The Ford Barn

daveymc29 · 02-23-2015, 11:47 PM

I sheared a shear-pin on an axle on my couple. I had a look at the pin and axle on the other side also. Both hubs appear to be pretty good shape, a couple of minor groves in each, but the axles both show evidence of having had the hubs shear a pin and then turned for quite a few revolutions, cutting several minor groves and each has one well pronounced grove. The axles run spot on with the new key and 125# torque. I'm thinking that to improve the contact area I could very carefully clean the groves and JB Weld them back up, file them to as near to original as possible and re-install the wheel and hubs. What would it hurt? It apparently has worked pretty well scored, so with the scoring removed, won't it work even better, maybe help prevent a repeat of shearing the key? Your thoughts?
Thanks as always, Dave another new guy.

hardtimes · 02-24-2015, 02:29 AM

Hey Dave,
The axle key is NOT the what should be keeping properly fitted hub and axle in proper relation to each other. Proper lapping and tightness of these two together WITH proper torque is what to strive for. Of course with worn out parts, shims with proper /adequate torque will also suffice. Do not put yourself in the position of depending on the key to hold these critical parts together.

Joe K · 02-24-2015, 07:33 AM

Hmm. I know what you're trying to accomplish (get to a "tighter" fit between taper and hub)

Make a logical extension to the thought - what if the "recess" were at the largest part of the taper? And you relied upon the outer 2/3rds of the taper to keep the hub on the axle? You've reduced the axle section in bending and proportionally reduced the strength of the axle as cantilever at the inner hub.

Or put the recess at the smallest 1/3rd of the taper. Now you've reduced the diameter and strength (and resultant compression to the taper) of the threaded portion of the axle holding the hub to the taper, just as if you turned down the threaded portion from 5/8" diameter to 9/16"

To reduce a section in the middle of the taper reduces BOTH of these to some smaller proportion.

Now the argument could be made that the scoring has ALREADY done this.

I say give it a try. You'll increase the unit pressure per square inch between the taper and the hub for the 2/3rds of the taper that remains and touches. And pressure on the taper translates through coefficient of friction to resistance of turning the hub on the axle.

Again I say - if you can achieve full torque on the nut - you're probably good to go.

and "transition" that recess at either end so as not to form a stress concentrating raiser at the juncture between recess and taper.

Interesting mind exercise - both in the consideration and in putting it to words.

Joe K

BRENT in 10-uh-C · 02-24-2015, 08:02 AM

Hard times is pretty much spot-on with his thoughts above. Contrary to what many do, there are many hubs that are worn out and need to be replaced due to wear inside the taper or grooves on the axle which if severe enough can set up stress risers.

1930artdeco · 02-24-2015, 03:43 PM

As long as we are on this topic. What is the best way to tell if the hub/axle mating surface is 100% correct and tight?

Mike

BRENT in 10-uh-C · 02-24-2015, 03:49 PM

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Quote:

Originally Posted by 1930artdeco

As long as we are on this topic. What is the best way to tell if the hub/axle mating surface is 100% correct and tight?

Mike

Best way is to look with a bore scope. Even Harbor Freight sells tiny cameras to peer inside of such areas. Next way is to use Prussian Blue to check contact area.

Mitch//pa · 02-24-2015, 03:50 PM

Quote:

Originally Posted by 1930artdeco

As long as we are on this topic. What is the best way to tell if the hub/axle mating surface is 100% correct and tight?

Mike

if one or both of the tapers are worn the drum would rub the backing plate or shoes.. the axle shims are for worn tapers but they can only make up for so much excessive clearance......

Joe K · 02-24-2015, 04:04 PM

I like the prussian blue. Even better using black magic marker.

I've made tapered centers for the lathe and used magic marker to blacken the center and check fit. For a lathe if you get 80 percent contact, that is considered good enough. (it will change when you use the lever to clamp the tailstock quill.)

Joe K

hardtimes · 02-24-2015, 04:30 PM

I agree with Prussian blue use/statements. Being of meager tools/skills (

), I love the 'black magic marker' use idea and use it for many things. Hm, just wish that they weren't so darn expensive ,eh

!

Now, to the 'both' worn statements and use of shims. Recently, I put NEW drums on my worn axles. Yup, had to use two shims and a little black marker to grind off the parts rubbing (backer to drum) surfaces. Quiet as a mouse now and got 175 lbs of torque on each axle nut comfortably

!

