Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 03-18-2020, 06:21 PM   #1
chrs1961815
Senior Member
 
chrs1961815's Avatar
 
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 700
Default Hub Hardness and Cutting

A friend of mine is helping me redo my brakes and we were having a hard time cutting one of the hubs on the lathe even with a carbide bit. He remarked that "some hubs cut nice, others are very difficult."

This led me to think: why is that? Ford obviously hardened the hubs originally but why are some harder than others?
__________________
"The more things change, the more they stay the same."
chrs1961815 is offline   Reply With Quote
Old 03-18-2020, 11:22 PM   #2
midgetracer
Senior Member
 
midgetracer's Avatar
 
Join Date: May 2010
Location: Bismarck ND
Posts: 934
Default Re: Hub Hardness and Cutting

Do you mean "cutting the drums"? I see no reason to cut the hubs. sometimes cast iron drums can get quite hard if they are overheated.
midgetracer is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 03-19-2020, 12:02 AM   #3
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 4,877
Default Re: Hub Hardness and Cutting

chrs, if you are talking about original steel drums, they are very difficult to machine. They squeal and chatter terribly.
If you're talking about the rear hubs for a wheel bearing repair, they are hard at the diff end and as soft as cheese at the outer end. Ford's hardening process here left a bit to be desired. That said, they did last for a surprisingly long time. If they were hardened properly, we would never need to repair them even after all this time and who knows how many miles. From Ford's perspective in the day, that would have been overkill.
__________________
If schools stay closed too long, parents will find a vaccine before the scientists.
Synchro909 is offline   Reply With Quote
Old 03-19-2020, 03:53 AM   #4
chrs1961815
Senior Member
 
chrs1961815's Avatar
 
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 700
Default Re: Hub Hardness and Cutting

I am talking about truing the hubs on a lathe. You take off metal until it is hitting everywhere.
__________________
"The more things change, the more they stay the same."
chrs1961815 is offline   Reply With Quote
Old 03-19-2020, 06:56 AM   #5
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 9,215
Default Re: Hub Hardness and Cutting

Quote:
Originally Posted by chrs1961815 View Post
I am talking about truing the hubs on a lathe. You take off metal until it is hitting everywhere.


Ummmm, you don't need to take it that far. Just a skim pass of no more than 0.005-0.010 is sufficient. This generally trues the area around the hub bolts which is all that is needed. The issue with taking too much off of the hub is it locates the drum closer to the Brake Housing (Backing) Plate and it also affects the riveting process of the bolt due to the bolt shoulder being too long.


BTW, an interesting bit of 'trivia' that I learned awhile back. We have all used the term swage when we discuss installing new brake drums. Actually, when you study the A-1107 and A-1118 Ford print, it refers to the term 'Rivet' when it states to "Rivet over after assembly" on the print (see below). So when you look for the definition of 'swage', it is actually the special tool that is used to rivet the hub bolts -and not the procedure itself. Funny thing though, you 'rivet over' the rivet.

.
.
Attached Images
File Type: jpg A-1107-B Hub Bolts Front2.jpg (38.7 KB, 81 views)
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Old 03-19-2020, 11:30 AM   #6
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Alberta, Canada
Posts: 2,462
Default Re: Hub Hardness and Cutting

Definition of swage:
https://www.merriam-webster.com/dictionary/swage
__________________
Play it again Sam.
katy is offline   Reply With Quote
Old 03-19-2020, 01:09 PM   #7
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 9,215
Default Re: Hub Hardness and Cutting

Quote:
Originally Posted by katy View Post
I got my definition from a machinist handbook. I wonder where Webster got their definition??

Also, I wonder why Ford Engineers used the term Rivet instead of Swage??
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Old 03-19-2020, 01:22 PM   #8
Joe K
Senior Member
 
Joe K's Avatar
 
Join Date: Jul 2010
Location: Cow Hampshire
Posts: 3,562
Default Re: Hub Hardness and Cutting

Some online instruction advise to "clean up the hub mating surface" on a lathe to give a square/perpendicular/level mount for the new drums to go on. THEN at the end the drums are "trued" in usual fashion.

I can see the desire - but as Brent says "How close does it have to be? One imagines it is possible to "true" the hub far closer than any wheel or tire (especially) applied to it.

Some perspective here...

