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loss of value in bow after spline


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10 hours ago, martin swan said:

Actually, although all this badinage is very endearing, I would quite like to take the discussion a bit sideways.

If we could set aside the question of value, let's say we have a very fine stick with a broken head, and we have a player who knows the bow and wants its playing properties retained whatever the sacrifice to the collectability, what's the best repair?

I have seen many Hill repairs (two brass screws on the top of the head) which have clearly lasted for ages, even if the alignment of the break hasn't been great. I have seen hardly any historic spline repairs, and had assumed that this was because they don't hold, or is it just because it's a recent approach?

What is the strongest possible repair to a broken head? If a spline, should it be wider, thinner, ebony, bone, pernambuco ...?

Is it really possible to do a spline that's as strong as the unbroken bow ... stronger even ...?

I think a spline is by far the best repair.

I've only had one fail, and that was on my wife's bow, but she had a habit of practicing in our basement at the time, which has a 7 foot ceiling!

Nowadays most repair shops have a decent lathe, and fine saws are readily available, so that the kerf can be cut extremely accurately. You just make the spline to the correct thickness and radius and Bob's your uncle. When I learned to spline a bow we cut a slot with a dovetail saw, and tidied it up with files. So the spline tended to be thick, and often didn't fit very well.  The profile of the head could be altered too, unless great care was taken, because of the thickness of the spline.

I have several lending bows that were repaired with silver pins long before my time. The holes are drilled and tapped, and the thread cut gradually on the pin with adjustable dies, till they are a snug fit. They have held up well, but they're as ugly as sin.

My wife has a Pecatte with a replaced head, attached with a single iron screw driven in through the mortice. The joint isn't as tight as it could be, and it all looks a bit dodgy, but so far so good... I think I'll be splining it at some stage.

I think the success of repairing a bow head will depend on how high up the crack is. If there's very little wood above the break, especially if the stick is fine at the head, even a well made spline might be susceptible to failure because of the twisting pressure when the bow' s in use. In that case, almost counter intuitively, I might probably make the spline as far forward as possible, and avoid coming back towards the throat.

 

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11 hours ago, Jerry Pasewicz said:

Of course it can be proven.  Take modern bows that have been broken outside of an accident, spline them back together, and how many break again?  

I don't know how and where the prove should be within this question about a very particular case. I'm talking about prove for the rigorous claim "Heads with welll done splines hold up better than bow heads without splines ". What kind will hold up better could be proven only by a long term and wide spread comparison as I described.

All we have untill now are more or less accidental observations about head repairs holding up a more or less long period, and others failing. How can we know how many repaired bows were put to waste in the meantime? How can we know if modern "high tech" repair methods will be holding up longer than the mentioned screw method of the Hill shop?

In my ears it would sound a bit more humble to say something like "We did our best with the most advanced methods, but only time will tell" than to make unprovable claims. We imagined (ironically, in case it's necessary to explain) an assurance firm rejecting a value compensation for Martin's Tourte basing on a statement like "the bow will hold up even better".

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4 hours ago, Blank face said:

I don't know how and where the prove should be within this question about a very particular case. I'm talking about prove for the rigorous claim "Heads with welll done splines hold up better than bow heads without splines ". What kind will hold up better could be proven only by a long term and wide spread comparison as I described.

All we have untill now are more or less accidental observations about head repairs holding up a more or less long period, and others failing. How can we know how many repaired bows were put to waste in the meantime? How can we know if modern "high tech" repair methods will be holding up longer than the mentioned screw method of the Hill shop?

In my ears it would sound a bit more humble to say something like "We did our best with the most advanced methods, but only time will tell" than to make unprovable claims. We imagined (ironically, in case it's necessary to explain) an assurance firm rejecting a value compensation for Martin's Tourte basing on a statement like "the bow will hold up even better".

I certainly understand your hesitance, but we have collectively 300 years of experience.....and personally 40 years of experience.... how much time do you need?  Those of us that do this for a living see head breaks all the time, and head breaks all the time that need to be re-done...those are never well done splines. This is not just one off anecdotal experience, and it is not humble or not humble, it is history.  Please search MN, this is not a new topic.

The proof in the claim is very simple, a flawed bow that is likely to break (the proof being it DID break), did not break again with a spline, this happens over and over again.  Look at the percentages.  How many modern bows break at the head, and how many modern bows break at the heads after a well executed spline?  Look a bow heads that all logical thought would say cannot hold up because of the daintiness of the cut, with profilactic splines that never break.  If all else fails, check the logic behind crossgrainwood laminates....they are certainly not unknown to every person alive.....

