I've got a couple of little Dana 12 volt air compressors used
to inflate tires. Photos are at

http://nemesis.zefox.com/~bob/dana_compressors/

One of them has broken a plastic pulley and
a few questions come to mind:

First, does anybody recognize and/or know anything about them?
Probably no, but it can't hurt to ask.

Second, the broken pulley was a press fit on a 3/8" shaft with a
shallow spline rolled into it. Is there any chance an aluminum
pulley with dual setscrews might hold without an impossible-to-
remove press fit using only the setscrews? The pulley is:
https://www.amazon.com/dp/B07RGQJ751?ref=ppx_yo2ov_dt_b_product_details&th=1

Thanks for reading, and any insights!

bob prohaska

"bob prohaska" wrote in message news:ujatc5$3dd7g$1@dont-email.me...

I've got a couple of little Dana 12 volt air compressors used
to inflate tires. Photos are at

http://nemesis.zefox.com/~bob/dana_compressors/

One of them has broken a plastic pulley and
a few questions come to mind:

First, does anybody recognize and/or know anything about them?
Probably no, but it can't hurt to ask.

Second, the broken pulley was a press fit on a 3/8" shaft with a
shallow spline rolled into it. Is there any chance an aluminum
pulley with dual setscrews might hold without an impossible-to-
remove press fit using only the setscrews? The pulley is:
https://www.amazon.com/dp/B07RGQJ751?ref=ppx_yo2ov_dt_b_product_details&th=1

Thanks for reading, and any insights!

bob prohaska

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

You could install and align the pulley, then remove one setscrew and dimple
the shaft with a self aligning tap-size drill bit to give the setscrew more
bite without raising a burr on the shaft. Then do the other one.

On 11/18/2023 10:47 AM, bob prohaska wrote:
> I've got a couple of little Dana 12 volt air compressors used
> to inflate tires. Photos are at
>
> http://nemesis.zefox.com/~bob/dana_compressors/
>
> One of them has broken a plastic pulley and
> a few questions come to mind:
>
> First, does anybody recognize and/or know anything about them?
> Probably no, but it can't hurt to ask.

OW! Nope, never seen one before.

>
> Second, the broken pulley was a press fit on a 3/8" shaft with a
> shallow spline rolled into it.

I always figured those were molded in place.

>Is there any chance an aluminum
> pulley with dual setscrews might hold without an impossible-to-
> remove press fit using only the setscrews?

Of course there is a chance. I don't know how much of a chance, but
there is one.

The pulley is:
> https://www.amazon.com/dp/B07RGQJ751?ref=ppx_yo2ov_dt_b_product_details&th=1
>
> Thanks for reading, and any insights!
>
> bob prohaska
>

I'd probably measure the OD of the splines, and if possible see how much
runout there is. Then I'd probably do the following to give me the best
chance of success.

1. Bore the new pulley to a light press fit on the spline.
2. Mill a keyway on the shaft and broach a keyway in the pulley.
3,. Drill and tap for two grub screws in the pulley. On to bear on the
key, and one to bear on the shaft.
4. Drill a slight divot in the shaft for grub screw number 2 so it
doesn't raise a burr.

If I can spin the shaft sans belt and pulley I might try to put a
partial radius on the outsides of the splines for a better engagement as
step zero. I might try it under an end mill.

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

"Bob La Londe" wrote in message news:ujauoe$3dh0g$1@dont-email.me...

On 11/18/2023 10:47 AM, bob prohaska wrote:
>Is there any chance an aluminum
> pulley with dual setscrews might hold without an impossible-to-
> remove press fit using only the setscrews?

I'd probably measure the OD of the splines, and if possible see how much
runout there is. Then I'd probably do the following to give me the best
chance of success.

1. Bore the new pulley to a light press fit on the spline.
2. Mill a keyway on the shaft and broach a keyway in the pulley.
3,. Drill and tap for two grub screws in the pulley. On to bear on the
key, and one to bear on the shaft.
4. Drill a slight divot in the shaft for grub screw number 2 so it
doesn't raise a burr.

