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Any Details on Curved (Bach) Bows?


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I am planning to make a curved bow for my daughter to use with her cello.  While I am more than willing to make it all up from scratch, I would love any details that might prevent me from making too many false starts.  I have not seen any curved bows in person and the pictures I have seen have a hand over the critical parts.  

 

I am planning this along the lines of a normal cello bow, with these modifications:

 

Riven osage for the camlen, it is hard, flexible and durable.  The frog's tongue will be several degrees from parallel to the stick with the spread wedged in the ferrule to have a rounded back in so as not to dig into the hairs as the hairs are bent over strings.  I also plan for the frog to have an upper and lower section that can toggle open giving extra slack to the hairs when not in use.   

 

In any case I will have supplies to try and try again as I attempt to work this out.   As I try to keep the weight down, I would not be too surprised if I ruin a few sticks and frogs.   Until I get a functional one made, I will not be throwing any inlay onto the inevitable fire.

 

Bob

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Since there haven't been any other responses, I'll share my two cents. I believe part of why there hasn't been many responses to this thread is because there probably aren't many members of the forum who are intimately familiar with 'Bach' bows. From what I understand the 'Bach' bow is almost certainly historical conjecture, and lacks convincing evidence affirming it as historical fact. With no surviving bows to study, and no real reason to incorporate theoretical bows into historical music, there aren't a lot of reasons for a professional bowmaker (even one specializing in premodern bows) to spend time on 'Bach' bows.

There are some 'Bach' bows out there however, and perhaps one of the other forum members (or a little internet research) could point out some way for you to observe a bow personally - if one is available locally, you may be able to see it more than once and check your work as your bow progresses. This should help you answer questions about what it is you are making.

It sounds like you've been thinking about this project for awhile, and as if you realize that it could have some difficult spots for you. Probably everyone here on the board realizes the importance of persistence towards achieving excellence, and can respect your attitude as you enter this project.

If at some point you start encountering lots of problems as to how you will make the bow, then you might consider taking some further steps to bring your project to completion. Fortunately, there are some excellent opportunities for instruction out there nowadays - one that immediately came to mind is a workshop focusing upon premodern bows taught by David Hawthorne as an introduction to bowmaking - http://www.violinbows.net/workshop.html . He won't teach you how to make a 'Bach' bow, but you would learn how early bows were made, and how you should expect them to play (bows like these - http://www.youtube.com/watch?v=RrhF2xEKTP4).

Good luck,

Joel

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Thank you, Joel, I am not in a position to argue the history, virtue or authenticity, I simply consider this an addition to the range of an amazing family of instruments.

 

Here is an example of why this intrigues me.

Bach: Sarabande from Cello Suite No 3 in C major

Performed by Hartmut Lindemann  on Viola

26th July 2009

https://www.youtube.com/watch?v=GYMcQuK-fz4

 

 

Interestingly despite not being able to see the frog well, I can see clearly how he is holding the bow.  That in itself gives quite a bit of data. 

 

 

Also, thank you Stephen, going to his site, this answered the majority of my questions.  Links led me to the shop and that showed me how he was managing the release of tension and the wood, beech, that he is using.

 

Since the ability to spring readily with tension is desired, I think pernambucco would be the wrong wood for this.  I don't want to go through a series of pernambucco or brazilwood blanks in any case.    Beech is such a pleasure to work, a more cooperative wood could not be asked for.  Beech has also been used as a bow (with arrow) wood so it  can take some flexing while providing resistance.   While I am strongly temped by beech, I am more tempted by osage and some fine bows have been made with osage.

 

Osage will by no means be as easy to work as beech.  It is hardy as cooperative a wood as those usually used in instruments.  It is however the wood of choice if you want to lighten the bow somewhat.   To make a curved bow with the same hair length will require a bit more stick so lighter may be very good thing. .Seeing his mechanism, it is quite simple although it appears like it might be a bit heavy.  This is the part where I will probably need to make several models before I finalize on the design.

 

After all the considerations on bows, materials, craftsmanship and design, it is a bit fun to read the hot mandolin topic about the virtue of spending $50 on a  mandolin pick. 

 

Bob

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Glad that helped Bob.  Let me/us know how it works out. 

 

Honestly I agree that who cares about arguing the historical model of this bow. You can see versions of bows like the Michael Bach bow in  late Medieval illuminated manuscripts, but who knows what the intent was. At that time the shape of the bow was probably not for bringing out complex polyphony, but suerly they had the idea of double stops of drone strings. 

 

But how all that unfolded in J.S. Bach's time is the subject of a doctoral dissertation I'll never want to write! Agree it's a cool idea to make one in a modern context of cello playing whether you play J.S. Bach or a contemporary composers work or make your own.  

 

The only hitch I see is from a players standpoint. I have not had the opportunity to use a Michael 'Bach Bogen' but form what I hear the thumb does a lot of work and if I were to decide to work with one I would aim to create technique for myself that did not hold tension in the hand due to squeezing the frog lever to tension the hair. I would just watch that to make sure it does not develop into tension running up and down the arm or cause joint trouble at the third thumb joint. 

 

Beech or Osage orange sound like good choices. Both not expensive. Don't rule out making a curved jig of plywood and laminating thin strips of osage orange or even fir, or oak or birch together with epoxy. Four 1/8" x 1/2" x  32" strips could be smeared with epoxy taped together and then clamped up in a simple two part jig to make a laminated bow blank that you would not have to bend. 

 

To make that kind of jig you just cut out the shape of the bows camber from 3/4" plywood and glue that to a piece of plywood then press three of the wood strips into it and draw a pattern to make the opposite side of the jig/mold. Then line the jig with plastic wrap or foil and clamp the strips into it. 

