MkI receiviers were all treaded for the gas cylinder ?

[tr63]

I am looking for the front end of a MkI receiver . Were all of them treaded for the gas cylinder ? I am looking to build a MkI semi-auto . I have the MkI receiver sections with out the first 9'' which the gas cylinder is attached . I do have the front end section from a MII, could it be used ? Will all of the MkI parts work with the MkII front end welded on ?

Information

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[Peter Laidler]

The answer to the question is that yes, all Mk1 gas cylinders were threaded into place. I dare say that a Mk2 cylinder end part and cylinder could be joggled to fit a Mk1 but the external configuration would be slightly different. The problem with the Mk2 gas cylinders that really manifested itself in the 50's (when Mk2's and Mk2/1's were the norm in BAOR) was looseness of the actual cylinder and the looseness caused lack of gas and no means of tightening a loose gas c up.

[Joe H]

tr,

This pic was posted here previously. It shows just what Peter was saying. They switched back to the threads after the MKII.

Joe



Attachment 92702

[tr63]

Thank you for the excellent picture . Will a MKIII cylinder work in a MKI visa versa ?

[TactAdv]

Peter.......question, how were the threaded gas cylinders clocked to arrive with the locating "finger" in the correct radial orientation? We're the threads timed, or we're shims used, or......???
-TomH

[Peter Laidler]

Answers: Post 4. yes a Mk3 cylinder will fit a Mk1 gun and vice verca, In fact a Mk3 gas cylinder on a Mk1 gun will rejuvenate the gas system as it gets rid of the exhaust gas holes
ANDY'S Q: There was a gauge that slid into the gas cylinder and fitted tight to the tip of the body that had a slot cut out that would only align with the tongue when it was in the correct radial position. The very fine Z-TPI threads were very slightly tapered and would tighten up at the end of the run. SUPPOSEDLY! they were indexed but this was a fallacy. You threaded the cylinder in using a lot of graphite grease until it gauged-up and was tight. At this point the pin slot would align but the new cylinders would always require a slight bit of hand reaming. Then the pin would be pushed in and locked with a small tap with a hammer. There was a special 'C' spanner to tighten and remove the gas cyl. Sometimes you could do it with a bipod sleeve but most often you had to remove the real bastaxxs by welding a nut onto the cylinder ad undo it using sheer brute force. The answer was lots of graphite grease.

[Brian Dick]

Scariest job I ever completed, (with help!). A transferable Bren receiver is $25k in the USA. I had visions of the old, original 1940 Mk.1 cylinder coming out with no threads on it. Fortunately, that wasn't the case but it took a ton of heat from a big torch at my welder's shop and the welded tractor lug nut as mentioned above to break it loose and unscrew it. When it popped, I held my breath until it unscrewed and I could physically see thread. I'm not sure I'd want to do another.