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20 minutes ago, Jerry Pasewicz said:

...Those of us that do this for a living see head breaks all the time, and head breaks all the time that need to be re-done...those are never well done splines. 

How many modern bows break at the head, and how many modern bows break at the heads after a well executed spline?  

If you call every spline that break 'badly executed', than you are right. Too bad you never know if particular spline is good, you only can say it was bad after it is too late. And possibly, should you live another 100 years, you will find that all of splines were 'badly executed'

 

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1 hour ago, mendicus said:

If you call every spline that break 'badly executed', than you are right. Too bad you never know if particular spline is good, you only can say it was bad after it is too late. And possibly, should you live another 100 years, you will find that all of splines were 'badly executed'

 

No, there are given and very well known parameters that constitute a well done spline based on long collective experience.  If a repaired head breaks again, it is not difficult to determine the reason for the failure.  By examining these failures, and over the course of many careers, best practices are developed.  Much like a well done neck set, bassbar, or varnish re-touch.  Some of these are covered earlier in the thread.   But as long as you are on it, even poorly done splines hold up exponentially better than other types of repairs.

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Then I really don't understand why Yannick Le Canu and Pierre Guillaume would both say that in their experience splines tend to fail. Yannick flat out refuses to do them.

I can understand the concept that lamination would give greater strength, but we are only talking about lamination if there is absolutely no loss of strength in the glue joint that puts the head back onto the stick. If that joint is weak, given that it's subject to all the torsional issues Conor describes, then we have taken an integral piece of wood with a tendency to shear (an unbroken bow head) and replaced it with a massively thinner piece with less tendency to shear but only if the thickness was the same.

So Jerry, if you are saying that the glue joint gives a head that is is also stronger than the original unbroken head, then I would begin to believe a splined head could act as a cross-grain lamination and be stronger. 

 

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11 minutes ago, martin swan said:

Then I really don't understand why Yannick Le Canu and Pierre Guillaume would both say that in their experience splines tend to fail. Yannick flat out refuses to do them.

I can understand the concept that lamination would give greater strength, but we are only talking about lamination if there is absolutely no loss of strength in the glue joint that puts the head back onto the stick. If that joint is weak, given that it's subject to all the torsional issues Conor describes, then we have taken an integral piece of wood with a tendency to shear (an unbroken bow head) and replaced it with a massively thinner piece with less tendency to shear but only if the thickness was the same.

So Jerry, if you are saying that the glue joint gives a head that is is also stronger than the original unbroken head, then I would begin to believe a splined head could act as a cross-grain lamination and be stronger. 

 

You are missing the fact that the spline is cross grained wood.  It is the cross grain lamination that re-enforces the break. 

I cannot speak to why others have not had the same experience as I have not knowing the vagaries of the technique being employed,  however I can say that the highly respected restorers I know, that have done these things for careers and have specialized in restoration, are on the same page with minor disagreements on adhesive choice. 

 

 

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It's only cross-grain if there is no weakness in the glue joint where the head is broken ...

If it carries all the stress it's just a thin piece of wood.

Anyway, there are clearly differences of opinion. Form a purely logical point of view, if a certain number of competent people say "splines don't fail" and the same number say "splines fail", then it seems to me that they sometimes fail ...

I don't dispute that unsplined heads fail, but I see at least 100 intact bows for every one I see with a splined or repaired head.

As for the economics, if loss of mounts causes a devaluation of 20-30%, and a head break causes a devaluation of 80+%, then it's fair to say that a broken/repaired stick without mounts could be argued to have zero value. The value depends on the perspective of the person who has it in their hands, and I would take each case separately and not try to generalise.

 

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2 hours ago, Jerry Pasewicz said:

 

The proof in the claim is very simple, a flawed bow that is likely to break (the proof being it DID break), did not break again with a spline,

That's still a limitation to a very special case (flawed wood), and even within this it's arguable how much time and which circumstances reg. change of climate, use etc. would be necessary to give a "prove".

Searching MN, the opinions Martin referred to as well as 300 years of known (not to mention unknown) experiences, I can see no other prove as that it's challenged. Even the reasons for failing can't be defined so clearly, if some obviously wrong made repairs (screws) seem to hold better than many claimed to be superior splinings.

BTW, cross-grain repairs, aren't they very sensitive against shrinkage/swelling of wood?

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8 minutes ago, martin swan said:

It's only cross-grain if there is no weakness in the glue joint where the head is broken ...

If it carries all the stress it's just a thin piece of wood.

