Hurdy gurdy adjustment (part four)

(Please note: Some family responsibilities and a bit of travel have reduced my shop time lately. I will try to resume regular posting in October.)

Having adjusted, tuned, and intoned the two rows of tangents, the chantrelles are now playable, but not sounding very good just yet. I intend to experiment with different string sizes and materials such as gut or monofilament nylon. I also need to gain some experience applying cotton to the strings (more on that later).

Now I turn my attention to the drone string that will be tuned to a low “G”. It emerges from the pegbox and stretches under the buttons 1″ above the soundboard to its own bridge. For initial setup purposes, I installed a bronze wound steel string which I will replace later with something more appropriate.

The bridge is glued to the soundboard behind the wheel and features an adjustable, perpendicular post for the string to rest upon. I made the post from a piece of brass rod that I threaded on one end and slotted on the other. One string groove positions the drone string against the wheel in play and the other holds the string away while tuning others. The post can be turned in or out with a screwdriver to adjust the string-to-wheel contact.

a capstan salvaged from the back end of a piano key

The string tail is anchored to the tail block of the hurdy gurdy to a hitch pin of sorts. The plans specified a bent, brass wire, staple to which the string is tied. That would work well for plain end gut or nylon strings, but I might settle upon a manufactured lug or ball end string that just wouldn’t look nice tied. Instead, I improvised using a piano capstan with a head that has cross drilled holes. This will allow for either type of string.

Hurdy Gurdy adjustment (part three)

My hurdy gurdy is almost finished and mostly playable but I mostly can’t play it….yet.

The two chantrelles are tuned in unison to “D”.  At the wheel end of the tangent box I have installed two hooks that I made by heating and bending 1/8″ brass rod. By lifting one string off of the wheel and hanging it on its hook, I can tune the other string alone without interference.

Now I begin the long process of adjusting each tangent so that it contacts each string to produce the correct desired pitch. Initially, I’ll be doing this with the aid of the strobe tuner app on my iPod and then making final adjustments by ear. The two chantrelles need to play the same so I’ll be  setting one row of tangents on one string and then hopefully tuning the second row to the first. I will start by adjusting the tangent on key number seven straight on. This tangent engages the string at the halfway point playing the “D” that is one octave higher than the open string. I can also adjust the scale length by moving the nut and bridge so that key number seven is properly intoned at this straight on position.

From this basic intonation I will build the chromatic scale by adjusting each tangent so that it contacts its string at precisely the right position to produce its relative pitch on the scale. I do this by loosening each set screw, changing the contact point on the arc of the tangent, and then retightening the screw. The plans called for the tangents to pivot on small wooden dowels. Out of concern that these wooden parts could become troublesome with changes in humidity, I installed #2 wood screws.

In all there are twenty one keys or buttons. The twelve on the bottom row are the naturals  and the nine keys on the top row are the sharps. The chantrelles are tuned to open “D” so viewing the rows with the peghead to the left they are tuned like this;

D#        F             G#     A#         C#  D#   F        G#  A#

E         F#   G      A        B  C    D     E   F# G    A     B

The scale begins with open “D” (D4) and climbs up and beyond that button number seven which is the “D” (D5) an octave above.

Setting the tangents is not as straightforward as I had hoped. The tangents are tiny and were difficult to make consistent in size and shape. The keys are crowded together at the high end where, as neighbors, they don’t always get along. Some of the keys act as though drunk, wobbling this way and that. Additionally, the tangents stretch the strings to a degree causing them to go sharp. These are problems that I will be sorting out in the coming days. I have considered buying or making metal tangents like those that are available commercially. They feature narrow vertical posts that contact the strings, slotted fork like bases that are held by screws, and more adjustability than my wooden tangents.

metal tangents

Hurdy gurdy adjustment (part two)

Having just described the replacement of traditional viola pegs with mechanical “Pegheds” tuners, I will continue with other adjustable features that I have built into my hurdy gurdy.

A stringed instrument, the guitar for example, has a nut, a bridge, and frets, all made of resilient materials in a fixed arrangement. They are set up by the luthier or the factory and usually require little attention until wear, damage, or wood movement make it necessary to carve, file, fit, or replace them, sometimes years later. A hurdy gurdy is like this too but it is not the kind of instrument that you can just pick up and play. No matter how stable the instrument and environment are, small regular adjustments need to be made without carving, filing, and shimming, adjustments that can be made while out and about with fingers or simple portable tools.

For initial set up purposes I have installed viola “D” strings for the two chanters (melody strings). Each has its own nut which I constructed according to the plans. The two nuts are made of hard maple and are free to slide forward or back as necessary to slightly adjust the scale length. Fine sandpaper (abrasive side down) is glued to their bases so that they stay put.

