Gearbox ratio

Need a sanity check here ...

The DivisionMaster does whole number ratios, so 90:1 ... 67:1 all the way up to
5000:1, and for rotary tables with a fixed worm this is fine. However I've got a
customer asking for fractional ratios. Which I can sort of understand for 3:2
and similar, but he has a planetary gearbox doing 53.997:1 ... Is that even
possible? All the books I'm looking at give a whole number ratio simply because
there have to be whole number of teeth?

AH - looks like 143:144 comes into the equation somewhere ... 54 turns of the
input only gives 143/144 of the output ... it's some of the maths provided which
has to be wrong as it needs more than 54 turns to get 360 degrees on the output
... must be (54/143)*144 that is 54.3776223776:1 ... so is that a multiple chain
of stages of some sort?

Just heard ... Dewalt drill salvaged gearbox ... works fine as long as you scale
the angles and don't use division mode :(
--
Lester Caine - G8HFL
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