Mitch//pa · 02-24-2015, 04:53 PM

i have used the prussian blue also

RandyinUtah · 02-24-2015, 11:21 PM

Correct me if my thinking is off on this worn axle subject. My thinking is if you have a loose fit between the axle and old original hub the problem is because the hub has expanded over the years. My thinking is the axle would not shrink to a smaller size over time due to compression. If one purchased new hubs the axle /hub taper would again be a tight fit and no need for axle shims. I previously had to use axle shims but they were not needed after I installed new hubs. I think my old original hubs had expanded over time. Please comment on my thought process.
Thanks Randy

Joe K · 02-24-2015, 11:29 PM

Quote:

I think my old original hubs had expanded over time. Please comment on my thought process.

"Stretch" is the operative word. I think bolting the hubs on and pushing them up onto the taper stretches the hub centers and makes the hubs/drums end up too close to the backing plate.

New hubs, mean while, are made to the original Ford drawings - and should reflect what the car was when it was new.

Joe K

Tom Wesenberg · 02-25-2015, 12:22 AM

Here's what can happen if you don't have a tight axle nut. The key takes all the driving force rather than the axle taper tight fit to the hub. This axle is mint except for the wide keyway.

1929 · 02-25-2015, 07:16 AM

My whole front end is in the shop at Antique Ford in Bohemia being repaired from very poor maintenance from the previous owner, he couldn't understand why his steering was very hard. The axle and radius rod, drag link, tie rod, perches, front spring, most front end has to be replaced, there was loose nuts and bolts and some wrong size bolts. After seeing all this on this car I can only believe that there has to maybe be about 75% cars out there that need work on the front ends due to improper maintenance and the age of these vehicles.

dave in australia · 02-25-2015, 02:45 PM

One other cause for the taper not gripping and relying on the key is some form of lubrication between the axle taper and the hub. I heard some old timers say to use a bit of grease on the axle before installing the hub. This doesn't allow the axle and hub to grip each other through friction, which is what a taper relies on. When I bought my tudor, this was one of my rear end tasks, as well as a lot of work on the brakes just to get them up to a safe standard. Never assume the prvious owner knew anything about A's when they worked on them, let alone knew anything about mechanics in general.

Joe K · 02-25-2015, 04:30 PM

The question of lubricating machine tapers has been discussed in the machine taper world. See http://www.practicalmachinist.com/vb...tapers-233868/ for a three post entry regarding why or why not to lubricate morse or other machine tapers.

Quick overview: tapers are generally lubricated lightly on even self locking machine tapers primarily to allow disengagement without galling after the work is done.

I'm not so sure I would be that generous. Maybe a small amount of WD40 or other light lubricant? Maybe for no other reason than to exclude water and prevent rust?

Although rust would "fix" the bond, wouldn't it? And make the taper even less likely to come apart? But that would make new brake pads more difficult too, of course.

Joe K

Mitch//pa · 02-25-2015, 06:58 PM

Quote:

Originally Posted by Joe K

The question of lubricating machine tapers has been discussed in the machine taper world. See http://www.practicalmachinist.com/vb...tapers-233868/ for a three post entry regarding why or why not to lubricate morse or other machine tapers.

Quick overview: tapers are generally lubricated lightly on even self locking machine tapers primarily to allow disengagement without galling after the work is done.

I'm not so sure I would be that generous. Maybe a small amount of WD40 or other light lubricant? Maybe for no other reason than to exclude water and prevent rust?

Although rust would "fix" the bond, wouldn't it? And make the taper even less likely to come apart? But that would make new brake pads more difficult too, of course.

Joe K

brake shoes

hardtimes · 02-25-2015, 07:26 PM

Quote:

Originally Posted by dave in australia

One other cause for the taper not gripping and relying on the key is some form of lubrication between the axle taper and the hub. I heard some old timers say to use a bit of grease on the axle before installing the hub. This doesn't allow the axle and hub to grip each other through friction, which is what a taper relies on. When I bought my tudor, this was one of my rear end tasks, as well as a lot of work on the brakes just to get them up to a safe standard. Never assume the prvious owner knew anything about A's when they worked on them, let alone knew anything about mechanics in general.

Hey Dave,
X2 ! The idea of lapping is to get 'perfect' matching surfaces between these two. Any lube on either surface would defeat this purpose, IMO.

daveymc29 · 02-25-2015, 11:05 PM

Well I can tell you that lapping these axles and hubs was accomplished in the past when they have sheared the keys and spun the axles within the hubs. Of course that wasn't done in the way of lapping as hardtimes means it. So my thought was to built up the low spots with JB Weld, file it is true as I can get it and then torque the hub nuts to 125 pounds, thus putting most of the holding pressure back on the taper rather than on the key. I believe that I have done that, and tested it to see if there was any sign of the axle slipping within the hub by going from forward to reverse while listening and feeling, with the seat of the pants, for any sign of a click or feeling that either took up slack in going through the change in direction. I'm not 100% sure if my torque wrench is accurate, but with my impact wrench I took the nuts to the next cotter pin hole past the 125 mark and torqued again to see where it clicked. It had"t clicked at 140#, so I guess it is good. After my next trip, I may pull the hubs and see if things appear to have changed at all. JB weld out of place, that sort of thing. It did only stay filling the large grooves as the minor grooves din't hold the JB against my filing. Should have used 220 sandpaper and water probably an all day task. Next time.