At the other end of the 350mm scale is the bridge which can also be moved forward and back as necessary to maintain this critical length. Downbearing pressure holds the bridge in place. A violin “fine tuner” attached to the tailpiece maintains tension on a small gut string that is tied to the bridge. This counteracts the tendency of the bridge to lean toward the nuts.

I made the bridge out of hard maple. Another crucial adjustment that must be maintained is the height of the strings and how they contact the wheel. To make this easier I built little wheel adjusters into the bridge feet. By turning these thumbwheels, I can raise and lower the strings separately.

 

Hurdy Gurdy adjustment (part one)

The completion of my hurdy gurdy project is finally within reach. I began this challenging instrument last March and I think that a large part of the five months have been spent looking at the plans and deciding how to use them. The plans are for an “English Hurdy Gurdy”, built mostly in the traditional way, but with the modern improvement of a precision machined crankshaft. Although I have changed some of the decorative features, I’ve adhered to the plan’s critical elements of construction, scale, and size.

Temperature, humidity, wear, and fatigue ( and maybe even presidential politics) all have their way with whether things work or don’t work and the hurdy gurdy’s delicate system is particularly vulnerable to some of these influences. The string scale must be  adjusted so that intonation is accurate and consistent for both chanters. The strings must be fine tuned relative to each other and contact the wheel in a precise manner for the best sound. Strings must somehow be decoupled for separate tuning. The “dog bridge” must be carved and adjusted for the right amount of sensitivity and “buzz” (I am so NOT looking forward to that puppy!). All of these elements can be carefully set up to play the hurdy gurdy but what happens when environmental conditions suddenly change everything?

An old joke goes, “With an autoharp (or banjo, or harp, or fiddle, or whatever, insert here), you spend 90% of your time tuning and 10% of your time playing out of tune”. This certainly applies to the hurdy gurdy and the many elements that must come together for it to play. Since I want to have more playin’ pfun than adjustin’ adversity I’m including a few modern day features to help me handle this.

The plans call for tapered ebony viola pegs to be carefully fitted into matching tapered holes. Wooden pegs like these have been used successfully for centuries. They must turn smoothly and then hold the string at pitch relying on the increased friction from pushing and wedging them into their holes. Sometimes they don’t, and the potential hassles have led me to install modern, planetary geared tuning pegs called “Pegheds”. They have the same appearance of the specified viola pegs that they replace and allow fine tuning without the problems caused by environmental changes.

I have used and written about “Pegheds” many times before. Their appearance is so authentic that many folks, when they notice them, remark in a sympathetic tone, “Oh! you have wooden pegs.”. They seem surprised to learn that the pegs are geared like mechanical tuners.

 

 

Hurdy Gurdy, auditioning parts

Major and minor parts have been cast for the Hurdy Gurdy “production” and now it’s time for all the members to practice their roles, make changes, and develop a rapport that will thrill both the player and attentive listeners.

I have sanded all the parts with progressively finer abrasives ending with P320 grit sandpaper. Since cherry, spruce, and maple have fairly close grain and there is not a lot of walnut, I haven’t used a grain filler. Minwax brand “Natural #209″ stain was applied to the bare wood and allowed to dry overnight. I don’t know why they call it stain as it’s as clear as water, but it serves to “pop” the grain lending an attractive contrast to the curly/ burly grain patterns. Nearly two 12.25 oz. cans of Minwax satin lacquer were used to spray four or so coats of clear finish sanding between each coat with P320 grit. After the finish has hardened and before the final assembly, I will polish and buff the instrument to a satin lustre.

The tangent box fits into the mortices on the body and is secured to the top with four screws. A small arched area is cut away from each of the box’s sides so that it only touches the top at the points where the screws are attached.

With the tailpiece, bridge, wheel, and nuts in their basic positions, I have strung two scrap nylon strings to help me lay out the tangent positions. Now starts the long, tedious process of getting the keys to operate smoothly and aligning the tangents so that they engage the two chanters at the same time.

Hot progress

Progress on the hurdy gurdy has been slow partly because of the heat wave that has settled over much of the country. I feel a high degree (pun alert!) of responsibility because much of the heat here in the midwest is being generated by the friction from all the hand sanding I’ve been doing.

After completing the buttons I turned my attention to the tangents. They resemble little flippers and are fastened to the keys inside the box. When the buttons are pressed the tangents press against the two chantrelles at the proper interval to change the pitch. Being attached with screws, each flipper can be adjusted and held a little in either direction for intonation.

There are two sizes (heights) of tangents with the taller ones for the lower row of keys. I made a jig out of scrap wood to hold the blanks in position for drilling the screw holes. Then, using a disc sander, I shaped each one to a point.

