Dent Ball question...

Discussion in 'Trumpet Repair and Modification' started by Osren, May 22, 2012.

  1. stumac

    stumac Fortissimo User

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    Oct 19, 2008
    Flinders Vic Australia
    Dimensions of my two home made mandrils, both 16" long, the maximum length I can put in my lathe, the smaller needs to be 20" for trumpet.

    1, 0.5" to 1.125" taper over 13.5"

    2, 0.85" to 1.25" taper over 8.25"

    The smaller mandril approximates the average throat taper of several of my instruments, the larger the same rate of taper on aproximatly half the rod.
    With these two I can do 95% of bell work.

    Regards, Stuart.
     
  2. mrsemman

    mrsemman Piano User

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    Apr 8, 2010
    Massachusetts
    I use the Feree set with a Roth Dent Remover system.
     
  3. dsr0057

    dsr0057 Pianissimo User

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    Dec 20, 2009
    Denton, TX
    If you are just focusing on Trumpet and Cornet I would say get the #2475 Flat Side Dent Ball Set. A bit cheaper and has the specific sizes you would be using the most. Other than that you will need a delrin (sp?) hammer (I prefer a delrin hammer because it is less likely to leave any kind of pinging in the brass after working it thoroughly), a burnisher, some kind of driver system, and a way to clean the instruments thoroughly and effectively.

    Let me explain that last part: So the reason you want to clean the horn or slides before working on them is so that any dirt, gunk, or living organism is not stuck to the metal because when you remove dents you are putting a stainless steel dent ball under a thin sheet of brass and striking it with either a stainless steel hammer or hard plastic hammer. Guess where the impressions are left? If there is gunk or anything between the brass and dent ball it will reflect upon the brass and make the work look terrible. Common illustration is the orange peel effect you see on tuba's after magnet work is done. Think the same just on a smaller scale.

    Also you can make madrels fairly easily as long as you have the right set up on your metal lathe. Stainless Steel stock is fairly cheap right now. As per dimensions your guess is as good as mine.
     
  4. Osren

    Osren Mezzo Forte User

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    Oct 17, 2010
    Mesa, Az
    hmmm for SOME reason, I had over looked that set of dent balls. Do you think it is compatible with Ferree's P50 Dent Ball Holder Driver/Retriever? The Description leads me to believe that that system does have a THREADED fitting....

    good advice on that cleaning as well... I have been 1/2 considering getting an Ultrasonic cleaner... Mark Curry (on the Trumpet Herald forum) says that he uses the L12 which fits about 60% of a trumpet, then he just flips the trumpet and does the other side, and despite being from China, this one has never let him down. :) That's on my wishlist right now.....
     
  5. Brekelefuw

    Brekelefuw Fortissimo User

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    Mar 21, 2006
    Toronto
    The P50 only has a threaded brass nut at the end to hold the dent balls on the cable. It does not thread dent balls directly on to it. The balls float along a 2 inch piece of braided steel wire.
    Make mandrels out of Tool steel, not stainless. Stainless is softer.
    I use delrin hammers, steel hammers and a special hammer no longer made called "Scott's Red Hammer." The delrin and Red hammer don't leave marks, but with proper hammer technique, the steel ones won't leave a mark either.
     
  6. stumac

    stumac Fortissimo User

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    Flinders Vic Australia
    Unless you are removing dents all day every day there is no need to go to a tool steel for mandrills, mine are ordinary mild steel bar stock probably around SAE 1010. I have made a lot of tooling using SAE 1095 or thereabouts and until properly heat treated is no harder than mild steel and a lot harder to machine.

    I use the Votaw economy driver and can get all dents out of the bell bow to the 1st valve without having to take the bell off.

    My Lead hammer was made before WW1, deformes fairly quickly but only takes a few minuits to recast.

    Regards, Stuart.
     
  7. Brekelefuw

    Brekelefuw Fortissimo User

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    Toronto
    I remove dents all day every day.
     
  8. dsr0057

    dsr0057 Pianissimo User

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    Dec 20, 2009
    Denton, TX
    Model 51-15-236, Model 822 on Ultrasonic Power Corp.

    Much better company and their stuff actually works well! This is a decent sized one for trumpets/cornets/flugelhorns.

    Like said before the P50 uses a threaded wire and I use it with the Votaw set. Honestly I prefer the votaw dent balls because they are more precise in measurements and finished to a higher quality.

    Also I would suggest tool steel but most people don't have the precision machining to work on that 'quality' of material. Stainless is more readily available and easier to machine. Also doesn't corrode thus you rarely have to clean it off.
     

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