How to build an Indexer?

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JimGlass
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How to build an Indexer?

Post by JimGlass » Mon Dec 07, 2009 1:14 pm

I would like to build a CNC indexer as the 4th axis and wondering if anyone has made one or ideas on how to make one.

First thought is to have a stepper motor run worm wheel and worm gear but what about backlash?

I'm thinking about making an indexer where a stepper motor would be direct drive. No backlash :idea: :idea: . To lock the indexer in position, I was thinking about installing a brake system so the stepper would not do all of the holding.

Does anyone have some better ideas??? Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

jutz
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Post by jutz » Mon Dec 07, 2009 3:20 pm

I found information about one that used a stepper motor through a harmonic drive. The motor and drive fit quite neatly inside the body of the indexer and harmonic drives can be built with zero backlash but they are a bit pricey.

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GaryHart
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Re: How to build an Indexer?

Post by GaryHart » Mon Dec 07, 2009 5:03 pm

JimGlass wrote: First thought is to have a stepper motor run worm wheel and worm gear but what about backlash?
Jim, have built couple using worm gear reducers. Controlled gear backlash by using an eccentric for the bearing on end of worm gear and end play was having a spring washer behind bearing on worm shaft at stepper motor end and the other end with the eccentric is a single ball from a ball bearing that is pushed on by a set screw.

Replaced DC motor on a gear reducer motor with a stepper motor. The gear reducer was like new and had no wear on the gears. Made a new output shaft that matches the Sherline lathe spindle. I use this indexer a lot for making gears and rotary engraving.

Made another larger one from a lever operated 5-C indexer that had. This is too large for my little cnc mill but made it with a long enough cord so it could be used on larger manual mill. Made it few years ago and have yet to use it other then testing it. The small one gets used all the time.

Some pictures of inside of 5-C in photobucket album link at bottom.

Image
Image

http://smg.photobucket.com/albums/0903/ ... 20indexer/
Vancouver, WA

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Marty_Escarcega
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Re: How to build an Indexer?

Post by Marty_Escarcega » Sun Jan 10, 2010 6:56 pm

JimGlass wrote:I would like to build a CNC indexer as the 4th axis and wondering if anyone has made one or ideas on how to make one.

First thought is to have a stepper motor run worm wheel and worm gear but what about backlash?

I'm thinking about making an indexer where a stepper motor would be direct drive. No backlash :idea: :idea: . To lock the indexer in position, I was thinking about installing a brake system so the stepper would not do all of the holding.

Does anyone have some better ideas??? Jim
Jim, I'm going to take a Yuasa Dividing head and do just as you suggest. It has a threaded spindle and a chuck. Used to be a device called a FROG but I don' think its made anymore. There was another called DIVISION MASTER, I think its still around to program and drive the stepper.

Marty
"Jack of all Trades, Master of None"

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JimGlass
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Post by JimGlass » Sat Jan 23, 2010 10:45 am

A friend has asked me to make him an indexer so now I need to make two.

From Homosassa FL

Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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Marty_Escarcega
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Post by Marty_Escarcega » Sun Jan 24, 2010 12:02 am

JimGlass wrote:A friend has asked me to make him an indexer so now I need to make two.

From Homosassa FL

Jim
Jim, I am going to build this control for my Yuasa Dividing head and will add a stepper motor to my 6" rotary table as well and use the same control. You can by an inexpensive stepper drive controller on ebay from where else, China for under $20

I believe you are well versed in electronics and can build one yourself.
Marty

http://www.cnczone.com/forums/showpost. ... tcount=111
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