 

Anyway just a thought. People will look at you funny for making a bow like this so you may as well dazzle them.  :D Hope you keep us up on it I'll be following  a long. 

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Anyway just a thought. People will look at you funny for making a bow like this so you may as well dazzle them.  :D Hope you keep us up on it I'll be following  a long. 

 

Sounds fun, I'll post my work as I go along.  Expect lots of failures. :)   Just getting the balance and grip right is going to take a few trials.

 

Bob

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  • 2 weeks later...

I have started the construction of my first bow from osage wood.  I was hoping that I had some osage growing that might do, but it looks like a few more years before I can use my own.  Till then I will be grooming limbs to try and produce perfect bow wood.   Normally when we harvest wood, we select wood from the trunk of a tree and ignore the rest.  Limbs can warp in ways that preclude the normal use of such a wood.   For an archers bow however a horizontal limb cut in quarters will make an amazing, brilliant and two good bows.  The amazing bow is from the quarter that was at the top of the limb.  It grew with the white contracting sapwood pulling together and the yellow compression heartwood pushing out.  If you use the white as the back of the bow, you get a compound bow au naturel.  

 

Sadly I cannot perform this experiment yet as my best limbs are still to small and do not have a large enough section of heartwood to make a good bow.

 

Osage%2010%20Stick%20End.JPG

 

This limb needed cutting anyway and was too crooked for any purpose other than making a bent knife. :)

As I prune to encourage good wood, I do a few things that would not be done in normal tree grooming.  If a close y is producing a promising limb, I let it stay.  In best tree grooming you remove close V joints as that is where trees split and weaken.  Wide nearly 90 degree branch angles are healthy, tight Vs kill trees.   After I harvest what I need I will properly groom the trees better.

 

It is also best to remove the majority of limbs that are shaded by limbs above them.  In this case I want limbs to be working to grow straight and long to reach sunlight.  Instead I am grooming branches so they don't deform or develop knots.

 

Instead of using a limb,  I had to start with a chunk of heartwood.   The criteria on selecting the heartwood is the same as the criteria for an archers bow.  The grains on both sides of the final bow must go from tip to handle. The back of the bow must be the same plate from end to end.   The old way of doing this is to rive the wood.  Split it into billets along the grain.  The method I uses was to clean all four sides up and apply oil so the grain popped.  I mapped the core that I needed with a pencil matching the grain on both sides.  Then I made a leveling cut so that I could saw and be close to the plane of the wood ring as I followed the grain with my bandsaw.  From that I got several blanks.  I also got quite a bit of waste. 

 

So even with select wood with a select grain, a small portion of the wood was usable for making bows.  The rest will make some amazing finger planes and tool handles, but it is no good for bows.

 

Osage%2012%20Blank%20Reject%20and%20Saw.

 

The tool at the bottom is a nice flush cut dovetail saw with an osage handle.  This is what the wood will eventually look like.  Sadly there is no real way to protect the lovely canary yellow of the freshly shaped bow blank.  The board behind the blank sadly has character.  A nice wave to the grain.  Grain ends up being near invisible in osage and for a bow we want straight grain.  Character is fine for a frog, but no good for bows. 

 

The reject board does show how the yellow will fade in a day and brown in a month.

 

Osage%2009%20Wood%20Color%20Change.JPG

 

The wavy shape of the bow blank is the shape of the grain.  The shape will be adjusted when I do the bending.

 

Here is the final shape of the blank ready for a bit more refinement.

 

Osage%2011%20Blank.JPG

 

This blank now needs to be compared to a plan and refined a bit.

 

Osage%2015%20Bow%20Layout.JPG

 

 

François Tourte did an amazing thing.  He pretty much made the bow to end all bows.  Try as I can, I see no flaw in his design.  Simplicity itself with every part refined and perfected.  There is a reason why other bow patterns are curiosities. Yet my goal here is to make a bent bow to the best of my ability.  So I will be stealing from the best.  François' back bent curve gives his bow immediate response and immediate thunder.  The limit on his bow is the potential expression of a full chord.  In an orchestra, so what, multiple instruments mean chords can be spelled out in parts.  The soloist can express a melody on one or two strings with a rich background filling in the chords.

 

A curved bow can potentially give a depth to the thunder that cannot be duplicated by a solitary instrument with François' bow, but the violin's immediate response and instant thunder was a gift from Tourte.  Added to Tourte's amazing ergonomics and balance, the agility of his bow is going to make a curved bow limited in comparison for all but a few arrangements.   The first thing I need to steal from Tourte is his back bent bow.  His back bend means that the hair's curve of pressure to tautness is increased for even the lightest stroke and the hair's tension is multiplied when more pressure is applied.  This gives immediate response and immediate thunder.  If I can back bend a curved bow and have it give on pressure I may be able to have immediate response and more nuanced thunder.  I don't see how to quite capture all of the magic of François' bow without exactly duplicating François' bow.

 

So my first attempt will be to put three back bends with two more substantial knees.

 

Here is the rough bow and the rough pattern that I will be trying to implement.  With no better name, I am calling this bow form, the pipistrelle.

 

Osage%2016%20Bow%20Side%20Rough.JPG

 

Osage%2017%20Bow%20Top%20Rough.JPG

 

After I bend it, I will adjust the contours a bit more and then I will mount a frog, put bone on the tip and string up the bow.  Then the contours and balance will need to be refined even more before I put wire and leather on the bow.

 

Wish me luck please! I am venturing well of the beaten path and even if I get everything else right, balance and ergonomics may well defeat me.  If my daughter does not like it, it is all for naught.

 

Still it helps to pass the time while flaxseed oil is bubbling and colophony is boiling.

 

Bob

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