Under plugs

[Steve Phillips]

I was looking at some of my under plugs in relation to the Coal Torpedo and noticed that a few of them have the same small center hole. I wondered if they could have been designed to take slow match and be used in a time bomb like the torpedo could be used.

[John D. Bartleson Jr.]

Steve,
    That is a lot of plugs.  When used beneath the Bormann time fuse Gibbons states that it is filled with fine powder, the leather gasket fitted, the thin covering of the magazine is pierced and the Bormann threads coated with white lead and screwed home.
Regards,
John

[emike123]

Nice group, Steve.  The 0.80" diameter (smaller ones) fit the bottom of some "army" pattern Archer percussion fuses and a 0.65" diameter one fits the bottom of some Navy style Archer percussion fuses.

From a group I have, it seems like the Bormann underplugs are in the 0.94" - 1.07" diameter range.  The majority are closer to 1" diameter, and it seems like of the ones I have the ones that are around 0.95" diameter are iron so perhaps there has been some metal loss that slightly reduced the diameter.

The ones with the slots have been associated with Selma

There is a huge one that is 1 & 5/8" or so that went in the big naval balls in place of or under the Bormann fuses.  I also have a 1.26" diameter one which I think was made bigger so case shot balls could be added to the shell, but I could be wrong about that.

Some brass ones found their way into CS sideloader shells made at Adolphus Rahm's Eagle Machine Works

And, after all this, I too have at least one in a diameter and pattern that doesn't fit anything I've found to date! 0.845" diameter with a slot and single hole in the center.