Results 1 to 5 of 5

Thread: Inner bezel calculation

  1. #1
    Join Date
    Feb 2012
    Location
    Nottingham
    Posts
    20

    Default Inner bezel calculation

    Hi all,

    Pretty new to this and struggling with inner bezel(step inner bezel) calculations,round not oval yet,
    Outer bezel no problems,
    Inner bezel always to big tried different calculations/surfed the net/forum must be missing something somewhere any help appreciated.


    Thank you


    John

  2. #2
    Join Date
    Jan 2012
    Location
    dear old Blighty - (in deepest Wiltshire)
    Posts
    1,638

    Default

    Quote Originally Posted by Jazzy View Post
    Hi all,

    Pretty new to this and struggling with inner bezel(step inner bezel) calculations,round not oval yet,
    Outer bezel no problems,
    Inner bezel always to big tried different calculations/surfed the net/forum must be missing something somewhere any help appreciated.


    Thank you


    John
    Hi John, welcome to the forum


    there are two ways to do this.

    Firstly you make a flat stock of same proportions. For example; if you need 14mm of standard bezel, you will need 14mm of step sized bezel. You could solder these together (sweat soldering would be best here) But as you are a newbie... best you follow this route:

    you need to know the inner radius of the outer bezel... oh, that sounded weird, I hope it made sense.

    I think you need to apply this calculation for your round settings.
    (you could do it with an oval, but would need to cheat and measure around it with some wire, make it into a circle and then make the calculation)

    As I was saying, I think it is this:

    (diameter + width of metal) x 3.147 for general sizing.

    For the internal measurements, you will need to take it down by the width of the metal you are using so it would become (diameter - width of metal) x 3.147. (I am sure our Goldsmith - James, Dennis or Peter will put it right if I am incorrect)

    that should do it. (but bear in mind thinner metal can stretch and measure your diameter twice). Always check and double check your sizes. Saves time and a pain later. This works for all rounds, outer or inner. It will depend on the diameter. A good vernier caliper that takes internal measurements will be handy, if you don't already have one.
    Last edited by Wallace; 14-01-2013 at 10:19 PM. Reason: extra info

  3. #3
    Join Date
    Dec 2009
    Location
    Central London
    Posts
    8,845

    Default

    Here is my version with the same end in mind.

    It sounds a good idea to use your maths, but there are variables that let you down. Buy some six inch electronic calipers and do this:

    1. Cut bezel strip from 0.4 mm sheet(fine silver if using silver), 1.5-2.5mm wide, according to height of stone, and wind it around a rod of the same diameter as your stone. The stems of twist drills from a set work well for this, but allow for them being a little undersized. Try it on your stone and cut and solder.

    At this stage it is useful to have a tapered bezel mandrel, which helps to perfect the roundness. If what you have made turns out too big, you will have to cut it and re-solder. However if it is slightly too small it can be stretched by pushing manually, or by tapping on the taper.

    2. The inner bezel or bearer does not have to be as perfect, as it is out of sight. It can be added later, made from sheet or wire around a smaller rod whose diameter is that of the first one minus twice the thickness of the material used. In some cases it does not have to be soldered in and there can even be a little gap instead of a join.

    In the case of a cabochon, the bearer can be replaced by just the backing it is soldered to, unless you wish the stone to be taller.. Dennis.
    Last edited by Dennis; 14-01-2013 at 11:05 PM.

  4. #4
    Join Date
    Feb 2012
    Location
    Nottingham
    Posts
    20

    Default

    Hi Wallace,
    Thanks for that much appreciated will give it a go tomorrow no time tonight will keep you up to date on progress.
    Once again thank you.

    Kind regards

    John

  5. #5
    Join Date
    Feb 2012
    Location
    Nottingham
    Posts
    20

    Default

    Hi Dennis,

    Thank you for you reply last night which gives me options for tomorrow night no time tonight I have every confidence between you and Wallace I will solve my dilemma I will keep you up to date.
    Once again thank you.

    Kind regards


    John

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •