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Discussion Starter #1
How hard (or expensive) would it be to make a draw plate to change the diameter/taper of saxophone necks.

Ernest Ferron in his book advises using a draw plate with "holes graded in diameter by five hundredths of a millimeter in order to avoid having a neck that resembles a flight of stairs."

Attached below is a diagram of a SBA alto neck whose dimensions I measured for another project. As you can see the tapered portion past the cork starts at about 13.8 mm and goes to 22.8 mm. Using Ferron's advice to use .05 mm increments the 9 mm increase in diameter would require at least 180 holes! If one went with .10 mm increments it would take 90 holes.

I would estimate that the sheet of metal would need to be about 5 mm thick, and each hole would need to have its edges beveled or rounded. Allied supplies a draw plate that goes from 8 mm to 19 mm with 29 holes for about $100.

Is this "ideal drawplate" even doable or even practical? Or might there be an adjustable tool that would do the job just as well?
 

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it would be hard and expensive. The ideal drawplate would be .375" thick and the holes needs to be perfectly radiused and mirror polished. Mine has a radius of 100 mm (holes are radiused at that radius) and then the edge is relieved ("deburred") so chances of marring are minimal. I have divided the 250 "ring" sizes that I had made in 8 different plates. I had them custom made in 4340 steel (polishes up very nice and takes a hell of a heat treatment) and did the hand finish myself, then had it tempered. I spent a sh*tload of money on that. But then you can really get involved in neck repair and customization.
 

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I don't know how american machinists charge per hour and other details but I estimate at least 1.5k to get good tooling for this task. Pictures? c'mon, we're talkin a plate of steel with a buncha' holes in it... [rolleyes]
 

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...Ernest Ferron in his book advises using a draw plate with "holes graded in diameter by five hundredths of a millimeter in order to avoid having a neck that resembles a flight of stair...
By my calculations, this equates to making a draw plate with holes that are graduated in .002" increments. Most dentball sets are in increments of .005" . I have an Erick Brand draw plate graduated in .010 increments, but it does not go large enough to do sax necks. I think this would be a very expensive tool to make one at a time and do it for less than $800-$1000 and make money at producing them. (what jicanino said)

So in reading your question, the first thing that came to my mind was, He doesn't really intend to "re-size a sax neck" does he? Using a stepped drawplate? The amount of metal in the neck does not change by shrinking it with a die or draw plate. It has to go somewhere. By shrinking diameter sections of the neck you will likely be stretching the length of the neck and changing the curve of the neck. If you are resizing an entire neck as your picture implies (at least to me) Or, are you using the draw plate to repair damage from dents? If you are using the draw plate to burnish or repair areas of the neck that have been damaged, it could be a valuable tool, but I would only focus on making a draw plate that was sized for the areas of the neck that were most difficult to reach with dent tools. My solution for burnishing tubing was to make some ring burnishers that are "C" shaped. The C shape allows you to slip the burnisher over a small section of the instrument without unsoldering tubing or bracing. I use them on sax necks to burnish out dents as well. They are particularly helpful on Baritone horn and frenchhorn.
 

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I (was) a toolmaker by trade. The quickest way to produce a 5 mm plate with 180 holes graded in .05mm increments would be on a CNC mill. You'd probably need do do it over separate plates, even with CNC - to get this sort of accuracy you'd need to use a boring head which is a manual process. It would easily eat up 3 or 4 days of time.
 

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I (was) a toolmaker by trade. The quickest way to produce a 5 mm plate with 180 holes graded in .05mm increments would be on a CNC mill. You'd probably need do do it over separate plates, even with CNC - to get this sort of accuracy you'd need to use a boring head which is a manual process. It would easily eat up 3 or 4 days of time.
and then there's the radiusing!
 

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Modern technology makes mince meat of the job. I have access to a commercial cnc milling machine. It would take me about an hr to draw the item up with toolpaths. I just quickly roughed out a drawing of what your after and got the G-Code to calculate approx machine time, 2hrs 35minutes machining. Then polish and heat treat. If you asked some - one to do it by hand on a standard milling machine not computerised, then dig real deep.

However I agree with matt, stepped drawplate for reshaping a neck. Interesting
 

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Modern technology makes mince meat of the job. I have access to a commercial cnc milling machine. It would take me about an hr to draw the item up with toolpaths. I just quickly roughed out a drawing of what your after and got the G-Code to calculate approx machine time, 2hrs 35minutes machining.
Hmmm - if you can machine 180 holes to within 0.05 on one pass with one cutter and no measuring I'd be impressed.
 

