# Spindle indexing on a lathe!



## McRuff

Here is a project I made about 2 years ago to index the spindle of my lathe. I was using it to index the spindle for broaching splines on a reaccuring job I have. The hub uses 2 1/2" diameter x 3/8" thick index wheels with a center hole that matches to the center hole in the change gears of my South Bend 9", that way I can use the change gears also with a different plunger. I have 3 index wheels made  with 2 patterns on each wheel, gives me a ton of variations to use (2,3,4,5,6,8,9,10,12,15,18,20,25,30,36,50) plus any combination that falls in the change gears. The bar that the index pin goes thru is simply clamped to the steel tubed edge of my lathe bench, really need to go ahead and drill holes and make it so it repeats when I clamp it on. This design could be adapted to any number of lathes.


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## McRuff

The index wheels also fit a mini indexer I made to use on my mill so that I could make change gears and such.
It was made from basically scrap, no bearings (slip fit) and has 2 arbors that can be changed in a few minutes, one holds the gear blanks the other holds a small lathe 2 1/2" chuck I found at a swap meet.


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## McRuff

Here is a sample of several things I made with the lathe index head using the carriage to broach with.
The 1st is a driveshaft for a commercial Kubota mower bagging attachment, the 2nd is a spud shaft used to couple to a saginaw steering box to extend it past the crossmember for use in an old jeep.
To broach I just put a HSS tool in a boring bar like tool I made, set it up on center and true it to the work, simply take a .001-.002" per pass, stroke it in and out quickly advance again and repeat. I do not back the tool off during the broaching. The spud shaft in the 2nd picture has 36 splines .032-.033" deep, it takes about an hour to broach the serrated splines on the outside and about the same to do it on the inside.


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## mitsue

Very nice. This should give many of us ideas for projects after we build one like this.
Darcy


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## bcall2043

McRuff said:


> Here is a sample of several things I made with the lathe index head using the carriage to broach with.



Great application that gives me an idea for repairing an old Snapper garden tractor drive.

Benny


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## McRuff

etard said:


> That's awesome! So you just hand broach by winding the carriage in and out? I may have to try this on a project I have, can you post a pic. of the broaching bit?
> 
> Also, did you use an indexing table to drill the holes in your spindle indexing plate?
> 
> Thanks for sharing this setup!



Here are the tools for the Kubota shaft.





A couple of  pictures for the serrated splines used on the spud shaft.









And a photo of the index wheels. You do not need a rotary table to make indexing wheels, in fact its the worst way to make them. If your dials are accurate or you have DRO's on your mill lay the hole spacing pattern out witha free CAD software and crank them off and drill and ream them on your mill table.


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## HMF

Thanks again Mike! This article appears in the lathe section of the articles page:

http://www.hobby-machinist.com/content.php/208-Spindle-indexing-on-a-lathe!


Nelson


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## geckocycles

McRuff said:


> You do not need a rotary table to make indexing wheels, in fact its the worst way to make them.



If you have a rotary table why wouldn't you want to use it? I would think it is far more accurate than manually dialing in XY and dealing with backlash. I have no DRO on my Bridgeport though.


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## McRuff

geckocycles said:


> If you have a rotary table why wouldn't you want to use it? I would think it is far more accurate than manually dialing in XY and dealing with backlash. I have no DRO on my Bridgeport though.


Because the backlash is easy to deal with and consistent within .001 or less. Backlash is one ofthe very 1st things you are taught about in trade school or an apprenticeship, its not hard you just deal with it. The error in a rotary table cannot be accounted for and the farther from center you are the greater it is. You also have to calculate the degrees, minutes and seconds of every hole if it doesn't come out a whole number. Don't believe me calculate the error for the center of a hole on a 2" radius if you are off 15 seconds whcih is what most of these cheap tables are marked in but they are not that accurate, most have there accuracy marked in minutes not seconds.
Lets put it this way, I have been building precision injection molds for 30+ years no one would ever consider drilling or locating holes in a circular arc on a roatary table, ever! They would always be cranked out on a XY table and use the dials or DRO's.


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## geckocycles

THX, than that is what I will do on my next hole project.
Backlash isn't much of an issue with me and if I have the time to plan it I can have my buddy make a plate on his CNC BP.


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## Tenn

1200rpm said:


> Mike is dead on right about co-ordinates being the most accurate way- check out the jig borer section of Machinery Handbook.
> you can lay out and scribe and use a drill press and probably match the accuracy of a cheap rotary table. make the index wheel bigger than the part you`re making and you get an error reduction.
> 
> i was convinced i needed a dividing head until Mike turned me on to this method. saved the cash for other stuff.



THX for the tip on where to look in Machinery's Handbook :tiphat:


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## ftownroe

*CAD Software*

Could you please elaborate on what free software you use?
Thanks


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## geckocycles

I use http://solvespace.com/index.pl
Easy to learn and he supports it too. What I like about it is that there is no installer. Just run the .EXE file and you are up and running. Very small and powerful.


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