daveymc29 · 02-25-2015, 11:10 PM

Bye the way, thanks for all the comments and the references to other sites for other comment. Good educational tools. If it weren't for needing to change linings on the brakes, one could slather up the key and axle with JB Weld and immediately bolt it back in place. But even if one lubricated the inside of the hub, you would have to burn it off the axle to get it apart, so that isn't an option for me.

02-23-2015, 11:47 PM	#1
daveymc29 Senior Member Join Date: Sep 2010 Location: Danville, CA Posts: 1,554	Axles, just a thought I sheared a shear-pin on an axle on my couple. I had a look at the pin and axle on the other side also. Both hubs appear to be pretty good shape, a couple of minor groves in each, but the axles both show evidence of having had the hubs shear a pin and then turned for quite a few revolutions, cutting several minor groves and each has one well pronounced grove. The axles run spot on with the new key and 125# torque. I'm thinking that to improve the contact area I could very carefully clean the groves and JB Weld them back up, file them to as near to original as possible and re-install the wheel and hubs. What would it hurt? It apparently has worked pretty well scored, so with the scoring removed, won't it work even better, maybe help prevent a repeat of shearing the key? Your thoughts? Thanks as always, Dave another new guy.

02-24-2015, 02:29 AM	#2
hardtimes Senior Member Join Date: May 2010 Location: South California Posts: 6,188	Re: Axles, just a thought Hey Dave, The axle key is NOT the what should be keeping properly fitted hub and axle in proper relation to each other. Proper lapping and tightness of these two together WITH proper torque is what to strive for. Of course with worn out parts, shims with proper /adequate torque will also suffice. Do not put yourself in the position of depending on the key to hold these critical parts together.

02-24-2015, 07:33 AM	#3
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Axles, just a thought Hmm. I know what you're trying to accomplish (get to a "tighter" fit between taper and hub) Make a logical extension to the thought - what if the "recess" were at the largest part of the taper? And you relied upon the outer 2/3rds of the taper to keep the hub on the axle? You've reduced the axle section in bending and proportionally reduced the strength of the axle as cantilever at the inner hub. Or put the recess at the smallest 1/3rd of the taper. Now you've reduced the diameter and strength (and resultant compression to the taper) of the threaded portion of the axle holding the hub to the taper, just as if you turned down the threaded portion from 5/8" diameter to 9/16" To reduce a section in the middle of the taper reduces BOTH of these to some smaller proportion. Now the argument could be made that the scoring has ALREADY done this. I say give it a try. You'll increase the unit pressure per square inch between the taper and the hub for the 2/3rds of the taper that remains and touches. And pressure on the taper translates through coefficient of friction to resistance of turning the hub on the axle. Again I say - if you can achieve full torque on the nut - you're probably good to go. and "transition" that recess at either end so as not to form a stress concentrating raiser at the juncture between recess and taper. Interesting mind exercise - both in the consideration and in putting it to words. Joe K __________________ Shudda kept the horse.

02-24-2015, 08:02 AM	#4
BRENT in 10-uh-C Senior Member Join Date: May 2010 Location: Eastern Tennessee Posts: 11,519	Re: Axles, just a thought Hard times is pretty much spot-on with his thoughts above. Contrary to what many do, there are many hubs that are worn out and need to be replaced due to wear inside the taper or grooves on the axle which if severe enough can set up stress risers. __________________ . BRENT in 10-uh-C . www.model-a-ford.com ...(...Finally Updated!! ) .

02-24-2015, 03:43 PM	#5
1930artdeco Senior Member Join Date: May 2010 Location: Lynden, Wa Posts: 3,552	Re: Axles, just a thought As long as we are on this topic. What is the best way to tell if the hub/axle mating surface is 100% correct and tight? Mike __________________ 1930 TownSedan (Briggs) 1957 Country Sedan

02-24-2015, 04:04 PM	#8
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Axles, just a thought I like the prussian blue. Even better using black magic marker. I've made tapered centers for the lathe and used magic marker to blacken the center and check fit. For a lathe if you get 80 percent contact, that is considered good enough. (it will change when you use the lever to clamp the tailstock quill.) Joe K __________________ Shudda kept the horse.