If I can spin the shaft sans belt and pulley I might try to put a
partial radius on the outsides of the splines for a better engagement as
step zero. I might try it under an end mill.
Bob La Londe
-------------------------------------

That's what I would do too, since I have a milling machine, keyway broaches,
arbor press and a lathe to make custom guide bushings for the broaches.

A lower tech substitute that works fairly well is to drill and tap a small
axial hole where a keyway would go, 1/2 in the shaft and 1/2 in the pulley,
and tighten a short screw into it, secured with Loctite. A drill bit won't
run straight in steel|aluminum but you could turn and bore a dummy steel
bushing to drill and tap the shaft side of the hole straight, then replace
the bushing with the aluminum pulley and do its side. I might drill the hole
in both first, then tap them.

An even lower tech fix is to align and tighten the pulley, remove it and
file flats where the setscrews marked the shaft. A second short setscrew
will help lock the first in place.

And then there's Loctite.

At Segway a valuable prototype was mistakenly assembled with the permanent
version of it. Guess whose bench that landed on to somehow repair.

I heated the screw heads with a soldering iron until the brass knurled and
threaded inserts loosened, and pulled them out. More heat loosened the
screws to salvage the inserts by tapping out the Loctite residue. Then I
epoxied them back in using new oiled cover screws to position them. Those
responsible were too embarrassed to give me credit for bailing them out.

The same trick with less heat backed out broken-off screws from a mobility
scooter I bought cheap and non-functional.

On 11/18/2023 2:32 PM, Jim Wilkins wrote:
> "Bob La Londe"  wrote in message news:ujauoe$3dh0g$1@dont-email.me...
>
> On 11/18/2023 10:47 AM, bob prohaska wrote:
>> Is there any chance an aluminum
>> pulley with dual setscrews might hold without an impossible-to-
>> remove press fit using only the setscrews?
>
> I'd probably measure the OD of the splines, and if possible see how much
> runout there is.  Then I'd probably do the following to give me the best
> chance of success.
>
> 1.  Bore the new pulley to a light press fit on the spline.
> 2.  Mill a keyway on the shaft and broach a keyway in the pulley.
> 3,.  Drill and tap for two grub screws in the pulley.  On to bear on the
> key, and one to bear on the shaft.
> 4.  Drill a slight divot in the shaft for grub screw number 2 so it
> doesn't raise a burr.
>
> If I can spin the shaft sans belt and pulley I might try to put a
> partial radius on the outsides of the splines for a better engagement as
> step zero.  I might try it under an end mill.
> Bob La Londe
> -------------------------------------
>
> That's what I would do too, since I have a milling machine, keyway
> broaches, arbor press and a lathe to make custom guide bushings for the
> broaches.
>
> A lower tech substitute that works fairly well is to drill and tap a
> small axial hole where a keyway would go, 1/2 in the shaft and 1/2 in
> the pulley, and tighten a short screw into it, secured with Loctite. A
> drill bit won't run straight in steel|aluminum but you could turn and
> bore a dummy steel bushing to drill and tap the shaft side of the hole
> straight, then replace the bushing with the aluminum pulley and do its
> side. I might drill the hole in both first, then tap them.
>
> An even lower tech fix is to align and tighten the pulley, remove it and
> file flats where the setscrews marked the shaft. A second short setscrew
> will help lock the first in place.
>
> And then there's Loctite.
>
> At Segway a valuable prototype was mistakenly assembled with the
> permanent version of it. Guess whose bench that landed on to somehow
> repair.

Speaking of Segway... It looks like they are a Chinese owned company now
according to this video from an influencer who claims they (or their
promotional company) stiffed him.

Segway Reps Tried to Force me to Post Fake Review! (Segway Cube)
https://www.youtube.com/watch?v=p5joLg6dikI

It was my background noise this morning while I had coffee and made
breakfast.

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

"Bob La Londe" wrote in message news:ujbbbi$3fmgr$1@dont-email.me...

Speaking of Segway... It looks like they are a Chinese owned company now
according to this video from an influencer who claims they (or their
promotional company) stiffed him.

