Bridgeport Series 1 Refurb Project

rpseguin · May 29, 2018

I just got a Bridgeport CNC knee mill with an old ProtoTrak Plus controller.
The mill is super dirty, but it is in good shape:

Bridgeport Knee Mill, Proto Trak Plus - Google Photos

I'm having my kids help me clean it up and get it ready to use.
The ProtoTrak Plus actually works, but is kinda dated.

So my questions are:

The Y way wipers are shot. Order from Hardinge/Bridgeport or elsewhere?

How do I clean up the ways and make them look nicer? They appear to be chrome ways, but have some scoring and groves in them.

What paint and color to use to touch it up? Bondo as filler?

Best way to make use of the Proto Trak Plus? Is it worth it to use it and interface via the RS-232 port?

Way to add quill as 3rd axis?

rpseguin · May 29, 2018

A lot of the paint is in good shape, but there is some chipping and areas that could use repainting/touchup.

Ram before cleaning:
Shared album - Ralph Seguin - Google Photos

Ram after cleaning:
Shared album - Ralph Seguin - Google Photos

Head before cleaning:
Shared album - Ralph Seguin - Google Photos

Head after initial cleaning (still in progress):
Shared album - Ralph Seguin - Google Photos

rpseguin · May 29, 2018

How do I clean up this scoring/groving on Y axis ways:
Shared album - Ralph Seguin - Google Photos

Shared album - Ralph Seguin - Google Photos

Randalthor · May 29, 2018

In the past, I've read on PM that people recommend stoning out any burrs, which I think is about all you can do, unless you were planning on scraping.

I got a new felt wiper kit (6 wipers) from H&W for about 9 bucks plus shipping. They will ship in a flat rate box if you check that shipping method on checkout, so the shipping isn't bad.

rpseguin · May 29, 2018

Randalthor said:
In the past, I've read on PM that people recommend stoning out any burrs, which I think is about all you can do, unless you were planning on scraping.

I got a new felt wiper kit (6 wipers) from H&W for about 9 bucks plus shipping. They will ship in a flat rate box if you check that shipping method on checkout, so the shipping isn't bad.

Thanks!
I know that the grooves won't really affect performance, but I just want to make it look nice!
Thanks for the tip on the wipers!

HWElecRepair · May 30, 2018

So here is what I (through Barry, cause he has been doing this longer than i have been alive) got...

1. Stoning the burrs down is something people do alot.
2. You are right, the divots and grooves wont effect performance... as long as those issues werent caused by something on the bottom of the saddle. You should get the saddle off to verify that the ways on the bottom of the saddle are not the issue. Barry recommends getting in there with a pick or something to get everything out of the grooves you have on there.
3. While you have the table and saddle apart, you need to go through your lube system. It looks like that machine was run without proper or probably even any lube running through it.

With those issues in the exposed ways (Barry thinks theyre maybe only 10 thou deep from the look), even though I hate way covers, it might make sense to put some on the machine to protect those grooves. It would suck to get more FOD up in those grooves which then transfer to the bottom saddle way and then shares its horribleness with the rest of your ways.

Jon
H&W Machine Repair

PS - @Randalthor, thanks for the plug!

JRIowa · May 30, 2018

rpseguin said:
The mill is super dirty, but it is in good shape

I really wish you guys wouldn't say that. This isn't in "good" shape at all. If asked to rate, it might be a 3.

As Jon said, it looks like the machine was run without way oil. There is only 1 way to fix the scoring and that's to scrape the ways. If you get cleaned up, you'll need to keep any dirt out of the grooves or it will just make matters worse. I'm guessing that if the ways look like that, the screws are also shot.
JR

rpseguin · May 30, 2018

JRIowa said:
I really wish you guys wouldn't say that. This isn't in "good" shape at all. If asked to rate, it might be a 3.

As Jon said, it looks like the machine was run without way oil. There is only 1 way to fix the scoring and that's to scrape the ways. If you get cleaned up, you'll need to keep any dirt out of the grooves or it will just make matters worse. I'm guessing that if the ways look like that, the screws are also shot.
JR

The ballscrews feel good. I haven’t had time yet to measure or profile backlash in them.
The one shot oiler is definitely producing and oil film on the saddle/Y ways.
I don’t see a need to rescrape the ways, as the grooves are more cosmetic than impacting performance.