02-24-2015, 04:30 PM	#9
hardtimes Senior Member Join Date: May 2010 Location: South California Posts: 6,188	Re: Axles, just a thought I agree with Prussian blue use/statements. Being of meager tools/skills (), I love the 'black magic marker' use idea and use it for many things. Hm, just wish that they weren't so darn expensive ,eh ! Now, to the 'both' worn statements and use of shims. Recently, I put NEW drums on my worn axles. Yup, had to use two shims and a little black marker to grind off the parts rubbing (backer to drum) surfaces. Quiet as a mouse now and got 175 lbs of torque on each axle nut comfortably !

02-24-2015, 04:53 PM	#10
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Axles, just a thought i have used the prussian blue also

02-24-2015, 11:21 PM	#11
RandyinUtah Senior Member Join Date: May 2010 Location: Ogden Utah Posts: 242	Re: Axles, just a thought Correct me if my thinking is off on this worn axle subject. My thinking is if you have a loose fit between the axle and old original hub the problem is because the hub has expanded over the years. My thinking is the axle would not shrink to a smaller size over time due to compression. If one purchased new hubs the axle /hub taper would again be a tight fit and no need for axle shims. I previously had to use axle shims but they were not needed after I installed new hubs. I think my old original hubs had expanded over time. Please comment on my thought process. Thanks Randy

02-25-2015, 07:16 AM	#14
1929 Senior Member Join Date: Jan 2015 Location: New York Posts: 943	Re: Axles, just a thought My whole front end is in the shop at Antique Ford in Bohemia being repaired from very poor maintenance from the previous owner, he couldn't understand why his steering was very hard. The axle and radius rod, drag link, tie rod, perches, front spring, most front end has to be replaced, there was loose nuts and bolts and some wrong size bolts. After seeing all this on this car I can only believe that there has to maybe be about 75% cars out there that need work on the front ends due to improper maintenance and the age of these vehicles.

02-25-2015, 02:45 PM	#15
dave in australia Senior Member Join Date: May 2010 Location: Victoria, Australia Posts: 1,177	Re: Axles, just a thought One other cause for the taper not gripping and relying on the key is some form of lubrication between the axle taper and the hub. I heard some old timers say to use a bit of grease on the axle before installing the hub. This doesn't allow the axle and hub to grip each other through friction, which is what a taper relies on. When I bought my tudor, this was one of my rear end tasks, as well as a lot of work on the brakes just to get them up to a safe standard. Never assume the prvious owner knew anything about A's when they worked on them, let alone knew anything about mechanics in general.

02-25-2015, 04:30 PM	#16
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Axles, just a thought The question of lubricating machine tapers has been discussed in the machine taper world. See http://www.practicalmachinist.com/vb...tapers-233868/ for a three post entry regarding why or why not to lubricate morse or other machine tapers. Quick overview: tapers are generally lubricated lightly on even self locking machine tapers primarily to allow disengagement without galling after the work is done. I'm not so sure I would be that generous. Maybe a small amount of WD40 or other light lubricant? Maybe for no other reason than to exclude water and prevent rust? Although rust would "fix" the bond, wouldn't it? And make the taper even less likely to come apart? But that would make new brake pads more difficult too, of course. Joe K __________________ Shudda kept the horse.

02-25-2015, 11:05 PM	#19
daveymc29 Senior Member Join Date: Sep 2010 Location: Danville, CA Posts: 1,554	Re: Axles, just a thought Well I can tell you that lapping these axles and hubs was accomplished in the past when they have sheared the keys and spun the axles within the hubs. Of course that wasn't done in the way of lapping as hardtimes means it. So my thought was to built up the low spots with JB Weld, file it is true as I can get it and then torque the hub nuts to 125 pounds, thus putting most of the holding pressure back on the taper rather than on the key. I believe that I have done that, and tested it to see if there was any sign of the axle slipping within the hub by going from forward to reverse while listening and feeling, with the seat of the pants, for any sign of a click or feeling that either took up slack in going through the change in direction. I'm not 100% sure if my torque wrench is accurate, but with my impact wrench I took the nuts to the next cotter pin hole past the 125 mark and torqued again to see where it clicked. It had"t clicked at 140#, so I guess it is good. After my next trip, I may pull the hubs and see if things appear to have changed at all. JB weld out of place, that sort of thing. It did only stay filling the large grooves as the minor grooves din't hold the JB against my filing. Should have used 220 sandpaper and water probably an all day task. Next time.

02-25-2015, 11:10 PM	#20
daveymc29 Senior Member Join Date: Sep 2010 Location: Danville, CA Posts: 1,554	Re: Axles, just a thought Bye the way, thanks for all the comments and the references to other sites for other comment. Good educational tools. If it weren't for needing to change linings on the brakes, one could slather up the key and axle with JB Weld and immediately bolt it back in place. But even if one lubricated the inside of the hub, you would have to burn it off the axle to get it apart, so that isn't an option for me.