Grey coating on cap iron

[Brian DeLore]

My last few additions have been type 11's and they all have a grey coating on the back of the cap iron. first two only partially there with rust and scratchs from sanding. Last one is complete and undamaged. I've not seen any mention of this anywhere and wondered what its purpose was and the period of its use.

Brian

[Jim Koepke]

My last few additions have been type 11's and they all have a grey coating on the back of the cap iron. first two only partially there with rust and scratchs from sanding. Last one is complete and undamaged. I've not seen any mention of this anywhere and wondered what its purpose was and the period of its use.

Brian

The change was around 1919. If you look at the rexmill type study for type 12, it is mentioned there.

Find the link in the Neanderthal Wisdom/FAQs.

jim

[Richard Darjes]

The coating is a form of bluing - similar to what you find on guns and such. I've had one plane with the coating, but I accidentally removed it by soaking the cap iron in "CLR" to get rid of the rust. The plane was no collector item that's for sure.

Rick in Oakville (Canada)

[Brian DeLore]

Thanks guys, It is mentioned at rexmill (last sentence of type 12). I looked up blueing and beleive it to be a form of cold bluing. It has a limited resistance to corrosion when used with a coating of oil, and is not very resistant to abrasion. Sounds about right. Thanks for pointing me in the right direction.