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JRIowa · May 30, 2018

rpseguin said:
I don’t see a need to rescrape the ways, as the grooves are more cosmetic than impacting performance.

Wrong on that count! Grooves or score marks and NOT cosmetic. They are a sign of something getting between the way surfaces and dragging. Depending on how deep they are on both surfaces depends on HOW MUCH the performace is affected.

Ball screws have no backlash. None! They almost need to be checked between centers to check radial and axial play. For that they also need to be clean. Are you even certain that they are ball screws?

You need to disconnect each of the lines from the oiler and check them. You should also check the passages in the saddle knee to make sure they are clear.

I've been in this business a long, long time. I know problems when I see them. Now, I'm just a hobbiest, but I still know the difference between good and bad way surfaces.
JR

rpseguin · May 30, 2018

JRIowa said:
Wrong on that count! Grooves or score marks and NOT cosmetic. They are a sign of something getting between the way surfaces and dragging. Depending on how deep they are on both surfaces depends on HOW MUCH the performace is affected.

Ball screws have no backlash. None! They almost need to be checked between centers to check radial and axial play. For that they also need to be clean. Are you even certain that they are ball screws?

You need to disconnect each of the lines from the oiler and check them. You should also check the passages in the saddle knee to make sure they are clear.

I've been in this business a long, long time. I know problems when I see them. Now, I'm just a hobbiest, but I still know the difference between good and bad way surfaces.
JR

Thanks for the oiler suggestions.

It has ballscrews and even ballscrews can have backlash.
I suspect the grooves will make little difference, but I will inspect it when I take it apart.

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Richard King · May 30, 2018

JR asked me to take a look at this and I can say I am a Pro and the machine is a 2 and not a 3.
It appears to be a rebuild or a bad build to me. In all the machines I have seen over the years the edges where it is chromed they are beveled, as chrome builds up on sharp edges. No bevel mean not professionally rebuilt or built or no chrome. That machines edges on the flat ways are not beveled. The flaking does not look original. The control does not look like it is original. I have never heard of a control made in California when the machine was made in Bridgeport or Elmira. It may have been rebuilt by a Defense Depot as it looks like you picked it up at one, or rebuilt at Mare Island Shipyard.... Those machines many times were rebuilt by self taught repairmen.

As JR says, those ways will get worse even after they are stoned. Another thing that seems odd is the table looks like it's a 50" er. I would dismantle the machine completely look at the bottom of the saddle ways. Inspect the ball screws. The head belts are surely shot and it looks like it has been sitting in the desert at the Defense Depot in Stockton. If that's the case all the head bearings are shot. Take some pictures of it apart so we don't have to guess. JR is more then a hobbyist and he is honest and knows his stuff. I would take head in anything he says! Rich

rpseguin · May 30, 2018

Richard King said:
JR asked me to take a look at this and I can say I am a Pro and the machine is a 2 and not a 3.
It appears to be a rebuild or a bad build to me. In all the machines I have seen over the years the edges where it is chromed they are beveled, as chrome builds up on sharp edges. No bevel mean not professionally rebuilt or built or no chrome. That machines edges on the flat ways are not beveled. The flaking does not look original. The control does not look like it is original. I have never heard of a control made in California when the machine was made in Bridgeport or Elmira. It may have been rebuilt by a Defense Depot as it looks like you picked it up at one, or rebuilt at Mare Island Shipyard.... Those machines many times were rebuilt by self taught repairmen.

As JR says, those ways will get worse even after they are stoned. Another thing that seems odd is the table looks like it's a 50" er. I would dismantle the machine completely look at the bottom of the saddle ways. Inspect the ball screws. The head belts are surely shot and it looks like it has been sitting in the desert at the Defense Depot in Stockton. If that's the case all the head bearings are shot. Take some pictures of it apart so we don't have to guess. JR is more then a hobbyist and he is honest and knows his stuff. I would take head in anything he says! Rich

Thanks for the input!

