My first attempt at key casting

[peeplj]

Jon C., thanks for the great pics and info!

--James

[Jon C.]

Hi Jon,

You might consider a more direct casting approach, similar to sand casting. Specifically look at these clay casting kits that Rio Grande sells (not precious metal clay). I occasionally use this approach and the results are fantastic once one gets the hang of it. I'd use it more except my torch is barely up to the task of melting larger quantities of metal.

Some cleanup is required but not much. However, I've found this approach to be no faster than my usual fusing, forging and cutting methods, which I've got down pretty quickly, with the aide of a few special tools, such as an in-cannel bevel chisel I had a friend forge for the inside curves of the key touches. What takes time is the fine tweaking of things which the forged metal allows - whereas the cast metal has a crystalline structure sometimes that will fail eventually if tweaked too much.

Good luck with your casting attempts.

Casey

Hi Casey,
I did look into using the clay casting, but I am trying to avoid the 10-20% shrinkage that you get with this process. I will get the clay casting set up also, along with a centrifuge casting set up, which looks like a lot of fun also... I have several antique flutes that need missing keys, so the shrinkage has to be minimal. With the "no shrink pink rubber and the low shrinkage wax, there is 0 shrinkage in the key. Another nice thing about the lost wax is I can replicate as many keys as I want, once I get the rubber mold made. Usually the jeweler would just take the wax models to a caster, and they will cast at a minimal fee, I ma just doing it for the fun factor...

Cold forging is definitely the best quality way to go about making keys, but I have yet to run across a antique flute that had cold forged keys, thye have all been cast. Since they are for the most part still functioning after 170 years, I figure that the keys on my flutes will be all right until the warranty runs out (another 30-40 years...) when I kick the bucket! I think the foot keys would be the most challenging keys to cold forge, I know the short F is not much fun, getting it wrapped around the flute!

[Jon C.]

Interesting stuff!
I've wondered for a long time (ever since visiting the Cutlery Museum in Sheffield about 14 years ago) why no-one seems to use hydraulic pressing for flute/general woodwind keys like they do to make forks and spoons? I do understand that making the steel dies would be expensive, but once done, you would be able to churn out keys very easily, all in one piece and in need of very little finishing. (Do the modern Japanese flute factories use this process at all?) The very curved ones like the short F might have to be done slightly flattened and then hand worked into final shape. I don't know the full technical details of the process, but I believe it gets you completely away from working with molten metal - you just need bar or sheet stock cut to appropriate size blanks for the press.

It would be a big investment, I'm sure, but no worse than the learning process Jon is going through with casting - and I know others have gone through that too - and with the growth in the number of makers playing this particular game, couldn't they club together on it? Besides, there are probably specialist silversmiths using such techniques already out there somewhere, and I believe some flute makers out-source their cast key work in such fashion anyway!

Avoiding wheel reinvention always seems a good idea to me, provided that it can be done in an economically viable way, though I know that it is sometimes better to learn the new skills and work from scratch for oneself when out-sourcing is prohibitively expensive or there is simply no-one available or prepared to do the specific work you want.

hi,
I think that lost wax casting is the most cost effective way to go for making keys. To set up a press like you describe would be quite a cash outlay. The industry has been using lost wax for a number of years now, it was developed about 3,000 years ago in India, to make statuary Deities. I can crank out wax copies with wax injection, about 1 every 3 minutes. These can be cast on trees or sent out to a caster for a minimal charge. With the new sterling silver alloys like Argentium Sterling® Silver, the silver is tarnish free and will be stronger then regular silver. I am using a low firescale silver for my casting, I didn't go for the Argentium, until I am a little more practiced, if I am going to make a puddle of silver out of it, it might as well be the cheaper stuff!
I actually like to make molten metal, so I guess I will stick with this process.
Where is our expert Gold smith when we need him?

[azw]

Can flute keys be tossed (cast) for divination (predicting the future etal.)?

Yeah, I get it now, but that was the first image that ran through my mind as I read the title of this thread!

Jon, there's a new niche for you "Jon C. Runes"! Instead of cards, you could make the physical characters, which look a little like flute keys.

That's very interesting, Jon. Thanks for sharing the pics!

[jemtheflute]

Hi Jon, thanks for your response, and for sharing all this with us! As an ex-archaeologist, I know (i.e. have read or been lectured to) a fair bit about ancient technology and technological development, so I know the antiquity and efficacy of lost wax, at least in theory. What I don't know are the actual practicalities of trying to do it! I've had more or less serious goes at various ancient and traditional crafts and technologies (e.g spinning and weaving), but never metalwork. I also know that all the C19th flutes had cast keys and that there must have been reasons why they continued to make them that way (probably because they were tooled up, had the skills in-house and weren't in the market for a big enough volume to be worth changing?) when the cutlery industry moved into die-pressing.

In a thread a couple of years ago on Woodenflute Robert Bigio described how Rudall Carte's craftsmen were hand cold-forging the cups/platters for Boehm flute keys by die stamping them into a lead block with a hammer, then assembling by soldering, in the 1950s! I'd guess that a mechanised equivalent is probably the norm in modern flute manufacture.

