How often should a bridgeport be torn down and cleaned?

SirRage · Apr 18, 2017

I'm in the process of fixing my J head 1961 Bridgeport and I started wondering how often one would tear down a Bridgeport like this to clean it?

The knee gib is broken, so I'm removing the table and saddle to reduce weight and stress on the knee. As I'm tearing it apart the old oil on the gibs and ways resembles the consistency of honey than oil. And chips everywhere, I mean everywhere. Not to mention it looks like some chips are stuck to the ways and other bearing surfaces.

I'm going though a lot of WD40 and elbow grease as I'm tearing it down.

I will say though, the saddle had an odd section where there was almost no wear and everywhere around it was worn down enough that I could catch it with my nail. When I have it cleaned up enough I'll start inspecting parts on the surface plate to see how warn things are.

SirRage · Apr 18, 2017

Also, would a 24x36x4" grade B plate be good enough for inspecting tolerances of the saddle? Or is the saddle too heavy for a 4" surface plate? My grade A plate (18x12) is just big enough for the saddle but too small for the knee.

JRIowa · Apr 19, 2017

You can't be serious! Never!

If you have worked in industry, you would know that you can't make money cleaning machines all the time. BPs are disposable like a lot of other machines. In a job shop, they are replaced and sold on CL. In the job shops I've worked in, when a BP was 10 years old, it was junk and replaced. In the factories that I've worked in, the only machines that were rebuilt were those that couldn't be replaced or that cost over 300K new. Everything else was run until it quit.

In a home shop, a BP should last you for a long time. My mill is almost 30 years old. But, I take care of it. Oil the head, pump the one shot, and don't use air to clean. About the only thing that I've taken apart to clean is the damn trip mechanism for the quill feed.

While a lot of you home shop guys are worried about how your machine works, I'm making chips.

As far as "inspecting" BP parts, maybe John F or Richard King will weigh in as to what they use. I'm sure it's larger than what you state. Also, what about a granite "knee" to check squareness?
JR

rons · Apr 19, 2017

If you read posts in this section, often there is a new owner who can't wait to take the mill apart and clean it, then paint. Then when they put it together they wonder about the strange noises the mill makes. My advise is to clean the mill and fix only what needs fixing. Then use it for a while.

Some repaint jobs make the mill worse off than if nothing was done.

BTW, WD40 is only good for lawn tools. WD40 is :icon_bs:

DMF_TomB · Apr 19, 2017

old maintenance piece of advice
.
if it aint broke dont fix it
.
preventative maintenance normally is just replace way wipers and digital readout chip scraper/wipers

Maschine · Apr 19, 2017

I just bought my first - and possibly last - Bridgeport in my lifetime. I removed the ram, head, table, saddle and knee and cleaned everything up. It had 50 years of chips trapped in every nook and cranny. And plenty of chips were trapped and deeply embedded between the wearing surfaces, steadily grinding away at the chromed and non-chrome ways every time the table or knee was moved. I also verified the full functioning of the Bijur oiling system. Turned out one of the knee ports was plugged, so I cleaned it out and now I know everything is being lubricated perfectly. I wouldn't have known that if I hadn't broken it down to check.

I also cleaned and lubricated all leadscrews and their trapezoidal nuts, including the 90 deg gearbox for the Z axis inside the knee. I also inspected everything to see what I was dealing with for future rework or refurbishing options. The ram and head tilt gear were very sticky and had rust on the ways and gears. I happily cleaned it all up and oiled it, so that now it moves back and forth like glass. It was an easy and pretty quick job too, it didn't take that long.

I also replaced all of the felt wipers with upgraded new ones that spanned the entire length of the Y table slide. These really keep chips out. I also plan on putting the rubber bellows guards on them to further keep chips out. And also, I never clean the mill with compressed air. Instead, I have a wall mounted shop vac nearby that is used to keep the machine chip free.

I didn't paint the machine as I thought that was a lot of work for no real value added in return.