Segway Reps Tried to Force me to Post Fake Review! (Segway Cube)
https://www.youtube.com/watch?v=p5joLg6dikI

It was my background noise this morning while I had coffee and made
breakfast.

Bob La Londe

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

Little but the name remained when I left. As soon as the lean steer version
went to production the engineering staff moved on, some to work on 4-wheeled
electric vehicles.
https://media.ford.com/content/fordmedia/fna/us/en/people/doug-field.html

Like most of the R&D projects I've been on it was fun while it lasted.

Jim Wilkins <muratlanne@gmail.com> wrote:
>
> And then there's Loctite.
>

I've been wondering about Loctite and/or epoxy. The
compressor gets too hot to touch in the area of
the cylinder and head. I'd imagine the input shaft
might remain quite a bit cooler but am not sure.
If smoking heat is required to remove Loctite it'll
probably work well. If boiling water softens it,
likely it won't last.

I don't have the tools nor skill to make keyways
and will have to content myself with boring the
pulley and putting small flats/divots on the shaft
to take the setscrews.

On reflection the maximum torque doesn't seem huge.
At 100 PSI there's roughly 100 pounds force on the
piston with a half-inch lever arm. With a 3/16
inch shaft radius it's only 270 inch pounds. Have
I got that right?
The new pulley seems to be coming direct from China
and should arrive sometime late in the month. When
I get a good look at it there will probably be more
questions.

Thanks very much for writing!

bob prohaska

"bob prohaska" wrote in message news:ujdmk8$3u0v2$1@dont-email.me...

I don't have the tools nor skill to make keyways
and will have to content myself with boring the
pulley and putting small flats/divots on the shaft
to take the setscrews.

----------------------
I don't know who has machine tools here. You can't do much serious
metalworking without them, or the skills of an 18th century clockmaker.
https://en.wikipedia.org/wiki/Jacques_de_Vaucanson

The semi-magical toymaker Drosselmeyer in The Nutcracker was similar to real
master craftsmen of the time (1816), as was the creator of the automated
female android Coppelia by the same author. Androids look human, robots may
not, though writers play loose with the terms.

If the setscrews have cup points that leave a ring indentation you can use
it as a guide to file the flats. File deep enough to see the entire ring and
try to make it disappear simultaneously all around. It may help to blacken
the developing flat with a marker. Match-drilling a divot in the steel shaft
without the guidance of a milling machine risks the setscrew threads in the
aluminum pulley.

bob prohaska <bp@www.zefox.net> wrote:
>
> On reflection the maximum torque doesn't seem huge.
> At 100 PSI there's roughly 100 pounds force on the
> piston with a half-inch lever arm. With a 3/16
> inch shaft radius it's only 270 inch pounds. Have
> I got that right?
>

Intuition suggests there should be a reasonably
direct relation between press fit force and torque
holding ability, at least when all dimensions are
close to 1. Is there a rule of thumb or table?
A few hundred pounds of press fit wouldn't be very
hard to apply.

Here's a photo (sorry for the blur)
of the compressor shaft:
http://nemesis.zefox.com/~bob/dana_compressors/IMG_0031.JPG

Here's a view of the back of the crank:
http://nemesis.zefox.com/~bob/dana_compressors/crankcase/IMG_0010.JPG
Supporting the crank in a press (vise) or against an anvil might
make it fairly easy to assemble by force.

The tip shaft diameter is .350 inch, the splines
appear to be knurled in before hardening (the shaft feels file-
hard) with a diameter of .355 inch. The basic diameter of the
crankshaft is .375 inch. Looks like I'll have to do some boring.
The pulley bore is .316 or .317, nominally 8 mm.

> The new pulley seems to be coming direct from China
> and should arrive sometime late in the month. When
> I get a good look at it there will probably be more
> questions.
>

The pulley showed up direct from China, postage paid,
in about two weeks. Really rather amazing for $8.65 .

Thanks for reading,

bob prohaska

"bob prohaska" wrote in message news:uke52u$23huu$1@dont-email.me...

bob prohaska <bp@www.zefox.net> wrote:
>
> On reflection the maximum torque doesn't seem huge.
> At 100 PSI there's roughly 100 pounds force on the
> piston with a half-inch lever arm. With a 3/16
> inch shaft radius it's only 270 inch pounds. Have
> I got that right?
>

Intuition suggests there should be a reasonably
direct relation between press fit force and torque
holding ability, at least when all dimensions are
close to 1. Is there a rule of thumb or table?
A few hundred pounds of press fit wouldn't be very
hard to apply.

Here's a photo (sorry for the blur)
of the compressor shaft:
http://nemesis.zefox.com/~bob/dana_compressors/IMG_0031.JPG

Here's a view of the back of the crank:
http://nemesis.zefox.com/~bob/dana_compressors/crankcase/IMG_0010.JPG
Supporting the crank in a press (vise) or against an anvil might
make it fairly easy to assemble by force.

The tip shaft diameter is .350 inch, the splines
appear to be knurled in before hardening (the shaft feels file-
hard) with a diameter of .355 inch. The basic diameter of the
crankshaft is .375 inch. Looks like I'll have to do some boring.
The pulley bore is .316 or .317, nominally 8 mm.

> The new pulley seems to be coming direct from China
> and should arrive sometime late in the month. When
> I get a good look at it there will probably be more
> questions.
>

The pulley showed up direct from China, postage paid,
in about two weeks. Really rather amazing for $8.65 .

Thanks for reading,

bob prohaska
----------------------------------------
I struggled unsuccessfully with such low tech repair methods until I bought
a lathe and milling machine that have probably paid for themselves with the
money saved by repairs and custom tools, and again by advancing my project
responsibilities at work. For example I bought a "worn out" snowblower for
$100 and brought it back to like-new function if not appearance by
correcting its wear. Bushing the worn hole that I just mentioned to Bob was
a part of it. It's old enough to be all metal that can be repaired better
(thicker) than new.

At work I demonstrated that I could handle the mechanical design and
machining of a project, not just the electronic work that my job title
suggested. That's what got me into Segway, in fact they gave me the work
that required old-fashioned hand craftsmanship as well as machining.

"bob prohaska" wrote in message news:uke52u$23huu$1@dont-email.me...

bob prohaska <bp@www.zefox.net> wrote:
....
A few hundred pounds of press fit wouldn't be very
hard to apply.

Here's a view of the back of the crank:
http://nemesis.zefox.com/~bob/dana_compressors/crankcase/IMG_0010.JPG
Supporting the crank in a press (vise) or against an anvil might
make it fairly easy to assemble by force.

----------------------
The exposed end is the offset crank throw. Push too hard and you might bend
it. Pushing against the counterweight may be safer, if you can.

Jim Wilkins <muratlanne@gmail.com> wrote:
>
> ----------------------
> The exposed end is the offset crank throw. Push too hard and you might bend
> it. Pushing against the counterweight may be safer, if you can.
>

understood. Ideally the pressure would be applied in balance on both.
That would require some sort of stepped (or undercut) mandrel.

After thinking it over, I believe the force required to create
a press fit between a smooth shaft and a smooth hole would be
roughly equal to the torque applied at the hole radius needed
to make it slip.

On paper, if the torque generated by the piston/rod/crank was
270 inch pounds a press fit nominally tighter than 270 linear
pounds would be expected to hold. I'm assuming shearing friction
is equal in both axial and azimuthal direction. That obviously
won't be true in my case, thanks to the axial splines knurled
into the shaft.

If somebody sees an error in this reasoning please point it out.

It's not clear I want to use a press fit (disassembly will be
extremely difficult if it's ever needed) but it looks like an
option.

Thanks for reading,

bob prohaska

"bob prohaska" wrote in message news:ukfj0g$2dkh5$1@dont-email.me...

Jim Wilkins <muratlanne@gmail.com> wrote:
>
> ----------------------
> The exposed end is the offset crank throw. Push too hard and you might
> bend
> it. Pushing against the counterweight may be safer, if you can.
>

understood. Ideally the pressure would be applied in balance on both.
That would require some sort of stepped (or undercut) mandrel.

