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1930artdeco 01-26-2015 07:51 PM

axle threads
 

2 Attachment(s)
I bought a spare axle in pieces and one of the shafts has trashed threads about a third of the way in. I had a club member use his axle thread tool to restore what was left of them and ended up with the first picture. Now I can screw an axle nut all the way up to the point and beyond where the cotter pin goes. My question is, is this a good shaft? I have access to a good axle from the same club member. Should keep this one in reserve?

Thanks,

Mike

Big hammer 01-26-2015 08:04 PM

Re: axle threads
 

You could use a stack of washers and torque down nut and see if threads hold,
before reassembly!

glenn in camino 01-26-2015 08:09 PM

Re: axle threads
 

I think I'd use some blue Locktite on it

Fullraceflathead 01-26-2015 08:11 PM

Re: axle threads
 

If all of the Threads are good under the nut when it's at the cotter location that's about as good as it gets. I'd use it! If you later on have to rethread a stripped axle while still on the Car. I made a video of doing just that.
  1. https://i.ytimg.com/vi/lC_zIvb1Yuo/mqdefault.jpg
    8 videos

    1928 Ford Model A stripped axle thread repair




Joe K 01-26-2015 08:17 PM

Re: axle threads
 

Actually, the proof of this pudding is in the torquing. The WORST stress any bolt will endure during it's life is in the torque of installation.

If you can put it on, and tighten it up to the point where the hub is "solid" and torqued to a decent degree, and doesn't fail in the process, it will keep the hub on indefinitely.

Now what torque a common question. The model A as it was assembled did not use any torque values, Henry relying instead on calibrated tools, or the arm-strength of his able workers. Today we know a little better.

Given that this thread is 5/8-18 UNF, there are charts on the 'net which indicate torque value for a modern bolt. The chart I like is at http://www.mpi-online.com/technical/torquechart.htm for 5/8-18 the chart number is 128 ft-lbs. for Grade 5. I would like to choose grade 8, but Henry had no inkling about grades of steel in 1928. Steel was of fairly high quality, but probably not our grade 8. So I chose grade 5.

The chart gives some additional information though, specifically...

Quote:

Above values are for zinc plated nut and bolt assemblies. Increase torque by 33% if using unplated (dry, unlubricated) nut and bolt assemblies. Decrease torque by 45% if using lubricants (oil, grease, or antisieze lubricants).
So we should reduce this a bit to account for lubricant which you probably will be using. I like NeverSeize, but I've used MolyCoat and a few others I get free from my work.

So reduce to perhaps 70 ft-lbs

If you can torque your nut on lubricated to 70 ft-lbs, you've probably got it covered. If the nut ruins and strips the thread, find another axle or play a game of turning down the thread to the next size of 9/16 UNF (which I have done with impunity and still torqued to 70 ft-lbs.)

All the nut does is keep the hub from "turning off" it's taper. The key drives the hub.

Hope this helps
Joe K

scrapiron 01-26-2015 08:33 PM

Re: axle threads
 

Just a thought, use a new nut, or make one using a fresh tap and a slightly smaller than normal tap drill to maximize thread engagement

Tom Elliott 01-26-2015 09:19 PM

Re: axle threads
 

Love video's like that. Hand's on demonstations just can't be beat. Thanks

Roger V 01-26-2015 09:43 PM

Re: axle threads
 

Quote:

Originally Posted by scrapiron (Post 1022687)
Just a thought, use a new nut, or make one using a fresh tap and a slightly smaller than normal tap drill to maximize thread engagement

My understanding is the original Ford rear axle nut is hardened and much stronger than today's repro or hardware store nuts. My opinion is to use an original nut if in good condition. I have run a file across an original and it doesn't cut like a new nut.

Ron in Quincy 01-26-2015 09:49 PM

Re: axle threads
 

The original axel nut is a special hardened 5/8-18 Nut, if you use a standard 5/8-18 Nut you can ruin the threads on the axel. If you doubt what I am saying, look at a Dealers Parts Price List and it shows the axel nut as "Special".

