Thread: Indexing Dividing Super Spacer what's the essential difference?

Ok maybe we forget the names and just call them by what they do
Direct Indexing
Indirect Indexing
Differential Indexing
????

Found something that I thought was interesting(even if I've never seen a table like it). A indexing head that wears in not out. (Of course there is a table that can use a sine bar to set angles between the steps.)

I can post a scan of one page of a book right? hope its readable

Stuart

Originally Posted by Stustoys

Ok maybe we forget the names and just call them by what they do
Direct Indexing
Indirect Indexing
Differential Indexing
????

Found something that I thought was interesting(even if I've never seen a table like it). A indexing head that wears in not out. (Of course there is a table that can use a sine bar to set angles between the steps.)

I can post a scan of one page of a book right? hope its readable

Stuart

I like the self correcting error idea.. very clever.


So for nomenclature we have... in order of accuracy?

Spin indexer
Super Spacer
Direct Indexing
Rotary Table must fit in here somewhere?
Indirect Indexing
Differential indexing

and not sure where to put the latest addition to the family...

Indexing table with meshing radial serrations.. ( super accurate, but I think only integer degrees? )


Ray

Hi Ray

Yes that's what I though was so interesting.. the more you use it the better it gets as long as you arent repeatedly using the same angles.
I guess you could use a worn rotary table to make one then use that table to make another one and be pretty damn close.
Making dividing plates is about the only other thing I recall that can "self improv", though thats a little different.

Well not exactly what I meant.
Spin indexer, super spacer, some rotary table, some dividing heads= direct indexing
rotary table, dividing heads, things with worm wheels etc= indirect indexing
Dividing heads that are geared to another axis=Differential indexing

Lets not even start on dividing heads with 2 axis indirect indexing

So the one device might well come under to or even three headings... just depending on how its being used.

Its not really an order of accuracy.... that would me more about who built it. I remember Greg showing some pictures of a optical indexing head that the had a correction table supplied to correct errors in the worm wheel even though every wheel was lapped it a new lap etc etc.

" but I think only integer degrees? ) "
No, as I tried to say in my last post, there is a model that takes care of that.
I wonder if anyone has ever seem one in the flesh? lol... looks light

Stuart

Stu, remember the Hirth Coupling thread? I bet that is the principle at work here.
I still haven't got around to making one, but building a simple indexer sounds like a good excuse.
Oh wait, I have all this other stuff to do...

PS: It was actually in your shaper thread, regarding adjustable tool holders:
https://www.woodworkforums.com/showth...th#post1213831

Originally Posted by Grahame Collins

I think dividing head and indexing head are the same animal and can divide down into part of a degree, while a spin indexer is only does fixed degrees. Don't know a bout a super spacer, though.
Never mind, someone will come along who knows this and more.

Grahame

I'm not sure, but I was under the impression that Spin Indexers could theoretically divide down to a tenth of a degree, courtesy of a vernier action with the choice of detent hole.
Rob.

Ahh, I may just have seen some light. It would seem that the vernier action was to get individual degrees, not the tenths I was confusing myself with.

Originally Posted by RayG

This weeks question in the ever growing category of misused confusing terms...

What's the difference between a "dividing head" an "indexing head" a "super spacer", let's throw in "spin indexer" as well, just to help muddy the waters?

Ray

Ray, to mud the waters even more you could add the rotary table to your list. It is indeed a confusing theme. Essentially they all do some sort of dividing, but each are optimised for different tasks.

The "Hartford Super Spacer", as well as an "Indexing Head" or a "Spin Indexer" all belong to the category of Indexers. Indexers do not use an "analog" drive like worm gears to set angles or divisions. Indexers use a "digital" type of mechanical indexing. Most usually this is an exchangeable indexing plate with square teeth, but sometimes a hole plate or a common gear is used as the indexing plate. Sometimes the indexer is as simple as a number of equally spaced holes drilled at the circumference of a chuck or it's backplate.

Anyway, an indexer always has an integer number of divisions, it cannot be set to any arbitrary angle in between. Sometimes it is easily possible to convert a fixture back and forth from "digital" to "analog" dividing modes, by disengaging the indexing feature and instead engaging a worm drive (with or without indexing discs). Or you could use a CNC approach, with a step motor driving a worm drive, which would let you choose either way how to use it (either as a divider or to set any random arc or angle).

The advantage of a (digital mechanical) indexer is speed, reliability and ease of use, as it can very quickly be set. Imagine an indexer based on a gear with 24 teeth. Move it 12 clicks to divide by 2. Move it 8 clicks to divide by 3. Move it 6 clicks to divide by 4., and so forth. Very quick and easy to drill holes in a flange or the like, and it is hard to do a mistake too. But there is no way with a 24T indexer to divide by 5 or 7 or 9 or 10 or 11.... So you may need a number of different index plates.

A "Spin Indexer" is usually a simpler design than a "Dividing Head", made to accept collets, not tiltable, and fitted with a hole plate and vernier. There are motorized versions too, but unlike CNC controlled dividing heads or rotary tables, these motorized rotary indexers can only index to the steps given by their hole plate. Not to any arbitrary angle.

Originally Posted by Bryan

I still haven't got around to making one, but building a simple indexer sounds like a good excuse.

Me either lol One day. I still have way to much stuff to do as well.

Stuart

Originally Posted by Stustoys

Me either lol One day. I still have way to much stuff to do as well.

Stuart

One day how about something like this....

Hercus' simple indexing attachment for their vertical milling attachment - https://www.woodworkforums.com/showth...96#post1403096

or if you like knurling -

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BT