strange apparently military compass restricted to 5 degrees for id

[rrickoshae]

good evening, please see the attached photos of a strange compass that appears to be British military - typical British green. It measures 2.75 inches long by 7/8ths wide & deep. It has 4 lugs indicating that it fitted into something and the needle can be locked. The needle is restricted to 5 degrees either side of the centre line. The only marking is a number 7 on the underside.

Anyone any thoughts what it might be from or for?

many thanks, Dave

[Narcis]

Trim gauge?

[rrickoshae]

For an aircraft? The RAF never used this shade of green inside an aircraft. I wonder what else a trim gauge would be used on, perhaps others will expand on your suggestion.

Many thanks, Dave

[reneblacky]

artillery?

[rrickoshae]

Yes that’s a possibility and the paint job would be correct. Perhaps someone with hands on experience of artillery equipment will add something
Any thanks, Dave

[Narcis]

Trim gauge?
I meant the horizontality of an artillery platform, not aviation.

[HARRY THE MOLE]

Used by the artillery. As an ex-gunner I am ashamed to say that I do not know how it was used... but somewhere in our house is a larger walnut cased example marked to the gunnery school at Larkhill.

Cheers,
Steve

[rrickoshae]

Cheers Narcis, your thoughts are confirmed by Steve aka Harry the mole!

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Cheers Steve, that’s good enough for me, artillery use it is

Thanks, Dave

[HARRY THE MOLE]

Dave, I've found out a bit more information for you. The instrument is a trough compass - also known a 'plane table compass'. It was used for aligning the plane table (plotting table) to establish an exact magnetic north. What sickens me is that I know I have one in the house somewhere... it is dated 1916 and stamped to the school of artillery, and every so often I have a search for it - along with some other bits of WW1 miltaria which was moved to a 'safe' spot when we were carrying out some work some years ago!

Cheers,
Steve