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-   -   Rear Axle Keys (https://www.fordbarn.com/forum/showthread.php?t=220828)

RawhideKid 05-15-2017 06:03 PM

Rear Axle Keys
 

Since the rear axle keys are x what is preventing me from using x HSS tool stock?

Before you say it, I know I will need to taper both ends since I have 1 good key as a pattern.

40 Deluxe 05-15-2017 06:12 PM

Re: Rear Axle Keys
 

The key is basically just a hub locator. If the axle nut is tightened properly, you could remove the key and throw it away and keep going. The fit of the hub on the tapered axle is that good. If the nut is not tight enough, the hub will fret on the axle and bad things will happen!

Kurt in NJ 05-15-2017 06:16 PM

Re: Rear Axle Keys
 

Nothing is preventing you from using it-----but if you are having problems shearin an original key there is a problem with the axle or hub, the taper fit is what prevents rotation, ideally the key is just there, but not really taking any load----if you put in a key that is harder than the axle or hub they will get damaged instead of the key

Art Newland 05-15-2017 06:27 PM

Re: Rear Axle Keys
 

Just put my rear hubs on a few days ago, the repro keys fit great and were cheap.

Synchro909 05-15-2017 06:47 PM

Re: Rear Axle Keys
 

The only time the key drives anything is when the taper has let go, usually because the nut is loose. By this time, nasty things are happening in there and you should be able to feel it when you engage the clutch after going from reverse to 1st gear or overrun to drive. If there is any sound from the area or lost motion, things are loose. By having a hard key in there when this happens, you will destroy the axle and/or hub rather than a cheap key (the axle and hub might still be damaged anyway). As has been said above, the key is just there for the ride in a secure hub - it is the taper that provides the grip.
I wouldn't use HSS to make a key.

BILL WILLIAMSON 05-15-2017 09:02 PM

Re: Rear Axle Keys
 

IF you ever SHEARED a key, by GOLLY you'd use the HIGH TONED KEY!!!!--Get REAL!!!
AND, if you're DUMB enough NOT to torque the nut properly, I DON'T feel SORRY for you!
Chief always said, "I'm sorry too, BUT I've lurned to live with it"!---LOL
Bill Nonwalker

Big hammer 05-15-2017 09:15 PM

Re: Rear Axle Keys
 

Your time is worth more than the cost of new keys, let alone axles and hubs!
Outboard motors have brass sheer pins and for a good reason, to keep from messing up the lower end.

harleytoprock 05-16-2017 04:56 AM

Re: Rear Axle Keys
 

If the taper is what only holds the grip then why is there a key in there anyway? No reason for hub to axle location orientation.

George Miller 05-16-2017 06:34 AM

Re: Rear Axle Keys
 

Quote:

Originally Posted by harleytoprock (Post 1473097)
If the taper is what only holds the grip then why is there a key in there anyway? No reason for hub to axle location orientation.

It is to keep it from creeping. Say you let the clutch out real fast. the key would keep it from creeping. But under normal driving with the nut proper torque it would not move.

BILL WILLIAMSON 05-16-2017 08:09 AM

Re: Rear Axle Keys
 

I "think" MANY of us are guilty of this: We wait for the answer we WANT to hear!-LOL
It's just our HUMAN nature. Chief always sed, "Don't CONFUSE me with FACTS, my MIND is already made up"!
Sure miss him, he was a FUN DUDE & LOVED Model As. He was sort of a "self taught" GENIUS, only went to the 8th grade, which was quite common in his day.
Proud Bill W.

SeaSlugs 05-16-2017 08:13 AM

Re: Rear Axle Keys
 

I made several sets for my AA out of key stock, didn't take long at all and with a belt sander can match the taper pretty exact. The ford originals had the ford logo with the engine stamp star in between the repeating ford logos...

Jeff M 08-11-2017 02:13 AM

Re: Rear Axle Keys
 

2 Attachment(s)
Does anyone have pictures on how the keys look installed? I have some I ordered but they look like the ones pictured with two small tapers on each end. They don't have a long taper on one side like the other pictured.

I've never messed with a banjo rear before. I'm going to lap the axles and hubs but want to get the keys right. Also one keyway is pretty loose towards the taper, how does one fix this?

Dave N. 08-11-2017 06:15 AM

Re: Rear Axle Keys
 

So the taper on the axle and the taper on the hup is a dry fit only, no anti seize to help take it apart many years later?