Also, since I've never owned a Bridgeport or been into one before, the whole process was a terrific learning experience. I just took my time, and took it step by step. It's not rocket science and it was great to learn how the machine is put together. I also learned how to inspect any other machine I might buy in the future. It's the best way to learn about what makes a Bridgeport tick.

So heck yeah, I was very glad to have broken it down and cleaned it up. I don't care what the big shot "pros" say. Go ahead and grind your machine down to dirt "making money." Although I understand in a commercial setting, the machines are consumable. But on the other hand, I can assure you taking 3/4 of one day to break the machine down and clean it once every coupla years would definitely make it last a lot longer. My machine is my hobby machine and I want it to last my lifetime if need be. Cleaning it the way I did will certainly help me accomplish that goal.

comstockfriend · Apr 19, 2017

My BP had been greased by the PO so the table and saddle came off to get the grease out. With the knee gib out, I could clear the grease in it. Went back together, still with the original paint and I've done nothing since but oil it and run it. (Did replace the saddle way wipers when it was apart, and adjusted the feed nuts.)

I don't have a one shot lube on it, I should have added a line for the feed nuts. The oil hole is always under the vise...

John

plastikdreams · Apr 19, 2017

Maschine said:
I just bought my first - and possibly last - Bridgeport in my lifetime. I removed the ram, head, table, saddle and knee and cleaned everything up. It had 50 years of chips trapped in every nook and cranny. And plenty of chips were trapped and deeply embedded between the wearing surfaces, steadily grinding away at the chromed and non-chrome ways every time the table or knee was moved. I also verified the full functioning of the Bijur oiling system. Turned out one of the knee ports was plugged, so I cleaned it out and now I know everything is being lubricated perfectly. I wouldn't have known that if I hadn't broken it down to check.

I also cleaned and lubricated all leadscrews and their trapezoidal nuts, including the 90 deg gearbox for the Z axis inside the knee. I also inspected everything to see what I was dealing with for future rework or refurbishing options. The ram and head tilt gear were very sticky and had rust on the ways and gears. I happily cleaned it all up and oiled it, so that now it moves back and forth like glass. It was an easy and pretty quick job too, it didn't take that long.

I also replaced all of the felt wipers with upgraded new ones that spanned the entire length of the Y table slide. These really keep chips out. I also plan on putting the rubber bellows guards on them to further keep chips out. And also, I never clean the mill with compressed air. Instead, I have a wall mounted shop vac nearby that is used to keep the machine chip free.

I didn't paint the machine as I thought that was a lot of work for no real value added in return.

Also, since I've never owned a Bridgeport or been into one before, the whole process was a terrific learning experience. I just took my time, and took it step by step. It's not rocket science and it was great to learn how the machine is put together. I also learned how to inspect any other machine I might buy in the future. It's the best way to learn about what makes a Bridgeport tick.

So heck yeah, I was very glad to have broken it down and cleaned it up. I don't care what the big shot "pros" say. Go ahead and grind your machine down to dirt "making money." Although I understand in a commercial setting, the machines are consumable. But on the other hand, I can assure you taking 3/4 of one day to break the machine down and clean it once every coupla years would definitely make it last a lot longer. My machine is my hobby machine and I want it to last my lifetime if need be. Cleaning it the way I did will certainly help me accomplish that goal.

Purchasing a new or better taken care of machine would have prevented you from spending time that you will never get back...Twice. once for tearing down a ragged out mill and the other for writing about it.

The only time a Bridgeport should come apart is when something needs to be replaced.

lucky7 · Apr 19, 2017

From what I've seen, machines, including turret mills, get maintainence by small job shops during recessions when there's not much else to do. The smart shops are then ready to go having done a tiny capital outlay when business picks up again. Last big slow down locally was 1999-2000 so lots of machines are ready for maintanence or the scrapper now... My experience is with small job shops, not the JRIowa sized behemoths. Totally understand the big boys could care less about maintanence of small machinery.

