rob moore

Uilleann and Northumbrian pipes, Hurdy Gurdy, Lira Organizzata, Eclectic Instruments

A Method of Key Making For the Amateur Builder

This article first appeared in the quarterly journal, “The Pipers’ Review” winter 2004 of the Irish Pipers’ Club, Seattle.

I believe that for the amateur builder, the making of keys can be one of the largest stumbling blocks on the road to making a set of pipes.  Key making falls somewhere between the trades of jeweler, machinist, and metal fabricator.  It is far removed from the type of experience that might befall many a fine Canadian lad while being directed through the educational system.

It is not the kind of work that many people would be trained in doing.  Nor is it the kind of thing that one might encounter with many hobbies or pastimes.  Yet it need not and should not deter you from the goal of making your own set of pipes, or for that matter adding a key or three to a keyless chanter so as to increase it’s range. Why, even a 17-keyed Northumbrian Small Pipes chanter need not daunt the ‘Amateur Builder’ once he or she has mastered the procedure.

A Brief Look at Metallurgy

Keys may be made from various materials using a variety of methods and designs.  I will concentrate on describing the simplest method that I know of which is relatively non specific for choice of metals.

However, to give an appreciation of the scope of metallurgy for the amateur craftsman, I will give you a brief sketch of the Copper family.

The two terms, Brass and Bronze, have been misused and confused ever since the Neolithic Age, perhaps for as long as 3000 BC.  To name but a few ambiguities: Commercial Bronze, Tobin Bronze and Jewelry Bronze are really Brasses and Nickel Silver contains no silver. It is not within the scope of this article to sort out or even give a reasonable account of the subject.  I will deal with the making of keys and leave the metallurgy to fester for another 5000 years.

Brass is in the family of Copper alloys, as is Bronze and Nickel Silver (German Silver).

It is inexpensive, readily available, and is well up to the strength and durability requirements that even the toughest piper can give it.  It is also one of the most suitable metal for electroplating with silver, gold, nickel, etc.

Basically, Brass is an alloy of copper and zinc.  The proportions of copper and zinc vary greatly.  Alpha alloys contain more than 62% copper and are known for their malleability and cold working properties.  As the copper content goes up the malleability becomes greater and the color goes from yellow towards red.  Color has always been used to describe copper alloys, thus terms like “red brass” and “yellow brass”.  Other elements are added to yield the desired properties.  A very small percentage of lead in the brass improves the machinability.  Iron, tin and even small amounts of nickel are used to increase the strength.

Bronzes are copper, alloyed with various elements including: tin, silicon, nickel, manganese, lead, aluminum, phosphorus, and others.  Percentages vary vastly, according to the intended use, the grade of the alloy and the manufacturer. Aluminum Bronze often has as much as 12% aluminum but when it comes to Phosphor Bronze it has much less than 1% Phosphorus, with typically 95% copper and 5% Tin.

Other members of the Copper family are Nickel Silver and Beryllium Copper:  The nickel content in Nickel Silver can vary from 10% to 20% or more; the copper content can vary from 50% to 72%; and the Zinc content can vary from 18% to 32%.

One group in the copper alloy family that stands apart from its relatives is Beryllium Copper.  This family of alloys contains copper, beryllium, cobalt, and sometimes silver.  It should be noted that Beryllium is a toxin and before working with it, one should become familiar with the proper safeguards.

Metal Hardness.

There is a correct alloy with the appropriate hardness for everything from a die casting to a spring with excellent electrical conductivity.  Copper alloys can come in hardnesses ranging from annealed (full soft) up to full spring (full hard).  The hardness of an alloy is determined by its contents, by the degree of work hardening it received while being rolled in the manufacturing process, and the heat-treating. Examples of heat-treating are: annealing to soften, low temperature heat-treating and precipitation hardening.  In spite of working for over 30 years in an environment were a metallurgist was never far away, I know little about the art.  It is actually a black art and I got the impression that some metallurgists thought so as well.

Not to worry for little of the above information on metals is pertinent if you follow the procedure described below. The method will work with almost all copper alloys.  It involves no forging, casting, extreme bends, and requires only a minimal number of tools. No power tools are necessary.

