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Index Super 55 Mill Repair

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cjtoombs

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#1
I purchase this mill quite some time ago and used it a some. I have since aquired another machine to replace it and decided to get rid of it. It was in bad need of some TLC, so I thougth I would tear it down, clean it up, make any minor repairs it needed and paint it. During the teardown, as I was pressing the shaft that rotates the spindle out of it's housing, this happened:
IMG_0191.JPG
Joy. I pondered what to do. That support provides radial and axial support in both directions. Brazing it back in was not an option, as I would not have been able to locate it, and it was pretty badly mangled up anyway. I decided to go a different route. This is what the housing looked like before:
Index Mill Repair Before v2.jpg
The upper recess was 2.25" and the spindle indexes in it. The lower diameter was somewhat larger and as cast. It was also a bit off center. I bored the housing till the lower portion cleaned up, about 2.625.
IMG_0197.JPG
I then turned a sleeve to a light press fit to go in the hole and drilled it 1" on the inside. This was pressed in with some bearing retainer Loctite and then the remainder of the machining was done on the sleeve. I then pressed in two oilite bushings and it looked something like this
Index Mill Repair After v11.jpg
IMG_0200.JPG
IMG_0201.JPG
I also needed to modify the shaft, the original shaft was crossdrilled for a pin that engaged a slot in the spindle housing to turn it (I didn't think to take the picture before I cut the end off the shaft):
Index Mill Repair Before Shaft.png IMG_0207.JPG
The end state for the shaft would look something like this:
Index Mill Repair After Shaft.png
I nipped the shaft off, drilled and tapped it and cut a 9/32" slot in it (I had a cutter that size):
IMG_0202.JPG

At this point, I would show you the picture of the completed end piece that goes on the shaft and drives the spindle housing, but my CNC mill crapped out part way through the making of it. I will have to finish it up on the shaper and lathe (with some design mods to accomodate) as I don't have another mill working right now. Most of the job is done and the remainder of the mill is nearly ready for paint and reassembly. The weather here is not accomodating my painting, so it will likely be a few more weeks before it is back together.
 

cjtoombs

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#2
There was another issue with this mechanism, I wound up breaking a tooth off the gear when I was trying to turn the spindle on it at some point. The issue was with the rear portion of the shaft, where it went throught the housing. It goes through and attaches to the rear of the drive housing, so that the entire drive housing rotates with the spindle head. This had rusted up and was a bear to get out of the column. This is what the gear wound up like (forgive my poor photography):
IMG_0203.JPG
I decided that whoever wound up with this mill didn't need this headache, so I drilled the column for a Get so that this would get some ocasional lubrication.
IMG_0204.JPG

The broken tooth won't actualy be a problem. The head on this mill can only turn through about 120 degrees, so I will just assemble the broken tooth 180 degrees from the worm (basicaly turn it over from it's original position). I'm sure glad they made it a whole gear, instead of a partial.
 
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cjtoombs

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#4
You have a serious ailment- the "fix it up before I sell it" disease :big grin:
I agree. It actualy wouldn't have been that bad, but I had to spend an awful lot of time on this part. Hindsight being 20/20, I would have just left this assembly together.
 

cjtoombs

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#5
I got the last part done and put this together. It works quite nicely. The mill is mostly together, I have to complete the drive now and do the electrical, then tram it and test it out and it will be ready for a new owner.

IMG_0271.JPG
 

cjtoombs

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#6
Coincidentally, I sold a shaper to some guys from LA a month or so ago, shortly after I had started posting this thread and they were rebuilding an Index 55 or super 55 and broke the same support our of theirs. If you have an Index mill and are planning on taking this thing apart, I would recommend leaving the shaft and gear in the housing and just work around it. It's quite a bit of work to fix it, and I think the likelihood of getting it apart in without breaking that support is pretty low.
 

ThunderDog

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#7
Very nice repair!!
No joke, I completely disassembled my Super 55 and the part you had to repair was the last to be disassembled for inspection and cleaning yesterday. I called it quits for the night and now I'm reading your post. I think I'll just leave that section together.:cool:

I am curious, when you were disassembling the original shaft/housing did you notice the shaft and large gear assembly have a slight linear movement?
Did you upgrade due to poor performance from the 55?
 

cjtoombs

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#8
I didn't notice the linear movement, but the way it is designed, some linear movement will not affect performance. I think I left in the neighborhood of .020 end play in that shaft. I've had that Super 55 for some time, when I bought it it was missing the motor pulley and some other parts related to the motor, and the motor had been rewired for 440 volt only operation. I built a motor adapter and put a 3 hp motor and vfd on it and used it some, but the slides, especialy the knee and y axis were always very difficult to move. I had gotten my tormanch and didn't use the mill much anymore, I also got a T&C grinder that needed a VFD so I robbed the one from the Index to go on it. The Index sat idle after that for quite some time. After I decided to get rid of it, I decided to tear it down and do a cleanup and paint and make minor repairs prior to selling, which is when I found out why the z and y ways were so tight. They had been lubed with grease at some point and that had dried and gummed up. They also had some bearings on the leadscrews that were bad. The cleanup and replacement of the bearings eleviated the gummed up movement issue. I should have done what I'm doing now when i first bought the machine, but didn't want to spend the time on it then. I upgraded becasue I got a great deal on a nearly new BP.
 

ThunderDog

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#9
I didn't notice the linear movement, but the way it is designed, some linear movement will not affect performance. I think I left in the neighborhood of .020 end play in that shaft. I've had that Super 55 for some time, when I bought it it was missing the motor pulley and some other parts related to the motor, and the motor had been rewired for 440 volt only operation. I built a motor adapter and put a 3 hp motor and vfd on it and used it some, but the slides, especialy the knee and y axis were always very difficult to move. I had gotten my tormanch and didn't use the mill much anymore, I also got a T&C grinder that needed a VFD so I robbed the one from the Index to go on it. The Index sat idle after that for quite some time. After I decided to get rid of it, I decided to tear it down and do a cleanup and paint and make minor repairs prior to selling, which is when I found out why the z and y ways were so tight. They had been lubed with grease at some point and that had dried and gummed up. They also had some bearings on the leadscrews that were bad. The cleanup and replacement of the bearings eleviated the gummed up movement issue. I should have done what I'm doing now when i first bought the machine, but didn't want to spend the time on it then. I upgraded becasue I got a great deal on a nearly new BP.
The grease issue was the same thing I found on mine. Many of the Zerk fittings were clogged and the ways were bone dry. So glad I disassembled it completely. I bought another grease gun to convert it to an oil only gun. No more grease for this machine, that's for sure.
 
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