reverse tumbler gears


John Gallo
 

Hi, I was just wondering if any one has tried the ball bearing reverse tumbler gears that I see on E-Bay? They make great claims about making the gear train quieter. Thanks, John


Mark Z
 

I have exactly the same question!  Mine is a 16" - what is yours?


John Gallo
 

Mark,

Mine is a 10L.

John


Gary Johnson
 

can’t seem to find the item on Ebay. Can you post a link?

There are a couple of discussions on how to make the conversion on Practical Machinist. Basically it eliminates the need for lubrication but nobody there is claiming a performance improvement. 

https://www.practicalmachinist.com/vb/south-bend-lathes/ball-bearing-tumbler-gears-10l-281847/

-Gary


david pennington
 

The answer to the question, whether substituting ball bearings for the journal bearings will reduce gear train noise, is likely "no".

A smooth, properly dimensioned and lubricated journal bearing is as quiet as quiet can be, mostly because there are no additional moving parts.

My lathe is a 1946 9C, and I've recently been studying the issue of gear train noise in setting up the banjo. My first approach to the issue--years ago--was to compute the theoretical center-to-center spacing, only to discover that's almost impossible to measure. For most of the eight years I've had the lathe, I've only used gears when threading, and then I've experimented till things weren't objectionably loud. Recently, I've tried something new: mimic the factory.

It occurred to me that the gear spacing from the factory--tumbler gears and the stud gear--are most likely right. There's a tiny bit of backlash (slop) in the meshing of those gears, and there's an approximate percentage of tooth length engagement.

So on the banjo, I set the gears to have about the same tooth length engagement and then check that there is a "tiny" bit of backlash. Right now, it's setup for fine cut, which involves the maximum number of gear meshing (5). The gear train noise is 'there', but it is smooth and not objectionable.

At the moment, the gears are essentially dry, though not "brake cleaner clean", as that would promote rust. When fully prepared for use, the gears will have a film of 95 wt gear lube. Yes, some oil will get thrown off, but that's what the gear cover is for. :)

Dave

David W. Pennington
Denver, Colorado
720-442-3744


On Thursday, July 23, 2020, 03:43:56 AM MDT, John Gallo via groups.io <johnnyblock1@...> wrote:


Mark,

Mine is a 10L.

John


John Gallo
 

Gary,

I am not sure how to post this link, but if you go to E-Bay and search South Bend Lathe, heavy 10, it is on the first page towards the bottom. I wish I could make it easier for you.

John


Rick
 


oscar kern <kernbigo@...>
 






ken campbell
 

on my 13 incher,  i use black chain oil on my gears and gear shafts ... it sticks ...and contains moly, for extra lube.  the moly embeds in the metal and is not a bad dry lube all by itself.  i even spray the quick change gears from under the box.

do not use it in the wick lubers though ... it is more a grease than light oil and won't wick.  i use mobil products for the wicks.

i take my spindle out about once a year and inspect the bearings ... i work some moly into the spindle bearings before i replace the spindle ... 18 years so far and the bearings look like new.

oh, the bad news .. this black stuff is dirty and persistent .... and stains everything.  remove it from your hands with soap and water .

oh, adjust the backlash by running a piece of copy paper between the gears as you tighten them ... you get about 2 to 3 thousandth clearance.  better slightly too much than no clearance.


david pennington
 

Thanks, Ken. I picked up some good tips from your post.

-------- Original message --------
From: ken campbell <deltainc@...>
Date: 7/23/20 13:54 (GMT-07:00)
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] reverse tumbler gears

on my 13 incher,  i use black chain oil on my gears and gear shafts ...
it sticks ...and contains moly, for extra lube.  the moly embeds in the
metal and is not a bad dry lube all by itself.  i even spray the quick
change gears from under the box.

do not use it in the wick lubers though ... it is more a grease than
light oil and won't wick.  i use mobil products for the wicks.

i take my spindle out about once a year and inspect the bearings ... i
work some moly into the spindle bearings before i replace the spindle
... 18 years so far and the bearings look like new.

oh, the bad news .. this black stuff is dirty and persistent .... and
stains everything.  remove it from your hands with soap and water .

oh, adjust the backlash by running a piece of copy paper between the
gears as you tighten them ... you get about 2 to 3 thousandth
clearance.  better slightly too much than no clearance.




Mark Z
 

These are the 16" ones.  I am tempted to be a guinea pig.....

16" gears - ebay
--
1969 16" x 6' South Bend Lathe
Garage full of old Mopars........