[SEL] OT: Spindle Oil, Lathes & Hammonds

[John Culp]

I've been playing around with the old Hammond organ down at the church 
in the Sunday school classroom again today. The sound of those things 
is generated by spinning shafts with wheels on them, the wheels having 
teeth cut in their edge that rotate past magnetic pickups, producing a 
constant frequency for each number of teeth and RPM. Those frequencies 
are blended together by a drawbar control system to make the different 
tones of the organ. The shaft system is maintained at a constant speed 
by a synchronous motor, but it's not self-starting and is started by a 
shaded pole induction motor with a Bendix drive that engages a starting 
gear, much like an automotive starter. The Bendix drive was sticking on 
this and didn't seem to be loosening up since I lubricated the tone 
generator 2 months ago, so I took off the back cover, found the Bendix 
and put a few drops of ATF on the starter gear and the shaft it slides 
on. (Had the ATF handy.) Works like a champ now!

That got me thinking again about the special Hammond tone generator 
oil. (I'd borrowed some back in January, and gave it back.) Hammond, 
like just about everybody else that's sold a car, motorcycle, chainsaw, 
weedeater, sewing machine, etc., claimed that only their oil could be 
used, and since they went out of business in the early '80s and 
Hammond-Suzuki which now owns the name doesn't have anything to do with 
the old ones, original Hammond oil has gotten to be an expensive item 
on eBay. The folks who work on Hammonds are true believers in the 
special nature of this oil and recommend nothing else. I just don't 
believe that Hammond would've actually had some custom formulated oil 
for that application, though. The tone generator is fundamentally a 
lathe, with sintered bronze bearings at each end and the middle of the 
three shafts. The main shaft rotates at 1800 RPM. (The two side shafts 
run at different speeds, but I'm not sure what they are.) There's no 
load on the shafts other than their own weight, and the whole tone 
generator assembly is very light. The oil is delivered to the bearings 
from a copper trough via capillary action through cotton threads, and 
the synchronous run motor is lubed through a felt pad. (Hammond techs 
think that that wick lubrication system is a unique design that demands 
a very special oil.) The Hammond oil is a very pale yellow color, a bit 
thinner than ATF but thicker than baby oil, and is very clingy to metal 
surfaces. I'll bet it's ISO 22 spindle oil, like this:
http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=00254201

I notice somebody on eBay is selling an "8 year supply of Hammond tone 
generator oil," that is, a 4 oz. bottle, for a $10 starting bid or $15 
"buy it now." It comes in a modern plastic bottle of a rather generic 
sort, and I'll bet that guy's bought a 5 gallon pail or 55 gallon drum 
of spindle oil and decanted it into those bottles. Sounds like a pretty 
good moneymaking racket to me!

That spindle oil's really pretty reasonably priced and ought to be a 
useful general purpose lubricant wherever a light oil's needed.

I stuck around and played on the Hammond a while, then slipped down to 
the choir room and tuned up the not-as-old all-electronic Thomas organ 
that was horribly out of tune. The oscillator tuning coils had frozen 
solidly in place, tight as Dick's hatband, but my old engine experience 
kept me from breaking anything. I applied some penetrating oil a month 
ago, and today all but one of the 12 coils were free, and that one 
happened to already be in tune!

Not engines or stack music, but I've had a pretty good day mechanically!

John Culp
Bristol, Tennessee, USA