A tale of three bridgeports, I need some help!

I don't know what I don't (or should) know!

I purchased 3 bridgeport mills. I am keeping at least one maybe two and put them to work. I bought them at a reasonable price.

I have two specific questions:

1. I want to learn how to evaluate these machines to make sure I keep the best one or two. Can someone direct me to a thread, book, video, etc? I understand the flaking on the ways gives a good reference for wear. Two of the machines look solid, the other not so much. I don't know how to evaluate the variable speed head, spindles, etc

2. All of my experience has been with servo (type or brand) table feeds. These have the 8f which are all lacking parts, motors, etc. How do I convert these to servo type feeds?

I used a very similar machine in a trade school 25 years ago and alway had a goal to own one. I'm excited to really learn as much as I can about them.

I appreciate the advice and information

Rprecision said:

I don't know what I don't (or should) know!

I purchased 3 bridgeport mills. I am keeping at least one maybe two and put them to work. I bought them at a reasonable price.

I have two specific questions:

1. I want to learn how to evaluate these machines to make sure I keep the best one or two. Can someone direct me to a thread, book, video, etc? I understand the flaking on the ways gives a good reference for wear. Two of the machines look solid, the other not so much. I don't know how to evaluate the variable speed head, spindles, etc

2. All of my experience has been with servo (type or brand) table feeds. These have the 8f which are all lacking parts, motors, etc. How do I convert these to servo type feeds?

I used a very similar machine in a trade school 25 years ago and alway had a goal to own one. I'm excited to really learn as much as I can about them.

I appreciate the advice and information

Click to expand...

To change to Servo feed you first need to remove the screw, shorten it, put a keyway in it then thread it for the crank nut, buy your servo kit and there you go. Were it me, I would fix the BP feed. Parts are available from H & W in Fort Wayne IN. 260 422 0020. Then use the money you save on the X axis feed to buy one for the Y axis and especially the knee. H & W sells Servo and has parts and service for them as well. Easy way to check the screws for wear is center the travel, turn the handle till you get movement, 0 the dial turn the handle the other way and read the lash. Move the axis to the end of travel and do it again. Subtract the end lash number from the center lash number and the result is the wear on the screw. The ways must be chrome, they look good. Vary speed heads get noisy when the shiv bushings are worn. I just bought rebuild parts, bearings, belts, shiv bushing kit, about 300.00 or so and easy to do. Looks like you have the newer style vary speed head, should have a 2hp motor. You should get a Kurt power draw bar as well, I will never have another BP without one.

Those mobile base wheels don't have a way to lock. So I guess you would shove a block underneath the wheel support bars. Just use a 2x4 cut into
a wedge.

Things to look for:
Chrome plated ways.
Free play in x y screws.
Motor/spindle noise.
Vari head noise.

You can swap parts across the machines. Keep the tables on their respective saddles.

Thanks for the information. I'm missing alot of parts off the table feed, is it still worth putting money into these feeds?

rons said:

Those mobile base wheels don't have a way to lock. So I guess you would shove a block underneath the wheel support bars. Just use a 2x4 cut into
a wedge.

Things to look for:
Chrome plated ways.
Free play in x y screws.
Motor/spindle noise.
Vari head noise.

You can swap parts across the machines. Keep the tables on their respective saddles.

Click to expand...

Your right about the wheels. I think once I settle on a location for them I will block them up, Remove wheels and install feet.

I think two of them have chrome ways,

Thanks

Rprecision said:

I don't know what I don't (or should) know!

I purchased 3 bridgeport mills. I am keeping at least one maybe two and put them to work. I bought them at a reasonable price.

I have two specific questions:

1. I want to learn how to evaluate these machines to make sure I keep the best one or two. Can someone direct me to a thread, book, video, etc? I understand the flaking on the ways gives a good reference for wear. Two of the machines look solid, the other not so much. I don't know how to evaluate the variable speed head, spindles, etc

2. All of my experience has been with servo (type or brand) table feeds. These have the 8f which are all lacking parts, motors, etc. How do I convert these to servo type feeds?

I used a very similar machine in a trade school 25 years ago and alway had a goal to own one. I'm excited to really learn as much as I can about them.

I appreciate the advice and information

Click to expand...

Great score depending on price?

All three machines look to be 1990's machines, they all will have chrome ways, it was standard by then.....

The Bridgeport power feeds can be replaced by a kit from servo, no need to modify the lead screw;

http://www.servoproductsco.com/specs/80857_focus-on_models_200_206_225.pdf

Here's another link to their website;

Power Feeds

Kevin

Thanks for the shoutout Moonlight... Good call on the backlash testing for screw/nuts.

The leadscrew on a 6F/8F actually ends underneath the table. The kit that Servo makes for it comes with an extension shaft to make the "leadscrew" the proper length.

The motor for the 6F/8F is actually pretty dang expensive, I think almost $900 not. So replacing it with a Servo might actually be cheaper.

Jon

Rprecision said:

Your right about the wheels. I think once I settle on a location for them I will block them up, Remove wheels and install feet.

I think two of them have chrome ways,

Thanks

Click to expand...

The table feeds are worth looking into. Get a schematic diagram. Those feeds have been discussed here before.

The chrome way machines are your two keepers.

The wheels don't have to be removed. You can drill/tap a hole in the flat bars for a long screw.
The top of the screw is turned clockwise and the other end will contact the ground.
The chunk of wood idea will also work, and there is no shame using some scrap pieces of wood.

If you search here you can see other ideas. This is from the site.

HWElecRepair said:

Thanks for the shoutout Moonlight... Good call on the backlash testing for screw/nuts.

The leadscrew on a 6F/8F actually ends underneath the table. The kit that Servo makes for it comes with an extension shaft to make the "leadscrew" the proper length.

The motor for the 6F/8F is actually pretty dang expensive, I think almost $900 not. So replacing it with a Servo might actually be cheaper.

Jon

Click to expand...

I'm going to shoot you a PM, maybe we can discuss what it will take

HWElecRepair said:

Thanks for the shoutout Moonlight... Good call on the backlash testing for screw/nuts.

The leadscrew on a 6F/8F actually ends underneath the table. The kit that Servo makes for it comes with an extension shaft to make the "leadscrew" the proper length.

The motor for the 6F/8F is actually pretty dang expensive, I think almost $900 not. So replacing it with a Servo might actually be cheaper.

Jon

Click to expand...

Thanks, I will shoot you a pm to see if maybe we can maybe figure it out

I forgot to mention that when I bought my mill the shop lent me their BP movement device. It was just one flat bar with a wheel on each end. You place the bar under
the base at the center. It moves quite easily. The bar looks like your bars. The only exception is that the wheels on their device did not swivel. So I think if you
mounted a couple of non-swivel wheels to one of those bars you could have a movement device.

I can tell you that having them on wheels is super handy! I cans see what you talking about.

I ordered a book on refurbishing bridgeports. Are there any key things I should be measuring or inspecting first which are deal breakers?

Thanks, I really appreciate all the wisdom here!