The key making described in this article is the C natural.  It is the most straightforward key to make and it is the most common key to be found on the uilleann chanter.

Tools and materials required:

Vise with smooth jaws

Files: 3 squared bastard, a 4 inch pillar, and a few flat smooth

6″  steel rule

A small hacksaw

A screwdriver

A scriber

A small center punch

Propane torch

Silver solder (as described in the text)

Handy FluxTM

A few fire bricks,

An abrasive pad  (as described in the text}

Various grades of abrasive cloth. 120, 240, and 400 grit.

Straight-pattern sheet metal snips.

A small ball peen hammer to rivet the spring in place.

A pair of round nosed pliers to bend the bearing end of the spring.

A pair of pliers to avoid hand contact with the hot metal.

A small countersink.

A drill press or an electric drill.  A hand drill would work fine but most people these days are more apt to have an electric drill or a drill press.

1/16″ drill bit (for drilling two holes in the key. One that will take the rivet and another that will take the pivot pin)

1/16″ diameter. Brass rod/wire for rivets and pivot pin.

1/16″ X 3/8″ Brass stock/strip.

1/8″ X 1/4″  Brass stock.

3/8″ hole punch

A small piece of soft leather.

An Adhesive for attaching the tone hole pad.

Other items that would make life easier:

Pickling compound to remove the hard flux scale after silver soldering.

Polishing compound,

Polishing wheel that would fit on a bench grinder

Words and random thoughts on tools and materials:

Any of the tools and materials required to get this job done may be acquired at your local hardware store, a jewelry supply store, a welding supply store, a recycle yard, or borrowed from a friend or neighbor.

Files need to be sharp just as knives do but if they are shiny and dull don’t throw them away they make great ‘other things’ for example a large half-round makes an excellent reed making gouge and a three squared (triangular) file makes a great scraper, the type used in machine shops around the world.

3M Scotch-Brite TM maroon and green abrasive pads are also very useful for getting a super fine finish on lathe turned pipe parts.  Using a strip of pad against the work-piece while it is turning at maximum speed on the lathe, followed up with a buffing, will give a magnificent finish without removing fine details, as a strip of abrasive cloth is prone to do.

The vise will need smooth jaws.  The cross-hatching that most vises come with will chew up your work piece.  One way of remedying this would be to cut two thin strips of brass, and adhere them to the existing jaws.  Some vises come with plastic faced jaws, not the best when the filling gets tough.

Larger vises come on sale often, but a good small yet inexpensive vice is more difficult to find.  I am a man with vices.  I have a jewelers vise with 1 3/4″ jaws that is great to use, but for the article I am using a vice with 2″ wide jaws that I got at our local Canada Tire Store.  I think it was made in China and it was a fraction of the cost of the jewelers vice.

Key Design.

Designing the key to fit your chanter will be dependent on several factors:  does your chanter have a key mount?  If so is it slotted to take the key?  What is the width and depth of the slot?

If your chanter has no mount, (like the chanter shown in this article)  it would be within the range of the amateur maker to make one and fix it in place; however the ethical issue of tampering with another maker’s work arises.  I will assume that you are building your own chanter or you have communicated with the original maker and he or she is comfortable with the idea.

Procedure:

The key is made in two parts: the key top (Part A), and (Part B) the underside, which locates the key in the slot.

Cutting and Shaping the Components

Part A: Start by laying out the key’s top profile onto a stiff piece of paper.

Cut the pattern and hold it up to the chanter.  Check to see that the pad end of the key covers the tone hole and you are happy with the length and shape of the key. Mark the position of the pivot position onto the paper.  This will be the reference for the pivot hole on Part B.

fig-1

Fig.1: Key pattern on brass strip.

Glue the paper key to a piece of 1/16″ X 3/8″ brass that has been cut to length. It may now be referred to as the work piece.  Take the work piece and place it in your vise.

fig-2

Fig. 2: filing key profile

With the work piece held firmly in the vice and the outline of the shank just above the jaws, proceed with the shaping.

