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First Run 9" Model B/A Gear Train....Slow and Medium Speed

mcload

Hot Rolled
Joined
Nov 5, 2007
Location
Houston, Texas
I thought I'd post a couple of videos I shot this morning of the gear train noise on my 9" Model B that has been upgraded to a Model A. Clearly, it was noisier at medium speed as opposed to slow (DUH). It bears mentioning that the gears are under only a slight amount of load, that being the QCGB and lead screw. It may sound different during an actual cut.

A couple things of note. I have yet to find a steel 20-tooth stud gear so I purchased a nylon one that I assume was printed. (It's the small white one)
It seems to work very well for the time being, and I'll bet it's much tougher than most of us think. For the cost of having a new gear actually made out of steel,
I could have a dozen of these gears ready to swap out; a new chuck, and a QC tool post set. So with any luck, a used one will become available somehow, somewhere.
I still have a bit of tweaking I can do I guess, but overall, I'm pleased.
Heck, the motor makes more noise that the gears. This little "American heritage" machine will probably never get put through heavy production work anyway.

Another issue I resolved was that the large "idler gear" was quite wobbly when I first started, and it made a ton of racket. I'll bet a lot of 9" have this same problem due
to wear. Even my Dad's 9" Model A has a wobbly idler gear. Clearly, the elegant solution would be to bore out the gear and press in a needle bearing, but that's much
easier said than done when you think about the process. Not hard, just time consuming....perhaps a winter project.

So what I was able to do is to insert some sleeves/bands that I cut out of stainless steel shim stock. Roughly speaking, it took a sleeve of .00015 to go between the gear
and the steel bushing, and another .003 sleeve to slip between the bushing and the square head bolt that holds it to the banjo arm. I works like an absolute charm;
no wobble at all and very free spinning.

In the "slow speed" video I disengage the gearbox and you can hear some ringing. I guess this is probably normal and the gears could use a heavier lubricant.
Like I said, still a bit of tweaking to do. All of the compound functions work great as expected. I have not messed with back gear yet as it needs oil and a spring for
the tensioner. Onward and upward through the fog. :-)

Thank you.

PMc

https://youtu.be/7PVLIx19UjU

https://youtu.be/Sgq_TSijjis



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Kevin T

Stainless
Joined
Jan 26, 2019
Looks great. What did you use to film the videos the sound is pretty good.
Where did you get the id plates? I could use something like that for when I don't touch the lathe for many months!
 

mcload

Hot Rolled
Joined
Nov 5, 2007
Location
Houston, Texas
Looks great. What did you use to film the videos the sound is pretty good.
Where did you get the id plates? I could use something like that for when I don't touch the lathe for many months!

Thank you sir. I used my iPhone 10, then transferred the .MOV to my desktop, then uploaded to You Tube.
I originally bought those plates to fit onto the lathe, but discovered they were too big for that when they arrived.
Luckily, I found a good spot for them.
I'll pass along the guy that has them after I locate his contact info.
Same with me; I sometimes forget which hole does what. :-)

Thank again.

PMc
 

tommy1010

Hot Rolled
Joined
Apr 21, 2010
Location
northeastern Pa, USA
Great job!! Where is the gear lube? I use that thick motor additive that is like STP.(It looks like honey) It removes almost all of the noise and doesn't fly off. I bet that gearbox would benefit from some of it also. Trouble is getting it on the gears from underneath. Do not use grease.

Getting that idler to run true with no wobble solves a lot of noise. Just make a new bushing as you need it to be proud of the width of the gear to bolt on tight to the banjo. A simple job for the SB9. No bearings needed.
 

Kevin T

Stainless
Joined
Jan 26, 2019
Thomas Utley from this 16" restore has his own ID tag company:
1943 South Bend 16" x 60" Lathe Resurrection

The company:
Machinery Restoration | Von Industrial, LLC

Check the gallery there, plus posts #313 and 314:
1943 South Bend 16" x 60" Lathe Resurrection

Oh thanks, I am familiar with Thomas and his work. His 16" restoration thread was an important primer for me to man up to tackling mine and we talked a few times during. He was offering me a full set of plates for my lathe at the time but I wasn't sure I wanted new tags all around and money was flying out the window getting my machine ready so I backed away from the purchase. I need to think about it some more. I could use the plates that cover the reverse feed lever and the carriage operations. I always need to run dry to re-orient myself before getting busy if it's been a while. One of those things that's easy to put off I guess
 

mcload

Hot Rolled
Joined
Nov 5, 2007
Location
Houston, Texas
Great job!! Where is the gear lube? I use that thick motor additive that is like STP.(It looks like honey) It removes almost all of the noise and doesn't fly off. I bet that gearbox would benefit from some of it also. Trouble is getting it on the gears from underneath. Do not use grease. Getting that idler to run true with no wobble solves a lot of noise. Just make a new bushing as you need it to be proud of the width of the gear to bolt on tight to the banjo. A simple job for the SB9. No bearings needed.

Thank you for the input Tommy. I can assure you that the gears in the gearbox were dripping of Type A spindle oil before installation. That photo was just to show its condition before installation.
And yes, I would never use grease on it. The heaviest I would use the the Type B oil as recommend by SB.

I'm really not a very big fan of "oil honey" such as STP. I'm old enough to remember watching Andy Granetelli and his "STP Special" at the Indy 500. But I have never been interested in pouring that crap into my car's crankcase. Likewise, I just don't want anything sticky on my QCGB gears. I'm not sure what that stuff turns into after 6 months in open air and all of the solvents have evaporated. Maybe something that resembles sticky chain lube? If I'm not willing to use something on my lead screw, then I'm not going to use it on my gears. I would also be concerned of ruining the oiling felts that took so much work to install. With that said, I can see how STP would quieten the gears somewhat.

With that said, I always go back to the days when I was opening up a car's differential or gearbox (like on my flathead V8 Ford or XKE). Talk about a torturous environment for gears! So I will "paint" on some 80 weight gear oil onto the mating TEETH of the side gear train only, but never up into the QCGB, at least not yet. But I'm always open to suggestions and ideas for this, so thank you for your comments. If I understand correctly, it's the wax/paraffin in auto lubes that clog the felts.

As mentioned, fixing the wobbly gear is not complicated, just time consuming. But if I have to make a new bushing to a .001 tolerance, I may just as well make it for a needle bearing.
At least that resolves the direct metal-to-metal wear. The shims work fine for the time being.

Thank you.

PMc
 








 
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