[GreenKeys] [External] Nylon and fiber gears

[Ralph Mowery]

Sometimes they may be better sometimes not so.

I am thinking the gears on the model 15 printer is metal on the motor and
some sort of fiber on the print unit.  
The seem to last for ever.

The main thing is to keep them greased or oiled like the book calls for.  

I did have a 1974 car that used a fiber type gear in the cam timing area.
That thing went out twice about 40,000 miles  each time and left me
stranded.  Was told later by one of my shade tree mechanic friends that was
about normal for that car.

Ralph ku4pt



-----Original Message-----
From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of John, W9DDD
Sent: Tuesday, August 20, 2019 12:46 PM
To: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] [External] Nylon and fiber gears

OK, so bottom line is that you can mix gears and it might even be better 
in some combinations.

John, W9DDD
Ich habe dreimal abgeschnitten uns jetzt zu kurtz. (I cut it off 3 times 
and it's still too short.)

On 8/20/2019 11:40 AM, Richard Knoppow wrote:
>     I don't think all Delrin is black. For instance see:
> https://www.pennfibre.com/downloads/lit/Delrin_Sheet_Colors.pdf
>     Most seems to be either white or black.
>     Its possible the gears mentioned below might be stained although I 
> don't know if Delrin stains.
>     I would think fiber gears could have metal centers, perhaps to wear 
> better.
>     BTW, I suspect a lot of "Nylon" gears are actually Delrin, which is 
> a better material for gears.
> 
> On 8/20/2019 7:37 AM, Jones, Douglas W wrote:
>> On Aug 20, 2019, at 8:50 AM, John, W9DDD wrote:
>>
>>> Question, are all nylon gears white?  I have a gear that is dark 
>>> colored that at first glance appears to be fiber.  However, it has a 
>>> metal center and really looks more like a plastic than fiber.
>>
>> There are plenty of black plastic gears.  Delrin, an excellent plastic 
>> for making gears, is black.
>>
>>> Which leads to another question, mixing nylon fiber and steel.  I'd 
>>> assume it's not a good idea to mix.
>>
>> The converse is true.  It is a good idea to mix.  As far back as the 
>> 19th century, they knew that brass or leather gears (soft) running on 
>> iron (hard) led to both quieter operation and less wear.  I don't 
>> think it matters which gear in a pair is the soft one, so long as you 
>> aren't near any stress limits.  I've seen very small diameter steel 
>> pinions driving large diameter nylon gears, and I've seen small brass 
>> pinions driving large steel gears.
>>
>> To bring this into GreenKeys land, on the Teletype model 33, the motor 
>> has a steel pinion on the end of the shaft, and it drives a nylon gear 
>> that drives the timing belt.  On my model 33, the plastic gears are 
>> white nylon.
>>