Pulley for AR-XA (and how to polish your spindle)

[MuZak]

After AR quit using the delrin sleeve, they went to a big-block Ford, or Chevy valve guide from those days.....it was steel.....

Really? they used actual Ford/Chev valve guides??

Then they went with the phosphor Bronze sleeve...again a valve guide. 3/8" diameter.

This is an XA....
While the date stamp is long gone, I seem to
remember 1968 vintage, but not certain.
On cursory examination, it does seem to be
Bronze but plated.
I'll have a better look later.
A constant source of amazement to me is the
plethora of variations on this simple/budget table
over the years...

It looks like just a plain 'ol barrell-sleeve pressed
into the bearing-boss of the subchassis.

Biggest issue I've seen is the "wallering" of the sleeve. They become wider at top and bottom. I use a snap gauge to confim diamer size and amout of wallering. Standard machining sizes were .375" for the spindle, and .377 for the bore. Giving you .002 spindle to wall clearance. Pretty standard specs of those days.

Dunno if its out of round, and I don't have a snap
guage.
Bore guages/dial-indicators + stand are the tools
that I've always meant to but never got around
to getting..

In spite of the visually obvious damage, it didn't
seem to cause an audible problem as of last playing
(1987).
A testament to the tables.
(I DID always keep the oil fresh)

Maybe the (relatively) loose clearance actually
worked to advantage in this regard?

If you don't have access to a bore snap guage....the best way to check for wallering is lift the spindle about half way and rock it side to side and see how much movement there is....and then set it almost to the bottom and recheck.....putting it all the way down will contact the thrust plate and give you a "false" reading.

Well... Um....
Trouble is.......
YOU have the spindle.
I don't have one.
I need to get that from YOU
(spindle/inner-platter and top plate)

If you have a straight sleeve, you can wrap some 800 grit paper around dowell rod and hone it using a drill at low speed....

Yeah... I had planned to use a dowell/drill after
resolving the preliminary issues..

Do you happen to know what dowell size to use,
so'z I don't have to drag the subchassis to the
store and see what fits?

Also, what length to cut it to, to chuck it in the
drill??

clean extremely well with hot soapy water when done....add some Moly coat to the refinished sleeve.

I usually clean anything like this with Acetone
then alcohol, after hot & soapy to get the heavier
stuff off.

I always apply Moly after honing anything.
Either paste or liquid, depending...

(tip) GM differential additive is liquified moly
(mostly) mixed with light gear lube.
Has the consistancy of very heavy oil... spreads
easily and evenly.

The all-Derin bearing was first replaced by a Delrin cup with babbit sleeve.

Those are the type I remember seeing..
In fact, till I recently saw the all-Delrin type,
I thought thats what was meant by the Delrin
bearing.

Babbit is pretty soft stuff, and when I was polishing the spindle shaft I just stuck the spindle into the well and spun it while it was still coated with oil and buffing wheel compound, then cleaned it and spun again with oil only. With no belt on the platter, I can give it a good push and go make a cup of tea and it'll still be spinning when I get back from the kitchen.

That kinda makes me wonder... if it wouldn't
be a good idea to finish up with lapping compound
for bearing shaft to sleave interface.

--------------------------------

Comming to think of it.. any honing would increase
the already loose .002 clearance to the point
of problematic, no?

Maybe just drill out the old sleeve and press in
a new one, nicely polished inside beforehand??

[gkimeng]

That kinda makes me wonder... if it wouldn't
be a good idea to finish up with lapping compound
for bearing shaft to sleave interface.

--------------------------------

Comming to think of it.. any honing would increase
the already loose .002 clearance to the point
of problematic, no?

Maybe just drill out the old sleeve and press in
a new one, nicely polished inside beforehand??

I don't know if lapping would produce a noticeable performance improvement, but it's unlikely to hurt.

You might increase that clearance to as much as .0025.

[MuZak]

I took some pix of the bearing showing the wear
and materials (hopefully).

Gotta luv having this new digital cam!
Shouldda bought one years ago.

