I don't know who wrote this, probably someone here.
If you recognize your work, please claim it.

I found this to be more help than anything else I ran across in trying
to decipher my indexer.
-------------------------------

Using the indexer

48:1
It's just a simple division using 48 as the main figure and then work in
fractions.

Taking your example of 30 you divide 48 by 30 to get 1 and 18/30th
remaining.

This means that for each 1/30 of a tun you need to take the handle round
one full turn and 18 holes on a 30 hole circle.
As there isn't a 30 hole circle you need to reduce to the lowest
denominator so 18/30 = 9/15 = 3/5.
You have 15, 16, 17, 18 and 19 so out of these you need to move 9 holes
on the 15 circle.
---------------------
40:1
It's just a simple division using 40 as the main figure and then work in
fractions.

Taking your example of 30 you divide 40 by 30 to get 1 and 10/30th
remaining.

This means that for each 1/30 of a tun you need to take the handle round
one full turn and 10 holes on a 30 hole circle.
As there isn't a 30 hole circle you need to reduce to the lowest
denominator so 10/30 = 5/15 = 1/3.
You have 15, 16, 17, 18 and 19 so out of these you need to move 5 holes
on the 15 circle.

That plate you have is only part of a set of plates as with just these 5
numbers you won't be able to do all numbers.
It's also an odd one as there are usually six rows per plate and three
plates per set.
-----------------------------------

Each full turn of the handle will rotate the head 1/40 of a full rev. If
you want it to rotate 1/30 of a rev instead you need to turn the handle
1 and 1/3 turn each time (40 divided by 30 = 1 1/3). Since your plate
has a 15 hole circle one third of 15 equals 5. You would turn the handle
one full turn plus five holes. That location becomes the starting point
for the next turn of the handle which would be another full turn plus
five holes and so on.
---------------------------------
Suppose you wanted to do 72 divisions. You'd need to turn the crank
40/72 of a turn (and do that 72 times). So to get 40/72, or 20/36, or
10/18, or 5/9 of a turn, you'd need some plate with a row of circles
divisible by 9 in it. Using J Tier's plates, you could do it with the
27-hole circle on his #2 plate, for example.


-------------------------
You set up the distance to turn with the two arms that should be in
front of the plate. If you need to move 10 holes, you set to show 11
holes, and lock them together (they now turn as a unit).

That is the hole its in, plus the 10 to move.

When you have moved it, you push the arms along to mark the next move.

Whenyou work with it, always do the same order of operations, such as:
turn crank, lock spindle, set arms ahead.

Otherwise you will get discombobulated as to where you are....

Once you have the hang of the system it will only take you a minute or
so to figure the number of holes to move.

normal set per B&S, L-W etc :
Plate #1 is 15, 16, 17, 18, 19, 20.
plate #2 is 21, 23, 27, 29, 31, 33.
Plate #3 is 37, 39, 41, 43, 47, 49.















Wild_Bill wrote:
Would anyone here know what the actual increments/hole numbers are
correct for a 90:1 ratio Rotary Table?

I've read that there are a specific number of holes in plates, depending
upon the RT's turns ratio, but I don't have a good understanding of the
relationships of those numbers.

I know that there are folks posting here that know more about numbers
than I probably ever will, and maybe they could shed some light for
someone in the dark, about how the numbers on plates correspond to RT
positions.
Is this sort of information in Machinerys Handbook?

I bought a set of 3 plates and associated hardware, that were said to be
for a 6" RT, but the actual correct make/model of RT was unknown.
PYH is the brand on the label, and the plates' center holes are too
small for the Phase II RT.

So, since the plates may, or may not be the correct number of holes for
a 90:1 RT, I thought I'd take a chance on them.

If this plate set isn't the correct one for a 90:1 RT, they may work on
a dividing head or other indexing accessory.
Since the plate center holes and bolt circle don't match the 6" Phase II
RT, they might be adaptable to something else I may get in the future.


PYH TDM1F/6 6" Rotary Table Dividing Plate Set
Made in Taiwan

TDM1F/6
Cat # 51-225-1
Model # 05082466

Stock/SKU label number 87405082466 070 (looks like an Enco or maybe
MSC label)

These plates look about the same as the Enco/MSC import brand SPI 6" RT
plate set.