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