 

The hurdy gurdy’s top is made of 1/4″ spruce cut to the shape of the instrument with a slight lip or overhang. A slot has been cut for the wheel and its position on the shaft.  Since I may need to remove the wheel and shaft sometime without taking the instrument apart, I did several practice runs to make sure I could before gluing the top to the body. I insert the shaft through the instrument while sliding on the wheel and collars through the slot. An allen wrench is used to tighten the collars on each side of the wheel and on the inside of the end block. To access the end block collar I have drilled a 1/4″ hole in the top above it. This access hole will be concealed by the removable tailpiece.

Tangent box continues

After three afternoons on the hurdy gurdy’s tangent box I have completed the rough work on the peghead and key buttons. The peghead is 1/2″ thick curly cherry  and is drilled for the four “Pegheds” tuning machines that I will install later. A lot of time was spent shaping the box’s sides where they angle 15 degrees so that there will be a strong joint with the peghead. The plans indicated reinforcing this joint with small wooden pegs but I chose to increase the gluing surface by adding extra width to the sides and concealing two wood screws under the walnut trim to prevent creep.

The two rows of keys are now capped with maple buttons on the top row and walnut trimmed maple buttons on the bottom row. In play, I will rest my left hand on the box lid and curl my twiddly digits over the side to press these buttons. This chromatic hurdy gurdy has 21 buttons with whole notes on the bottom row and sharps in the top.

To make the buttons I cut a groove in the maple stock with a dado blade on my tablesaw. Each button, a different size and shape, was cut from this stock and then carefully fitted to its key before gluing. As the keys are aligned going from the nut to the bridge, the spaces become progressively shorter as do the buttons. All of these irregular buttons must work smoothly without catching.

Building the tangent box

The hurdy gurdy”s tangent box resides on the top in front of the wheel. Overhanging its end is the peghead which will be drilled and fitted with four tuning pegs. The box part will be fitted with a hinged lid under which will be two “chantrelles” or melody strings, with the tangent and key mechanisms that will change their pitch. This chromatic hurdy gurdy will have 21 keys in two rows arranged somewhat like the white and black keys of a piano.

The keys move through square holes in the side walls of the box. I seem to have misplaced my drill bits that bore square holes so I am aligning and cutting the holes by another method. The sides are temporarily glued together with small pieces of thin cardboard and hide glue so that they can be easily separated later. Paper templates of the hole positions are applied and the 1/4″ strip between the two rows is sawn away.

Three sides of each hole are sawn away with a band saw before the side pieces are separated. The top and bottom parts of both sides are then reunited with a strips of walnut to replace the spaces that were removed between the rows.

 

The keys are cut from straight grained maple and sanded to size on a small Micro-Lux thickness sander. A lot of tedious sanding and filing follows for a smooth fit before making the buttons.

Hurdy Gurdy Crafters

I have finally returned to my hurdy gurdy project having spent the past two afternoons trying to remember where I left off while slowly constructing the tangent box/peghead frame. I am working from full size drawings with metric dimensions, close tolerances, and unfamiliar techniques so I have to keep checking myself. I follow the old wisdom, “measure twice, cut once” but I cut some pieces twice or three times and they’re still too short.

Three weeks ago, Mrs. WHBIT and I had a great time at the Raintree Music Heritage Festival (http://raintreemusicheritagefestival.weebly.com/index.html) in Spiceland, Indiana.  Mrs. WHBIT attended autoharp workshops with champion autoharper Les Gustafson-Zook while I pestered “The Hurdy Gurdy Crafters” to a point that probably prevented them from speaking with any actual customers.

Mel and Ann Dorries

Mel and Ann Dorries , hurdygurdycrafters.com, displayed their beautiful instruments for one and all to enjoy and even play. This was my first opportunity  to actually see and play quality hurdy gurdys and to closely examine their features and construction. Mel and Ann have been crafting these unique instruments at their Michigan workshop for many years and are very generous in sharing their experience and insights. They displayed a variety of hurdy gurdys from the three string “Minuet” to the I- lost- count string “Maestro” which seems to feature three of everything in addition to a large number of sympathetic strings. Visit their website and visit them. They sell finished instruments, kits, supplies and repairs.

"Maestro" hurdy gurdy

"Minuet" three string

Baby steps

I have been anxious to post about the hurdy gurdy but progress has been slow. The warm sunny weather here in Ohio has me gardening already with fruit trees, flowers, and weeds blooming a month early. The hurdy gurdy is also stalled somewhat because the Delrin bearing/bushing stock that I ordered arrived in the wrong size. I have to have the bearings, crank, shaft, and wheel ready to install before I can glue the top plate on.

I have re-sawn, planed, and sanded three pieces of 3/16″ thick quarter sawn spruce. I glued them together side by side for the top. Like the back, the top will have a lip or overhang all the way around.

Curly cherry has been cut and planed to make 1/4″ thick sides for the tangent box and peg head. A curvy piece of cherry has been mortised as a head block  for the peg head and will be capped and drilled for the tuning pegs.