The world of model and hobby engineering

Subscribe

The Modelling Hub Logo

The world of model and hobby engineering

Subscribe
Buy Latest Issue

Forums

Help

Register

Log in

Lapping valve tapered plug

Advert
New Replies
Report Bug
Help/FAQs

Lapping valve tapered plug

Home › Forums › Beginners questions › Lapping valve tapered plug

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • 19 September 2009 at 09:19 #43635
    GoCreate
    Participant
      @gocreate
      Hi everyone
      I am building a 3″ scale Allchin, I am looking at making the draincocks for the cylinders which have a tapered plug. The drawing says the valve body and plug tapers should be ground in. I am concerned that if I lap/grind them in using a diamond or similar grinding paste then the abrasive is going to become embeded in the parts. (The drawing suggests bronze for both parts). I was just wondering what procedure is normaly used, is there a method of lapping in the tapers without impregnating the parts with abrasive? At this scale the plug will be 1/4″ diameter.
       
      Many Thanks
       
      Nigel
       
       
      Advert
      19 September 2009 at 09:19 #4764
      GoCreate
      Participant
        @gocreate
        19 September 2009 at 11:13 #43636
        mgj
        Participant
          @mgj
          I had the same thought on a boiler feed pump tapered valve. Not on an Allchin, but same idea.
           
          I turned the taper on the plug, and the taper for the body reamer at the same setting using a nose radiused cutter – so the finish was pretty glossy. Then I just added a dab of silicone grease.
           
          I havent tried it in service with water, only air, but that holds air without leaking at 150psi.  If it won’t hold water properly I shall just add a small O ring this side of the hole in the taper.
          24 September 2009 at 14:42 #43791
          GoCreate
          Participant
            @gocreate

            Hi Meyrick>>

            Thanks for your reply>>

            I was being led by the drawing saying grind in the valve plug but what you say sound good to me. Basically making the cutter/reamer and plugs at the same setting and keeping the quality good means there should be no or little problem.>>

             >>

            Unfortunately I work overseas most of the year which some what slows progress on my Allchin. However, I have a small Sherline that I use in my overseas apartment so progress can be made on smaller parts. I will make these parts following your advice but will not be able to test them until I get back to the UK in December.>>

             >>

            Again Thanks>>

             >>

            Nigel>>

             

          • Author
            Posts
          Viewing 4 posts - 1 through 4 (of 4 total)
          • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

          Latest Replies
          Report Bug
          Code of Conduct
          Help & FAQs
          Advert

          Latest Replies

          Home › Forums › Beginners questions › Topics

          Viewing 25 topics - 1 through 25 (of 25 total)
          Viewing 25 topics - 1 through 25 (of 25 total)

          View full reply list.

          Advert

          Latest Issues

          Subscribe
          Buy Latest/Back Issues

          Newsletter Sign-up

          Latest Replies