Why are some machine surfaces left unpainted?

[Junkmaster]

Hello All,

There are surfaces on the machine that were not painted when I purchased the machine. The surfaces were machined as part of the manufacturing process. For example the front of the knee where the Y drive handle is located. There is a large area of bare metal that I'm wondering if I could/should paint.

I can think of three reasons not to paint an area. First, if the surface needs to be used as a reference. You couldn't count on the paint be a uniform thickness. Second, if the area was used to hold or clamp something, the paint would be crushed by the clamping pressure and would chip off. Finally, the coolants/oils will lift the paint from the surface.

I am not concerned about the look or cosmetic aspects, I just want to prevent corrosion.

Evan R.

 

[Hawkeye]

Evan,

Two things would help to get you an answer. You don't say what the machine is - apparently a Van Norman or Cinci, but what model?

A picture is going to do more than anything else to get you the answer you need.

 

[Junkmaster]

Fair request. It is a Van Norman 12. The attached picture has some red arrows pointing to the areas that were unpainted when I purchased the machine.



On other images I've seen of different milling machines these areas are not painted. I am **guessing** It has something to do with the oils and coolants lifting the paint.

 

[Shopsweeper]

Junkmaster,

My dad I just talked about this. I am looking at a VN12 tomorrow and taking my dad who is a retired mechanist is going along. When I showed dad the pics of the mill for sale he commented about the table being painted (it looks to have at least 5 coats of Navy gray on the sides of the table).

Dad said that if I bought the mill, he would scape all of that paint off for me first thing (generous offer, I know). He said that he never liked painted tables due to oil/coolant flooding over the tables sides and "pulling" the paint away. He says painted sides always breakdown in time.

By the way, I liked your "Gib Scrub" tip. I stole a similar idea from the vintage machinery "A Basic Machinery Restoration Guide" and chucked up a large scotchbrite pad in an old 1/2hp 1ph motor.

Also, I learned a lot from your "Should I use Anti-seize.." tread.

Hopefully I will have a 12 of my own this time next week.

 

[Cal Haines]

Hello All,

There are surfaces on the machine that were not painted when I purchased the machine. The surfaces were machined as part of the manufacturing process. For example the front of the knee where the Y drive handle is located. There is a large area of bare metal that I'm wondering if I could/should paint. ...

On the machines of that vintage that I've worked on, machined surfaces are usually left unpainted. Typically only the unmachined cast iron is painted. Some of it is probably due to function, some is just how it was done back in the day.

If you wipe the machined surfaces down with way oil from time to time you should have no problem with rust.

Cal

 

[Kevin45]

Most of the surfaces that you see on the above picture that are not painted is because these parts were machined. To paint them they would have to go back and rough them up to hold paint.

I worked at Rockwell in the Power Tool Division back in the late 70's early 80's and would work in the paintroom if they needed a painter. The only parts that were painted were the cast parts. They would be sent around on conveyors, through a washing station, then down through a dryer then through the paint booths to be sprayed.

About the only smooth parts that would be painted were sheetmetal parts. But as far as the machined part, they were unless it was something real special, then portions of it would have to be masked off. Cheaper and quicker just not to paint it. Back at that time, it was pretty amazing at the amount of any one part that got painted per shift.