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Author Topic: Ultrasonic drilling - Bits to horns  (Read 1028 times)

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lithicbeads

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Ultrasonic drilling - Bits to horns
« on: April 04, 2015, 06:50:57 PM »

 The stainless steel tubes I use for ultrasonic drilling ( stainless wire may be used also ) are connected to the horn of the ultrasonic drill. The horns are removable from the machine with a wrench. The soldering of stainless steel to the mild steel horn is a process that can be problematic. The narrow end of the horn has a recess , the pot , in which solder must first be placed. The proper flux is crucial to this process or the solder will not adhere to the pot on the horn nor the drill rod.If the horn is full of solder and the solder is adhering to all sides of the pot you can usually pass on  adding more flux to the pot itself. If the solder in the pot looks like it has a layer of scum and oxides on it the tip of the horn must be heated until the solder in the pot is molten then a small amount of flux may be added on top and then the top of the solder may be swiped gently with a drill bit to clear the unwanted material which would impede the completion of a good bond. Only experience will determine the tipping point where the pot solder must be cleaned.
  To solder bits the key is preparation. The used horns with their remnant bits ( or mis -soldered bits) must first be thoroughly cleaned with a stainless steel brush. The  silver solder ( I use a proprietary flux from Imahashi the maker of my drill ) will only stick to the bits if a very thin and very even scrim of the granular flux is spread on the parts of the bit you wish to coat with solder once the bit is in the pot. A stainless steel brush is first used to clean the oxides of the end of the drill bit ( about 25 % of the length of the bit) then the cleaned end is rolled in the slightly damp flux to coat it. Any part of the bit left unfluxed will not be covered in solder which can make for a failed or inferior bond between bit and horn. The last 3/4 of an inch of the horn tip is then heated until the solder is molten and the remnant drill bit may be removed with pliers.The pot is then topped up with solder. The  replacement bit is then placed in the jaws of the pliers while still heating the pot as extra heat is needed to keep the solder molten as the relatively cool bit enters the solder in the pot. The bit has to penetrate all the liquid solder so that the bit is in direct contact with the bottom of the pot. If this is not the case you can have energy provided to the horn while drilling wasted by cavitation and usually in short order the bit - horn connection fails. The bit is then held about an inch above the horn tip so that rising heat from the heating of the tip may thoroughly dry the  damp flux. It should look dry  . The thoroughly heated horn tip is now ready to plunge the bit into it. The flame from the torch must be removed at the same time as the bit is plunged because if the bit is heated to cherry red it will fail during use. I never use any direct flame on a replacement bit. The bit must then be held in a relatively vertical position until the solder hardens , about 15 seconds. The horn next to it may be preheated at this time so as to not waste time or fuel. The horn is quite hot and should absolutely never be quenched. If you are in a hurry you can use welding gloves to handle the horn and attach it to the machine. Horns can get very hot in use so a hot horn tip is not an issue.The tip of a horn in use  will boil the water carrying the grit to it or will cook any skin that touches it so great care must be used while drilling.
 I prefer map gas but as it is no longer available I use map gas pro which seems to have a lot less btu in it as I think it is dirtier as well. I do not want oxygen bottles near my house so most other forms of heat are out for me. Wind , dark  and an aching body can all adversely affect drilling as can inattention but they happen as this is work and if you are on a schedule you learn to do your best and live with the result.
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Gina

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Re: Ultrasonic drilling - Bits to horns
« Reply #1 on: April 04, 2015, 07:09:38 PM »

We use wire for ours.  When my husband does it, he mounts the wire and horn in the milling machine to hold everything in place while he solders it.
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wampidy

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Re: Ultrasonic drilling - Bits to horns
« Reply #2 on: April 04, 2015, 07:24:48 PM »

Quite a process. What kind of longevity do you get out of each bit/tube? They sell this really high dollar drill to you then you have to work your butt off to use it. lol Don't they have a snap on model?

The way I shake now on some days I would have solder in my shoes, shirt pockets and pants wrinkles.
Jim
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lithicbeads

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Re: Ultrasonic drilling - Bits to horns
« Reply #3 on: April 04, 2015, 08:57:30 PM »

 I make big holes so the tubes work best for me. I shake also . Nothing good to follow that up I am afraid.Each bit if properly soldered lasts about an hour or a bit more . At six to ten minutes per preform with a 4 mm bit that is not bad. The 1.25 mm bit holes are much faster. The cool part is that as the bit shortens you can turn the frequency way up with little chance of the bit and horn parting ways so the drilling is very fast but the preforms get quite hot at that drilling rate. I hate the soldering but love the drilling.
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Minkos61

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Re: Ultrasonic drilling - Bits to horns
« Reply #4 on: April 04, 2015, 11:32:24 PM »

Very interesting topic . Alot to this ultrasonic drilling .
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Ernie

Helene Fielder

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Re: Ultrasonic drilling - Bits to horns
« Reply #5 on: April 05, 2015, 07:36:53 AM »

Some tasks never get better.   I often try to brainwash myself into enjoying things that I dont, like going to shows.  Conversion tactics not working yet. 

Your end pieces seem well worth the soldering. 
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Helene
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