I was asked to do a more detailed log on my indexer project that I posted in the "what I did today" section, So here goes.
I found myself needing an indexer several times so I thought I would build one. So far I have no money invested in this project as it is made from materials I had lying around. There are no real prints for this. I have two working prints that I add to as I go and I will post those later.
This is the nearly completed indexer as it sit today. I still have to mount the plunger and thread the rear of the spindle for lock nuts and a take up bearing. The spindle does not spin, it is designed to be positioned and locked for machining operations so no bearing is needed in the body.
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The body is a piece of 3 inch diameter aircraft quality aluminum. This is tough stuff and should hold up fine. I bored a hole for a steel spindle I made that accepts 3C collets. there is .002" clearance on the bore and a slot cut up from the bottom. A 1/4" socket head bolt pinches the .002" and locks the spindle in position.
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The angle base is a piece of 5/8" thick angle which is a drop from a car hauler bed (more high grade , tough aluminum). A 1/2 " grade 5 bolt is fit in a precision drilled hole in the rear and threads into the body to lock the tilt feature. I decided this thing needed to tilt to any angle from 0 to 90 degrees and I engraved lines on the body every 5 degrees for a reference when tilting.
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The above photo shows the parts to the indexer. I decided (although it really isn't needed, but I tend to over engineer sometimes) to install a front support bearing. This is a steel bearing made from drill rod and has a flange in the middle that is captured in a recess in the front of the body. This allows free rotation but it cant slide in or out. The front plate has two 90 degree slots. The smaller one is for a 12-24 socket head bolt that locks the tilt feature from the front. This is also kind of redundant as the 1/2" bolt in the rear is the main lock. It is just well locked in position. The larger slot allows rotation of the spindle lock bolt as the body is tilted to an angle. There are also two 1/8" dowel pins that locate the front plate so if it is removed, it always goes back exactly as needed.
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There is a hub on the front that has a recess for the spindle index plate mounting hub. This hub holds the banjo that holds the spring loaded plunger which engages the hole pattern in the index plate. The following photos show this hub and the banjo. The banjo tilts in a 10 degree range for any weird index angles between holes but has a detent in the hub to always locate to the original position.
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The spring loaded plunger assembly is pretty straight forward as seen in the following photos. There will be a slot in the banjo for this plunger to slide in or out to locate on different hole circles and different sized plates. The plate here has 36 holes which cover most of the bolt circles I use, But I am making a 6 inch plate with four more circles of different number of holes and this will cover any hole pattern I will ever need.
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The indexer is nearing completion. The two main things to do is thread the rear of the spindle for a lock nut and mount the plunger ( unless i come up with any additional features I might want:thinking: ). I made a 3C collet blank that has a backing plate for a 4 inch chuck made right on it. I have a 4 inch, 4 jaw chuck that mounts on the backing plate and can be put in the spindle for various holding capabilities I am going to add all the photos I have taken during this project here at the end to hopefully answer anything I may have missed. This indexer has a 6" total swing and works horizontally, vertically , or any angle in between. It will let me drill bolt circles or index a part to mill flats such as making a hex head on a draw bar. Yes , I am going to make a tail stock for it. That is the next project. This project has been fun and best of all FREE. It is small and fits my Burke No.4 mill nicely.
Thank you for looking,
Mark
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