Need help with dividing head...

I think it's wise to treat offshore stuff as a part finished kit and not assume anything, particularly where instructions are concerned.
 
As Caroll Smith once said of the customer formula cars coming out of England in the 70s and 80s; "They come preassembled purely for the convenience of shipping".

The Android app I use is Universal Dividing Head Calculator by Ariyant Creative.
 
I was confused about how these dividing heads worked until I got one. It is really simple enough that tables are unnecessary. Here’s my method: Divide the turns ratio by the number of teeth. That’s the number of turns per tooth. Think of it like third grade...it goes in n times with r left over. So that means make n full cranks, followed by r holes out of the number of teeth. That’s a fraction, r/teeth. Reduce that fraction as much as possible. Then any plate which is a multiple of the denominator works, and the fraction r/teeth of that plate will be a whole number of holes.

Ex: 40:1 head, want 30 teeth. 40/30 is 1 remainder 10/30. Which reduces to 1/3. So any plate divisible by 3 will work. If it’s a 18 hole plate, 1/3 is 6 holes. So the answer is 1 turn and 6 holes.

I tell you, think about it a bit, try it, you’ll never look at a table again. :)
 
Lo-Fi said:
I think it's wise to treat offshore stuff as a part finished kit and not assume anything, particularly where instructions are concerned.
Click to expand...

I would use the word "assembled" rather than "finished"

In any event, I treat everything that shows upin my shop as needing to be disassembled in order to be properly cleaned and then reassembled; correctly.
 
Hi brad not sure if you’ve resolved the issue or not.
I would suggest the manual is correct.
You can check this with basic formulas.
If you’re dividing head is 40:1 it will take 40 equal turns to return to exactly your starting point.
To use an indexing plate for 4 equal flats at 90 deg.
40 (head ratio) / 4 (number of flats, or gear teeth)
40/4 = 10 1/1
Denominator or bottom of fraction =1 (number of holes on indexing plate)
Numerator or top of fraction =1 (number of turns)
Since we don’t have a plate with 1 hole the following formula can be used for any indexing plate. Eg 15 holes.
Take our formula of 10 turns 1 hole on indexing plate of 1 hole.
1/1 x 15 = 15/15 which equals 1
Set ur indicators to leave 1 hole visible on 15 holes and set pin in this hole
Turn 10 times returning to same hole and do not move indicators
Repeat x 3 and u will have 4 equal flats.
The same formula is used for any amount of divisions.
Eg you want to make a gear with 18 teeth
40/18 = 2 2/9
Multiply fraction to make denominator = the number of holes on any indexing plate u have
2 2/9 x 2 = 2 4/18
2 full turns + 4 holes on 18 hole plate
Number of holes between indicators = 4 + 1
+1 allows for number of moved holes. This needs to be applied to any formula or table of number of holes
Eg If table says 6 add 1.
hope this helps
 
Some dividing heads allow you to disengage the worm. They have a 24 hole plat on the spindle and a shot pin on the body to engage those holes. If you index head has that capability it beats the hell out of cranking 22 1/2 turns.
 
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