Just to be clear, I’m not doubting anybody’s honesty or experience here and my comments and questions shouldn’t be taken as such...

The head is actually quite quiet compared to many of the other heads I’ve heard.
I am 99.9% sure the control and ballscrews, ... are a retrofit, as that is what the Proto Traks are.
I have it on pretty good authority that this machine has been in an engineers shop at home doing prototype work for quite a long time.
The control seems to work fine for the canned cycles I’ve tried, but it is pretty old so the user interface is somewhat clunky due to my lack of familiarity with that type of control.
In between work and kids, I’ve run a couple of quick tests with a good dial test indicator and it looks pretty good so far.
I don’t know the pedigree or heritage of the ways or full history of the machine, but I’ve been told it was in an engineer’s shop at home for 20+ years.
The serial number stamped on the knee says 12/BR 104129
I’m curious as to what year it was made.
I’ll take a picture of the serial number on the head.

I’m not planning on taking apart the head as it sounds really good and runs true.

I’m going to run some more experiments and machine some parts and look at finishes and tolerances before I commit to taking apart the saddle.

Thanks again!
-Ralph

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rpseguin · May 30, 2018

rpseguin said:
Thanks for the input!

Just to be clear, I’m not doubting anybody’s honesty or experience here and my comments and questions shouldn’t be taken as such...

The head is actually quite quiet compared to many of the other heads I’ve heard.
I am 99.9% sure the control and ballscrews, ... are a retrofit, as that is what the Proto Traks are.
I have it on pretty good authority that this machine has been in an engineers shop at home doing prototype work for quite a long time.
The control seems to work fine for the canned cycles I’ve tried, but it is pretty old so the user interface is somewhat clunky due to my lack of familiarity with that type of control.
In between work and kids, I’ve run a couple of quick tests with a good dial test indicator and it looks pretty good so far.
I don’t know the pedigree or heritage of the ways or full history of the machine, but I’ve been told it was in an engineer’s shop at home for 20+ years.
The serial number stamped on the knee says 12/BR 104129
I’m curious as to what year it was made.
I’ll take a picture of the serial number on the head.

I’m not planning on taking apart the head as it sounds really good and runs true.

I’m going to run some more experiments and machine some parts and look at finishes and tolerances before I commit to taking apart the saddle.

Thanks again!
-Ralph

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So, according to Internet lore, serial number 104129 was made in 1967 and the 12/BR indicates a 12 inch table.

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Ziggy2 · May 31, 2018

That Bridgeport has a Southwest ProTrak conversion kit on it. It also might have actually been converted by Southwest, so in some ways it sort of is a Frankenstein.

It should have ground ballscrews on X and Y. It should not have Chromed ways as Richard said but it might have Turcite on the ways if Southwest did the conversion.

This would be consistent withe the visible surface scoring with no way oil and contaminated Turcite being run for a long time.

The control console is old enough that it is no longer supported as far as repairs go. When it quits, you will have to upgrade to a newer version.

You need to take the advice that Richard and JR have told you. You are also going to decide how much you are willing to spend to get it back to a somewhat usable condition. Considering the amount of way scoring, the ball screws are likely severely worn.

Assuming the control does work, you will have a very difficult time trying to mill an arc or a circle and have it actually be round and not elliptical. The control does use glass scales which helps but any backlash in the ball screws will be reflected in a sudden divot appearing in the contour. Any backlash greater than .0001-.0002 will be unacceptable unless you just settle for straight line milling unless a bumpy surface finish is acceptable to you.

The machine is probably repairable but it will take effort in labor and dollars.

rpseguin · May 31, 2018

Ziggy2 said:
That Bridgeport has a Southwest ProTrak conversion kit on it. It also might have actually been converted by Southwest, so in some ways it sort of is a Frankenstein.

It should have ground ballscrews on X and Y. It should not have Chromed ways as Richard said but it might have Turcite on the ways if Southwest did the conversion.

This would be consistent withe the visible surface scoring with no way oil and contaminated Turcite being run for a long time.

The control console is old enough that it is no longer supported as far as repairs go. When it quits, you will have to upgrade to a newer version.