This pic shows the wear... the patterns in one
section, but more importantly, why I think its
crome plated.
Look near the top/center of the pic. (inside the bearing)

It looks to me like there are 2 materials.
If you look at the wear marks on the left side,
it looks like bare (scratched) metal...
nearby it looks like shiny chrome.
Not just polished bare metal.
The contrasts at the very top-center show it
well too.

Another example... different angle/section:


Another section:


-----------------
This one shows overall condition, and why I say
its a pressed-in sleeve:

The brownish-orange areas are what made me
think its bronze under plating.
It may just be remnants of the rotted foam
thats hardened.
I'll have a closer look with a stronger glass later.

[MuZak]

You might increase that clearance to as much as .0025.

By honing with 800 grit on a drill?

Take a look at my above pix... are those gouges
likely to be only .0025 deep?

[gkimeng]

This pic shows the wear... the patterns in one
section, but more importantly, why I think its
crome plated.

If these started life as engine valve guides, plating would make sense. Bronze valve guides are often chrome plated to improve heat transfer and reduce carbon buildup in the valves.

[panman]

I have bought and refurbed many AR XA's ,bearing well wear is a common problem.Your t-bar is shot because the bearing well is worn.Years of non-oiling,dust,debris cause this problem.
polishing the well? You dont bore an engine block over then use the original rings and pistons.Tolerances should be as close as possible with the shaft and bearing well.Wont even make a good boat anchor due to its light weight...toss it.

[gkimeng]

By honing with 800 grit on a drill?

Take a look at my above pix... are those gouges
likely to be only .0025 deep?

No, but you probably don't need to grind the bore totally smooth. Once you honed down any burrs or raised edges that might scrape against the spindle shaft and the platter spins freely that should be good enough. It's not as if you're rebuilding an engine and need to worry about losing a seal.

[panman]

as seen in the pictures,(or at least what i think i see) there is pitting in the well,this is not good and cannot be repaired unless replaced with a new sleeve or well.Also,any sanding of spindles and wells is not the greatest of ideas because it may not be done in a uniform manner when done by hand.
this is only my opinion.

[gkimeng]

as seen in the pictures,(or at least what i think i see) there is pitting in the well,this is not good and cannot be repaired unless replaced with a new sleeve or well.Also,any sanding of spindles and wells is not the greatest of ideas because it may not be done in a uniform manner when done by hand.
this is only my opinion.

Can't be "restored," i.e. made new again, but can be "repaired," as in made to work acceptably. Removing raised bits will eliminate scraping that translates to noise, and general polishing will reduce friction.

I wouldn't recommend hand sanding either, but machine spinning something the right size with just enough abrasive, like a cutting/polishing compound.

[MuZak]

First off, thanks fellas for the considered replies!!!

If these started life as engine valve guides,
plating would make sense.
Bronze valve guides are often chrome plated
to improve heat transfer and reduce carbon
buildup in the valves.

Yes, knew that/seen those... its what made
me so fascinated by Marc's statement to that effect.

It's not as if you're rebuilding an engine and
need to worry about losing a seal.

True 'nuff, and a good point... but tight tolerances
sure are nice..
Especially if you want to build a nice table rather
than slap together a junker to dump.

there is pitting in the well,this is not good and
cannot be repaired unless replaced with a new
sleeve or well

Yes there is definately pitting.
Yanno, its funny... I only noticed that after studying
the pics...
Couldn't get a light in with a powerful enough
mag glass to see it before.
The cam flash provided the light and its high
rez sufficient magnification.

Replacement looks like the way to go.

What you have is a galled sleeve....
...that is smeared metal, that is also pitted...

Its worse than galled...
The grooves are deep.
It was definately chrome plated too... lets assume
they did that for a reason, given the metal used
under the plating.
The chrome is wasted bad.

several choices....find another T-bar....pull the
sleeve and install a new one....3/8ths valve
guides are a dime a dozen..

I'd rather stay with the parts I have and install
a new sleeve.
I want to re-do as much as possible of (my old-friend)
existing parts (rather than concede defeat).
I like the idea of the project anyway... sounds
like fun too.

So lets DO this!!
Lets take on this project and add it to the knowledge
base.