I use a torque wrench and torque the axel nut to 90 foot pounds, then increase enough to inset the cotter key; have never had a problem with a loose drum on the axel.

Ron

George Miller 01-26-2015 10:03 PM

Re: axle threads
 

It is not a great thread, it might hold. If you have a good axle I would use that.

Pete 01-26-2015 10:33 PM

Re: axle threads
 

"but Henry had no inkling about grades of steel in 1928."
WRONG.
He had his own steel mills and was extremely aware of using various grades of steel in appropriate places. He even developed variations of standard SAE formulas that are still in use today.
I have analyzed various steel forgings and machined parts from early Fords and they are as good as anything in use on modern cars.

As far as using the axle in question, I would not unless you have installed safety hubs.
It can however be saved by welding up the thread area and re-machining the threads.

Anything to do with holding wheels on the car does not need to be "farmer fixed".
It can be a matter of life or death, maybe you, maybe the guy coming at you.

Joe K 01-26-2015 10:46 PM

Re: axle threads
 

The parts vendors sell rear axle/hub nuts. Below a pix of Snyder's version.

http://www.snydersantiqueauto.com/up...A4242-7386.jpg

Note that these are cad plated. If they are cad, then they are not alloy.

Given that they are cad plated, then it is unlikely they are even Grade 8. Grade 5 exists at several providers on the Internet - almost universally cad plated.

Now Grade 8 slotted/castellated is available at a few sources on the 'net. One of which http://www.asmc.net/5-8-18-grade-8-s...f-black-pk-25/ All of these I see are not cad plated.

Now Grade 8 is not alloy/heat treated/hardened. That would be Grade 9. I have not found ANY castellated or slotted nuts available in Grade 9 on the Internet.

So one might conclude based on the Ford parts list that a modern rear axle nut conforming to Ford standards may not exist?

So we may have to settle for the Grade 8 nut I mentioned above?

But this may not be as dire as it seems. Generally material properties are better than they were made in 1928. More consistent certainly. And heat treatment may be a way to improve material properties when one doesn't have the best to start with. So in our case, beginning at a higher standard, heat treatment may not be essential.

We are, after all, only trying to translate torque into tension in a helical inclined plane. And - if this is done successfully through torquing, then the game is won?

I'd be interested to know if anyone has found castlellated/slotted nuts at SAE rating higher than 8?

Edit: I just saw your post.

Quote:

"but Henry had no inkling about grades of steel in 1928."
I'll correct that. Henry used his own grading system and not an ASTM standard.

He was also limited by his own economics and did not necessarily have to satisfy a client that demanded higher standard.

He made what he thought would provide greatest corporate profit.

Joe K

larrys40 01-27-2015 01:48 AM

Re: axle threads
 

Quote:

Originally Posted by 1930artdeco (Post 1022653)
I bought a spare axle in pieces and one of the shafts has trashed threads about a third of the way in. I had a club member use his axle thread tool to restore what was left of them and ended up with the first picture. Now I can screw an axle nut all the way up to the point and beyond where the cotter pin goes. My question is, is this a good shaft? I have access to a good axle from the same club member. Should keep this one in reserve?

Thanks,

Mike

Mike,
They sound Marginal and probably not enough solid threads for a full torque/use.
I would recommend finding/using only axles with very good threads on them. With clean threads on the axle and nut, your want to thread the nut on and test to make sure there is no wiggle or wobble in the threads with the nut on the shaft. It should be a good snug fit. I agree original nuts in good condition are the best if available. If the axle needs replacing because the threads are bad then replace it. Depending on the condition of the rear end and needed service at the time it can be done as a repair job with the axle still in the car or a rebuild with removal of the unit and complete disassembly and rebuild.