You need to take the advice that Richard and JR have told you. You are also going to decide how much you are willing to spend to get it back to a somewhat usable condition. Considering the amount of way scoring, the ball screws are likely severely worn.

Assuming the control does work, you will have a very difficult time trying to mill an arc or a circle and have it actually be round and not elliptical. The control does use glass scales which helps but any backlash in the ball screws will be reflected in a sudden divot appearing in the contour. Any backlash greater than .0001-.0002 will be unacceptable unless you just settle for straight line milling unless a bumpy surface finish is acceptable to you.

The machine is probably repairable but it will take effort in labor and dollars.

Thanks!
It does have ground ballscrews.
It is using TravADial style encoders not glass scales and I think there are also encoders on the servo motors.
The head actually runs very quiet and indicates true. The control works, but it is definitely old.
Some quick tests of the canned cycles seem good, but that is unloaded, no cutting forces at play, so we’ll see what it looks like when actually cutting.

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Ziggy2 · May 31, 2018

rpseguin said:
Thanks!
It does have ground ballscrews.
It is using TravADial style encoders not glass scales and I think there are also encoders on the servo motors.
The head actually runs very quiet and indicates true. The control works, but it is definitely old.
Some quick tests of the canned cycles seem good, but that is unloaded, no cutting forces at play, so we’ll see what it looks like when actually cutting.

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If it is using encoders on the motors, then the ballscrew condition will be crucial for proper positioning.

TravaDial is okay until it slips but the problem is you probably won't know it.

rpseguin · May 31, 2018

Ziggy2 said:
If it is using encoders on the motors, then the ballscrew condition will be crucial for proper positioning.

TravaDial is okay until it slips but the problem is you probably won't know it.

Thanks!
Yeah.
I actually really like TravADials for manual machining, so I was kind of surprised when I saw them on a CNC. I suspect they are probably being used strictly for the DRO aspect of the control and not actually closing the servo loop.

rpseguin · May 31, 2018

Ziggy2 said:
That Bridgeport has a Southwest ProTrak conversion kit on it. It also might have actually been converted by Southwest, so in some ways it sort of is a Frankenstein.

So, according to the stamping on the knee, it should be a 12" table, but I measured it as a 9"x48" table, so at some point the table got swapped. Maybe during the conversion.

The 2HP variable speed head has a serial # 274834 stamped on it, but I know that heads get swapped on mills all the time.

rpseguin · May 31, 2018

Richard King said:
JR asked me to take a look at this and I can say I am a Pro and the machine is a 2 and not a 3.

Well, that's a bummer to hear!

Richard King said:
It appears to be a rebuild or a bad build to me. In all the machines I have seen over the years the edges where it is chromed they are beveled, as chrome builds up on sharp edges. No bevel mean not professionally rebuilt or built or no chrome. That machines edges on the flat ways are not beveled. The flaking does not look original. The control does not look like it is original.

I looked at it and I don't see any beveling on the saddle.
It may not be chrome ways.

Richard King said:
As JR says, those ways will get worse even after they are stoned. Another thing that seems odd is the table looks like it's a 50" er. I would dismantle the machine completely look at the bottom of the saddle ways. Inspect the ball screws.

The table is a 9"x48", even though the mill serial number stamping indicates that it was built in 1967 with a 12" table.

Richard King said:
JR is more then a hobbyist and he is honest and knows his stuff. I would take head in anything he says! Rich

I am definitely heeding what he and you and others have to say.
I still want to try machining a few parts and see what the finishes come out like and whether circles are circles and tolerances are maintained or not.
If it works fine, great, but if not, then I guess I'll have to bite the bullet and disassemble it.

I guess I'm just hoping for a usable machine and/or not too much work to get it to that state.
I don't have the money or time to go on a wild goose chase with replacing parts.

Thanks.
-Ralph

rons · May 31, 2018

You probably meant 42" table.

Go to a few auctions. I have been getting those mailings from Ashman Company for years. You can get on their mailing list or look at their schedule. When you see what is out there you might appreciate what you have.

Bridgeport Series 1 Refurb Project

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