After thinking it over, I believe the force required to create
a press fit between a smooth shaft and a smooth hole would be
roughly equal to the torque applied at the hole radius needed
to make it slip.

On paper, if the torque generated by the piston/rod/crank was
270 inch pounds a press fit nominally tighter than 270 linear
pounds would be expected to hold. I'm assuming shearing friction
is equal in both axial and azimuthal direction. That obviously
won't be true in my case, thanks to the axial splines knurled
into the shaft.

If somebody sees an error in this reasoning please point it out.

It's not clear I want to use a press fit (disassembly will be
extremely difficult if it's ever needed) but it looks like an
option.

Thanks for reading,

bob prohaska
----------------------------------------
https://amesweb.info/press-fit/interference-fit-calculator.aspx

On 12/1/2023 7:34 PM, bob prohaska wrote:
> bob prohaska <bp@www.zefox.net> wrote:
>>
>> On reflection the maximum torque doesn't seem huge.
>> At 100 PSI there's roughly 100 pounds force on the
>> piston with a half-inch lever arm. With a 3/16
>> inch shaft radius it's only 270 inch pounds. Have
>> I got that right?
>>
>
> Intuition suggests there should be a reasonably
> direct relation between press fit force and torque
> holding ability, at least when all dimensions are
> close to 1. Is there a rule of thumb or table?
> A few hundred pounds of press fit wouldn't be very
> hard to apply.
>
> Here's a photo (sorry for the blur)
> of the compressor shaft:
> http://nemesis.zefox.com/~bob/dana_compressors/IMG_0031.JPG
>
> Here's a view of the back of the crank:
> http://nemesis.zefox.com/~bob/dana_compressors/crankcase/IMG_0010.JPG
> Supporting the crank in a press (vise) or against an anvil might
> make it fairly easy to assemble by force.
>
> The tip shaft diameter is .350 inch, the splines
> appear to be knurled in before hardening (the shaft feels file-
> hard) with a diameter of .355 inch. The basic diameter of the
> crankshaft is .375 inch. Looks like I'll have to do some boring.
> The pulley bore is .316 or .317, nominally 8 mm.
>
>
>> The new pulley seems to be coming direct from China
>> and should arrive sometime late in the month. When
>> I get a good look at it there will probably be more
>> questions.
>>
>
> The pulley showed up direct from China, postage paid,
> in about two weeks. Really rather amazing for $8.65 .
>
> Thanks for reading,
>
> bob prohaska
>

Its my understanding that the Chinese government very heavily subsidizes
postage and takes unfair advantage of the international agreements on
postage delivery.

RANT: Unfortunately the US Post Office does neither. I've had
customers in Canada send me samples. They usually send a photo of their
receipt to provide tracking. I can see clearly they went to a shipping
center and paid the full calculated price from their end, and the US
Post office still decides they didn't pay enough and charges me
additional shipping charges in violation of the international postal
delivery agreements. Not just once either. I don't understand why they
fuck business between nominally friendly/partner countries, and do
nothing about shipments from China.

Excuse my spelling. I meant to spell FUCKS!!!

--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

On 12/2/2023 8:37 AM, bob prohaska wrote:
> Jim Wilkins <muratlanne@gmail.com> wrote:
>>
>> ----------------------
>> The exposed end is the offset crank throw. Push too hard and you might bend
>> it. Pushing against the counterweight may be safer, if you can.
>>
>
>
> understood. Ideally the pressure would be applied in balance on both.
> That would require some sort of stepped (or undercut) mandrel.
>
> After thinking it over, I believe the force required to create
> a press fit between a smooth shaft and a smooth hole would be
> roughly equal to the torque applied at the hole radius needed
> to make it slip.
>
> On paper, if the torque generated by the piston/rod/crank was
> 270 inch pounds a press fit nominally tighter than 270 linear
> pounds would be expected to hold. I'm assuming shearing friction
> is equal in both axial and azimuthal direction. That obviously
> won't be true in my case, thanks to the axial splines knurled
> into the shaft.
>
> If somebody sees an error in this reasoning please point it out.
>
> It's not clear I want to use a press fit (disassembly will be
> extremely difficult if it's ever needed) but it looks like an
> option.
>
> Thanks for reading,
>
> bob prohaska
>
>
Here is an alternative. Drill and tap a bolt at the seam. Then a close
slip or light press fit might just do. Might be hard without machine
tools if its aluminum against steel. Of course if you had machine tools
you would have made a pulley a long time ago and been done with it.

