[GreenKeys] [External] Nylon and fiber gears

[Richard Knoppow]

    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.
> 
> 		Doug Jones
> 		jones at cs.uiowa.edu
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL