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General control line discussion => Open Forum => Topic started by: Bootlegger on April 25, 2010, 12:01:21 PM

Title: pressure fittings
Post by: Bootlegger on April 25, 2010, 12:01:21 PM

  Some time back I remember seeing a question about pressure fittings, the question was which is better for stunt, 4-40 or 6-32.
 I don't remember the suggestions as to which is better, so I'm asking again.
   Thanks, Gil

Title: Re: pressure fittings
Post by: john e. holliday on April 25, 2010, 02:41:01 PM

You talking about pressure fittings or mounting bolts.  In reality a lot depends on the engine being used.   H^^

Title: Re: pressure fittings
Post by: Bootlegger on April 25, 2010, 03:10:12 PM

 Pressure fittings to create muffler pressure to have a steady pressure to the uniflow on the tank.
  Didn't mean to create confusion. Thanks for pointing that out Doc...

Title: Re: pressure fittings
Post by: john e. holliday on April 25, 2010, 03:13:45 PM

Well I have several Fox mufflers that have 4-40 threads.  On the OS mufflers I think they are 6-32.  Which do you need or are you just adding one to a muffler? H^^

PS: Opening in the Fox is 1/32" jeh

Title: Re: pressure fittings
Post by: Paul Smith on April 25, 2010, 04:29:22 PM

Also M3 or M3.5.

In the past, 4/40 was pretty much standard, so you could insert the pressure fitting in lieu of one of the backplate bolts.  

A crankcase pressure fitting needs a tiny hole to restrict the pressure.

A muffler pressure fitting needs a gapping hole to get all the pressure it can,  Thus, a muffler pressure fitting would be better off with a 6/32 or M3.5 thread.  Or for that matter, a chunk of 1/8" tubing glued in with high temp epoxy.

Title: Re: pressure fittings
Post by: Bootlegger on April 25, 2010, 06:41:28 PM

Doc, I sent ya' a p m..  Thanks, Gil