# Spindle Indexing



## bearbon (Jan 10, 2016)

I have a 9c South Bend lathe. I saw a video on youtube about mounting a 72 tooth gear on the back of the spindle with an expanding mandrel and a pawl to hold the gear from rotating. I then had an idea that I could use the back gear already mounted on the spindle in the same manner, but after counting the teeth I was puzzled why the back gear had 76 teeth! Why would South Bend use such an odd number of teeth instead of something that would divide into 360? Oh well, it was a good idea while it lasted.


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## McRuff (Jan 10, 2016)

Here is how I do mine.
I can use the round indexing plates as shown or my change gears with a plunger as my lathe was originally a B model.



The wheels and gears also work on my little indexer for my mill.


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## McRuff (Jan 10, 2016)

I used the indexing setup to make this driveshaft for a Kubota lawn tractor along with making change gears on the indexing block on my mill using a drilled plate asa master for the 3 gears I made. 16, 20 and 32 tooth, I also used the indexer to mark my  larger lathe dials.


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## David VanNorman (Jan 10, 2016)

Nice work.


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## TOOLMASTER (Jan 10, 2016)

that must really flop around when you turn it on..


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## John Hasler (Jan 10, 2016)

bearbon said:


> but after counting the teeth I was puzzled why the back gear had 76 teeth!


Whenever possible mating gears are designed so that the largest common divisor of the numbers of teeth is one.  This results in every tooth on one gear periodically coming into contact with every tooth on the other so that wear is distributed evenly.


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## Ben Nevis (Jan 11, 2016)

I mounted a 5C spin index on the back end of the lathe spindle. A 1 1/16" collet will fit the spindle. A piece of angle iron was used to hold the spin index stationary.


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## David VanNorman (Jan 11, 2016)

Nice paint job on the lathe.


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## David VanNorman (Jan 11, 2016)

Nice paint job on the lathe.


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## DoogieB (Jan 11, 2016)

Ben Nevis said:


> I mounted a 5C spin index on the back end of the lathe spindle. A 1 1/16" collet will fit the spindle. A piece of angle iron was used to hold the spin index stationary.



Now that's a clever idea.  If you ever get a chance it would be nice to see a picture of that setup.


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## martik777 (Jan 11, 2016)

Create any number of divisions with this: http://www.cgtk.co.uk/metalwork/reference/divider

Make a round disc (index wheel) and stud from hardwood, fit to the spindle hole, rig up a pointer. 

Print the divider and glue to the index wheel. Tension up your drive belt and the spindle should remain steady.

I've made many gears, graduated dials  etc with this method.


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## aametalmaster (Jan 11, 2016)

Here's how I do it on my SB 10K...Bob


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## roadie33 (Jan 11, 2016)

Bob,
How did you make the wheel?


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## aametalmaster (Jan 11, 2016)

Yes from 4" alum bar and the dial is from McMaster carr. It had a 7/16" hole so I made a punch with a 7/16 nub and punched it bigger to fit the hub I turned on the alum bar which fits onto the end of the spindle with a set screw...Bob


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## aametalmaster (Jan 11, 2016)

Here are some more pics...Bob http://s110.photobucket.com/user/aa...pindle indexer and spindle lock?sort=3&page=1


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## martik777 (Jan 11, 2016)

Nice setup.  How do you lock the spindle?  

One issue with a fixed scale divider wheel, is that you cannot accurately index parts with a fractional degree. For example, a 28 tooth gear requires 12.857 degrees per tooth, a 100 division dial is 3.6 degrees per division

The printable wheel divider can be customized for the exact number of divisions. You could easily glue stick one to the fixed wheel  for temporary setups


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## Ben Nevis (Jan 11, 2016)

Here are a couple of crappy pictures (taken 20 some yrs ago with a polaroid camera) of the spin index mounted on the lathe.
   It is held in place with a piece of 2"x 2" angle about 10" long. A hole drilled in one end is secured to the lead screw, and the index is C clamped to the other end.

I mounted a Sears die grinder in a Palmgren milling vice on the compound. Sort of a cludge, but it worked fine for woodturnings.


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