Bell sweep

Discussion in 'Pattern making' started by Petee716, Apr 2, 2020.

  1. I've seen some G clamp patterns with similar but severe shrinkage in aluminium bronze castings, small steel "Chill plates" were embedded in the sand mould to make those areas solidify first. The specially shaped chill plates had holes drilled to align with pins on the pattern to keep position during ramming the sand. In the clamps in the photo you can see early castings without the chill plate that have shrink holes in the castings around the threaded area the clamp screw threads into.

    G clamps.jpg
     
    Last edited: Dec 31, 2020
  2. Zapins

    Zapins Silver Banner Member

    One thing I've been wondering about with bells. I see many/most of them seem to have a hinge or pivot point on the top to allow it to swing and move around, is this necessary or if they are rigidly fixed in position does it have some kind of downside?

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  3. HT1

    HT1 Silver Banner Member

    the first bell with the hinge is a POS :

    1) it's done as a cost savings, no machining, just drill a hole , shove a bolt through it,
    2)bells made like that are extremely light, they have to be they are hanging on a tiny screw,
    2B) light bells sound "tinny"
    3)the top of the bell is asymmetrical, potentially effecting the tone ( a bell should sound the same whichever side the clapper strikes on the interior circumference) with the crown not being symmetrical, the fore-aft and sides of the bell may sound different
    4) what's the clapper hanging from??? a piece of wire cast into the interior top of the bell, if that wire breaks, you have no way to hang the clapper

    want more proof of how light our cheap bell is??? look at the wall mount , notice it is not structurally designed, it's stronger side to side then up and down, the way the bell pulls, once again the bell is lite and tinny
    look at how the pull rope is attached a wadded up piece of wire , while the other is a neatly rolled ring


    Bells should be through bolted or have a proper crown

    V/r HT1
     
  4. spelter

    spelter Copper

    Another reason for an allowance for movement at the mount is to limit breakage. Bells have to deform significantly to sound well. Massive as they are, they are lightly built. In the European tradition, church bells are swung into the clapper not because it's easier, but because it's harder to overstrike. In the orient, bells are often stationary but struck with wood (on the outside, with the end of a log suspended sideways).
     
  5. Zapins

    Zapins Silver Banner Member

    So it sounds like the better quality bells are rigidly attached rather than swing freely? Or at least if I made one rigid it wouldn't be detrimental as long as it was securely attached?
     
  6. HT1

    HT1 Silver Banner Member

    you need to do some digging, there are alot of ways to skin this cat, bells are a musical instrument and require a certain degree of expertise, i'll get you started
    http://everyspec.com/DoD/DoD-SPECS/DOD-B-24673_23252/
    here is the military bells, follow these instructions, you will get the tones you want

    V/r HT1
     

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