Comptometer / adding machine oil?
ard at p850ug1.demon.co.uk
Sun Aug 27 16:45:47 CDT 2006
> The other advantage of clock oil is its long life - it is designed not to go
Indeed. That's one reason I use it.
> "tacky" for at least 20 years! (it is also designed to stay in pivots - it
> has a high surface tension).
There is claimed to be a substance you can put on mechanism plates, etc,
to stop the oil spreading. Some camera manufactures specified it (Nikon?).
>From what I recall, it was very expensive.
> You do need to strip the mechanism and remove the old lubricant - if you
> just wash the mechanism, all you do is drive dirt into the pivots, and
I am sure I was flamed either here or on a camera repair forum for making
much the same point. I regard fluching a mechanism with solvent as being
a real bodger's trick, likely to do more harm than good.
> accelerate wear. This is the ideal project to use your digital camera on,
> lots of pictures help reassembly!
Assuming you have a digital camera. Fortunately (as I don't), I've never
had a problem putting something back together if I've taken it apart.
> I use clock oil a lot in vintage electronics, for switch spindle (NOT
> contact) lubrication, and for lubricating the dial cord pulleys in old
> radios. As Tony says, HMP grease is also useful for sliding parts.
I'd use grease on the detent mechamism of a switch, too.
Watch out for graphite grease. It's mildly conductive (of course) and can
cause major problems if it gets onto insulators, etc. I don't normally
use that on anything electrical unless the manufacturer specifies it.
There is a reasonable 'special plastic grease' available, I think from
Farnell (it's actually an Electrolube product). Unlike some other
greases, it doesn't attack most common thermoplastics, and is good,
therefore, on plastic mechanisms.
> As regards small gears, anything running against a fibre gear normally runs
> dry, as do gears of dissimilar metals (e.g., steel and brass in clocks,
> though these will often benefit from one or two drops of oil), gears of the
Most, if not all, clock repairs would disagree with you there. Oil on
clock gears tends to attract dust and accellerates wear. And oil on some
parts of the escapement will cause the parts to momentarily stick and
will cause all sorts of timekeeping errors.
Gettign abck to classic computers, though, I don't think a drop of oil on
any of the gears in, say, an adding machine will do any real harm. And
obviously if a mechnaism was designed to run in an oil bath (e.g. some
Tally punches) you need to keep that oil at the right level.
> same metal do need lubrication.
Maybe. The gears should be designed to have essentially rolling contact,
and therefore almsot no rubbing or friction between the teeth. And thus
no wear. That's not to say you can run you car's gearbox without oil ,
but smaller mechanisms, trasmititng minimal power, shouldn't need much.
 Not least because it's likely to use helically-cut gears which do
have sliding contact between the teeth.
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