# Rotary indexer tables needed

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--It's been so long since I used my rotary indexer that I've lost track of the nice little printed table of turns and fractions-of-turns that I used to get divisions right. I've got a project where I need to have 28 equal divisions of a circle for a bolt hole pattern. Can anyone point me to a table I can download? --Thanks,

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Ed, Is yours a 40-turn table ?

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--Not a table, but an indexer, but yeah I think so. It's the kind that takes index plates, so there's no dial like you'd see on a rotary table.

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isn't it just down arrow left arrow, 28 enter enter............sorry, my universal indexer is under the lathe keeping that spot on the floor clean

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40/28 = 1 & 12/28 = 1 & 3/7 1 full turn and 3 holes on a 7 hole plate or 6 holes on a 14 hole plate or 9 holes on a 21 hole plate... etc.
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Ed,

I don't have a table but the drill would be:

Divide 40/28 = 1 + 3/7 ; That means 1 full turn of a 40 turn table plus 3/7 of a turn remaining for each of the 28 holes. Using your plates and sector arms find plates of the following numbers of holes: 7; 14; 21; 28; 35; 42, etc. Hole numbers to be sectorized on the appropriate plate(s) would be, respectively: 3; 6; 9; 12; 15; 18.

Bob Swinney

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Get yourself a TI 30 calculator. Find the ratio of your table, be it 40:1 or 90:1 Enter the number as a fraction. 90 / X Display shows the number of turns, and a fractional turn, reduced to a lest common denominator.

If you have a 90 turn table, you type in 90 [a b/c] 35. Display: 2

4/7

So, it takes 2 and 4/7 of a turn to index 35 times. Easy. No Charts to decipher.

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