Help with Bridgeport Mill Restoration - Newbie

Hello all,

My name is Nick. I am a degreed mechanical engineer working in manufacturing QC. I am mechanically inclined, but have little hands on experience with machining. I did some machine work in college and loved it, but haven't gotten my hands dirty since. My grandfather and uncle were master machinists and ran their own shop for many years. After my grandfather sold the business, he put some machines in storage (not climate controlled), where they stayed for many years. I think my uncle always wanted to get them running again, but as he aged he realized it wasn't going to happen, so he bestowed his Bridgeport mill to me.

I finally got it moved into its resting place in my garage last weekend. It is currently in 4 pieces: Column+knee, ram, head, and table. It has some surface rust, and the paint is flaking off in many placed, but it appears as if the moving parts are still free to move (the knee and table, at least).

I am interested in restoring it, but not necessary to factory perfection. I would like it to work (of course), and be reasonably accurate for home and hobby use.

I can get the specs of the machine when I get home, as he was able to provide a bunch of documentation in addition to the plates on the machine. I will get some photos as well.

All in all, my question is: where do I start? Its a daunting looking task which I have no experience with. I was thinking that removal of rust would be first to see what I am dealing with. Any guidance out there for a complete newbie? Any and all advice is greatly appreciated. Thank you!

Nick

Buy some light oil, like WD-40 or something and a spray bottle and just hose down the rusted areas. Maybe use some scotchbrite to remove it if it's bad. Then oil it up and put it to work.

You won't know what you have until you can use it. You'll probably need a phase converter or VFD or something.

As JR always points out, don't buy a BP instruction manual, it's available for free from the manufacturer:

http://www.kneemills.com/index.asp?html=Documentation

Also for figuring out what you have:

http://www.lathes.co.uk/bridgeport/page8.html


If any repair is necessary, I found this to be a good 'shop manual'

Bridgeport Mill Rebuild Manuals for J Head and 2J Head - Buy Both and Save $

Lot's of YouTube video's some good, some not so good. You should be able to tell.

John

Thank you for the replies! I actually do have phase converters that my uncle had, but I need to run a 240v outlet in the garage.

So, rust removal is really first order of business. As soon as all this hurricane business passes by I can get started on that.

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You will need a hoist of some sort to get the ram on the column. The head is pretty heavy and needs lifting help too. The table can be set on a rolling cart and moved into position. That's if you just want to remove the surface rust and put it together. But consider this.

You have the opportunity to inspect/replace a bunch of things. Paint all the pieces is an option. You might get more opinions if there are pictures.

Yeah, we had a hoist to move it. I will have to borrow rent one again.

Pictures:

Apart from the rust she looks pretty good. I would definitely want to remove the surface rust from the sliding surfaces before reassembly. I'd use way oil and probably scotch brite but do a little research. As for painting wher its still intact it looks like a light degrease then keying the surface is all you need.

Good luck with the hurricane if there nothing more important to do, coating all of the sliding surfaces with oil wouldn't be a bad thing to protect them from further damage

Tray said:

Apart from the rust she looks pretty good. I would definitely want to remove the surface rust from the sliding surfaces before reassembly. I'd use way oil and probably scotch brite but do a little research. As for painting wher its still intact it looks like a light degrease then keying the surface is all you need.

Good luck with the hurricane if there nothing more important to do, coating all of the sliding surfaces with oil wouldn't be a bad thing to protect them from further damage

Click to expand...

Can you define "keying" the painted surfaces?

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Fair bit of rust there; I don't think it will render the machine unusable by any means, but it will take a good bit of elbow grease. Others have suggested scotch brite; I like to use steel wool if I can, but the amount of rust you have may encourage moving more quickly to scotch brite. Regardless, make sure you clean ALL the abrasive, of whatever type, before assembly.

I didn't see in the pictures whether you had a Bijur type oiler or oiling zerks. In either case, while it is apart, this is the time to make sure all of your oil delivery system is working correctly.

Hugely helpful resource: H&W Machine Repair, H&W Machine Repair & Rebuilding - Parts and Service for the Metalworking Industry - they have all the parts, but more importantly they have enormous expertise which they are willing to share. I cannot recommend them highly enough - they do business the right way. 'Nuff said.

On edit: Personally, I wouldn't bother with repainting at this point; I'd just clean it up and start using it. If you do decide to paint, I'm thinking that "keying it" means putting some tooth on the existing paint (e.g., using coarse sand paper) so that new paint will adhere better. Don't rely on that, though - I may be misunderstanding what Tray has in mind.

And as others have said - stay safe in the storm!

nstiesi said:

Can you define "keying" the painted surfaces?

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Click to expand...

Means to rough the surface for new paint adhesion.