So...
1) What valve guides to get?
(brand/model, etc)
2) Are the right height/depth, or will they need
cut down to size? (besides reaming out)
3) What are all the correct dimensions?

Ie: Outside dimension to fit the subchassis?
Inside dimension, but not only correct but ideal..
factoring in ideal clearance.
Plus height/depth.

I'll go get a pair of valve guides once I know
these things.
Might as well do both bearings while at it.

[MuZak]

How 'bout These
I tend to favor the part# listed as "Shovel & Pan Head 1200 (1948-1979)"

[panman]

that would be awesome if you could fit one of these valve guides into existing well,...or use it as the bearing well itself,thread the end, put on a cap,maybe have put together a thrust plate for it, and a common problem with the XA model would be solved/fixed with this modification,at a reasonable price. The $68.00 Xa debuted in the 60's flash forward in time to 2009 a bunch of guys are talking about shafts and bearing wells more than 40 years later.Twilight zone music....
i guess it all depends on how far you want to go with the project you are involved in.
good luck!

[gkimeng]

True 'nuff, and a good point... but tight tolerances
sure are nice..
Especially if you want to build a nice table rather
than slap together a junker to dump.

I'd rather stay with the parts I have and install
a new sleeve.
I want to re-do as much as possible of (my old-friend)
existing parts (rather than concede defeat).
I like the idea of the project anyway... sounds
like fun too.

Tight tolerances are nice, yes, and tighter tolerances than factory are theoretically even better, which is one reason why there are aftermarket parts. My replies were based on trying to get the old parts working again with as few changeouts as possible, which was my impresssion of your goal from your original post.

If you can locate a suitable replacement part and have access to a machine shop with the necessary equipment (at minimum, a drill press and an arbor press), I don't see any reason why this couldn't be done. If not, you should reconsider the offer of a replacement subchassis or just try to smooth out the problems in the existing bearing, because the chances of being able to extract the old bearing and install a new one properly with only hand tools are nil.

[MuZak]

that would be awesome if you could fit one of these valve guides into existing well,...or use it as the bearing well itself,thread the end, put on a cap,maybe have put together a thrust plate for it,

I think going the route of opening up the boss
on the subchassis is the easier way.
There might even be a valve guide out there that
is the correct dimension from the jump.
.500 according to Marc, and he knows this stuff
inside-out.
I've only begun to search out suitable valve guides
Then it should be just a matter of drilling out the
old, and pressing in the new.
At most, just boring it out a bit further.

and a common problem with the XA model would be solved/fixed with this modification,at a reasonable price.

Thats a big reason I'd like to take it on.

The $68.00 Xa debuted in the 60's flash forward in time to 2009 a bunch of guys are talking about shafts and bearing wells more than 40 years later.Twilight zone music....

Yeah.. wierd man....
On the other hand.. simplicity and value are
enduring traits!

i guess it all depends on how far you want to go with the project you are involved in.
good luck!

Exactly...
I'm willing in this case...
Partly for personal reasons, having to do with
nostalgic feelings for (the parts from) what was
the table that went thru school with me and
has a storied history... as well as a desire to
experiment/learn.
But also, many here have made "poineering"
contributions to the "knowledge base" and I'd
like to do my share in that regard...
on what is, as you say, a common problem.

I might find its to difficult... or to expensive for
others to want to persue, but I'm willing to try it.
Somebody's gotta take the risk and make the investment,
IF these things are to get tackled.
Who knows, it might even pay off.
Especially with the help of the great/knowledgable
folks here!
So... thanks for the wish of good luck!!

Btw... your "sig" makes the point nicely!

My replies were based on trying to get the old parts working again with as few changeouts as possible, which was my impresssion of your goal from your original post.

Yes...
That was the original goal...
Naturally everyone wishes to save $ and effort.
I'm greatful for your replies to that effect!
For my sake and others, they provided the knowledge
about what is possible and can work well.

But.. the goal changed...
When the consensus of posts was that that bearing
is to trashed to repair.
A replacement subchassis is a fine option... perhaps
even the smarter course.
It just doesn't satisfy my personal ends.

I don't think there's any reason to take it personally.