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

resitance

Advert
New Replies
Report Bug
Help/FAQs

resitance

Home › Forums › Beginners questions › resitance

Viewing 5 posts - 1 through 5 (of 5 total)
  • Author
    Posts
  • 1 February 2012 at 21:26 #83652
    michael burton 1
    Participant
      @michaelburton1
      hi many thanks to the replys of my other post much apprecaited, this may seem a stupid quistion but i really dont know the answer, well today my graphited yarn arrived and i proceded to fitting it to the tich pistons what a nightmare of a job first it wasnt 3/16 it came up bigger (is this right) anyways i finnally get thew packing in and would now like to know what is a sensible amount of resitance obvousily it cant be to tight but at the same time i should imagine beening to loose is pointless please help me out with this one thanks to all you have all been a great help so far
       
      many thanks mike
      1 February 2012 at 21:26 #5913
      michael burton 1
      Participant
        @michaelburton1
        1 February 2012 at 22:16 #83661
        MICHAEL WILLIAMS
        Participant
          @michaelwilliams41215
          Hi Michael ,
           
          Packing with graphited yarn is a black art .
           
          The fit that you want on a newly packed piston is ‘ just stiff ‘ in the cylinder bore . Bit difficult to quantify but something like 1 to 2 lbf to move it is ok . After just one steam up the yarn will settle down and run much more easily .
           
          As bought graphited yarn can be to some extent ‘ rolling pinned ‘ to a better shape and size – just roll a bit of round bar along it against a clean hard surface .
           
          You may wish to consider fitting O rings instead . If you want to do this ask again and I or someone else will tell you how to set about it .
           
          MW
          2 February 2012 at 00:07 #83668
          michael burton 1
          Participant
            @michaelburton1
            hi many thanks for the reply rolling pin great idea, also they are slightly stiff will roll but needs abit of a push but is getting easier the more i turn the wheels hopefully with abit of air test and some steam up its pipe it will run in nicley.
             
             
            many thanks
            2 February 2012 at 00:12 #83669
            Ian S C
            Participant
              @iansc
              Mike the method I was told, and used was , pack the grooves tightly, and using a narrow strip of wood, and a hammer tap it down, but leave it proud of the surface of the piston, then enter the piston into the cylinder (this should have a sharp edge, not a taper that you have with cast iron rings), the edge of the cylinder will shave the surplus of the yarn off. Ian S C
            • Author
              Posts
            Viewing 5 posts - 1 through 5 (of 5 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 Issue

            Subscribe
            Buy Latest/Back Issues

            Newsletter Sign-up

            Latest Replies