Loctite retainer or sleeve and bearing locker might be an alternative
for you as well.
--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

Jim Wilkins <muratlanne@gmail.com> wrote:
> ----------------------------------------
> https://amesweb.info/press-fit/interference-fit-calculator.aspx
>
>

That calculator solves the inverse of the question I'm asking, using
dimensions and material properties. I'm thinking in the reverse direction:
I know only the force required to press a pulley onto a shaft and the shaft
diameter. How can I estimate the torque the joint can transmit?

My simplistic estimate is that friction is friction, and friction that
resists axial motion will equally resist rotation. So, for a given assembly
force, that force multiplied by the joint radius will be the absolute
torque limit. Far as I can see that's the whole story, apart from
material properties and stiction.

Thanks for writing!

bob prohaska

"bob prohaska" wrote in message news:ukgasm$2hbns$1@dont-email.me...

Jim Wilkins <muratlanne@gmail.com> wrote:
> ----------------------------------------
> https://amesweb.info/press-fit/interference-fit-calculator.aspx
>
>

That calculator solves the inverse of the question I'm asking, using
dimensions and material properties. I'm thinking in the reverse direction:
I know only the force required to press a pulley onto a shaft and the shaft
diameter. How can I estimate the torque the joint can transmit?

My simplistic estimate is that friction is friction, and friction that
resists axial motion will equally resist rotation. So, for a given assembly
force, that force multiplied by the joint radius will be the absolute
torque limit. Far as I can see that's the whole story, apart from
material properties and stiction.

Thanks for writing!

bob prohaska

--------------------------------------
As you wrote yourself, the splines break that relationship. Personally I'd
determine an interference on a separate sample that's a little too tight to
press on, bore the pulley without changing the lathe boring bar setting,
then heat the pulley to expand its bore and press it on, against a stop,
with one rapid stroke. Do you have a gear puller to undo a failed attempt?

The sample could be bored in short steps to see how the force increases with
the amount of interference. Less than 0.001" can make quite a difference.
You don't have to measure the bore, just keep the last setting. This is
probably hopeless on a drill press with the ~0.010" gap between letter sized
drills.

No lathe? Then you are limited to buying what you can't make.

"bob prohaska" wrote in message news:ukgasm$2hbns$1@dont-email.me...

Jim Wilkins <muratlanne@gmail.com> wrote:
> ----------------------------------------
> https://amesweb.info/press-fit/interference-fit-calculator.aspx

That calculator solves the inverse of the question I'm asking, using
dimensions and material properties. I'm thinking in the reverse direction:
I know only the force required to press a pulley onto a shaft and the shaft
diameter. How can I estimate the torque the joint can transmit?
---------------------

When a calculator doesn't let me enter what I want as input I close in on it
by changing what can be entered until the results are close enough.

Jim Wilkins <muratlanne@gmail.com> wrote:
>
> The sample could be bored in short steps to see how the force increases with
> the amount of interference. Less than 0.001" can make quite a difference.
> You don't have to measure the bore, just keep the last setting. This is
> probably hopeless on a drill press with the ~0.010" gap between letter sized
> drills.
>
> No lathe? Then you are limited to buying what you can't make.
>

I do have a lathe. A well-worn South Bend 10L. While trying to sneak
up on the ideal pulley bore I overshot the mark (by less than the
radial play in the crankshaft) and ended up using the setscrews.

