On heat treating early 1903's.
The legend I read told me it had to do with "New Management"
A new "Top Dog" showed up ,walked around, decided the windows were dingy.
He ordered the windows cleaned immediately.
That changed the ambient light, which wreaked havoc with the "calibrated eyeballs" of the Gentlemen watching the color of the steel in heat treat.
In the dark shop, it "looked right" at a lower temp. In the light shop,the temp was higher. Too hot!
Someone mentioned the P-17/P-14 as not having these problems. I'm not well informed about these. Memory(which may be wrong) tells me the P-14 was OK, but some of the P-17's were brittle. Eddystone comes to mind as the ones that may be brittle. Please do not consider that as fact. I suggest if you have a P-14/P-17 you are going to put your face behind and pull the trigger,do a little research. Many of them are good. Some series,not good.
I do not have a copy of "Hatchers Notebook" Its probaby been 40 years since I read it, As I recall it goes into this stuff.
The legend I read told me it had to do with "New Management"
A new "Top Dog" showed up ,walked around, decided the windows were dingy.
He ordered the windows cleaned immediately.
That changed the ambient light, which wreaked havoc with the "calibrated eyeballs" of the Gentlemen watching the color of the steel in heat treat.
In the dark shop, it "looked right" at a lower temp. In the light shop,the temp was higher. Too hot!
Someone mentioned the P-17/P-14 as not having these problems. I'm not well informed about these. Memory(which may be wrong) tells me the P-14 was OK, but some of the P-17's were brittle. Eddystone comes to mind as the ones that may be brittle. Please do not consider that as fact. I suggest if you have a P-14/P-17 you are going to put your face behind and pull the trigger,do a little research. Many of them are good. Some series,not good.
I do not have a copy of "Hatchers Notebook" Its probaby been 40 years since I read it, As I recall it goes into this stuff.