Bushing an LBSC unbushed backhead

Bushing an LBSC unbushed backhead

Home Forums Beginners questions Bushing an LBSC unbushed backhead

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  • #184554
    David Haynes
    Participant
      @davidhaynes53962

      Hi Folks,

      I have asked this question elsewhere but am now able to also post images here to go with the query.

      I would like to add bushes to an LBSC 'unbushed' backhead but on the regulator I am a little tight for space. I propose to replace the original 9/16" dia clearance hole with a 3/4" dia hole for a 7/8" dia bush. Whilst this is an improvement on screwing straight into the 13g backhead, it does means that the fixing screws threads are partly in the bush and partly in the backhead.

      Thoughts please…

      Dave
       
       
      tich backhead.jpg
       
      tich firebox.jpg
       
      regulator bush.jpg

      Edited By David Haynes on 26/03/2015 20:19:20

      #7535
      David Haynes
      Participant
        @davidhaynes53962

        Request for suggestions to deal with clearance problem

        #184555
        JasonB
        Moderator
          @jasonb

          Can you not take the hole upto 13/16" so more of the fixings are in teh bush? you will still have a 1/32" lip all round to locate the bush, may have to nick the inside of the flange for it to fit in.

          Does your drawing have the bush higher up eg ctr 1/2" diwn from the wrapper top rather than 1/2" down from the flanged backhead?

          Edited By JasonB on 26/03/2015 20:27:05

          #184559
          JasonB
          Moderator
            @jasonb

            With 13g copper as per your post you won't need to notch for a 13/16" hole but if 12g like on the LBSC drawing then a slight notch which won't hurt will be needed

            backhead.jpg

            then keeping teh bush at 7/8" OD it will stop the holes going through the side

            backhead2.jpg

            Edited By JasonB on 26/03/2015 21:00:18

            #184566
            David Haynes
            Participant
              @davidhaynes53962

              Thanks Jason,

              I has wondered about reducing the step on the bush to only 1/32". However, as this step is only to act as a register for concentricity and give a greater solder contact area, and not resist pressure, that should not be a problem.

               

              Dave

              Edited By David Haynes on 26/03/2015 22:37:02

              #184568
              julian atkins
              Participant
                @julianatkins58923

                hi david,

                what you propose above is what alec farmer of Reeves fame always advocated and in his book, and what don young did in his later designs, and what i have always done.

                cheers,

                julian

                #184586
                David Haynes
                Participant
                  @davidhaynes53962

                  Thanks Julian,

                  Jason, I have corrected the small error – it looks better now.

                  Dave

                  regulator bush#2.jpg

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