Bridgeport mill top end rebuild

[Cahark]

Hey guys, rebuilding the top end of my milling machine this evening and the next day or so. Thought you guys might get a kick out of some of these pictures.
I'm not planning on doing a full write up, there's tons of information out there on these machines already. No use in beating a dead horse
Here I am trying to get situated in a decent position to lift off that heavy motor.







Sent from my iPhone using Tapatalk

 

[Iron-Iceberg]

Did you stay on for 8 seconds?

 

[Cahark]

Lol. And then some. Took nearly 5 minutes to get that heavy son of a gun off of the machine.


Sent from my iPhone using Tapatalk

 

[SuperCheyenne]

You do realize the head will rotate? Right?

 

[Cahark]

Yes. Been running bridgeports for about 9 years. I am a small guy, so this method actually worked well. All I had to do was grab onto the motor and lean back instead of standing with my arms outstretched. There were a few hiccups along the way so this method worked out very well. It was much easier to just set the motor back in its place then having to hold onto it in space while I make adjustments.
There are many methods on how to do this job. This one worked well for me.


Sent from my iPhone using Tapatalk

 

[SuperCheyenne]

There are many methods on how to do this job. This one worked well for me.

It's all good. Enjoy the process and keep posting progress.

 

[Cahark]

https://uploads.tapatalk-cdn.com/
20170225/6ad512adc95bc50b424201146548f830.jpg





Sent from my iPhone using Tapatalk

 

[Cahark]

Ran into an issue today. I found out that I have the dreaded teal blue bushing. Supposedly it wears a little bit longer, however it cannot be replaced with the standard bushing kit.
After doing a little bit of research, I found out that a lot of guys make new bushings out of Delrin and epoxy them in. Afterwards they set them up in the lathe and turn them to fit the shaft. I have a friend of mine that is setting me up with a nice piece of Delrin and I will proceed to document the process of fixing this.

Unfortunately this job has change from a days work, to a few days work.



Sent from my iPhone using Tapatalk

 

[Ign]

Very cool. Why are you rebuilding? Noise or something else? My head has howled for years, I should do something about it.

When I installed my riser block my HF gantry was much appreciated!

 

[Cahark]

I'm rebuilding because it sounds slightly like a tractor. Lol. It's time. The bushings have a ton of slop, and I can't stand to listen to it anymore. I wanted to do a top half rebuild because it's not much more work to go ahead and replace bearings and belts while I'm at it. Plus, I have some time between projects at the moment so it's not really setting me back too badly.

I have also considered the HF gantry, but I have a small space. I'm almost debating on building one. We will se how it goes.


Sent from my iPhone using Tapatalk

 

[NOZZLEMAN]

My current bridgy is in parts for rebuild/paint. Haven't disassembled the head yet... but have done many over the years. Good Luck !!

 

[Cahark]

Finished getting the top end back together. All but the motor. I think I'm going to replace the bearings in it.

I was also able to get the bushing out in once piece. This will allow me to get some dimensions off of it to make a new one from Delrin. There doesn't seem to be a lot of info on the teal bushing replacement, so I may do a write up on it.







Sent from my iPhone using Tapatalk

 

[Firebrick43]

I would chuck the reeves drive and install a vfd and a polychain belt. Best thing we ever did on the bridgeports here

 

[Cahark]

As I was going through old posts I realized that I never finished this one. Here are some pictures of making the new bushing out of nylatron. So far it's held up very well and the head is very quiet.




After I was done turning it in the lathe I split it with a hacksaw to make room for the key. Then I made a plug so I could glue the bushing in and hopefully keep the size.

Unfortunately, the bushing closed up on me a little bit and I had to set it back up in the lathe and turn a few thousandths out of it

Here is the sketch that I made of the bushing in case somebody else needs dimensions for one.



Sent from my iPhone using Tapatalk

 

[Cahark]

While running the mill over that last few months, I noticed an annoying drag on the quill at the top 1” of the stroke. I also noticed that the gear selector seemed to be tough to engage and disengage. I’ve been busy in the shop, so I have delt with the problem until now.

Over the weekend, I finally got fed up enough to mess with it. I can’t believe my luck.

I decided that the issue had to have been an alignment issue between the spindle casting and the upper housing due to the spindle being free up until the top 1”. I decided to loosen the top 3 nuts slightly, and give the top housing a shimmy. I also worked the quill while doing this. I slowly and evenly snugged the bolts back up while working the quill. The stars aligned, and the angels sang as everything remained silky smooth after everything was torqued.

This was a complete guess, and it worked in my favor. Hopefully this helps someone in the future.





Sent from my iPhone using Tapatalk

 

[tarbellb]

Good thing you documented it, come back and read/look at this when something goes sideways on you and need a reminder it does not always go to sh!t.

Also, thanks for contributing.

 

[Ign]

Nice to see some solid tech here.

Thanks for following up

 

[Cahark]

After I did my dc conversion I read somewhere to loosen the 3 bolts and let it "Seek" it's own center, I did it and it got smoother and quieter. My machine is a step pulley so I assume the noise reduction came from the hi-low clutch dogs.



Bill

Do you let it “seek its own center” while it’s running?

I did all of my alterations with the machine off.


Sent from my iPhone using Tapatalk

 

[OccupantRJ]

Good writeup Cahark.