Thread repair tools do can help do an emergency fix ( clamp on style/thread restorers) but I would not use any dies as they will cut good metal off that is better pulled back to shape with " thread restorers" as I mentioned.

I have done partial replacement/ repairs ( to fix a broken axle) start to finish in 3 hours without removing the entire axle. The radius and axle housing drivers side together snaked out and removed and then the axle/carrier assembly removed for repair. It is possible.... If you have someone schooled in rear axles in your area I would have them help inspect what you have and need to have done for a solid permanent repair. I would discourage against temporary fixes.

Larry Shepard

Mike V. Florida 01-27-2015 02:42 AM

Re: axle threads
 

Quote:

Originally Posted by Joe K (Post 1022771)

I'd be interested to know if anyone has found castlellated/slotted nuts at SAE rating higher than 8?

I did not know there was any SAE grade above 8 (8.2)?

tbirdtbird 01-27-2015 02:52 AM

Re: axle threads
 

"All the nut does is keep the hub from "turning off" it's taper. The key drives the hub. "

If this were all that was going on you would not need a taper.
Tapered axle technology is not unlike the use of a Morse taper in a lathe or other machine tool. The dry taper is designed to grip the chuck shank or whatever you are using, and grip it does. This is why ppl are instructed to NOT use any never seize etc on rear axle tapers. This is also why a properly assembled hub/axle with good parts (not all boogered up) is so hard to get apart....the 2 tapers nearly become one with each other. This is a very strong method of torque transfer. Way stronger than a mere key can provide

ARP fasteners are grade 13. Heavy equipment such as excavators, dozers, etc use grades way over 8

Chris in CT 01-27-2015 08:57 AM

Re: axle threads
 

Hi Mike,

Consider two alternatives, since the axle is out of the car. Best alternative is metal-spray (used commercially to build up worn shafts) to build up the axle stub, then it is turned to size, then threaded to original specifications. Costs money, though...

Second best is to re-thread to 9/16ths-18 SAE NF which can also be done by someone with excellent die-starting skills on the car. If your axle is out of the car, your can put it through the headstock bore of your lathe, turn the OD to size, and thread it to the above size. This would insure accurate thread-running. A number of the guys have done this with great success... Happy Motoring!

George Miller 01-27-2015 09:11 AM

Re: axle threads
 

Ford spent a lot of time on steel, his steel was the best of the time. He studied steel from other country,s.

john in illinois 01-27-2015 01:59 PM

Re: axle threads
 

I agree with Joe K. The nuts the vendors sell are very poor quality. They are a loose fit on the threads and are soft steel. If you run a tap through a Ford axle nut it will not cut the threads at all. this is why I always look for good original nuts.

John

1930artdeco 01-27-2015 04:03 PM

Re: axle threads
 

Wow thanks for the info guys. Since this is a spare axle I am in no hurry to fix it. But, it looks like I have some options for repairs and a replacement option. That is an original nut and it went on quite stiffly(?). And if for some reason I need to pull the RE out of the car then I have those axles which are still good. Eventually I may get a another axle just in case though. We are still trying to figure out how they destroyed the threads like that....:confused:

Mike

edmondclinton 01-27-2015 04:22 PM

Re: axle threads
 

Quote:

Originally Posted by Joe K (Post 1022771)
The parts vendors sell rear axle/hub nuts. Below a pix of Snyder's version.

http://www.snydersantiqueauto.com/up...A4242-7386.jpg

Note that these are cad plated. If they are cad, then they are not alloy.

Given that they are cad plated, then it is unlikely they are even Grade 8. Grade 5 exists at several providers on the Internet - almost universally cad plated.

Joe K


The prospective customers may not like the price but Snyder's, or anyone else for that matter if they have the money and a need for a large quantity, can have nuts manufactured to whatever strength specs they desire within manufacturing capabilities, good as Henry's original or better, and have them cad plated (sidestep the EPA) or whatever plated including but not limited to zinc, combination zinc/alloy, decorative or just left as plain steel.


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