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Discussion Starter #10
I don't know how american machinists charge per hour and other details but I estimate at least 1.5k to get good tooling for this task. Pictures? c'mon, we're talkin a plate of steel with a buncha' holes in it... [rolleyes]
You said you had 8 plates made. A picture would demonstrate the size of each plate and the configuration of the holes. Yes, I am interested in a picture that shows the design and construction of the plates you made, if you don't mind. It would be a simple matter to take a picture of one or more of the plates and post it in this thread so myself and others can see what we are talking about. Thanks.
 

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Discussion Starter #11
Thanks for your comments Matt. The idea is not to take out dents, but to alter the taper by shrinking certain areas of the neck tube to correct intonation problems. Expanding the diameter in certain areas using dent balls/barrels is no problem. It is making the diameter smaller that is the challenge. Techs like Mark Aronson must have something similar to this tool to re-taper sax necks and make them a better fit intonation-wise to the saxophone they go with.
 

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Hmmm - if you can machine 180 holes to within 0.05 on one pass with one cutter and no measuring I'd be impressed.
Be impressed then.
The cnc machine I use for this stuff has 24 seperate tool stations with an operating speed of 60,000mm/min. Its used every day to machine parts for aircraft, the tolerance and accuracy is 0.001mm. Next time Im using it Ill take a photo.

When you right G-Code for holes, you machine it 0.1mm undersize, so there is a safey border which allows for any tool flex during operation, then included after machining hole is clean up process where it machines to exact size. You do not peck drill in this situation but pocket machine
 

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Be impressed then.
The cnc machine I use for this stuff has 24 seperate tool stations with an operating speed of 60,000mm/min. Its used every day to machine parts for aircraft, the tolerance and accuracy is 0.001mm. Next time Im using it Ill take a photo.

When you right G-Code for holes, you machine it 0.1mm undersize, so there is a safey border which allows for any tool flex during operation, then included after machining hole is clean up process where it machines to exact size. You do not peck drill in this situation but pocket machine
Which was my point - you'd still need to come back and manually size each hole with a telescopic gauge so you can creep up on the desired size. Doing that 180 times would take at least a day or two if you were working hard. The other thing is that pocket machining never gives you a perfect round. This is why guide pins in injection moulds are still bored with boring heads to this day.

I know how they work, I was cutting ISO code in the 80's. and 90's On Mazaks, Fadals, HAAS and about 10 other machines I've forgotten the names of.
 

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Then you should know, you dont need to come back and telescopic measure the holes, maybe 20-30 years ago you had too, or today if you use a cheap cnc milling machine or one you made at home.

Since the 80's and 90's machine advancement has come a long long way.On top of this G-Code writing is nothing like it used to be either, The programs that right this stuff are in excess of 30K, just for the programs. The machines calibrate and compensate for tool wear, I know this becuase I have used this machine for the manufacture of aviation parts which have to be made to a manufacturing tolerance of 0.0005". And this is a measured tolerance carried out by NATA accredited laboratries, not just a lets state the tolerance.

Maybe in the industrial world, they are a bit more blazzay / persay. But aviation very controlled very regulated and very expensive.

That being said, it does not take away from my earlier comment

It would take me about an hr to draw the item up with toolpaths. I just quickly roughed out a drawing of what your after and got the G-Code to calculate approx machine time, 2hrs 35minutes machining. Then polish and heat treat. If you asked some - one to do it by hand on a standard milling machine not computerised, then dig real deep.
I am referring to me and the tooling I have access too, no body else.
 

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I haven't used one for over 10 years. If we're talking aluminium I wouldn't argue, but I am still skeptical that you would finish pass 180 holes in steel without checking as you go.

I wouldn't say what I used to do accepted "Blazzay" as a practice. I used to build injection moulds for the automotive and consumer industries where +-0.02mm was common place. The reality is you can't get closer than that unless you are in a temperature controlled room because the expansion coefficient comes into play - on hot days we had to calculate for it.

Simso - I'm not looking to argue, moreover I'd really like to see you do that in one pass in steel because I know for a fact up until the late 90's that was impossible on even the best DMG (German) machines.

Cheers
 

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Its all good mate.

I was not inferring your work is blazzay, I have no idea your work ethic / quality / standard and would not infer any discredit upon you or others, apologies if it came across as that.

I can only comment on what time it would take me to do it using the equipment I have at hand, nothing more nothing less.

When it comes to CNC, Im a kind of geek in that world, absolutley love it. (almost my hobby). Ive made cnc routers, made cnc mills, made cnc lathes, have access to a large range of commercial units from previous jobs. Still even sub-contract back at those places when there desperate, hence why I have open access to the machinery. I have my own cnc lathe my own cnc router and my own cnc mill, however these do not have the accuracy that is presented when using commerical quality units.

