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Republic 14x40

Nadobill

Plastic
Joined
Oct 12, 2017
Republic lathe dial

Hello again,
Still moving slowly with my lathe spruce up... Was wondering if anyone had any insight into this item. I know the center portion is a threading dial, but what of the big pointer and the outer ring? When moving the cariage, the thread dial moves inside independent of the needle which also moves around the large scale. Is this a built in traveldial of sorts? Is it in metric maybe? LagunThreadDial (1).jpg
Also , some pics of the new paint. Motor got new bearings too. They were a little noisy.
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1102171552.jpg1102171552b.jpg
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I doubt that the second dial is for threading in metric.
From looking at the threading chart and assuming that the lead screw has 4TPI. I read that on settings (4 and one) with (49)(75))(98) you get a 4TPI thread when cutting. This means that the (4 and one) gear setting is doubling the speed as the (49)(idler)(98) is halving.

For the fist metric setting 7.5mm lead, this is roughly generated with the same setting but with different change gears being(49)(idler)(83)
So. (49/83)*(2)*(0.25inch)*(25.4mm/1inch) = 7.49759mm ~= 7.5mm

Since this isn't an exact translating to metric with a loss of 2.4um per revolution, letting the chuck spin without the half nut engaged will quickly run through the tolerance. If it was an exact translation then the threading dial may have worked.

whether it was as travidial could have been answered by whether it comes to zero at presumable 0.2 of saddle travel
= republic lathe threading chart2.JPG
 








 
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