[GreenKeys] Nylon vs. Fiber/steel gears?

[John Canfield]

 From what I remember, Model 28-35s all had steel pinion gears and nylon 
drive gears, more than one time I had the typing unit lock up and the 
nylon gear served as a circuit breaker of sorts.

John WB5THT (TTY Technician for several years a long time ago.)

On 1/11/2024 3:23 PM, Ivan Hafstrom via GreenKeys wrote:
> Probably both noise and cost, but I have no direct knowledge.
>
> However, it is probably not a good idea to switch from nylon to 
> fiber/steel unless you have the older intermediate gear assembly with 
> an overload disconnect.  That had a spring loaded detent arm 
> connecting the (steel) intermediate gear to its shaft, so that if the 
> printer was somehow locked up, that gear could stop and slip on its 
> shaft, preventing printer damage.  The printer main shaft had a fiber 
> driven gear with that arrangement.
>
> With the later intermediate gear assembly's (nylon) gear fastened to 
> its shaft by a screw, the nylon speed gears would strip if the printer 
> jammed, acting as a mechanical "fuse."
>
>
> On Thu, 11 Jan 2024, John, W9DDD wrote:
>
>> [EXTERNAL EMAIL]
>>
>>
>> Gentlemen, why do you suppose there was the transition from fiber and
>> steel gears to nylon?  Noise, cost or other considerations? My guess is
>> that the nylon can be molded and therefore less costly to make, but I
>> can't back that up with facts.  Noise, I don't have enough experience,
>> I'm just now switching a nylon 100 speed pair to 60 fiber/steel pair.
>> Will I notice? And if I do will it be the gears or the speed?
>>
>> BTW have you ever looked to find the right part number for screw that
>> goes with the steel pinion?  I never did find it referenced anywhere.
>> (no I didn't look at the original Navy manual which even tells you how
>> to make your own springs.)
>>
>>
>> -- 
>> ---
>> ----
>> You said "tomorrow" yesterday.
>>
>> The above comments or recommendations are SWAG. Use at your own risk.
>> John, W9DDD