Long and Tedious

Really, I got a lot done today honey!!

Today was another productive day in banduristan.  I managed to shape and glue on my "lift" (which I'll get to in a moment), make the bridges and lay out all the drilling to be done - and there's a Ton of it to do.

The String Lift - In Kyiv banduras, there's quite a bit of downforce on the bridge from the strings, particularly the "diatonic row" or приструнки which start low, go up to the top of the bridge and then down do the level of the deck.  Something I do in my Харків instruments is create a "lift" at the bottom of the instrument to take some of the load off of the bridge. Many would argue that this downforce affects the timbre of the instrument and I'm sure it does but, as with any changes, this won't necessarily have a negative effect on the timbre.

Typically, instruments that use a tailpiece type of design, the downforce from the strings keep the bridge in place.  I glue my bridge down so the need for that massive downforce is not necessary and allows me to keep my top and bracing lighter.

One thing about having a domed top is that everything must be arched to match the dome of the top.  Using a spherical dome makes matching that arch much simpler.  In the picture to the right, you can see my 25' domed workboard on my motorized sander.  The "lift" is glued to a piece of larger wood using hot melt adhesive to give a little something more to hold on to.  The lift is 3/8" tall.

I purchased a matched set of a 25' dished workboard and a 25' domed workboard at the same time.  If you search the internet you can find many techniques on how to make your own but in my mind, the $80/board I spent was well worth it when you consider how much time and effort is spent making your own.

Here you can see how I keep track of how much sanding I've done.  I want to lose as little height from the lift as possible.  I draw on the bottom with a white pencil.

Here you can see I've almost made it to the edge

Once sanded to match the domed top, I glued the piece on and used my flush trim bit  to get it right.  There were some mistakes made but I have no intention on going into them now.  Needless to say, good thing I'm building a prototype first!

The reason I needed to get that done was because I need to lay out the шемсток (shemstok) for drilling.  It needs to be drilled prior to being glued to the rim because the holes for the tuning pegs are angled.  If I'm doing a layout, I may as well do everything at once.   To that end, I made the bridges as well.

Below is the setup I use for layout - which I've covered in previous posts.   The rub with this method is it takes a very long time but, it's ultimately flexible.  While it's not suited for serial production, it's very suited toward one offs.  Seeing as I'll only be building one more of this style of instrument, I see little point in making dedicated jigs for this.

Not the greatest shot, but here you can see the шемсток with all the layout marks for drilling.  Next step is to build a fixture to hold it in the proper angle for drilling the tuning peg holes

And finally, here's a shot of the perfectly fitted bridge with the spherical dome.  I found a local source of Bolivian Rosewood so I'm using it for the trim and bridge pieces.

Starting to look like a bandura - I managed to have several good evenings of work and have gotten to the point below (note to Yuri P. - those are not the bridges I'll be using and are there just for the photo!). Soundboard is glued on, shemstok is fitted and the instrument is bound and purfled. Fitting the shemstok to the curve on the top of the bandura was a nightmare and I do not look forward to doing it again but, here's the steps necessary.

Template Routing - This is a trick I remembered from my non-luthier woodworking days. Basically, using a router with offset collars, you can make two objects which fit together. I made a template from the shemstok (upper string holding thingy) that I'll be using on the next instrument (purchased from the Lviv Factory). I then vary carefully made a second template of the curve I'm fitting using a 1/2" flush trim bit that ends up 1/2" under sized. With that template carefully aligned and using a 1.5" diameter collar (providing a 3/4" offset to make up for the 1/2" offset plus 1/4" radius of the bit) with a 1/2" diameter bit, you can cut a perfect mating surface.

In the shot below, you can see the template on the bandura. What's not in this shot is an alignment template screwed on top used to position the 1/2" under template. The alignment template is nothing more than a "practice run" to make sure everything's o.k. I left it screwed on so that I could properly align the real template. The goal in alignment is to remove as little material as possible and still get a good fit.

It should be mentioned that the template is very hard to position on the top, even with the alignment template because the top is not flat remember. I had to make several tapered shims to get the template to sit 90 degrees to the edge and still be solid.

Here is a picture of the router with the 1.5" offset collar and a router bit.
And finally below is a picture of the material removed. It may seem like nothing but it's essential to have a perfect fit not only for the glue to hold, but so that it looks good too. Because of the shape, I ended up hand fitting the very end of the shemstok because to do otherwise would have required removing a ton of material from the rim.

And here's a shot with the shemstok clamped into position - perfect fit!


Actually there is a small gap near the neck and a small gap on the back side in one spot. Neither should be structurally significant and I should be able to hide them. The next step is binding and purfling.

Binding Channels - Bindings serve two purposes - they hide the end grain of the top and also provide sort of a bumper to protect against mild hits. I think that mostly it's an esthetic thing. I cut binding and purfling channels using a bearing piloted rabbet bit. I use a home made fixture to hold the router.

The binding channel must be cut parallel to the sides but the top is domed. Simply placing the router on the top to cut the channel would result in a binding channel that was wider at the bottom than at the top to you need some method of holding the router parallel to the sides. The fixture I use is a copy of a common design that's been floating around. I think it cost about $10 for the drawer slides and probably around $10 for the plywood I used.


Here is a shot of the router indexing along the side of instrument. I've found that single good passes make for the most uniform channels, but not necessarily the cleanest. I had a lot of fuzz to clean out by hand.



A shot of the purfling and binding channels.



And at long last, a shot with the bindings and purfling in place. Because this instrument is a prototype, I didn't do anything fancy. The binding is white ABS plastic left over from my guitar kit and the purfling is a simple BWB (Luthier code for Black White Black). I tape them into position using Stew Mac's Binding Tape . Once in position, I flood with CA glue . It should be noted that some types of CA glue can stain the spruce used for the top when absorbed by the end grain. To avoid this, I seal the binding channels with a coat of shellac. My current bottle of CA does indeed stain and the shellac has prevented staining.


Scraping the sides - Purflings are installed a little bit higher than the top and then scraped flush. Bindings are usually installed perfectly flush or a tad inset from the sides which are then scraped to be flush with the binding. We scrape the sides instead of the binding because we want a uniform thickness for the binding.

In scraping the sides I noticed what might be a big shortcoming of the compwood I'm using for these builds: there was serious cupping in the sides, perhaps 1/16". The only way to get rid of that on this build is to sort of taper the sides so that they get thinner toward the back of the instrument. I worked on it with card scrapers for about an hour and then needed a break. I checked the other frames and luckily, the frame for the "real instrument" is crowned which should be easier to deal with.

Today should be another productive day and I hope to post pics soon.

Top Bracing, Rim, Back Bracing

In spite of a lack of posting, I have indeed been working. I've done much and work is keeping me very busy so I apologize in advance for my brevity. As (mostly) usual, clicking on the pics will enlarge the images.

Below you'll find a picture of the braced top with the braces mostly completely un-carved. The top already has a rosette installed which I'll take some pictures of later - it's a very basic design and I've gone over this before. The sticks coming from above are called "go bars" and make it very easy to clamp things down. One problem though is that I have to make the base of the "go bar deck" stronger as it was deflecting under the load of the go bars.

The bracing pattern is the same as my last Харків (Kharkiv) version. The only difference is that this time I didn't I-beam the braces. Even so, the top came in right at around 450 grams - perhaps I beam bracing isn't that necessary. Below is a shot of the braces in their final shape.

Next is a shot of the completed rim:

I'm finding this type of rim a bit more difficult to make because of the exact shapes required. Because the final model (remember that this is just a prototype) will be using a pre made "Шемсток" or Shemstok, the angles between the neck and the rim have to be perfect. As it is in this model, they're not but I've got some ideas on how to get it right next time. Mostly it involves building assembly fixtures to guarantee that things line up the way they're supposed to . Good thing I'm building this prototype!

What I'll do for this version is to cheat the angle a bit on the shemstok to get it right rather than "straighten" the frame because it's much easier. That's o.k. for this one but the next instrument will require it to be perfect out of the gates.

Below is a shot showing how I've got to fix up some wavy-ness in the rim. If you read in a prior post, I'm using a material called "compwood". One of the side effects are that heavy clamping can compress the wood. Here's a shot of me flattening the area where the shemstok will be glued on:

Finally, here's a shot of the back with it's rough bracing glued on. I'm bracing this top a little more as I had some warpage issues at Kobzarska Sich last year. I'll be trying to shave the braces down until the tap tone of the back is either about a semitone higher or lower than the top (haven't decided yet).

I'm Back!! Latest Projects

It's been a very long time since my last post!! Although I haven't been posting, I have been working. The last two months have been very slow bandura wise but I did get some work done prior to that, I was just too lazy to post. Below is a picture of six rims I've bent.

From left to right, we have the rims for two Kharkiv style instruments with a slightly modified shape from what I've been doing before, two baby kharkiv style instruments and two Kyiv Style instruments (I'll get to that later). As usual, click on any picture for an enlarged version.


The most interesting things about these rims is the material I used for the rim. In the past, I've laminated three thin pieces of hard maple, roughly 1/8" thick to make my rims. In order to save time and effort, I decided to use a material called "Compwood" Compwood is a regular wood that has been compressed to make it flexible. Once it's dry, it holds its shape.

Below are the forms I used to bend the compwood. I made two forms for Kharkiv banduras, one for baby and one for Kyiv.



Once the wood has been bent to shape, it must be dried. I made a simple kiln from styrofoam board with a small space heater inside. It takes roughly 3 days for the wood to dry.



Below you can see some of the forms and various rims that I made. I used C-clamps to hold the wood to shape while it dried.

So far my impression of the compwood is pretty good although it does have some shortcomings:

Because of the compression process, the wood arrives kind of wavy and such making it rather difficult to resaw. It's also very flexible and bounces a lot during the process. It's quite difficult to get an even cut.

Because it's still quite wet, you can't run it through a power planer because it tears out something awful. The drum sander works quite well but you must again be careful because it bounces so much. My drum sander doesn't have infeed and outfeed tables but that would help tremendously. If I decide to stick with this stuff I may have to add them. Because of the uneven cut, it takes many passes through the sander. I ended up using 3 different grits to get a nice finish on the non-bent pieces.

Over all though, I believe it is less work to use the compwood than it is to laminate.

Current Project: Kyiv Bandura (x2)

Because of some things that have happened in the past, I don't like to build multiple instruments at once. I bent several rims together because it's very efficient but now I'm switching back to serial production.

Anyone who knows me knows that I have little interest in Kyiv Style banduras however, a good friend of mine convinced me to build him one. He's interested in a concert style instrument with re-tune mechanisms. At first I refused because of the magnitude of the project - designing a re-tune mechanism is a huge undertaking - but then I had a though: if I could get a complete retune mechanism from the Lviv factory, it wouldn't be all that hard to do so, I agreed.

Because I've never built a Kyiv instrument, I decided I should build a prototype first before spending a lot of time on a fancy concert instrument. I'm planning on making a few changes to the standard Kyiv / Lviv design to go along with my current philosophies on Bandura design. I'll go into the details in my next entry.

Below you can see the roughly carved neck for the prototype. Initially, I didn't intend on doing a fancy scroll carving on the prototype but since I'm not very good at carving it would be good practice.

Finished at Last!

Here's some pics (click on any picture for a large view):

The neck:

The rosette

And the back:

Over all, it came out pretty well. The top has sagged some under the string tension, but not too much. I might change out the chromatic strings to a lighter gauge, but I'd like to wait a bit first. I think that with some slight modifications to the bracing, I should be able to get the top strong enough to resist the downforce from the string tension and still be loose enough to get a good sound.

Speaking of the sound, you can check out a sample HERE. The sound quality is pretty good, but I'm still trying to figure out how to get a good sound on a solo recording in my living room. The mic I was using sounds like it was boosting the mids a bit. Of course as soon as I hit record I forgot how to play too!!

The highs sound really good and the basses are a nice balance. The mids I'm still deciding whether I like these or the one on bandura # 3 better.

Please drop a note or comment and let me know what you think!

A Sneak Peek!

About 10 more coats and it will be ready to cure. I'll post all of the finishing details at a later date.

I can see the light at the end of the tunnel!!

The end seems to be in sight!  And, although tedious, I've finally figured out how to get all of the pictures to have links to their larger versions.  Click on any pic to get an enlarged view.

I've been working on it quite a bit and here's what she looks like now:

Since my last post I've managed to shape, drill and glue the upper bridge or шемсток, drill for the semi-tones, add the trim piece and riser for the pin block, shape and drill the bridges, glue in the structural bracing and glue on the "fingerboard" (which isn't really a finger board).  Here's some of the details:

Shaping the bridge is not very challenging, but drilling for the holes is.  The first step is to align the bridge in the position it's going to be when it's completed.  Using my domed sanding disc, the fit between the bridge and the top was great:

Once in position, I use a laser level and some graph paper with 6mm spacing to lay out each string.  I found the graph paper on a site here .  My setup looks something like this:

Here's a close-up of how I use the laser to mark the holes for each string. I line up the laser with the correct hole in the upper bridge, then the graph paper, then make a mark on the bridge.  To align the graph paper, I use a ruler to extend the line of the neck so that the bass strings will be parallel to the treble strings.

While I'm at it I mark the locations of the tuning pegs and semi-tone strings.  Unlike the main row of strings, It's very difficult to mark their locations using a template.  Once marked, I use an awl to start each hole. this setup to drill the holes at the correct angle. If you look, you'll see that I use surgical loupes to get a better view.

Unfortunately, I screwed up the first bridge and had to re-do it.  Once everything is drilled, I can drill two pilot holes in each bridge to hold them in position for temporary work and for final gluing. In this next shot, you can see the little wires with a hook on the end sticking out of the bridge.  I've also attached the template to mark for the tuning peg holes.

Finally, here's a picture of the inside of the instrument with the structural braces glued in.

To drill the holes for the semi-tone strings which go into the wood at a weird angle, I use a jig of my own design below.  I later learned that surgeons have been using a similar jig for ACL reconstruction...go figure.

At this point, there's not much construction left, mostly final shaping and finishing.  Stay tuned!