Anecdotally, couldn't believe how busy the mom and pop smaller steel service center was last week. They said busiest in twenty years.

Lucky7

ewlsey · Apr 19, 2017

I usually tell people to tear them down after every use. But, if you're willing to risk it, you could push it to once a week.

Since it takes a week to tear it down and put it back together, you pretty much have to start the next tear down as soon as the finish the last one. This is also a perfect way to prevent wear.

Maschine · Apr 20, 2017

plastikdreams said:
Purchasing a new or better taken care of machine would have prevented you from spending time that you will never get back...Twice. once for tearing down a ragged out mill and the other for writing about it. The only time a Bridgeport should come apart is when something needs to be replaced.

Really? Well lets see: a new Bridgeport delivered with the features and extras mine has is about $25K. I got mine for about $4K delivered and it took me about 8 hours to take my machine down, clean it and reassemble. I could do it in half that time now that I've learned how. So, ($25K-$4K)/8hrs = $2625/hr or $5250/hr after the learning curve. I'd say that's "worth my time." What's the billable rate at your shop again?

And since all of this exceeds your attention span, here's something a little suitable for your intellect:

plastikdreams · Apr 20, 2017

Maschine said:
Really? Well lets see: a new Bridgeport delivered with the features and extras mine has is about $25K. I got mine for about $4K delivered and it took me about 8 hours to take my machine down, clean it and reassemble. I could do it in half that time now that I've learned how. So, ($25K-$4K)/8hrs = $2625/hr or $5250/hr after the learning curve. I'd say that's "worth my time." What's the billable rate at your shop again?

And since all of this exceeds your attention span, here's something a little suitable for your intellect:

im actually more into spongebob squarepants, never liked barney.

as for billable rate...i make fixtures and prototypes for tantilum trabecular metal implants so its probably pretty high

Yan Wo · Apr 20, 2017

Maschine said:
[great explanation of his initial maintenance deleted]

Well said! You, sir, are a man after my own heart. I have never understood the "if it ain't broke, don't fix it" philosophy. Your experience is a great example of why it's best to fix it before it breaks!

Thanks,

Jon

rons · Apr 20, 2017

I read two different philosophies here.

How often to tear down the machine and go over everything. As in scheduled maintenance.
Initial inspection and tear down of machine right after purchase to make everything sanitary.

Maintenance:

main·te·nance
ˈmānt(ə)nəns,ˈmān(t)nəns/
noun
noun: maintenance

1.
the process of maintaining or preserving someone or something, or the state of being maintained.
"crucial conditions for the maintenance of democratic government"
synonyms: preservation, conservation, keeping, prolongation, perpetuation, carrying on, continuation, continuance
"the maintenance of peace"

I see maintenance as oiling, cleaning, slight adjustments, to avoid the need to tear down.

Monarchist · Apr 20, 2017

ewlsey said:
I usually tell people to tear them down after every use. But, if you're willing to risk it, you could push it to once a week.

Since it takes a week to tear it down and put it back together, you pretty much have to start the next tear down as soon as the finish the last one. This is also a perfect way to prevent wear.

Sound Engineering approach!

But the bean-counter in me sees an efficiency gain if a Bee Pee is torn down but the ONE time, pieces sold-off, and no need of reassembly labour, burden, HVAC, utility share, or other overheads & G&A.

Might even gain money enough to buy something productive for the business.

A milling machine, f'rinstance. CNC and not with obsolete servos or controls, either.

Monarchist · Apr 20, 2017

plastikdreams said:
im actually more into spongebob squarepants, never liked barney.

as for billable rate...i make fixtures and prototypes for tantilum trabecular metal implants so its probably pretty high

Prolly get a nice pay rise when you learn to spell 'tantalum' so as not to scare the s**t out of the customers over use of 'mystery metal' as well.

plastikdreams · Apr 20, 2017

rons said:
I read two different philosophies here.

How often to tear down the machine and go over everything. As in scheduled maintenance.
Initial inspection and tear down of machine right after purchase to make everything sanitary.

