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[digr]

Index plate hole calculator

[Ironman]

Originally Posted by digr

Index plate hole calculator

Using that calculator and displaying the table, it says:
To produce 51 divisions (7.059 degrees between divisions) using a 1:60 ratio rack, use the following combination of plates:

Plate Full revolutions Remainder holes
17 hole 1 3

So it's do-able, I'll have to dig them out.
Later.....
I dug out the dividing head and stuff and attached it using the plate with the 17 hole row.
I also went and re-calculated the ratio of the table. 1 turn is 4 degrees, so 90:1 ratio.

So with the 90:1 ratio corrected it now says:
Plate Full revolutions Remainder holes
17 hole 1 13

I'm going to read up on that bit, 1 full rev I get, but the 13 remainder stuff is a puzzle.

[digr]

One rev. + 13 holes then repeat one rev. + 13 holes

[arizonian]

Originally Posted by digr

One rev. + 13 holes then repeat one rev. + 13 holes

Easy peasy.

90 turns x 17 = 1530 total holes

1530 / 51 = 30 holes

30 holes - 17 holes per rev = 13 remaining holes

1 rev + 13 holes will space out your teeth equally.

The light will come on once you play with the DH in your hands.

I assume there are two adjustable arms to use as stops on the plate surface. Set one of the arms 13 holes forward and you are in business. Don't forget to advance the PAIR of arms once you advance the dividing head crank to the next position. Lather, rinse, repeat.

[LKeithR]

It's been years since I played with a dividing head so my memory of how one works is a little dim. Never owned one myself but a good friend did and several times back in the 80s when I needed to create discs with multiple holes I borrowed it to do the job. You're pretty smart mechanically (trying to score some points here ) so, as others have said, once you're hands on it should become clear pretty quick. I know that's how I figured it out.

Machinery's Handbook has a pretty good section on indexing so if you've got a copy it would be a good place to look. I was just browsing through my copy and I noticed that--according to MH--you cannot achieve 51 divisions with direct indexing, you need to use differential indexing to get there...

[greywynd]

It also depends on the ratio of the rotary table/dividing head. I’ll see if I can figure out what I have this weekend. I don’t have a dividing head, may be able to borrow one. I do have a rotary table and a simple indexer.


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[Ironman]

Originally Posted by greywynd

It also depends on the ratio of the rotary table/dividing head. I’ll see if I can figure out what I have this weekend. I don’t have a dividing head, may be able to borrow one. I do have a rotary table and a simple indexer.


Sent from my iPhone using Tapatalk

I have the dividing plate and the scissors installed, I still had all the parts and screws for it. Even the baby tailstock was still there. I found a pdf called 'How to Use a Dividing Plate" from Little Machine Shop.com. It made sense and so I'm ready to make chips when the cutter arrives.

[Ironman]

Originally Posted by LKeithR

once you're hands on it should become clear pretty quick. I know that's how I figured it out.
you cannot achieve 51 divisions with direct indexing, you need to use differential indexing to get there...

Once it was installed it started to make more sense, you are right.
Is differential indexing a name for the remainder number?

[GWIZ]

see if this helps. pdf book
https://www.shopfloortalk.com/forums...9&postcount=24

[LKeithR]

Originally Posted by Ironman

Once it was installed it started to make more sense, you are right.
Is differential indexing a name for the remainder number?

I never used differential indexing so I really don't understand it--I barely understood simple indexing and that was a long time ago.

According to Machinery's Handbook: "...change gears are used to transmit motion from main spindle of dividing head to index plate which turns (either in the same direction as the index crank, or in the opposite direction) whatever amount is required to obtain the correct indexing movement."

It's interesting to note that all divisions 50 and lower can be achieved by simple indexing. For divisions 51 and up, some can be achieved with simple indexing while others require differential indexing. The lowest number of divisions requiring differential indexing is 51. Aren't you lucky.

As I mentioned, Machinery's Handbook has pretty detailed info on how it all works...