# What is a "spin indexer" and how does it differ from a "dividing head"?



## HMF

What is the difference between a full dividing head and a "spin indexer"?

Spin indexers:

Stevensons:
http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Fixtures


On Ebay:

http://www.ebay.de/itm/ws/eBayISAPI.dll?ViewItem&item=140496496795&ssPageName=ADME:X:eRTM:DE:1123



:tiphat:Nelson


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## Alan Douglas

This one at least (a Hardinge) indexes only every 15 degrees.


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## Tony Wells

A true dividing head is capable of odd divisions like you might see on gears or splines with odd tooth-counts. Spindexers are not, at least none I have used. Probably more accurate also.


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## yugami

A spin indexer will only allow you to divide things into full degree increments.  The holes are spaced to give you 5 degrees then switching between holes in the top vernier allowing you to get 1 degree resolution.

This is good enough for a lot of things; a 24 tooth gear for instance is divided into 15 degrees between teeth (360/24 = 15).  However if I need to do a 7 sided shape that's 51.42857 degrees between sides.

A dividing head allows you to get down to the nitty gritty and move it in very fine increments depending on the ratio between the worm drive and the number of holes on the plate. 

Assuming a 40:1 ratio dividing head you would do 5 full turns (360/40 * 5 = 45 degrees) then 20 of the holes on the 28 hole ring (360/40 * 20/28 = 6.42857).  Both together give you 51.42857.

A spin indexer is easier to use for what it can index, count holes and move it directly to where you want to go.  A dividing head fills in the gaps allowing for odd angles - do the math or use a look up table and crank + count holes.


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## HMF

Is a spin indexer used for "direct indexing"? As opposed to a dividing head, which is used for "indirect indexing"
or are these different concepts?


:tiphat:Nelson


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## yugami

Allthumbz (Nelson) said:


> Is a spin indexer used for "direct indexing"? As opposed to a dividing head, which is used for "indirect indexing"
> or are these different concepts?



Sounds about right to me.


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## McRuff

Tony Wells said:


> A true dividing head is capable of odd divisions like you might see on gears or splines with odd tooth-counts. Spindexers are not, at least none I have used. Probably more accurate also.



There are more than just the crude spindexers he linked to. A Harig grind-all is a spin indexer capable of degrees minutes and seconds and also has hard indexes, the Neaubold (sold by Hermann Schmidt) indexer uses 5c collets and does the same along with more features than a dividing head can do, they are very expensive over, $6000. Both of these models can be motorized for other functions. I have used them for many years in the shops I have worked at and at one time even made them when RJ was friends with a shop owner I used to work for, before Schmidt bought the rights from him.


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## JACK-TR6

Good information on indexing


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## BWSmith

Interestingly,in the process of putting a 4" chuck on a Yuasa indexer. Was going to post a question to the group about it,then well.... didn't. I sorta need it for some setups and,just gonna have to see if it works out?


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