WWI-type Engineer Collar Disk with 3F

[Fort Susquehanna]

I have found a WWI-era screw-back EM Engineer Collar Disk. Above the castle, where a unit number goes, is 3F. I have searched and not found anything on this marking. Any ideas? Thanks!

[atb]

Company F, 3rd Engineers

[RustyCanteen]

This is where things get confusing, the basic marking is for Company F, 3rd Engineers - but which unit is open to conjecture.

 

In 1917, the Army created volunteer 'Reserve' Engineer regiments numbered 1-10. In July 1917, these units were re-designated to avoid confusion with the regular Army units sharing the same numeral. Of course, when the insignia first reached the units prior to being redesignated - it was often this type of disc that was sent. After the redesignation, many retained the discs (I suspect to show themselves as 'old hands'). It is quite common to find these discs on uniforms and in groups especially, from the 11th-19th Engineers Regiments, Railway.

 

So, this could have belonged to an engineer in the 3rd Engineers, or the 3rd Reserve Engineers (later 13th Engineers) which was formed in the Chicago area.

 

RC