How To Remove Rust Without Removing Original Scrapings

[Susan_in_SF]

Hi guys,
As many of you know, I wasn't planning on buying a Bridgeport mill, but then I recently stumbled across a super deal on one. This 2J Bridgeport had been used for years at a San Jose vocational school before it ended up with the private high school that I bought the mill from. The private high school in Santa Rosa had the mill sit in an unused workshop for a year before the facilities manager was told that the students wanted to work on "new" CNC machines, and not on the old big dirty Bridgeport. To that, I still have to say, "WTF?!"

I shared the mill's history since it will explain the situation that I need help with. Also, fyi, I did try google for answers before having to turn to you wonderful guys

Basically, the mill is dirty and has rust on the table. It had been checked out by two separate machinists, and I was told the only thing it needed was to grease the table's leadscrews.

I will post various pics of the table below at different angles and with/without flash to show, what looks like, the original factory scrapings. For comparison, I will also post a pic of the ways behind the milling table that really show how the scrapings originally looked like. Btw, sorry if the pics aren't great - my cell phone camera kinda sucks.

So, in a nutshell, I'd like to know if it is possible to remove the rust without removing the scraping remnants on the milling table. Also, please tell me if I am being silly or not in wanting to preserve the scrapings.

Table





Rear ways


Front ways


The table seems unusual by that it looks like some inattentive students milled or drilled into the table a couple of times, and it looks like they dropped stuff onto the table quite a bit, yet, there are still scraping marks present. I plan on using metal filler to repair the holes/indentions, as instructed in the recent book I bought, "A Guide to Renovating the Bridgeport "2J" Variable Speed Milling Machine."

Also, I looked up the serial number. Apparently, this $450 mill was built in 1976.

Btw, I have tried Evaporust before on tools. I just don't like how it can turn the metal black. So, could I get away with using a scotch brite pad and WD-40 instead?

I will post a pic of the entire Bridgeport inside my 1 car garage later. My friend Mike, who owns a machinery transportation company, had tilted the head before using his forklift to put the mill in my garage. The head is still tilted. After I straighten the head later today, I will take some full body shots - for those of you who appreciate machine porn ;-)

Thanks in advance for your friendly replies

Susan

 

[Ecosta777]

Scotch Brite and oil or WD-40 will work. You want to retain the scraping marks since they help hold oil in the table / ways to help prevent rust. Since the scraping marks are not just 'surface scratches' (like an engine turned finish for example) the scotch brite wont remove them.

 

[4ssss]

That looks more like a build up of grease and oil rather than rust

 

[Firstgear]

get some Evaporust, I believe they make it in a gel as well.....works great. After letting it sit over night, use water to clean it up. Safe on skin.....works well. I am going through my taps that I bought, used, and some have rust spots on them, I put them in that overnight and then washed off the next day does a good job. Get rid of the grease and muck and if you still have rust, try this stuff. The gel stuff is what you would want, I think some people get the best results by putting on the gel and then covering with saran wrap......do some reading and you will find the best approach.

 

[Bob Korves]

First, that is not scraping, it is flaking. You can tell by the deeper half moon marks. The mating surfaces are ground at the factory, and that would leave metal flat against metal, which causes stick slip and also causes galling and wear. So they flaked the surfaces. Flaking also looks nice, which is an important sale factor. In the case of the table, flaking is done ONLY to make it look nice. The table is not a way, it is a mounting surface. Flaking is much deeper than scraping, though it does still wear away with time and use. I agree with the idea of Scotchbrite and a lubricant to clean up the table. Don't get carried away with rubbing it, the areas between the flaking are the original table surfaces, less whatever wear has occurred since new. You do not want to add to the existing wear. Scotchbrite has grit in it, so make sure not to get it into other parts of the mill while working on the surface you are cleaning, so clean everything carefully after using the Scotchbrite. Scotchbrite also comes in different colors, which have coarser and finer grit. I would recommend light gray. If all you have is maroon, then go easier with it, it is more aggressive. Flaking is ideally added to the UPPER surfaces facing down, so they can hold oil for lubrication. Flat metal on flat metal does not allow that. Putting flaking on the bottom surfaces, facing upward, is strictly for making it pretty, and it causes swarf and grit to accumulate in the pockets, causing ongoing wear. "Monkey likes shiny." So keep those pockets cleaned out. Actually, do whatever you want with it, Susan, it is your machine, not ours...

 

[benmychree]

Instead of Scotchbrite, you might try a medium grade of steel wool and wd40 or solvent, like paint thinner, especially on gummy oil/rust.

 

[Cadillac]

Looks like a good one. You could also use a aerosol cleaner like a degreaser of sort. Spray her down and go at it. I wouldn’t use any abrasives more than a fine steel wool. The paint might not be that bad under all that goop and you don’t want to make worse if you don’t have to. I can tell you plain white vinegar will take the rust off and not effect the unlying surface.
The table doesn’t look to bruised I’ve seen some look like Swiss cheese. One or two little oopses can be fixed with some epoxy and cast iron chips or just jbweld if u wanted.
From the picture it looked like your knee has chromed ways and from the pic the end closest to operator the flaking was almost gone. Closest to the base you can see good flaking. Shows where they worked a lot.
Clean her up you be able to see a lot more about the condition. Does it have a Oiler. Happy cleaning

 

[benmychree]

Another good cleaning product is Oil Eater, it's 409 on steroids; it softens paint, but when it evaporates, the paint re hardens, I use it full strength.

 

[EricV]

Nice find! An old gunsmith trick for dealing with rust w/o damaging bluing or other finishes is to coat it with white petroleum jelly, (A.K.A. Vaseline), and let it sit for a day or two. The petroleum jelly softens the rust and allows it to be cleaned off w/o hard tools. Typically I will use a soft brush on a firearm when applying a second coat to work it a bit, if necessary, but you could get slightly more aggressive on the mill. As others have said, it's the table, not the way. Not as much concern, except for your desire on the finish/appeal.

Good luck!

 

[danny12]

Purple power will take rust off. I like the zep brand concentrated I mix it a little hot.