Bridgeport cnc series 1 * i need advice & documentation for spindle bearing problem

[Billcase]

Hello

I bought these 2 Bridgeport NC mills, series 1, i have no idea what to call them so look at the pictures. (probably had Boss3 controls which are long gone) They have been sitting for maybe 30 years in storage. I pulled the cap off and got rid of the shives? (vari speed snowmobile style pulleys) and put in direct drive with a "b" size v belt, and installed a frequency drive for speed changes. I have done this to a couple of Hurco Hawks with success. BTW, i used the Centroid Acorn controller and 1.8kw servos. (i know they are too much power) The motion of the machine is great, i set rapids at 250 inches per minuet. (out of a possible 600 inches per minuet) Unfortunately, I believe the grease in the spindle bearings is dried up, and the heads are very noisy, the noise sounds exactly like in the old days when we made skate boards with steel wheel roller skates and rode on cement.
I took the "nut" off the bottom of the spindle, like you would do with a manual machine and the spindle didn't pop out, it is stuck or there is stuff above that's holding it in. I didn't want to force it so that's where it is now.

Does anyone know the steps needed to replace the spindle bearings?
Does anyone know where i can get a schematic of this head?

There are many U Tube videos on replacing bearings in a manual machine head, but i couldn't find any on the cnc head. As you can see, these mills will be very sweet machines after the spindle issues are solved. FYI, The 3 buttons that were spindle and e stop are now cycle start, feed hold, and e stop, so i don't have to deal with the "touch screen" buttons.

Any info is very appreciated!

Thank you,
Bill

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[Billcase]

My son found a web site and found out my machines are 1980 & 1981 models. We searched for hours and found a 1988 manual for a newer model but i think the basics are the same! The head looks the same except the big plastic housing for Bridgeport's controls.

http://manuals.chudov.com/Bridgeport...ser-Manual.pdf

we went by that manual, took the nut off the bottom of the spindle, used a 1/2" piece of conduit and from the top, tapped down and out it came!!!

I was correct, the grease is dried up in the bearings. I squirted some WD40 through the crack in the seal and they spun way better.

NEW problem: The first thing i was going to show my son is the marks on precision bearings and how they have to be lined up. No marks! the bearings were clearly marked Fafnir M207KDD and when we looked them up, i don't even think these are thrust bearings! I can buy these new in the box off e bay for $10. The description is they are a deep groove bearing. I think I'm going to research what they sell for these spindles, and continue on.

Any comments or suggestions are welcome.\

Thanks for the help

[Billcase]

A better picture of the head, not sideways.
The pic of the back of the monitor, if you look very close, you can see the little antenna for the MPG, also the wire that hangs, the end is just under "Kurt" is an extension to a USB port in the computer to get your program from offline cad cam into the machine. You could also do it wireless. A tip for you guys doing your first retrofit: that computer is new and NEVER was used for anything but for this machine. We only put it on the internet for a windows upgrade test, then never again. Don't be putting other software's in your machines computer, you don't want problems!! You can see the computer in the first batch of pictures in the side panel that has the 110 step down transformer. in the upper left you can see the little square computer we used. Its about 5" square and 2" deep.
The pic of the head with no cap on, has the 2 taper lock pulleys for the "B" size v belt, we elongated the mounting holes for the spindle motor and is has perfect adjustment to tighten the belt as tight as we want.

[tonyfoale]

Bill,

You might find this of interest: https://www.cm-spindle.com/spindle-s...pack-upgrades/

I was surprised to find that BP used normal deep groove ball bearing instead of a pair of preloaded angular contact bearing common in other precision spindles. The two to four bearing change might be worth consideration.

I have a question. Have you used the Acorn enough to have an opinion on how well it works?

[Billcase]

I thought I answered this, maybe it got rejected. I'm ordering #8 and they work great!