My Bridgeport head rebuild...was only top end now both. 2hp variable speed.

expressline99

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Well a few weeks back while attempting to get my Bridgeport table feed to quit letting it's magic smoke out. (There is another thread on that mess.) I decided to start working on the top end. The top end was making a horrible amount of noise that got worse as you increased the speed. My first thoughts were that it was pulley bushings like I see in every rebuild kit. But you can get a couple of different kits. This depends on the color of the bushings you have... either teal or black.

Finding out what you have requires pulling the motor. Being located on the very top of the machine made it look like a horrible job. Tons of people on various threads seem to be horrified by the weight of the motor. I think around 60 pounds or so. It's not tiny and pulling it off while 6 ft in the air on a ladder by myself wasn't the right way to go about it. About that time I ran into mrpete's video on removing his Bridgeport head using a table mount he made.

So I built a table mount. The mount uses a piece of round stock welded up to some plate with 3 gussets for stability. ...and a large washer to help displace some of the weight of the head sitting on it. The gussets I just cut the corners off of the plate I was using to build the thing with. I think the round stock was 1" and I turned it down to fit in the spindle. The idea is simple. Once you have the table mount in place you carefully raise the table until it's firmly into the spindle. Firmly but not forcefully. If you put pressure on the head removing it will be a bear. Once in place you can remove the 4 nuts holding it in place. Bring the table out towards you... It should come out pretty easily. *******UNLESS you don't realize that the ram is too far forward! I managed to not notice this and once I got to the end of the table travel was baffled as to why mine didn't come off like I had seen others do. I messed with this forever trying to move the head around until it finally came free. Only after that did I see that I could have simply moved the ram backwards allowing the head to come off. The only reason it was so far forward was for delivery using a forklift several months ago.
View media item 95821
I have a better picture of this I'll have to put up later.

Having the table all the way down and looking right at the motor instills much more confidence that it being over your head.

During this rebuild I am/was following The book "A guide to Renovating the Bridgeport "2J" Variable speed milling machine". Wonderful book for most of the steps. But as with any book they can only fit so many pictures. I have taken a couple hundred pictures of the assemblies as I went as well as pictures of what it looked like inside...dirty and cleaned. (Rick) wanted lots of pictures. Anyway, the point of so many pictures is to allow people to see the parts from several angles. Like you are holding the part in your hand and trying to figure it out! Most books and pictures you see avoid this just because of space. Frequently I'm pointing at things in the picture to show where something goes or something to watch for. So if you are looking at the thumbnail pictures there aren't a bunch of duplicates as it may appear. Just lots of angles.

Trying hard here to give back to this community.
http://www.hobby-machinist.com/gallery/albums/bridgeport-series-1-vs-2hp-tear-down.570/

I am still adding lots of pictures.

The motor was not too bad to remove once loose. I did stand on a milk crate and bear hug the thing after I worked it free of the belt. But you have to take pressure off of the lower Vari-disc by compressing a pulley spring using screws from the cap that covers the access to it.. ****NOTE the whole point is to remove this pulley spring together. Do NOT do what I did and unscrew the screws once you remove the snap ring! This spring is under a bunch of pressure and will shoot across the room! I have no idea why I did it but i happened....and the spring went flying after it bounced off the floor. Lucky it didn't hit me.

Once I had the motor off I was able to check out the bushings... mine were black and in good shape! So what in the world was causing the problems? At this point there was no reason to order a kit including bushings.

The first thing I ran into was in the belt housing... Something had gotten into the belt housing and ruined the timing gear. View media item 96011View media item 96010
Wonderful.

Next I found that the "Spindle pulley Hub" had some kind of issue where the Key Way was destroyed. I think this could have been a manufacturing defect as it seemed like the entire thing was too thin. Also, at the same time as I was disassembling the Spindle pulley hub... the Stationary Vari-disc at it's base is supposed to be held in place by a key...that matches the key way above. The key was gone....just gone.
View media item 96013View media item 96012

I continued and made my way down into the gear housing....but before I did that I got to looking at the gear housing plate...
View media item 95805

Huh... Something doesn't seem right... Oh it's this:
View media item 95807That's supposed to be one piece! And the smaller piece was just loose laying on top of the bull gear....