Currently Im purchasing a commercial cnc router 2400mm by 1200mm and a commercial cnc 3d laser scanner 1200mm by 1200mm. I wont buy a commercial lathe or mill as I cannot afford them or justify the purchase after all the two are in excess of 1/4 mill. But I have acces to them, and thoroughly enjoy using them

As you can guess I embraced modern machining a while ago. Feels funny almost running a lathe or mill by hand
 

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..Expanding the diameter in certain areas using dent balls/barrels is no problem. It is making the diameter smaller that is the challenge. Techs like Mark Aronson must have something similar to this tool to re-taper sax necks and make them a better fit intonation-wise to the saxophone they go with.
I would like to see the technique for doing the expansion and contraction as well as the technique for consistantly measuring the neck along the curve on the inside of the neck. I worked in an overhaul shop and have taken out many dents as well as modified tubing by expanding and contracting it, I can tell you that doing this in a work hardened brass metal tube (aka sax neck) to a consistant and measureable tolerance of some sort would be very difficult for me. I would personally have difficulty with this and I consider myself excellent at working with the brass in musical instruments.

Is there known measurement data to support the theory that modifying the neck in certain areas will affect intonation in a certain way, or as I suspect the technique is to attempt to match a sax neck taper to a known good/well playing neck? OR, Is the goal to be able to go to a repairer that is good at this technique and say, my sax plays sharp/flat in this range, can you retaper the neck to solve this problem? If you or anyone else does this successfully and can teach us to do it, I would love to learn it.
Matt
 

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Simso,
So do the shops you have access to charge an hourly rate for you to do this kind of stuff, or is it a matter of letting you use the machines during down time because you have a working relationship with them? I suspect the later.

Even if the drawplate can be done in the length of time you suggested (I don't doubt that it can) the hourly rate for machining on one of those machines has to be astronomical for us mear mortals in the DIY CNC realm. I would suspect that the real cost of making low volumes of something like this plate on high tech CNC would be similar to days of working on manual machines to make the plates.

FYI, I got to go see the automated blood pressure cuff manufacturing line that Welch Allyn started a few years ago. They make single user blood pressure cuffs as well as many other medical devices. High tech automation is just amazing to watch running and it has helped to make our lives so much better and more affordable. You would have loved to see this...I'm a CNC Geek as well.

Matt
 

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Yeh mate, they charge about 300 an hr plus material, my stuff is free - good working relationship. The machines are going non stop most days, making aviation seats / bearings / bushings / undercarriages / rams all the stuff that manufacturers make

However when I want to do my stuff I also do there stuff at the same time,running g54 and g55 offsets. Means they get a free machinist for a few hrs. Also means I tool up for a couple of jobs, not to sure if youve ever used a cnc with tool carousel. But you set the tools needed for the job, first physically fit them into each individual holder, then zero each tool in all 3 axis's then load the tools offsets into the machine, calibrate the machine offset for each tool, then run your g54's for each job position and set new homing positions relevant to each job, then obviously when your writing your g-code call the right tools. Hit the go button and hope like hell you programmed it all right, my point being it takes a while to set up each job, hence me jigging and setting up there jobs as well as mine saves them money,

Most jobs the shop does, are yes no less than a 1000 odd dollars at a time, sometimes one job can be worth 20k plus, Ive known the machine to be running non stop processing one batch order for about 46 odd hrs. Definetly out of the reach of us mere diy'rs
 

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Discussion Starter #20
I would like to see the technique for doing the expansion and contraction as well as the technique for consistantly measuring the neck along the curve on the inside of the neck. I worked in an overhaul shop and have taken out many dents as well as modified tubing by expanding and contracting it, I can tell you that doing this in a work hardened brass metal tube (aka sax neck) to a consistant and measureable tolerance of some sort would be very difficult for me. I would personally have difficulty with this and I consider myself excellent at working with the brass in musical instruments.

Is there known measurement data to support the theory that modifying the neck in certain areas will affect intonation in a certain way, or as I suspect the technique is to attempt to match a sax neck taper to a known good/well playing neck? OR, Is the goal to be able to go to a repairer that is good at this technique and say, my sax plays sharp/flat in this range, can you retaper the neck to solve this problem? If you or anyone else does this successfully and can teach us to do it, I would love to learn it.
Matt
All I know at this juncture is that increasing the taper of a conical woodwind brings the partials closer together, and decreasing the taper makes the partials farther apart. Benade gives a formula with which to estimate the changes. The the extreme case of decreasing the taper to the point the cone becomes a cylinder causes the 1st partial to expand from an octave to an octave and a fifth as in the case of a clarinet.

Also, from Benade and Ferron - contracting the diameter of an air column at a pressure anti-node raises the frequency of that particular mode. Conversely expanding the diameter at the same location lowers the frequency of the same mode. At least in theory if one could identify the exact location of each of the pressure anti-nodes inside a saxophone neck for each individual note and the first 2 harmonics of that note, then it would be possible to make small adjustments to the intonation of that instrument. This would give the tech another tool in addition to crescents and key heights to address intonation issues.
 
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