Anyway, there are clearly differences of opinion. Form a purely logical point of view, if a certain number of competent people say "splines don't fail" and the same number say "splines fail", then it seems to me that they sometimes fail ...

I don't dispute that unsplined heads fail, but I see at least 100 intact bows for every one I see with a splined or repaired head.

As for the economics, if loss of mounts causes a devaluation of 20-30%, and a head break causes a devaluation of 80+%, then it's fair to say that a broken/repaired stick without mounts could be argued to have zero value. The value depends on the perspective of the person who has it in their hands, and I would take each case separately and not try to generalise.

 

I do not think you are quite getting the point of the cross grain wood, or the strength of wood along the grain.

In any case, if you wish to make the case that a stick, depending on the case, has zero value, that is reasonable.  But to say that bows that have been broken have "100% devaluation" or that they have "no commercial value" is not credible being as that is stated without your 20% of the frog and button.  So, it looks like you and I can agree provisionally on the example, but there is the 20% that we can also agree is about 20% away from 100%.

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17 minutes ago, Blank face said:

That's still a limitation to a very special case (flawed wood), and even within this it's arguable how much time and which circumstances reg. change of climate, use etc. would be necessary to give a "prove".

Searching MN, the opinions Martin referred to as well as 300 years of known (not to mention unknown) experiences, I can see no other prove as that it's challenged. Even the reasons for failing can't be defined so clearly, if some obviously wrong made repairs (screws) seem to hold better than many claimed to be superior splinings.

BTW, cross-grain repairs, aren't they very sensitive against shrinkage/swelling of wood?

Indeed it is a limitation to a very special case (flawed wood) which is exactly the point.  The flawed wood is still flawed after the break and yet no further break, that was kinda the point.

  I would certainly encourage you to do any tests you deem necessary to prove the concept, but then you can hardly make the argument using an anecdotal screw repair out lasting a spline repair of proof of you point.  If there is a 95 yr olds who smoked a pack a day since his teens it is not proof that smoking makes you live longer.

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As someone who worked as a carpenter and ran a sawmill I'm very familiar with wood properties. I accept that a lamination of a spline into an unbroken bow head would increase its strength if done well. Don't think anyone could argue with that. 

The problem is the lack of continuity of strength in the reglued head before you introduce the spline.

If the head can be glued back together without loss of strength then the lamination/spline will up the overall strength. If the glue joint between the broken off head and the stick is weak (and it must be or you wouldn't need the spline) then the spline is doing a lot of work. 

If the spline travels back into the stick, there is also a point of weakness where you have less thickness of long grain in the stick. In the case of our cello bow. this is what's predicted. The stick is quite fine, the spline will have to travel back into the stick, so the stick is weakened. Unless there is some way of fitting in two splines, one of which travels a long way back in the stick.

So I accept that all this could be covered by your general statement about the spline being done well, but it seems to me that the spline must be very carefully matched to the position of the break, and that the usual break, at the very top of the head, is much more problematic than if the head splits off further down.

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51 minutes ago, martin swan said:

As someone who worked as a carpenter and ran a sawmill I'm very familiar with wood properties. I accept that a lamination of a spline into an unbroken bow head would increase its strength if done well. Don't think anyone could argue with that. 

The problem is the lack of continuity of strength in the reglued head before you introduce the spline.

If the head can be glued back together without loss of strength then the lamination/spline will up the overall strength. If the glue joint between the broken off head and the stick is weak (and it must be or you wouldn't need the spline) then the spline is doing a lot of work. 

If the spline travels back into the stick, there is a point of weakness where you have less thickness of long grain in the stick.

So I accept that all this could be covered by your general statement about the spline being done well, but it seems to me that the spline must be very carefully matched to the position of the break, and that the usual break, at the very top of the head, is much more problematic than if the head splits off further down.

Yes, as I explained earlier, the spline should never cross the line of the back of the head, that is a demonstrably bad idea as Jacob can now attest. Also, yes the spline is much more comfortable if the break is lower towards the ivory, but with today's better tooling along with better cleaning methods and adhesives, even bows that I thought would never hold due to lack of glue surface high on the head, have never failed.  As far as strength after a break, of course the spline is doing a lot of work, but cross grained wood can handle the task.  All you need to do to prove this concept is compare the pull strength of wood along the grain compared to cross grained.  I think you will find the strength of wood along the grain far exceeds the strength across the grain, and much more than necessary to fulfill your equation. 

