T.Mi.Z.42 and 43 igniter screw on detonator pocket

[BMG50]

Are T.Mi.Z.42 and 43 igniters screwed into the mine or inserted. Any one have one of these igniters with the screw on gain or detonator pocket that they could show us. Does any one know if the Germans used imperial sizes as it appears the tread size to these igniters are a real oddball size in both metric and imperial, measures at 13.70mm or 0.540"inch.

 

[bombmonki]

The field Enginering and Mine Warfare pam 4 Mines- individual mechanisms describes inserting the igniter as :

"Unscrew the cap in pressure plate, screw a detonator into the igniter, Insert the igniter and replace cap, screwing down until the snap of the weak shear wire is heard."

I assume form this that it is not screwed in but just inserted.

Leo