I will continue this as I have done a ton on this thing. I will be making complete picture albums for putting it all back together and I've started that process...just not put any of the pictures up yet.

Again the break down album (not yet complete) : http://www.hobby-machinist.com/gallery/albums/bridgeport-series-1-vs-2hp-tear-down.570/

Paul
 
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Well done! I've just completed an upper rebuild of a J type, which is much simpler. Glad I got the J instead of the variable speed, now that I see what you went through! I'll get the same functionality using a VFD on my 3PH motor... (shows visible relief on his face...)
 
Well done! I've just completed an upper rebuild of a J type, which is much simpler. Glad I got the J instead of the variable speed, now that I see what you went through! I'll get the same functionality using a VFD on my 3PH motor... (shows visible relief on his face...)

Thanks,
It would be super fast and probably done by now if I wasn't taking 400 pictures. LOL with lots of time committed and broken down into sections it hasn't been horrible. But as of right now. I've gone through a box of paper towels and a box of gloves....half a gallon of purple power for cleaner.. a can of wd40. I'll put more detail on the way back up from the bottom of the lower end. I'm most of the way through putting the lower end back together. For the top end I've got a big pile of new parts waiting. 7 bearings. None for the spindle they appear to be fine. But we will find out.

Paul
 
Wow! That's a lot of parts.

Nice job documenting the work. I appreciate the time and effort it takes for you to help others.
 
I'm still working on this. I went to put the spindle back in and couldn't help but take it apart. Then I could stand the idea of putting it back without new bearings. So I've ordered those and a new dog screw for the collet alignment. I'll have these pictures up soon. Also fitting new bearings on my logan 200 at the moment as well since I got a deal on those....another thread but moving on. I need to post more pictures of things going back on the unit. I'll link them here when I get that far. Not much left on the bottom just the front scale and the spindle rebuild. Maybe by end of week.

Paul
 
The photos documenting this are invaluable! There really isn't too much detailing all of the possible problems and solutions.
I'm shopping for a used BP mill, but don't want to do a full reconstruction. A good reconditioned BP is very expensive and buying used
is kind of a gamble. A new PM may be a better decision. This is a great project if you have the time and money. All those parts and the labor
add up quickly. Just like buying a used vintage car. I admire your dedication. Nice work. Keep us updated.
 
Last night I finished the spindle rebuild and will be posting those pictures soon. I was able to get "super precision" bearings for the lower end of the spindle and a double sealed top bearing.

As well, I've received the rest of the repair parts for my top end so I'll get that going as quickly as possible.

Paul
 
I've got the lower end rebuilt and sitting on the table stand waiting for the rest of it to get done.
Almost done listing and explaining all the pictures for the lower end. I pointed out everything I could think of and any issues I had.
They can be seen here: http://www.hobby-machinist.com/gall...s-2hp-lower-end-putting-it-back-together.589/
I'll put up a separate album for the spindle rebuild. I've completed installing the new bearings just haven't put it all up on the site yet.

The gear housing I've put back together with new bearings and the new to me back gear cover. (replacing the one that was randomly in two pieces floating around in there.

Also, I was looking at the belts and even though they look "OK" there are a few spots and I couldn't leave it alone so I ordered those today. While I was looking at the vari-disc pulleys I noticed it was missing a shaft key. Since I do not have any dimensions or anything to reference on the bushings I've decided to replace them even though they might pass. They aren't wallowed out but if they are new I know for sure they are in tip top shape.

Paul
 
I have uploaded and completed the full tear down and rebuild for the spindle bearings. Full description details with each picture.
86 pictures total. If you are familiar there are lots you can skip but it's detailed.

Spindle bearings tear down and rebuild album: http://www.hobby-machinist.com/gall...eries-1-vs-2hp-spindle-rebuild-tear-down.590/
http://www.hobby-machinist.com/gall...eries-1-vs-2hp-spindle-rebuild-tear-down.590/
Also the lower end rebuild album is also completed link above in the previous message.

Paul
 
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