Unusual bearing seat erosion? VN #12 1952

[GlocaDoc]

1952 VN universal mill #12
I'm new to machining.
New to vintage metals.
Never seen this..
I'm optimistic. But concerned/disappointed.

Uncovered a weird issue with one bearing journal closest to the bronze lead screw bearing.
during a complete tear down of my saddle.
It's eaten away. A cavity. A cancer.

What caused this?

My best semi educated geuss is
A: poor casting. Poor quality control.
Not van Normans style so doubtful.
Out the window with such thoughts..

B: original owner not last owner . who DID use the sump/coolant was poor at maintaining it.
That showed when I scraped out the sump of black goo. 15 pounds of it..
Never serviced his coolant let it get caustic or even electrified.
This is a know occurrence in cast iron engines as well.
Explains why the harden steel( opposite side is sleeved/ protecting the casting) is unaffected.

Just want to know the root cause really.

Then how to fix it/fill it with minimal skills

I'm a great welder but I know better.

Open to any thoughts as to why it happened and ideas to repair please .

Otherwise Ill just finish the cleaning and slap it back together. Forget all about it. Maybe even fill it with JBweld OR pr11 at that point. Still last another 70 years.

 

[Aukai]

The ugly stuff looks like electrolysis to me, I'm not smart enough to suggest a fix. An epoxy might do it though.

 

[DAM 79]

I also saw your post of this on FB . Welcome to the Few The Proud The VanNorman Mill owners club . I’m not sure what caused this but it definitely isn’t a good thing I would say the proper way would be to fill it in with weld and then machine it back out again to what it was originally BUT that would take time and a Big Mill or HBM to do !! I would think something along the lines of Epoxy or JB weld to fill in and then you would have to file it smooth again . Is that where that tapered pinion gear sets and rides ? Is that like a housing ? Looks like there is a cap that goes on top and is bolted down?

 

[pdentrem]

I would believe that it was electrolysis as well. It is too spotty in my experience to be incompatible oil. As for filling, with out proper prep of the damaged area I suspect that anything pressed in would not stay in place. The area is small compared to the whole surface, I would just clean out any loose pieces and reassemble. Proper lubrication will protect what you have left for years to come.
Pierre

 

[ps15toolroom]

My guess is electrolysis rust removal or rust removal by some other means. Searching photos of electrolysis rust removal shows similar pitted metal surfaces. I would ignore it and continue cleaning.
Welcome to the forum. Feel free to message me with questions about machining or the VN, as a fellow PA van norman owner.

 

[whitmore]

Looks like a blemish, more than a major fault; there's a LOT of surface that isn't missing. I'd wire-brush to
get loose stuff out, maybe paint in with some zinc-content antirust paint or primer (that'll keep the exposed
bare metal from re-rusting), and reassemble. As I understand it, you'd have to preheat the whole
casting and use nickel or copper-nickel rod to 'heal' it with welding, and that's a lot of work for little reward.
We see mainly cast steel nowadays, older machines with cast iron had more mass because there
were always some spotty regions.

Congratulations on cleaning out the sump! Maintenance is a talent that will serve you well.

 

[woodchucker]

I don't think it will affect it. I would not do anything.
As far as what caused it, An oil or coolant with something that the bronze did not like.

If something needs to be done, I would investigate filling it with lead to keep the dirt out. Find out if the bronze and lead agree with each other.
The lead can be easily cleaned up with a bearing scraper. Also the lead is a lubricating metal...
Now maybe others will chime in on the efficacy of this idea.

edit forget what I said, it looked like bronze in the pic. Just went to my big screen, it's clearer and re-read the post that I skimmed.
Again though, I would just fill it with lead. Easy to get it back to shape with a bearing scraper, or any scraper. The rest of the cast iron will take care of the load. I WOULD NOT use a nickel rod.. you will never get the shape back, nickel is just too hard. Even the epoxy is a better choice.. I still like the lead... Or even babbit.. but babbit is harder than lead, so it will require more work.

 

[sdelivery]

Been there fixed that. Clean the pixx out of it many times and apply some metal fill two part epoxy mix a small batch and use a body filler spreader.
Fill the holes flush.
Work the easiest spots near the best of the surface and as your rebuilding the surface you will have more support for the more damaged areas.
Key is cleaning and small batches and areas.
You will be able to work the area with abrasives or a hone.
Don't go to big or you will have to sleeve it.
You can place the mating cap on the granite with some abrasive paper and remove some material that way. It will close the bore a little.
Prussian blue is your friend