Blind Barrel Drain Cock

[Orgasmatron]

It would seem that the hole in my blind barrel to take the drain cock is 7/16″ diameter and threaded 19 tpi.
Can anyone confirm this and advise where these can be purchased (Ebay doesn’t seem to have anything).
Also, can anyone recommend someone in Surrey who could spray my petrol tank.
Chris.

[Bob Mather]

Hi Chris,
The drain cock in the blind block of my 1932 Flyer is tapped 1/8″ x 28tpi BSPF. Yours could be 1/4″ x 19 BSPF.
Regards,
Bob Mather.

[Roger Moss]

Most barrels I get have had the drain holes repaired by tapping oversize, usually with a coarse thread that is not always successful.
I end up tapping and fitting a fine threaded brass bush tapped central 1/8 BSPT to take either a flanged hexagon headed plug ()1/8 BSPP for this) or stainless taper plug, or brass tap from a variety of vintage supply sources for Classic cars. Roger

[Orgasmatron]

Thank you both for your replies.
I have checked by using the 7/16″ end of my fuel tap and this fits perfectly.
So, it’s definitely 7/16″ 19 tpi.
I don’t suppose that I will find a suitable drain tap, so will use a 7/16″ plug.
Chris.

[chris wastell]

Better to fit plug anyway as its impervious to inquisitive fingers.

[Clawed]

1/4″ B.S.P.T has 19 T.P.I and a minor diameter of 0.4506″. Not that far from 7/16″. 0.4375″.

Clawed

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