[TowerTalk] TIC plastic gears

[George Skoubis]

I bought some from there in 2020 and they ran around $15 per gear.  

I bought a couple of sizes as didn’t have an old one to compare. 

The 64p meshed fine.  

  I wound up using a 4O3A Rotator Genius controller with the electronic compass direction indicator so the gears are in my parts box. 

  Here is the best I could do to copy on my iPhone:

round
Product Number	Quantity	Unit Price	Total
A 1P 2-Y64072C

3	$14.41	$43.23
A 1P 2-Y64080C

2	$14.66	$29.32
Tax	$0.00
Shipping	$12.09
Fee Amount	$0.00
Total	$84.64

73,

George / W7GES 
> On Jan 6, 2023, at 4:54 PM, Leeson <leeson at earthlink.net> wrote:
> This looks like a very good call. I was browsing various other catalogs for Delrin 64 pitch hub spur gears, and eventually came up with the same page Jim had already identified. I should first have read his posting in more detail, I would have saved some time. There appear to be other gears of this same type that are used on different TIC Ring versions, including the 72-tooth gear on the same page.
> 
> Part Number   Teeth  PD     OD   Hub Dia. Set screw
> A1P2-Y64 055C  55   .859   .891   33/64    6-32
> A1P2-Y64 072C  72  1.125  1.156    5/8     6-32
> 
> As background, pitch characterizes a family of gears that can mesh, since the tooth size and spacing is the same for all members. Pitch is defined as the number of teeth that a gear with 1.00" pitch diameter would have. Pitch diameter can be calculated from OD:
> (Pitch Dia) = OD * (number of teeth)/(number of teeth +2).
> 
> A remaining uncertainty is the possibility that the TIC Ring gears aren't 20° pressure angle, but that value seems most common.
> 
> For some general info on plastic gears, see https://www.mcmaster.com/plastic-gears/component~gear/ Click on Gear Pitch, then click on the info symbol, "i" in a circle. For another summary of the formulas used to characterize gears, see http://www.omnicomponentscorp.com/64-pitch-delrinreg-spur-gears.html
> 
> Because I want a bullet-proof setup, my own long-term plan is to use a boom-mounted electronic compass with DC output to replace the current pot setup, which loses direction all too often and finally led to a coax parting. I'm leaning toward using a compass chip in a waterproof plastic box, mounted to the boom. Most chips for this purpose nowadays seem to use I2C, and to get 0-5V I've found an inexpensive compass and I2C DAC on Adafruit. See https://www.adafruit.com/product/5579 and https://www.adafruit.com/product/935#technical-details These are really inexpensive, and I'm hoping someone will grab hold of the idea and integrate such a device.
> 
> But even if I can get more reliability, I don't want to rely on direction indication alone as the critical element of a limit system. So I also plan to set up some physical limit switches, as for example KZ1W has done with his TIC Rings. I plan to do this also on my prop-pitch rotators.
> 
> Dave, W6NL/HC8L
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