Jigs: Bridge Jack/Lift

A bridge lift or bridge jack can be very useful for lifting the stings momentarily for making adjustments to a bridge on an instrument that is already setup.

I was disappointed with the cost of commercially available jacks so I made this one on my own.  Two short pieces of coat hanger wire act as guides on each side.  The lifting screw sits on the head of a filled down screw in the lower portion to prevent it from sinking into the wood.  Make sure the tensioning knob is small enough to pass between the D & A strings when placing the bridge jack next to the bridge, otherwise you would have to remove the screw each time!

Note: obviously a bridge jack is not useful in setting  a sound post.  The setter and inspection mirror are sitting next to the bridge jack because they live in the same box 🙂

Jigs: Benchtop Cradle

A cradle is very useful for working on assembled instruments.  Tasks like setting sound posts are easier and less prone to damaging an instrument when the instrument is held in a cradle.

The cradle is no more than a thick piece of wood (or in this case several sheets of inexpensive plywood) hollowed on one side to fit the back of an instrument and lined with cork or leather.  Its also helpful to put something on the bottom to keep the jib from slipping on a bench.

Aside: I keep my setup tools in the old cigar box pictured below.  This are nice boxes and can be found fairly cheap.  Most cigar stores will have a pile and only charge $5 or $10 for the nicest ones, sometimes less.

Jigs: Vee-Board

A vee-board is very useful for fine fret saw work, such as for rough cutting the f-holes, I also find it quite useful for work where the edge of plate (belly or back) needs to overhang, such as using a purfling marker or cutter, or filing edges to shape.

Roger Hargrave outlines how he uses a vee-board in his article Purfling & Edgework in Cremonese Instruments in the library section of his website.

 

Jigs: Edge Fluting

 

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This swivel cradle is ideal for edge fluting.  The cradle rotates in a vice.  It’s designed so that tightening the vice locks the rotation of the jig.

The jig is also useful for final shaping and finishing.  The jig is hollowed so that the inside of plates can be worked as well.

The four corner holders are lined with cork and are slotted so that they can fit a variety of plate sizes.

Cutting the Purfling Channel

I’ve tried a new method for cutting purfling channels, this uses Roger Hargrave’s interpretation of the Stradivari method.  Among Strad’s artifacts, now in the Museo Del  Violino in Cremona, Italy, are two single bladed purfling cutters.  Roger believes that Strad used these to cut independently the outside and inside edge of the purfling groove.

I used this method on my most recent violin and found it worked well on the back, but was especially useful on the top, where year growth rings can cause a freely held knife blade to be pulled into the soft summer wood.

To do this I re-ground two of the blades from an Ibex-style purfling marker to be double edged (pointed) so they could cut in both directions.  A narrow taper ensures the blades won’t over-widen as they cut around the turns and corners.  I then mounted each blade in its own purfling marker.  I added a small brass ‘L’ to act as a depth stop which meant less checking of my depth of cutting.  The cutters worked well, but I did occasionally use my knife.

To setup the cutting position, test with a scrap of wood with the purfling you plan to use for the instrument under construction.  Also in the pictures above you’ll see a file which i converted to purfling picker.

Restoring a Glue Pot

20151026_171723Traditional hide glue was prepared in Glue Pots.  Hide glue is used in making violins for a variety of reasons, don’t take your violin to anyone who doesn’t use traditional glues they could seriously damage your instrument.  Read more about hide glue here.

Before the 20th century and the advent of PV glue, glue pots used to be as common as frying pans.  I found this typical old glue pot and decided to fix it up.  At one point it may have been enameled, this prevented rust from coloring the glue.  I won’t use the glue pot for my own work, but I like to have a 100+ year old glue pot on the shelf to put things in perspective.

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The pot is cast iron, I removed the rust by soaking in vinegar (this will etch the surface and would cause visible damage if the surface were polished, but this pot won’t notice).  I then ‘seasoned’ it with olive oil like you would a cast iron pan.  You can see the final result at the top of the post.  It turned out quite nice I think.

09a0282v1Lee Valley now sells a small stainless steel pot replica which would work well if you like the traditional look and feel.  It can be used with a small electric hot plate or coffee cup warmer which they also sell.

 

Rib Thicknessing: Scraping Planes

One option for taking down the thickness of ribs prior to bending is a scraping plane.  I was taught to use a low angle block plane to reduce rib thickness and added a few passes with a Lee Valley Scraping plane for final finishing of ribs.  The is a perfectly valid method and works provided that the plane is super sharp and the cutting depth is kept very small.  The downside is that it’s a slow process if your ribs are thick, due to the need to keep the cutting depth small.  Two ways to improve the amount of material taken with each pass include using a toothed blade or increasing the blade bevel angle.  Another option is a Scraping Plane with a toothed blade set at 70 to 90 degrees, or a York/Pitch plane with a blade set at about 50 degrees.

I have been researching traditional Japanese planesDai Noshi and became aware of  Sole Flattening planes (Dai Naoshi) which are traditionally used to adjust the soles of wooden Japanese planes.  For the interested, the soles of Japanese wooden planes are not flat, but are relieved in front of the blade and behind the blade leaving three or four contact points.  Also worth noting is the use of tapered laminated steel blades and specially shaped chip breakers in Japanese planes. Traditional Japanese joinery is amazing, check out this video.  For our purposes, the Dai Naoshi form is a useful model for a scraping planes for rib thicknessing and is a tool easily in reach of the construction skills of a violin maker.

While I was pondering a new plane to speed up my rib thicknessing, I saw Davide Sora’s video on rib thicknessing.  He uses a toothing plane with a toothed blade set at about 90 degrees.  Check out his use of the plane here.  Given his success I decided to build one of my own.

Here is my version.  Using separate sides makes it a quick build.  In my design the wedge goes behind the blade, while a wedge is not usually included in Japanese Dai Naoshi because it has a wedge shaped blade, it is necessary here as my blade is flat.  The dimensions of my plane were roughly based on the recommendations of this post.

Scraping Plane

I’ll keep you posted on how well it works.

Jigs: Purfling Miters

20160214_132358This jig is handy for cutting purfling miters.  The jig is made from a maple block in the shape of a c-bout inserted at an angle into a plywood piece used for clamping the jig to a work bench.  This idea came from Olivia Pelling who taught me violin making while I built my first violin.

I use this along with a small very sharp chisel to set the purfling miter.  After bending the purfling to shape on the bending iron, I mark the beginning and end of the mitre with a pencil and then cut on the curved surface of the jig so that the bend of the purfling is supported.  From there it’s trial and error to adjust the miter cut to remove any gap.

20160213_222613A loop comes in handy to check the result.