A useful tool for shaping is a 6″ three squared bastard file.  I know why it is called a bastard but why is a triangle file called three squared?  I think we must keep in mind the fact that those tool designers who authored the terms got their start as engineering students.  We know about them, they are known for things like drinking too much beer and taking automobiles to pieces only to be reassembled on the tops of buildings.

One of the corners of the file may be used to start the shaping in the area above the tone hole end.  When you get close to the line, level off the file and shape away.  It is an aggressive file and in a minute or two you will have a pile of filings.  As the key profile approximates the paper key template, you can change to a smoother file.

When shaping the tone hole end of the key, a small flat smooth file with the teeth missing on one edge, known, as a pillar file, is very useful.  They are double cut with one edge safe (uncut).  I have a 4″ Swedish made Pillar file that finds more uses in pipe making than any other file that I own.  The one sided cutting edge will focus your work in specific areas.  It is just less than 1/8″ in thickness, making it also ideal for cleaning up or widening a key slot.

Make sure the section of the key that you are filing is well supported in the vice and not hanging out where it is liable to get bent.  A flat surface is essential when soldering the two components of the key together.

Now that you have a key shaped piece of brass with the shank section left slightly over-size, you are ready to make the underside of the key (Part ‘B’) that will be silver soldered to Part ‘A’.

You will need to determine its shape by the position of the pivot on Part A, and the depth by the slot size. You may want to make a paper template, or scribe its shape directly onto a piece of 1/8″ X 3/16″ brass that has been cut to length.

fig-3

Fig 3: A finished key shown with the two main parts for a similar key.

Leave a generous amount of material as the key’s final shape will be filed further when the two pieces have become one.  When the parts are supporting each other, the finer filing procedure is easier.

Now comes the time when the two shall be one, never to be parted.

Soldering

“Set up your work space:

If you haven’t a fume hood in your shop, it would be safer to do the soldering outside.  Your soldering surface may be a firebrick.  Station additional firebricks to the sides and back.  This acts as a furnace and holds in the heat.  When you are using only a single hand-held propane torch with the large tip, it will be easier to reach the flow point with the firebricks arranged in the furnace mode.  Avoid the bright lights, for by the time you see the metal turning red in the bright light, it is too hot. Over heating will vaporize the zinc in the alloy and cause all sorts of problems.

Silver soldering:

If your first question is “Why silver solder, when soft soldering is faster, easier, and cheaper?  I would have to say, ” Soft soldering would be a marriage of metals that could easily end in separation.”  I have run into pieces of pipes that had been joined together for years, and without warning, have fallen apart.  Reuniting them can be problematic.  The problem is that even the slightest trace of the old soft solder could render the reunion a failure.

Silver solder comes in various alloys and forms.  The alloy I used here is ‘ Fast Flow Silver Alloy’,  it has 45% silver, a melting point of 1125F, and a flow point of 1145F. It comes in wire and strip form.  For this article I am using silver solder that comes in a 1″ wide strip X.005″ thick.

Soldering preparation

A good bond is dependent on the right conditions.  The area of the join must be free of oxides, and all contaminants.  Even fingerprints or pencil marks must be removed.  Make sure you can see no light between the pieces, if you can see light, the key top probably got bent and must be straightened.  Next, give the pieces a light rub on a strip of 400-grit emery cloth on a flat surface.

By using a strip or shim of solder you will have both hands free for controlling the heat in the soldering operation.  Cut out the solder to the same width and length as part B. The silver solder is best cleaned by pulling it through a 3M Scotch-Brite TM maroon abrasive pad or equivalent to remove any oxides or contaminants. At this point I wash my hands, boil water and have a cup of tea.

Next I take a ‘Q’ tip TM that has been soaked in acetone and wipe down the pieces.

Handy flux TM can now be sparingly applied to the matting surfaces of Part A and Part B.  It is not necessary to put flux on the solder shim, it will receive its coating in the sandwich.  Put the pieces together in their correct position with the shim forming the sandwich.  It helps the pieces stay in one place if the solder shim is flat. The shim can be made to be flat by pulling it gently over the edge of your fingernail.  Be sure to re-clean with acetone.