Some housewives would kill to get a stressed paint finish like that on their kitchen cabinets.

If you remove rust from a painted surface the metal will eventually rust over again. Unless you coat it again. Hard to say what is best for you not knowing what paint experience you have. You can think about the painting idea while you are removing the rust.

Looks like no oiler as you have zerks all around. Note that these are NOT for grease!!! Way oil only!!! Lot's of discussion on this board about a suitable oil gun to use on the zerks. Or you may want to upgrade to the one shot oiler system.

Kay Fisher has a talk through here on putting an oiler on a BP M head. You can check out his refinishing technique also:

http://www.neme-s.org/shapers/bridgeport.html

John

I recommend you start by reading this thread:

Then buy this book:
"Guide to Renovating the Bridgeport Milling Machine Series I"

The rust you see appears to be superficial and will likely come off easily. I recently cleaned the table of my mill which looked similar. The rust typically comes right off with WD-40 and a green scotch brite pad. Resist the temptation to use sand paper or anything with a cord on it as you can damage precision surfaces (and create abrasive dust). When cleaning flaked surfaces, you need something soft like a scotch brite pad or steel wool.

A Harbor Freight buffer/polisher is a good investment for the hand wheels, cranks, dials etc. I used scotch brite pads like Brad recommended in the thread linked above (tho I didn't get quite the finish he did). Its pretty rewarding to polish up the controls.

I followed Brad Jacobs process: I soaked everything I could in Purple power to clean and degrease. Rusty stuff went into Evaporust. I polished the bare parts, painted the castings and reblackened the hardware with cold bluing. Purple power will remove paint if you leave it soak long enough. I did very little sanding of painted surfaces.

Painting is a pretty big deal. Good industrial paint isn't cheap. I paid $100 for a gallon (min qty) and used a tiny fraction of that. Cleaning, masking, and spraying are time consuming. I used a HF spray gun, which I never quite got the hang of. The filler used on the casting is a pain to deal with. I patched with bondo, sanded and filled and sanded and filled. You can really get wrapped around the axle painting these things, but they are pretty when they are done.

As to where to start, I think, given the condition that mill appears to be in, you should at least disassemble, clean, derust, and reassemble. You do this one component at a time: Take the motor off. Take the head off, then the ram. Take off the table, then the saddle, then the knee. Then remove the turret and you should have essentially a bare column. You should be able to tip it and move it around, vacuum it out etc. I used a HF engine crane to remove the knee, ram and table. Everything else I manhandled. If you are going to install feet or casters, now is the time to engineer that. Rebuild each of the components above separately is my advice.


I am not finished my mill yet. This is where I am so far.

Here is my table. It looked just like yours. I just ran it under a tenths indicator. It was within .0025" of flatness despite the rust and my scrubbing.

Thank you all for the great advice! I'm reading and re-reading and digesting it all.

I'm all shuttered and secured for this storm now, so I'm on hold for now. Thanks all!

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Yes keying is simply abrading existing paint with e.g. ISO 300 grade abrasive to help the new paint adhere. On rusted surfaces that are meant to have paint there are products that are formulated to go straight over grease free rust.

Luckily the hurricane looks to miss us here on the east coast....best of luck to the west side!

As I sit around and wait this out I begin to wonder: should I remove the saddle and knee to clean the rust off the ways without getting any abrasive or rust stuck between the machine surfaces?

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I FINALLY got a chance to start working on this beast tonight. The hurricane spared us, so big win there. Last weekend I got the garage cleaned up a bit so I could start working.

I did end up removing the saddle...it was not nearly as hard as I thought it would be. In a perfect world I would remove the knee, but the knee ways look really good, so since I don't have means to lift it off, it stays. With the saddle off I have plenty of access for a good cleaning inside.

I removed the saddle, a bunch of handles, and other bits, and the saddle lead screw. Everything got a healthy dose of wd40. I'm gonna let it soak and then get to scotch brite-ing.

When I'm done with rust removal, I should clean off the oil with a degreaser? Something else?

Also, I have read a ton that ways are to be oiled, not greased. What about lead screws and nuts? In this machine they were heavily greased.

Thanks!

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I used to love fixing up old machines, after working for a machinerey dealer for a few years and fixing up hundreds of them I am pretty much over it. Get some evaporust it will help clean the ways I would also paint it you will like it more. Once you get it all done you will really love it but you will probably never want to do it again. Do a good job so that all the pain and work is worth it in the end.

NO GREASE!! There is a set screw in the center of the table you pull to oil the screws/nuts. Front of the table/saddle to the left has marks to line up so you can lube screws/nuts.

Excellent. I'll use this opportunity to clean off all that grease and start relatively fresh.

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