Bell Mandrel

Discussion in 'Trumpet Repair and Modification' started by GijsVis, Aug 27, 2012.

  1. GijsVis

    GijsVis Piano User

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    Does anyone here have a trumpet bell mandrel? I want to make one myself on a lathe, but I need dimensions and measurements for that, having the width of the mandrel every cm of 1/2" would be great.

    Thanks,
    Gijs Vis
     
  2. stumac

    stumac Fortissimo User

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    Do you want to make a bell from scratch or for repairs, there are a great number of different designs of bells with different flares, throats and rates of taper.

    For repair I made 2 which do 95% of the repairs I attempt, they were made from scrap steel bar I scrounged. The maximum I can swing between centers in my lathe is 16", the smaller one I had to weld a 5" extension to be able to hold it well. Both were turned to the same taper by setting the tailstock over 1/2" for a 16" bar.

    1/ 1 1/4" bar, 16" long, small end 0.85" length of taper 8 1/2"

    2/ 1 1/8 bar, 21" long, small end 0.5" length of taper 13.3"

    These were arrived by measuring a bell and aproximating the taper.

    I have made most of my own repair tools, the only ones I have purchased are the Votaw economy dent ball set and driver.

    Regards, Stuart.
     
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  3. GijsVis

    GijsVis Piano User

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    Allright, thanks.

    They would mostly be for repairs, but to have an option to make one from scratch would be great.
    Can you maybe make a picture or a drawing with the dimensions of the two mandrels, because I think I get it, but I'm no native English speaker, so I might understand it wrongly. I'll also just measure a bell to make sure, but some second party knowlegde is always great.

    Yes, I've made my own tools as well, like a mouthpiece shank straightener or dent rods, that wasn't too hard to do.
     
  4. Chuck Cox

    Chuck Cox Forte User

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    Could you make a bell mandrel out of spray foam first and then copy the measurements to a lathe ? Put a cork or rubber stopper up in the bell about 6 inches with an eye hook in the stopper with a string attached. Spray a release agent like cooking oil or hydraulic fluid covering the inner bell completely, then fill with foam , let harden, and pull out the form. Either that or buy a mandrel and make a dozen copies to sell to us to recoup your cost.
     
  5. GijsVis

    GijsVis Piano User

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    Brilliant, I will think of doing that. Yes, I'll make a few anyway, so I might make some for some TM guys as well :)
     
  6. Cornyandy

    Cornyandy Fortissimo User

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    Discount for those on this side of the pond
     
  7. GijsVis

    GijsVis Piano User

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    Well, a piece of steel of that size I can probably get at 10 quid, about half an hour work, 10 quid, so 20 quid plus sending for our side, and like, 100 plus sendig for the other side? :lol:

    No, just kidding, the States are great ;)
     
    Last edited: Aug 27, 2012
  8. Cornyandy

    Cornyandy Fortissimo User

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    GjisVis

    I raise my glass to you (I'm having to finish the Stella Cidre of which some has gone into my dinner, what a shame)
     
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  9. trumpetsplus

    trumpetsplus Fortissimo User

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    Not quite sure what you are asking here. If you have the ability to machine your own mandrel, surely you have the ability to measure your choice of bell.
     
  10. GijsVis

    GijsVis Piano User

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    Yes, but I wanted some other opinions of techs what they do.

    How long do you make the shallow end, that goes into the bell stem? Like untill the very end?
     

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