Soldering the work together:

Place the sandwich onto a firebrick.

With the flame of the propane torch playing over the key assembly and the lights turned down low, it is only a mater of a minute or so before everything is up to temperature, and then that magic moment occurs and all parts become one.

Handy Flux becomes clear and fluid at 1100 F, that lets you know you are getting close to the flow point.  When the temperature gets up to the flow point, the two pieces might try to slide around, so a light touch of the screwdriver (one that you don’t mind getting too hot and losing its temper) will hold the two parts of the key in position until the temperature drops and the two are one.  It takes only seconds to cool to that point.  It will take longer to get the heat to the flow point.  It is important that all pieces being soldered reach soldering temperature simultaneously.

An advantage of a silver solder shim sandwich, is that when the temperature reaches the flow point, everything flows together and you are less likely to over heat your work.  Another advantage of the shim sandwich is that you are less likely to over solder.  A well-soldered joint is one that you cannot see.

fig-4-sil-sol

Fig.4 The key components in position for soldering, with the silver solder shim in place

After the Key (‘the work piece’ has now become ‘the key’) has cooled, it may be held in the vise and filed to shape and size.  File the shank with a smooth file until it will fit into the key slot.  File away the excess metal, until the lines flow without a step, so that the spring will have room to work, and so the key will not look too clunky.  Round off the top of the key, starting with small files and finishing with narrow strips of emery cloth.  The lighter the key, the less work for the spring.  As long as it’s structural integrity is not compromised, the lighter the better.

fig-6-key-shaping

Fig. 6: filing the rough key in the vise

The Spring

Material

Phosphor Bronze is my alloy of choice when it comes to springs.  Typically Phosphor Bronze contain from 3-10% tin.  The strength increases with the tin content – hardness ratings range from soft to extra spring.  As the metal gets harder, the tensile strength increases dramatically.  Anything from extra hard, to extra spring, should work fine, although extra spring might be a little on the hard side if you were to use a very sharp bend on the bearing end.  The bearing end of the spring is the end that bears against the body of the chanter.

It can be purchased in sheet metal form in various thickness and hardness ratings.

For this key (C natural) I used .020″ thick, with a hardness of spring.  If your key is heavier or if you favor a heaver key action try, say, .025″.  If you don’t know how hard the spring metal you are using is, then it wouldn’t hurt to err on the large side and file and shape it to were you like it.

I usually make a tapered spring as I feel it gives a progressive spring action.  Phosphor Bronze may be cut to shape using a pair of sheet metal snips.

Take out any twist from the spring, then, using a pair of round nose pliers, curl up the bearing end as shown in Fig 7.  Round off the ends, remove sharp edges, and polish the bearing end for a smoother action.  With the spring held between both hands, carefully form the gentle curve that will give the spring it’s spring. Fig 7

Now drill a 1/16″ diameter hole through the key and the spring in preparation for riveting.  Countersink the top of the hole. Take care not to go too deep.

fig-7psd-copy

Fig.7: finished key with spring components and countersink in position.

The Rivet

The rivet may be made from a short length (.2″ max.) of 1/16″ diameter brass rod or wire.

If you want it to be invisible, you may use an alloy of the same color as the key.

However, the less the Zinc content of the brass the better it is for cold working.  No matter the alloy, it will need to be annealed to attain a desired state of softness.  So turn down the lights, set your Phaser to recrystallize, and slowly bring the brass up to a dull red, hold it at that temperature for a few seconds and let air cool.

Riveting:

The riveting method suitable for our requirements is refereed to as Flush or Invisible riveting.  You won’t need ‘The Cloak of Invisibility’ for this job.  If the rivet is a close color match to the key and you are careful peening the rivet into the countersunk hole, then it should in fact disappear.  It will further increase your chances of invisibility if you start with a rivet that is the correct length with squared off ends.  Don’t try to make the under side of the rivet invisible.  The spring is a little thin to be countersunk and besides the extra size of the head of the rivet will hold it all together.

For a work surface, I use a recycled piece of 1″ steel plate with the edge rounded off.  The radius lessens the likelihood of damage to the key.  To shape the underside of the rivet while allowing the key assembly to sit flat on the steel plate, I drilled a shallow 3/32″ hole close to the edge of the plate.

image015

Fig.8: Riveting spring to key.

rivet-detail-1of-fig-8-copy

Hammer away until the rivet has completely filled the countersink.  You might want to turn the key over and give it a final tap to flatten the rivet against the spring.  Keep in mind that all this hammering is work hardening the brass; so do not get carried away with the hammering.

Finish off the key top with a file, strips of emery, and then polish.

Fitting the key to the chanter:

Now that you have a shiny new key all it needs is a home.  This is where it must undergo bending to make adjustments.  Before you start bending, the tone hole end will need a pad.  You can use soft leather, punched out with a 3/8″ hole punch and set in place with an adhesive of your chose.  My choice is shellac.  I heat the end of the key using an alcohol lamp; melt a dab of button shellac onto the hot surface and place on the leather pad.  Only use enough heat to melt the shellac and not enough to remove the temper from the spring.

The tone hole end will probably require bending slightly so that it seals the tone hole. The touch end will need bending to set the amount of key travel.

While bending, use a scrap of soft leather between the key and the vise jaws so you will leave no marks on the key.  When adjustments are done, a small soft leather pad set onto the underside of the touch end of the key will make for quieter key action.

With the key held in place in its keyway at the right height and with the tone hole centered to the key’s tone hole end, make a mark on the key through the pivot hole in the mount.

Take the key out of the mount and center punch the mark that you made with the scriber.  The center made by the center punch will ensure that the drill does not walk around when you are drilling the pivot hole.  Make sure the key is held down firmly.  Drills have a tendency to pull themselves through brass.  You don’t want to see the key pulled from your grasp, spun around at high speed and thrown across the shop.  If you took a small hone and gave the drill a few light strokes at a right angle to the cutting edges, it would help in getting a safer, better and more accurate hole.  All that is required now is a pivot/axel pin made from a short length of 1/16″ diameter hard brass.  It may be held in place by deforming one end slightly in order for it to jam in the key-mount hole.  There are other ways of doing it but this seems to be the simplest way.

fig-9-key-in-chanter

Fig. 9: Key in place on chanter.

Well this might not be your key to pipe making but it could be a key for your pipe. If you ‘give it a go’, this method should work for you, and if you decide to make pipes, you will no doubt develop your own method of making keys.  I hope I have in some way shed a little light on the subject and maybe removed a stumbling block from your path.

Incentive

I knew a man years ago by the name of Bill House.  Bill was in the British army stationed in Hong Kong when it fell to Japan in the early stages of WW2.  Bill along with several thousand Canadian and British prisoners was used as slave labor and was moved from various locations, ending up in a gun factory.  His job, along with hundreds of other prisoners was to scribe the profile of gun parts onto small pieces of steel and file away, all day, every day until the war was over.  Guards walked up and down the rows and rows of benches to make sure you weren’t having fun.

If you didn’t do your quota or your work wasn’t up to the standards, you got nothing to eat that day.  Complaints were cause for beatings and absentees were shot.

It was amazing how many prisoners from all walks of life were able to master the required skills and still get their bowl of rice.

Now I don’t offer the same incentive program, however I am confident that any reader that ‘gives it a go’, can come up with a well made key that will give you years of service.

I would like to thank my friend Gordon Pollock for his talents in photography.  Gordon with his digital camera captured most of the images for this article.

To find out more about keys, springs, and their design-go to your library and take out Vol XXI No 2-Spring 2002 of The Pipers’ Review and read or reread David Quinn’s very fine article on the subject.

To find out more about silver soldering or metalsmithing, I recommend the book     “The Complete Metalsmith” by Tim McCreight.  It should be available at a jewelry supply store or a rock hound shop in a city near you.

If you want to find out more about making keys, or for that matter, more about making a set of pipes, check out Mike Nelson’s web site:

All the best,

Rob Moore