Tom Wesenberg 08-11-2017 06:36 AM

Re: Rear Axle Keys
 

Quote:

Originally Posted by Dave N. (Post 1511676)
So the taper on the axle and the taper on the hup is a dry fit only, no anti seize to help take it apart many years later?

For sure only clean, dry, and smooth.

Railcarmover 08-11-2017 08:08 AM

Re: Rear Axle Keys
 

To create a locking taper there is a degree difference in angle between the shaft and hub. I respectfully disagree with Mr Wesenberg in this one area,I use anti-seize on tapers and splines,it doesnt alter the locking value of the taper difference and prevent galling during future disassembly.

katy 08-11-2017 09:23 AM

Re: Rear Axle Keys
 

Quote:

Since the rear axle keys are x what is preventing me from using x HSS tool stock?
Just use regular mild steel key stock.

Bob C 08-11-2017 10:08 AM

Re: Rear Axle Keys
 

Self-Holding Tapers

http://www.calqlata.com/prodimages/Friction%202-2.png Fig 2. Self-Holding Tapers

A special case for the beneficial use of friction is 'self-holding' Tapers (Fig 2) for easy machine/equipment component assembly and disassembly such as drill chucks and lathe tail-stock accessories.
A self-holding 'Taper' is an accurately machined tapering shaft and mating sleeve (both of which are dry and clean) that lock together using the coefficient of friction between the two surfaces (shaft and sleeve) and an assembly force (F). If the Taper is machined correctly, the same force (F) will be needed to separate the shaft and sleeve.
If the angle of the Taper is 'exactly right', the shaft or sleeve will be capable of driving the other with no additional assistance for light duty applications and yet part easily with no resultant damage to either of the mating surfaces.
It is important to remember that a plain self-holding taper is only capable of transmitting a force achievable from 'frictional' grip and is thereby limited in its driving capacity. For heavy duty applications the taper is usually provided with a key, the frictional grip providing the holding capacity only.

hardtimes 08-11-2017 12:18 PM

Re: Rear Axle Keys
 

Quote:

Originally Posted by Bob C (Post 1511749)
Self-Holding Tapers

http://www.calqlata.com/prodimages/Friction%202-2.png Fig 2. Self-Holding Tapers

A special case for the beneficial use of friction is 'self-holding' Tapers (Fig 2) for easy machine/equipment component assembly and disassembly such as drill chucks and lathe tail-stock accessories.
A self-holding 'Taper' is an accurately machined tapering shaft and mating sleeve (both of which are dry and clean) that lock together using the coefficient of friction between the two surfaces (shaft and sleeve) and an assembly force (F). If the Taper is machined correctly, the same force (F) will be needed to separate the shaft and sleeve.
If the angle of the Taper is 'exactly right', the shaft or sleeve will be capable of driving the other with no additional assistance for light duty applications and yet part easily with no resultant damage to either of the mating surfaces.
It is important to remember that a plain self-holding taper is only capable of transmitting a force achievable from 'frictional' grip and is thereby limited in its driving capacity. For heavy duty applications the taper is usually provided with a key, the frictional grip providing the holding capacity only.

Hey Bob,
Very good info for all who care to know details of this matter, and not rely on old tales and hearsay that has been passed on. NOW, maybe this will be passed on and help those with axle problems...but do not know WHY !

Proper amount of Model A axle nut torque has not been discussed, so far.
Just what is the proper amount ? When the number of ft lbs is told, the number is NOT believed by most...why ?
Without new axles/nuts, Model A owners say....oh, that's not right, is tooo much, I just torque them till their tight :) !
Again, if not lapped right, and not torqued right....nothing is right according to the excellent info that has been provided above.

hardtimes 08-11-2017 12:34 PM

Re: Rear Axle Keys
 

The original keys are cheap/easy to obtain and made as Ford made them to perform intended function. I'd stay with that metal / key.
Because of the fit of the rear axle/hub, I occasionally check/recheck to ensure proper torque. IMO, you WILL be surprised at what you find, that is, that re-torque check is worthwhile.
Only possible exception would be 'perfect' mating/lap joint, IMO.

Al 29Tudor 08-11-2017 01:24 PM

Re: Rear Axle Keys
 

Bob C,
Thanks for the explanation on self holding tapers. The model 'A' axle tapers and hubs, (sleeves) I've seen are everything but accurate and honed tapers. Mine are pitted warn and gouged. And in many cases not torqued to 100 plus pounds. Thanks for mentioning the use for light and heavy load uses for keyed and non-keyed applications.
Al Leach


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