[Jon C.]

Hi Jon, thanks for your response, and for sharing all this with us! As an ex-archaeologist, I know (i.e. have read or been lectured to) a fair bit about ancient technology and technological development, so I know the antiquity and efficacy of lost wax, at least in theory. What I don't know are the actual practicalities of trying to do it! I've had more or less serious goes at various ancient and traditional crafts and technologies (e.g spinning and weaving), but never metalwork. I also know that all the C19th flutes had cast keys and that there must have been reasons why they continued to make them that way (probably because they were tooled up, had the skills in-house and weren't in the market for a big enough volume to be worth changing?) when the cutlery industry moved into die-pressing.

In a thread a couple of years ago on Woodenflute Robert Bigio described how Rudall Carte's craftsmen were hand cold-forging the cups/platters for Boehm flute keys by die stamping them into a lead block with a hammer, then assembling by soldering, in the 1950s! I'd guess that a mechanised equivalent is probably the norm in modern flute manufacture.

Here is what I found on Google:

The Manufacturing
Process
Shaping the components

A flute is made of hundreds of components, ranging from the relatively large body to tiny pins and screws. Although some of the small components are interchangeable and can be purchased from outside manufacturers, the vast majority of the components must be individually shaped for each flute.

* 1 Early flutes were made with hand-forged keys. The modern method is usually die casting. Molten metal is forced under pressure into steel dies. A group of connected keys may be made in one piece. Alternately, individual keys may be stamped out by a heavy stamping machine, and then trimmed.

So it looks like they are already using your idea.
Still for the eight key variety, i think a lost wax casting is probably the best way to cast and most cost effective.

[jemtheflute]

So it looks like they are already using your idea.
Still for the eight key variety, I think a lost wax casting is probably the best way to cast and most cost effective.

Indeed; hardly "my" idea, nor did I think it so! I'm sure you (as an active practitioner) know exactly whereof you speak. Me, I'm just musing and asking questions...... informed ones, I hope!

[Jon C.]

Can flute keys be tossed (cast) for divination (predicting the future etal.)?

Yeah, I get it now, but that was the first image that ran through my mind as I read the title of this thread!

Jon, there's a new niche for you "Jon C. Runes"! Instead of cards, you could make the physical characters, which look a little like flute keys.

That's very interesting, Jon. Thanks for sharing the pics!

Yes, I am beginning to see my future...

[kkrell]

In a thread a couple of years ago on Woodenflute Robert Bigio described how Rudall Carte's craftsmen were hand cold-forging the cups/platters for Boehm flute keys by die stamping them into a lead block with a hammer, then assembling by soldering, in the 1950s! I'd guess that a mechanised equivalent is probably the norm in modern flute manufacture.

The key cups on my Boehm flute by Ewen McDougall (50 years at Rudall Carte and Flutemakers Guild of London) were hand stamped by him. That was in the 1990s.

Kevin Krell

[kkrell]

Yes, I am beginning to see my future...

Then stop sprueing around.

Kevin Krell

[Jon C.]

In a thread a couple of years ago on Woodenflute Robert Bigio described how Rudall Carte's craftsmen were hand cold-forging the cups/platters for Boehm flute keys by die stamping them into a lead block with a hammer, then assembling by soldering, in the 1950s! I'd guess that a mechanised equivalent is probably the norm in modern flute manufacture.

The key cups on my Boehm flute by Ewen McDougall (50 years at Rudall Carte and Flutemakers Guild of London) were hand stamped by him. That was in the 1990s.

Kevin Krell

Here is his bios:

Ewen McDougall

1. STARTED: I went straight from school to Rudall Carte in 1950.
2. TRAINING: I began a five year apprenticeship with RC, at that time it was the only place in the U.K. where one could find such an opportunity. I worked there (less three years in an army band) until 1961. At that time I joined Flutemakers Guild, remaining there until 1983. Since then I have been working independently.
3. HOW MANY: I have just sent No. 34 to the USA where it has been well received. Although I only make flutes, I make heads for flutes and piccolos.
4. MATERIALS: Silver and gold are my usual materials. I leave wood to Flutemakers Guild and Robert Bigio, who have all the skills and machinery needed. Silver, after wood, is the traditional material for giving a good sound and lasting qualities for an economic outlay. Gold is fine for a celebration or outward display, platinum is too costly and it looks uninteresting.
5. PITCH: Everyone plays different. I aim at A=440. Why have 442, pull out the head to get one note right: all the lower notes are relatively sharp, higher notes are flatter because the left hand holes (vents for the upper register) are too far down the tube since you pulled out the head to start with.
6. PLAYERS: I made a complete 9ct gold flute for the first flute in the Minnesota Orchestra in 1985. Sadly he died and the flute has passed to another player. Another 9ct flute was finished in 1996. Some of the students for whom I have made flutes, are now finding orchestral and solo places.
7. OTHER MAKERS: I suppose we all adopt certain good features of the work of others; this is necessarily a backward look, seen from today! Although some clean and tidy workmanship is seen, the character and style is not present these days, to the same extent. The commercial look is in.
8. DO YOU PLAY?: I had lessons with Harold Clarke, and later a few with Geoffrey Gilbert. I enjoy playing but not reading music, which I find very hard work! Having some knowledge of the instrument is a help with understanding flautist’s difficulties.
9. SPECIFICATION: I don’t need to advise people about what sort of flute they need. They usually have a good idea before they get to me. I think no one is bothered these days by wall thickness. In 1961 it was different. Open holes are OK for those who can cover them – but they do make fingering more tidy. I offer a G key hole half offset, which makes life a lot easier. I’ve seen some open holes so far offset I play behind the hole! B foot joints darken the sound a bit and are useful for the B, but can you find the C when you need it? I don’t like E mechanisms. Play open G sharp.
10. RETUNING & WOOD: I’m not happy about knocking an old silver flute apart and refixing all the holes in new places. Often the keywork is not rebuilt properly so that the cups cover holes accurately and reliably. I’ve seen a fair number with funny heads and odd lip plates. Given that the head produces the best part of the sound, is this the right thing to do? Wood flutes of high pitch A=452 can only be rebuilt properly one way – new low pitch body and the mechanism properly rebuilt onto it. Only a few people would ever be able to tell if it had been modified. Robert Bigio has made several low pitch bodies for which I have rebuilt the mechanism, they have been very successful. I am very pleased to see Flutemakers Guild sending so many wood flutes around the world. If Rudall Carte had adopted the rectangular embouchure shape, a bit smaller, and used the right size in the head tube, allied to a deeper chimney, the silver flute might not have had such an easy time of it!
11. FUTURE: Makers are finding new methods of production, which can lead to commercial standards. The individual makers will find their own ways, but they start minus that training or apprenticeship which is all important. New materials are being tried for head joints, albeit at high cost and possibly involving gimmicks. On expensive flutes there is a sad tendency to use carbon steel (silver steel/drill rod) for mounting the keys, instead of stainless steel. Often there is no steel point in the F sharp pillar to carry the ends of left- and right-hand rods.
12. OTHER COMMENTS: I have always been interested in presswork and I have made a set of tools to produce chimneys for heads. Another process I have just finished is the making of tools for the open hole cup. This comes out of a silver bland disc, hole and all! Probably nothing new in this, but satisfying for me. I make all my flute parts for keywork from 4mm and 5mm square silver. No castings anywhere on my flutes.

Well he has only made 34 flutes so far, so I guess he takes his time! What is the serial # of yours, Kevin?

[Tjones]

Jon

I'm watching with interest. The different methods tend to be suited for different situations. If I want an exact copy I'd use the mold process and lost wax, like what you've done. Just a word about spruing, though, make sure everything runs downhill like the example on the right in your picture. The one set up in the center must fill from either side and there might be issues of porosity which would weaken the key. I haven't done to much with silver over the years other than making models, and never Argentium Sterling® Silver. I'm mainly working in gold and Platinum, Although, I just finished my first palladium ring this last week. The Hi tech way would be to scan the keys and use you cad-cam stuff to make your models and modify them to suit, and then mold them. I must say though, it can be very satisfing banging on silver, a good way to release tension.

Tom

[Jon C.]

Jon

I'm watching with interest. The different methods tend to be suited for different situations. If I want an exact copy I'd use the mold process and lost wax, like what you've done. Just a word about spruing, though, make sure everything runs downhill like the example on the right in your picture. The one set up in the center must fill from either side and there might be issues of porosity which would weaken the key. I haven't done to much with silver over the years other than making models, and never Argentium Sterling® Silver. I'm mainly working in gold and Platinum, Although, I just finished my first palladium ring this last week. The Hi tech way would be to scan the keys and use you cad-cam stuff to make your models and modify them to suit, and then mold them. I must say though, it can be very satisfing banging on silver, a good way to release tension.

Tom

HI Tom,
I agree with your thoughts on the spruing, that was a early photo, I added a sprue in the center, before casting. These key shapes are a challenge for getting the sprue right... If I could only figure out that Cad/cam program, I could make them with the CNC, and then could dimension them properly. I just can't afford the $10k program that I would need!
Palladium looks interesting, "The look of Platinum at the price of gold" a little pricey for my keys...

[Tjones]

Jon,

I'm looking at a program called Rhino for under a grand.
http://www.rhino3d.com/ - but then I need all the other stuff to make it happen.

Cheers,

Tom

[Jon C.]

Jon,

I'm looking at a program called Rhino for under a grand.
http://www.rhino3d.com/ - but then I need all the other stuff to make it happen.

Cheers,

Tom

Rhino is a good 3 D modeling program, but then you need a cam program to turn it into G code, that is the language that talks to the CNC mill. A program like Bob Cadcam or Surf cam is another $2 k! The $10 k program has the built in macros to generate everything in 3D, it has a ll the basic ring models for you to build on. I don't know how it would work for keys though... you can get a CNC mill for around $2K and a rotary table for about $300 and you are in business...