 

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2 hours ago, Jerry Pasewicz said:

Heads with welll done splines hold up better than bow heads without splines.

and

The proof in the claim is very simple, a flawed bow that is likely to break (the proof being it DID break), did not break again with a spline, this happens over and over again.

The flaw in this argument is that you are referencing flawed bows and stating that the repair is stronger than the original wood with a flaw. Hardly surprising.

Then your original statement should be:

"Heads with welll done splines hold up better than flawed bow heads without splines ".

What about unflawed and unbroken heads? I think this is what BF was getting at. How would you ever know? I suppose you could take a bow that you examined carefully to see if there were any flaws, apply force until the head broke and examine again to see if it did in fact break along a flaw. If not, repair it and see if it can withstand greater force.

Andrew

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7 minutes ago, rudall said:

The flaw in this argument is that you are referencing flawed bows and stating that the repair is stronger than the original wood with a flaw. Hardly surprising.

Then your original statement should be:

"Heads with welll done splines hold up better than flawed bow heads without splines ".

What about unflawed and unbroken heads? I think this is what BF was getting at. How would you ever know?

Andrew

Yes you are correct.  Of course a broken head can be considered a "flaw" hence the devaluation.  If you wish to argue the other end of your query, all you need do is look at any number of resources on the strength of laminated wood vs non-laminated wood.

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2 minutes ago, Jerry Pasewicz said:

Yes you are correct.  Of course a broken head can be considered a "flaw" hence the devaluation.  If you wish to argue the other end of your query, all you need do is look at some of the La Fleur from 1840...common sense would tell you they never would have lasted this long without splines.

Sorry - I added to my post while you were replying.

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I would love to have a splined bow by a great maker that I could never afford normally.  It would be better to know who did the spline as they are not all created equally to say the least.  It occurs to me that the cross grain of the head of the bow is a weak point that you can't do much about other than pick the best wood possible.  It might not be a bad idea to put a spline in at the time the bow is made but I doubt that would be accepted at any level.  Perhaps a way to impregnate the wood of the head it epoxy via the tip mortice using some sort of vacuum system.  I think I may be applying technology to a non-existant problem though.

DLB

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26 minutes ago, Blank face said:

After all it's a circular argumentation like "a broken head is flawed, an unbroken spline is flawless". Not convincing at all B).

Hardly.  Splined bows hold up better both when the wood is not flawed (laminated material across all uses and industries) and with flawed wood (bows that have broken with natural flaws and man made flaws I.e. cracks).   Your argument is we do not see failed splined bows because they must have already failed, therefore we cannot say they do not exist. And we cannot say they do not exist because we have not done enough tests proving that they do.  Circular argument,  it defines the term!

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This my first post after lurking for some years. I am now retired after over forty years as a studio ' cellist in London and have been moved to join this board because of the approbrium being heaped on Jacob Saunders (who I do not know and have never met).

Speaking personally I would never buy a broken bow however well it may seem to be repaired, nor would I sell one. A broken bow has no utility value and therefore no commercial value to me as a player, however the frog and button do have a value as possible replacements on another bow if they are of sufficient quality and in good condition. A player needs to have full confidence in their equipment. 

This maybe an old-fashioned view, but it has stood me in good stead over the years, and if you think acquiring a good quality fine instrument is fraught with difficulty then steer clear of classic French bows (especially if you think you can buy one "on the cheap"!)

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20 hours ago, martin swan said:

OK  got it!

I for one would love to find a highly experienced restorer who could spline a historic Tourte bow and guarantee at least equal strength, and preferably greater strength.

David Orlin has taken on some very difficult repairs. Scroll way down on the following page to see the repair of a bow broken behind the head.

http://burgessviolins.com/Oberlin/oberlinrestoration.htm

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David, thanks for this ... I must have seen these photos ages ago and the "double spline" did stick in my mind.

Although our bow is broken in the usual place, I do think something like this could be right, given how slender the stick is behind the head. 

The violin head Tourte cello bows are a special case - they are inherently weak, which is why Tourte and everyone else moved away from this design.

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When I was bow shopping for my son last Fall I initially tried to scout out some fine bows that had been repaired such as head spline repair talked about here.  Admittedly, I didn't search very hard after hearing a couple of times that dealers do not like to carry repaired bows because of the potential liability.   So while I believe certain repairs are reliable and do not affect a bows playing characteristics, these bows are basically not on the market.  Worked out fine for me as my son got a new bow that he loves from a bow maker.  Just curious if my impression was correct that repaired bows are mostly shunned by dealers which makes them basically unsaleable except maybe at auction or private sales.

Thanks,

Jim

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