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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