The setscrews haven't slipped in the initial testing. If they do
slip I'll mark the spots and try to grind seats for them in the
shaft. That can be done fairly easily with a Dremel grinder. It
isn't at all obvious how to get the crankshaft out of the case.
Or, for that matter, how it was assembled. It wouldn't be a bad
thing to clean and lubricate at least the crank, rod and wristpin.

Thanks for writing!

bob prohaska

There's very little space to bring a puller to bear. At least the
setscrew approach will make further repairs a little easier.

On Sun, 3 Dec 2023 03:15:18 -0000 (UTC)
bob prohaska <bp@www.zefox.net> wrote:

<snip>
>There's very little space to bring a puller to bear. At least the
>setscrew approach will make further repairs a little easier.

Doesn't matter now... but check out Bearing Separators, may be handy to
know about them someday if you don't already. Short video, ~2 minutes:

https://www.youtube.com/watch?v=JRiMIorP-oQ

Nice repair project you've done there👍

--
Leon Fisk
Grand Rapids MI

"bob prohaska" wrote in message news:ukgrs6$2nc6o$1@dont-email.me...

I do have a lathe. A well-worn South Bend 10L.

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

I have a 10L too, a 1965 model from a trade school that abused it, such as
using the tailstock spindle as an anvil horn. The dealer replaced it with
another that's a slightly loose fit. Some day I may bore out and sleeve the
tailstock casting, which might not be the original.

They are what the National Bureau of Standards used before they bought
Hardinges, and an old review Google can't find anymore claims the SB was
more versatile as general purpose lathe. I bought a 6" threaded and a 4" 5C
mount 6-jaw chucks for it that I use quite often on jobs that don't need
repeatable centering accuracy.

Leon Fisk <lfiskgr@gmail.invalid> wrote:
> On Sun, 3 Dec 2023 03:15:18 -0000 (UTC)
> bob prohaska <bp@www.zefox.net> wrote:
>
> <snip>
>>There's very little space to bring a puller to bear. At least the
>>setscrew approach will make further repairs a little easier.
>
> Doesn't matter now... but check out Bearing Separators, may be handy to
> know about them someday if you don't already. Short video, ~2 minutes:
>
> https://www.youtube.com/watch?v=JRiMIorP-oQ
Useful-looking tool. Too burly for my foreseeable needs, but maybe someday.

> Nice repair project you've done there?

Hard to tell, so far. When the plastic pulley split the machine
became unusable, so fixing for less than $10 seems worthwhile.
If I get another thirty years out of it, that's a a bargin.
I got worried enough about the setscrew grip to grind a pair
of divots in the shaft. Doubtless that'll help some, but the
aluminum is quite soft and the screws have a mushy feel I
don't really like.
The more I think about it the more mysterious the assembly
sequence becomes. Physically it's identical to a large model
airplane engine. The cylinder and crankcase are one piece,
it looks impossible to dismantle non-destructively.

The photos are still at http://nemesis.zefox.com/~bob/dana_compressors/
if anybody's game to hazard a guess.

Thanks for everybody's attention and thoughts!

bob prohaska

On 12/3/23 17:16, bob prohaska wrote:
> The more I think about it the more mysterious the assembly sequence
> becomes. Physically it's identical to a large model airplane engine. The
> cylinder and crankcase are one piece, it looks impossible to dismantle
> non-destructively. The photos are still at
> http://nemesis.zefox.com/~bob/dana_compressors/ if anybody's game to
> hazard a guess.

Remove the cylinder liner.

https://www.youtube.com/watch?v=TuzEco3EDUM

Pothos <fn@smoothwater.com> wrote:
> On 12/3/23 17:16, bob prohaska wrote:
>> The more I think about it the more mysterious the assembly sequence
>> becomes. Physically it's identical to a large model airplane engine. The
>> cylinder and crankcase are one piece, it looks impossible to dismantle
>> non-destructively. The photos are still at
>> http://nemesis.zefox.com/~bob/dana_compressors/ if anybody's game to
>> hazard a guess.
>
> Remove the cylinder liner.
>
> https://www.youtube.com/watch?v=TuzEco3EDUM

Ahhh! Thank you 8-)

bob prohaska