Maintenance:

main·te·nance
ˈmānt(ə)nəns,ˈmān(t)nəns/
noun
noun: maintenance

1.
the process of maintaining or preserving someone or something, or the state of being maintained.
"crucial conditions for the maintenance of democratic government"
synonyms: preservation, conservation, keeping, prolongation, perpetuation, carrying on, continuation, continuance
"the maintenance of peace"

I see maintenance as oiling, cleaning, slight adjustments, to avoid the need to tear down.

Yes...Good maintenance avoids the machine falling into the ragged out category like the guy above...If I saw a machine with chips between the ways and other crucial parts I'd walk away at a brisk pace...I guess when it's just a hobby it really doesn't matter though. If you want to take it apart that's fine, don't preach to guys that do this all day every day that we don't know what we are talking about.

Gotta say though I liked the big shot pros comment, the thing is if you are a pro you aren't going to grind the machine down with use, lots of use doesn't mean lots of wear if it is cared for correctly. A true machinist will do just that. That's why both our 20+ year old bridgeports can still hold tolerances less than 1k all day long. Oh and they are CNC retroed and get used all day long cutting 17-4 and haven't been apart since new except for one head rebuild each. Maybe it's time I take mine apart? Lol

Monarchist · Apr 20, 2017

plastikdreams said:
Gotta say though I liked the big shot pros comment, the thing is if you are a pro you aren't going to grind the machine down with use, lots of use doesn't mean lots of wear if it is cared for correctly. A true machinist will do just that. That's why both our 20+ year old bridgeports can still hold tolerances less than 1k all day long. Oh and they are CNC retroed and get used all day long cutting 17-4 and haven't been apart since new except for one head rebuild each. Maybe it's time I take mine apart? Lol

Seen that, too. Not always a 'good thing' though.

Company so uber-careful about cleaning and oiling that iron-bearing SB nines bought 1920's through 1940's were not only still in use 1960 when the first Hardinge was rolled-in ten or twenty years late, they were still in use 1970's. Second Hardinge was never bought, as the new Manager that bought the first one threw up his hands at the staff inertia and farmed the work out to Switzerland instead.

There's an illustrative scene written up in - IIRC - "A Short History of Machine Tools", L.T.C. Rolt, wherein a B&S salesman trying to sell gear-making machinery to a British firm had them proudly show him a hundred-year-old Whitworth still making their gears.

His frustration was that his machines could outproduce the old Whitworth to higher precision and tenfold throughput, further that B&S already had better designs in test that hoped to do enough better yet within a few short years to justify scrapping the present line before it was old or much worn at all.

It was not economically sound to keep old machines too long.

Then or now.

Eventually the makers starve for lack of renewal market, a race to the bottom ensues then migrates off-shore to cheaper-seats, we have fewer viable choices at all, reduced quality, higher costs for what we can get, not lower, and ultimately LESS progress.

Didn't stop with the passing of manual machine tools. We've got CNC dinosaurs all over the map.

plastikdreams · Apr 20, 2017

Monarchist said:
Prolly get a nice pay rise when you learn to spell 'tantalum' so as not to scare the s**t out of the customers over use of 'mystery metal' as well.

Yeah spell check got me lol...Nice raise...Hah that's a long shot.

Monarchist · Apr 20, 2017

plastikdreams said:
Yeah spell check got me lol...Nice raise...Hah that's a long shot.

BEFORE spell-checkers, the VP I worked for and I corrected and re-corrected each other's spelling error in an important proposal - can't even remember the word now -something like seven times.

Finally got right up in each other's college-educated faces and looked it up. We were BOTH wrong! Horrified the proposal had gone out wrong either way.

Our shared HS GED secretary/typist on the IBM Selectric just smiled, pointed to the copy of final already sent-off.

Weary of the 'big dog' level argument, she had already looked it up and made the final correction, properly. And she DID get a raise.

How often should a bridgeport be torn down and cleaned?

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