Is it possible there is an error on the number of tpi here? Threads per
inch? Turns per inch?
73,
Gary...wa6fgi
----- Original Message -----
From: "Will Matney" <craxd1@verizon.net>
To: <amps@contesting.com>
Sent: Monday, March 13, 2006 12:24 PM
Subject: Re: [Amps] Proof of idiocy
> See, that's a shame. If I recall, those vernier dials are 8 revolutions
> per turn of 360 deg., and dial counters are set up for 10 turns used on
> ten turn pots. The old National verniers, I cant recall what ratio they
> were as they had the knob type, and the one with the large blank scale and
> pointer. It looks to me though like you'd be hard pressed to find anything
> that would come out right ratio wise. One might try to cheat it with
> belts, sprockets or gears, but that's a big mess to get into. To convert
> 23 to 20 turns, you'd need a gear ratio of 1.15:1 or for 10 turns into 23,
> 2.3:1. That 2.3 or 1.15 being an odd number, is impossible to get in off
> the shelf components. In gears and sprockets you'd need say an 12 tooth
> and a 13.8 tooth (for 1.15) which is an impossible thing. The only way
> left would be use pulleys and they can slip bigtime. Timing belts wont
> work as they have teeth like a gear. To me, what they done is about the
> absolute dumbest thing any engineer could have t
> hought of. At least they could have used a ratio without an odd number,
> say 1/4"-25. Then using a 12 tooth gear or sprocket which is about the
> smallest, you'd need a 15 tooth to match it. 25 / 20 = 1.25. 12 x 1.25 =
> 15. Then you would get 20 turns to the inch. I forget what the maximum
> movement is for the piston in those for a dial to work for full count.
> That would be the only way to do it is use belts and machine custom
> pulleys.
>
> Best,
>
> Will
>
>
> *********** REPLY SEPARATOR ***********
>
> On 3/13/06 at 2:40 PM HAROLD B MANDEL wrote:
>
>>Jerry at Economy says Jennings did this just to prevent easy fixes
>>that might void any warranty and to make the equipment
>>expensive to repair.
>>
>>Hal
>>On Mon, 13 Mar 2006 13:38:15 -0500 "Will Matney" <craxd1@verizon.net>
>>writes:
>>> Custom stuff is highly expensive. Thing is,
>>> Jennings had to pay extra too just to use an odd-ball size.
>>>
>
>
>
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