MTFCA Forum

My rear axle key ways are worn out. I am told I can get them re-cut on the opposite side of the shaft by a machine shop. What do I tell the machine shop for dimensions? According to this diagram halfway down the discussion: http://www.mtfca.com/discus/messages/50 ... 1231423423 The keyways are 2 3/4 inches long and 1/4 inch wide but the diagram does not say anything about depth? How deep should it be?

That's not something that I would do, but if you proceed, have the axles magnafluxed for cracks before you put any more $$ into them.

If the keyways are wallowed out pretty bad I would try to find a better used axle if you don’t want to spend the money for new ones. They are around if you look and some are still pretty good. I bought four at Chickasha a few years ago that weren’t hardly worn at all and were good. I bought them for spares.
Some people want everything brand new and replace most everything in a rear axle assembly and that’s OK.
But just because it has some miles on it doesn’t mean it’s not any good.
Cutting a new Keyway may be OK but make sure the axle isn’t worn badly on the axle shaft itself or cracked. If it’s worn badly in the keyway it’s probably worn everywhere else.

Replace the axle shafts. The rear axle is one place where you do not want to cut corners.
.Stephen

I'm going to join others here and say that's a bad idea. By removing additional steel and reducing the cross sectional area of the axle end, you're greatly reducing it's strength. Having two key ways, 180 degrees apart is also just poor practice anyway. The only thing I would even begin to consider, would be to cut the existing key ways a LITTLE BIT oversize if all they need is to be trued up for a snug fit with the key. That would require making stepped keys, with one side sized for the axle and the other sized for the hub. That said, I would only do this if the axles were magnafluxed and found free of cracks. When it's all said & done, it's not worth the time & expense for a T axle when new ones are available. (I have done this for a friend's 1915 Buick, where new axles are not available.)

Have never found a used axle on rear tear downs that met specs for safe touring requirement. Most times if the keyway is good, other details are poor. Both of these worn axles came out of the 25 Coupe.

Pickled and pecked Hyatt bearing surface with fingernail deep groove at end of surface, both showing poor running surfaces. No good. Threads on one chewed off, that one the wheel hub was loose too.

Many hubs are worn on the inside taper, putting such a part on a worn taper is asking for loose hub, that will wear the keyway.

Thankful we T guys can get new high quality replacements , with tad longer taper for common worn wheel hubs. With new bearing surfaces, new quality Hyatt sleeves, and using very good Hyatt bearings, a highly serviceable axle can be had for little cost.

Glad I didn’t have to order new axles if I had a Model A to fix, new A axles with gear are $500 each!

The only thing better would be it some enterprising individual would sell new axles with good gears already pressed on and keyways cleaned up to get rid of the ever present issue of stock keys not fitting. I just got mine done but would have paid up if someone offered these ready to install.

Or maybe weld more steel in and re-cut it? I don't know how much they would charge for something like that or if it would be worth it.

If you give the machine shop the axle and hub, and a new key, they should be able to figure it out.

You can buy stepped key stock, then you'd be able to machine the existing keyway wider, and use a new hub with it.

But for the cost of a new axle, I'd be buying a new axle. Actually, a pair of new axles.

While the key has it's job, it's the taper that keeps the wheel in place so needs to be a good fit. I have fitted stepped key stock to axles that did not need to be other wise replaced.
The other part of this is keeping the axle nuts tight and checking them every so often esp after pulling the wheels off, they need to be re-torqued several times (like heads). I don't know how many Model A's that have come into the shop with loose hubs because they were never checked after the hubs were off the last time. The torque on the Model T and A would be around 110-120 FP final, later the V8's went to over 200 FP but would not suggest that for T or A axles. If you are relying on the key to hold the hub in place because the taper is not doing its job, there are other issues that might need attention.

You'll gain nothing by repairing the old axles. Get new ones and be done with it.

Stephen

Stephen

Couldn't agree more

Isn't my T, but like my dad told me, 'son, learn from other's mistakes, less costly to you.'

Do you mean like this? $135 each? https://www.macsautoparts.com/ford_mode ... shaft.html How do you get the old gear off for reuse?

Lots of threads on that topic. Here are a couple.

http://www.mtfca.com/discus/messages/70 ... 1512053934

http://www.mtfca.com/discus/messages/41 ... 1417743227

No like these ones (it pays to do a little shopping! );
https://www.modeltford.com/item/2505HS.aspx

ivaldes1 wrote: ↑

Sun Jul 05, 2020 2:02 pm

Do you mean like this? $135 each? https://www.macsautoparts.com/ford_mode ... shaft.html How do you get the old gear off for reuse?

While your choice of new axles and suppliers. For me Lang's gives good service and this axle is the bit longer taper for typical used Ford rear hubs. These are what I'll be using for replacement.

If you plan to buy new axles it’s a learning process in removing the old axle and pressing the gear on the new axle. Do a forum search on the subject and check out the different posts in doing it.
Some times the gear comes off fairly easy and sometimes it doesn’t. Same story goes for pressing the gear on. Been there and done that. You can bend the axle if you try to ‘force’ it on. I took mine to a shop that had a large enough press and they bent the axle. So much for a ‘professional’ shop!
I found out later that Ford allowed a + or - range when machineing the parts. The axle maker supposedly used the same + or - range going be Fords original prints.

It’s turned out my gear was in the low end of the range and the new axle was in the high end.
In other words the axle was to big to go in the to small hole in the gear.
The supplier was good enough to send me another axle that was closer to my gear range.
Lesson learned on my part!

What I've been able to figure out on gear removal and reuse is stand the axle up in the press, use a hub to steady it because it can shoot out of the press if not centered. Press, remove the keeper, press it out. Steve Jelf's and other demonstration pictures helped.

I cut 2 two-foot lengths of angle iron ( 1x1x1/8") and clamped them onto the axle with hose clamps. I protected the axles from scratches with duct tape. The angle iron doubled the critical buckling strength of the axle from 14,000 pounds to 28,000. I did that to keep them from buckling in the press. It was cheap insurance.

I built an axle "cage" to prevent flex when pressing on the gear - I use a T hub in my 20 ton press with an axle shim covering the key way to press against. I've replaced dozens of gears - some fairly easy, some NOT !

the answer to your question is tell them to put the shaft in a swivel vise using v blocks.
swivel the vice until the taper indicates straight with the machine ways.
use a 1\4 woodruff key cutter and key it .135 deep.
philip

Philip wrote: ↑

Tue Jul 07, 2020 8:58 am

the answer to your question is tell them to put the shaft in a swivel vise using v blocks.
swivel the vice until the taper indicates straight with the machine ways.
use a 1\4 woodruff key cutter and key it .135 deep.
philip

That's not the right way to pick it up Phillip. If you do that, when you're done cutting the keyway, and checking with a depth mic., you'll find that the measured keyway depth will vary from one end to the other, with the keyway depth being shallower at the small end of the taper. If I recall, it will be about .007 shallower. It's a trap that reproduction axle manufacturers fell into early on, which resulted in keys getting pinched tight at the small end before the hubs could be seated. Lots of broken axles resulted.

Jerry VanOoteghem wrote: ↑

Tue Jul 07, 2020 1:03 pm

Philip wrote: ↑

Tue Jul 07, 2020 8:58 am

the answer to your question is tell them to put the shaft in a swivel vise using v blocks.
swivel the vice until the taper indicates straight with the machine ways.
use a 1\4 woodruff key cutter and key it .135 deep.
philip

That's not the right way to pick it up Phillip. If you do that, when you're done cutting the keyway, and checking with a depth mic., you'll find that the measured keyway depth will vary from one end to the other, with the keyway depth being shallower at the small end of the taper. If I recall, it will be about .007 shallower. It's a trap that reproduction axle manufacturers fell into early on, which resulted in keys getting pinched tight at the small ned before the hubs could be seated. Lots of broken axles resulted.

Maybe you're aware of this and the suggested .135 avoids the bind?