You said some interesting, but have you ever got a program made for a CNC ? Do you know how much these programmers charge for a simple program (as you said) to make rotors ? It seems to be simple, just a cylinder with a mini taper of 1 %, plus the two axles at top & bottom, perhaps taper too for 1% but the opposite way for top & bottom, some few other things too. Well, this task seems not difficult. But there are the two through holes in the upper part & in the lower part, where the cross-section should remain equal, even when the hole is squeezed, sharp edges must be avoided.
This all results in quite a complex program, even short but complex. It costs me about 1.000.- USD each program, for a rotor or a piston or a mouthpiece. Does not seem to be much. But the program does not fit any CNC machine, as there are some differences. You must experiment & test run the program. If you have your own machine, fine. Then the special tools, made to measure, special made if not available at the right measure. Not important financially, if you produce the rotors in 60 or 120 quantities. But still 3.000.- to 5.000.- USD at one payment (material, machine time, operator time, tools, machine adjusting & cleaning, etc.). But making a single set of 4 valve rotors ????? Better buying a complete valve system from the same maker for (say) 400.- USD or less (just valve stock with casing, rotors, "ears") & get your slides & main tubings soldered to the new "machine". This is all together not too difficult for brass valves or nickel silver valves (casings of the other metal off course). Aluminium is not to be recommended, as it corrodes terribly if in contact with moist & turns poisonous unless it is processed specially getting an extreme hard surface. This technique is used for expensive cars, where costs do not play a big role. But with horns ? We tried it successfully with double horn rotors, but gave it up. The percentage of imperfect coating was too high. We tried it with Viennese Pumpen (they worked superbly), but we got the same problem. The high voltage involved to convert the surface to extreme hard oxyd resulted in some lightnings which cut edges of, just mini cuts but enough to harm the perfect surface. As these rotors or pistons are not made in thousands, where a handful damaged pieces would not influence the cost calculation, the financial risk was too great. With Titanium everything is different. Most operators of CNC have zero experience with Titanium, which requires the cutting tools be with a different angle than usual, spindle running at a different speed than usual, cooling liquid other than usual, much more working time included. A work for the Titanium specialist. So the cost factor is enormous. But if they run, these titanium valves, they run forever. Lapping ? Well, be extremely careful with other dust near the rotor or the casing. Any particle fallen between (titanium) rotor and (whatever metal) casing results in an engraving into the inner wall of the casing, absolutely disastrous for the tightness. I play on a horn with titanium valve rotors. These rotors were hand made (dangerous work) on a small semi automatic lathe. But the man on the lathe had over 40 years of experience. He also made me some 4 sets of titanium pistons for Viennese Horns. One is in use the other will be ready next week. Be sure, I will report on the acoustical behaviour of this horn. The other two sets are reserved (if) for two players from an orchestra which uses these kind of horns. Guess who ? Titanium valves have the advantage not being very sensitive to change of temperatures. They are very light, near to aluminium, don't oxide , do (nearly) never stick. And if the stick, you just turn them on the wing in the back, forth & back, and the work fine as usual. Just from my own experience as player (since 1957) and advisor for horn production (since 1978) & producer of horns (since 1996). Hans Pizka -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Saturday, December 06, 2003 10:41 AM To: The Horn List Subject: Re: [Hornlist] Making Titanium Valves? In a message dated 12/5/2003 5:00:52 PM Eastern Standard Time, Valkhorn writes: > > I never thought of this before, and I'm sure it's very expensive, but if you > took one of your valves to a decent machining shop I'm sure they could copy it > into any material you wanted. And, if you provided the > material I'm sure they > could do it straight away. If you have access to a modern CAD program, you can draw the valve to scale on your computer. You can then then down load it as a DXF file and use it to program a computer numerical controlled lathe, CNC. Chuck up any material you like, and the machine will pop a valve out, correct to a couple of tenths. You might not have to lap it. Well, it's not quite that easy, but modern machines are getting pretty close. Setting up the machine is still time consuming, so one offs would have to be priced to support the shop time from beginning to end, several hours, certainly. A lot of technology is being developed to make it that simple, perhaps in ten to twenty years. Seriously, if you are careful to match the part being made to a proper machine, parts, like rotors, can be made from a DFX file derived from a simple drawing. It just has to get cheap. _______________________________________________ post: [EMAIL PROTECTED] set your options at http://music.memphis.edu/mailman/options/horn/hans.pizka%40t-online.de _______________________________________________ post: [EMAIL PROTECTED] set your options at http://music.memphis.edu/mailman/options/horn/archive%40jab.org