Joe in NH
__________________
Shudda kept the horse.
Joe K is offline   Reply With Quote
Old 03-19-2020, 03:31 PM   #9
MikeK
Senior Member
 
MikeK's Avatar
 
Join Date: May 2010
Location: Windy City
Posts: 2,873
Red face Re: Hub Hardness and Cutting

So you face the rear hub true and then bolt it on an axle that is 80+ years away from being true with the taper running concentric to the centerline. You may end up better or WORSE than where you started.

If you are into overkill you might as well pull the rear axles and true the tapers. Then deal with all the problems of using those dreaded spacing shims on the axle.

If you want to talk overkill without pulling the rear axles, prudence would have you crazy with dial indicators figuring out what combination will make things perfect with that particular hub mated and indexed by the key-way on that particular axle. You could end up facing those hubs on an indexed plane NOT exactly 90 degrees to the axle center-line. Lunacy! But the drums would then run true...
__________________
Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.
MikeK is offline   Reply With Quote
Old 03-19-2020, 03:51 PM   #10
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 9,215
Default Re: Hub Hardness and Cutting

Quote:
Originally Posted by MikeK View Post
So you face the rear hub true and then bolt it on an axle that is 80+ years away from being true with the taper running concentric to the centerline. You may end up better or WORSE than where you started.

If you are into overkill you might as well pull the rear axles and true the tapers. Then deal with all the problems of using those dreaded spacing shims on the axle.

If you want to talk overkill without pulling the rear axles, prudence would have you crazy with dial indicators figuring out what combination will make things perfect with that particular hub mated and indexed by the key-way on that particular axle. You could end up facing those hubs on an indexed plane NOT exactly 90 degrees to the axle center-line. Lunacy! But the drums would then run true...

Mike, to a certain extent I do agree with you however I am of the opinion that the foundation for drums/hubs running true to the centerline is set by the axle housing race, the hub bearing, and the ID bore of the rear hub where the bearing rides. If everything is within specifications, the axle shafts will be in a perfect centerline.

As far as axle shims, when I am rebuilding the axle housings, I generally remove about 0.030" from the mounting face where the brake housing (backing) plate attaches. This mounts the brake housing plates further inboard and away from the drum. That way the hub can ride further onto the shaft taper without the need for shims.


With regard to truing hubs, not every hub we find is actually cost effective to restore. Some have seen a mechanic weld hub bolts, some have seen bearing races spin internally, and quite a few rear hubs have the bearing area out of spec. This is generally a taper in the race area, or the area is worn too much, ...or both. I have an aluminum plug that we place down inside the hub's race area. With your hand over the opposite side of the hub, you should be able to hear a 'pop' created from a vacuum when the plug is quickly pulled out of the hub. If not, the drum will not be in centerline with the brakes nor the axles.
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Old 03-19-2020, 03:58 PM   #11
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 4,877
Default Re: Hub Hardness and Cutting

I've installed many new brake drums but I've never trued the hub beforehand. What's the point? The drum is turned once the studs are riveted so they are true. Rarely do I have to take any more than about 0.010 - 0.015 at the deepest point to clean them up.
IMO, this is overkill on steroids.
__________________
If schools stay closed too long, parents will find a vaccine before the scientists.
Synchro909 is offline   Reply With Quote
Old 03-19-2020, 04:06 PM   #12
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 9,215
Default Re: Hub Hardness and Cutting

Quote:
Originally Posted by Synchro909 View Post
I've installed many new brake drums but I've never trued the hub beforehand. What's the point? The drum is turned once the studs are riveted so they are true. Rarely do I have to take any more than about 0.010 - 0.015 at the deepest point to clean them up.
IMO, this is overkill on steroids.

Generally speaking, the hub flanges are bent 'proud' where the hub bolts were riveted onto the drum as this is a high pressure point. When you skim the hub flange just enough to flatten this area, you have a greater area of the hub flange concentrated over a larger brake drum flange surface. This should add to rigidity.

Is it overkill? I suppose it boils down to whether you are repairing or restoring. For me personally, I try to restore all assemblies back to factory specifications or tolerances first, and then replicate aesthetics. Not everyone shares that desire, ...and I totally get that.
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Old 03-19-2020, 07:06 PM   #13
redmodelt
Senior Member
 
redmodelt's Avatar
 
Join Date: May 2010
Location: Portland OR
Posts: 5,002
Default Re: Hub Hardness and Cutting

Lots of the flanges get bent over the years. We take a small cleanup skim cut as needed before putting on new drums. If the hub bearing surface is a bit worn they get the sleeves and later style bearings.
__________________
I know the voices aren't real but damn they have some good ideas!
redmodelt is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 01:20 AM.