements tommorow if you would like.
just curious myself but are you doing research or just curious?"
I would appreciate if you could get those dimensions. I just got my drum lathe running and am trying to figure out what I need for taper adapters. I had an old AA drum that I tried to mount on the lathe and it goes on the shaft further than the A drum so the taper adapters that work for the A drum don't work for the AA drum. I also did some research on this site and read where the outer end of the hub gets banged up and is not always concentric with the brake shoe area of the drum. One thing I am looking at is to find a taper reamer for the drive taper, but if the reamer cutting edges are straight it won't work because of the keyway. Probably more than you wanted to know. Don/WI
just curious myself but are you doing research or just curious?"
I would appreciate if you could get those dimensions. I just got my drum lathe running and am trying to figure out what I need for taper adapters. I had an old AA drum that I tried to mount on the lathe and it goes on the shaft further than the A drum so the taper adapters that work for the A drum don't work for the AA drum. I also did some research on this site and read where the outer end of the hub gets banged up and is not always concentric with the brake shoe area of the drum. One thing I am looking at is to find a taper reamer for the drive taper, but if the reamer cutting edges are straight it won't work because of the keyway. Probably more than you wanted to know. Don/WI
Last edited:
Chris in CT
Senior Member
Hi Don, A couple of random thoughts here... You will probably not be able to find a taper-reamer for the Ford rear axle, but would have to have one made, probably by re-grinding a Morse taper reamer. But if I understand what you are trying to do here, a reamer will not work for you. If you remove any material whatsoever from the inner diameter of your hub, it will move closer to the backing plate, and at a rate that will really surprise you. Further, a reamer will not "true" the center bore to the outer diameter of the drum, because the reamer will follow the path of least resistance, which will probably not be the true center of rotation for the assembly. In order to true the rotation to the center, you would have to hold the OD on a lathe, and then taper-bore the center hole to the outer rotation of the drum. Piece of cake for a skilled machinist, but a hard nut for a guy like me, and again, enlarging the bore of the hub will render it useless for application on the actual vehicle...
SeaSlugs
Well-known member
sorry i couldn't get em today but tomorrow for sure. I got several AA axle shafts sitting in the shed so i can pick the cleanest one and give you those measurements.
Usually what ive noticed on AA drums (ive only dealt with the 28/29 style) is either
1 their warped from getting beat on to get them off - guilty of this
2 axle nut gets loose and starts chewing up the taper/key (hence what that one is so rusty)
3 brake surface is so worn down in compared to the emergency brake band area its noticeable from 5 feet away...
4 the wheel bearing surface has rust pits
5 taper is worn and can see gouges in the inside of the drum from emergency brake pins and parts rubbing hard.
thats the junk drum that came off that junk shaft, only took a 3 ft sledge hammer, 3 jaw puller tightened with a 6 ft cheater pipe to get it off, all because of that taper being so rusted and the fact someone somehow tightened the brake adjusting wedge so far in the shoe pins fell behind the tapered cone so i couldnt back the brakes all the way off...
Usually what ive noticed on AA drums (ive only dealt with the 28/29 style) is either
1 their warped from getting beat on to get them off - guilty of this
2 axle nut gets loose and starts chewing up the taper/key (hence what that one is so rusty)
3 brake surface is so worn down in compared to the emergency brake band area its noticeable from 5 feet away...
4 the wheel bearing surface has rust pits
5 taper is worn and can see gouges in the inside of the drum from emergency brake pins and parts rubbing hard.
thats the junk drum that came off that junk shaft, only took a 3 ft sledge hammer, 3 jaw puller tightened with a 6 ft cheater pipe to get it off, all because of that taper being so rusted and the fact someone somehow tightened the brake adjusting wedge so far in the shoe pins fell behind the tapered cone so i couldnt back the brakes all the way off...
Joe K
Well-known member
Good sketch SeaSlugs.
For those who wish to go further, 13/16 SAE fine thread bolts and tooling/components are no longer "standard" but can still be found by the lucky.
I have a die that will cut (or clean up) the thread but we're talking back in the era of "Little Giant" Adjustable Die Sets by Greenfield Tool & Die (or Wells Brothers before them)
For the specifics on 13/16 SAE thread, take a look at http://www.vedge.org/tap-inch.html.en
Joe K
For those who wish to go further, 13/16 SAE fine thread bolts and tooling/components are no longer "standard" but can still be found by the lucky.
I have a die that will cut (or clean up) the thread but we're talking back in the era of "Little Giant" Adjustable Die Sets by Greenfield Tool & Die (or Wells Brothers before them)
For the specifics on 13/16 SAE thread, take a look at http://www.vedge.org/tap-inch.html.en
Joe K
I don't know what the A axle dimensions are. I was hoping someone had one apart and would measure it. My A's have the wheels on and are in a non-heated garage. It's supposed to get up to a high of 17 degrees today. Don/WI
Joe K
Well-known member
This almost a case of has anyone seen the actual Ford drawings? Tapers can be VERY problematical to measure - and fit. And reverse engineering is prone to inaccuracies.
Those who reproduce the axles (Snyders?) may have access to the information - and be willing to offer it on request "in support of the hobby" sort of thought - but then they may view this as an undercut to their market position - and refuse.
This yet another case where drawings from the source (Ford) should be available - but are not. (mostly)
Joe K
Those who reproduce the axles (Snyders?) may have access to the information - and be willing to offer it on request "in support of the hobby" sort of thought - but then they may view this as an undercut to their market position - and refuse.
This yet another case where drawings from the source (Ford) should be available - but are not. (mostly)
Joe K