Can you drill in from the smaller end and through the neck then plug the end with a piece of brass? Depends how much it will show.

Does the linking hole have to be at right angles, if not tilt the work slightly so you can get a drill into the neck area.

Edited By JasonB on 28/06/2018 12:09:43

If you can find someone who can do EDM on it a cranked electrode would work.

You could also make a plug Ø7 and 10mm long with a hole drilled in it as required then drill through the plate and fit the plug in position. Loctite, solder or braze as required and clean up.

Martin C

This is a pretty confident recommendation for Loctite 242

[quote] I went through the gasoline-compatible sealant issue recently (looking to seal threaded joints in newly created fuel delivery system; not stock). Here's what I found:

Loctite 242 (blue) is a very common thread-lock (medium strength) and thread-sealant that will not deteriorate when constantly exposed to several types of gasoline (leaded, unleaded, etc., aviation). Same applies to 242 and Ethanol (common gasoline additive in US).

Loctite makes several gasoline-proof sealants, but the above 242 is the readily available blue stuff for thread locking. [ … ]

Rich Boyd

[/quote]

MichaelG.

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Edit: deleted broken hyperlink to technical datasheet

Edited By Michael Gilligan on 28/06/2018 17:56:22

Jason's method was the best option but that was before the purpose of the holes was explained.

Brian's suggestion now seems the most appropriate and TBH discussions about plugs and sealant are pointless (in relation to this thread).

As the hole is just to connect the two chambers there is no special reason it even needs to be a round hole so it could be created with depressions cut from both with say a rotary burr.

Ian P

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Thanks for including the comment in parentheses, Ian

MichaelG.

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Just for clarity : My notes about Loctite 242 were specifically in response to Roger's question, posed at 16:29:04

MichaelG.