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Bow hair tension
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Mat Roop
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Joined: 24 Mar 2007
Posts: 911
Location: Wyoming Ontario

PostPosted: Wed Oct 10, 2012 10:48 pm    Post subject: Reply with quote

ctviolin wrote:
... and seat the actual knot itself at the bottom of the mortice. then cut and glue the knot on the ribbon, and place and wedge it in the frog....

Thanks CT... I get most of your method except the slight piece in the quote above... why would you seat the knot in the frog mortice before cutting the end off? In my knots, there would not be enough room in the bottom of the mortise for the uncut hairs to curl back up and out of the mortise on the front side. Maybe I am not quite understanding.
My method is to locate the position of the knot, cut the end, seal the end & knot , kink the hair between my fingers to get a nice 90 degree bend in the hair at the knot, then set with a plug... always remembering (sometimes Shocked ) to thread the ferrule onto the ribbon first!

My point of asking the original question was how best to determine the amount of hair for a given bow. Like you, I work primarily on student and medium quality bows, and some of the student bows are way too stiff so more hair is needed and some are soft needing less hair.
Using my sense of feel tends to vary from day to day depending on the quality of my breakfsast.
Cheers!... Mat
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Mat Roop
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Location: Wyoming Ontario

PostPosted: Wed Oct 10, 2012 11:13 pm    Post subject: Re: Bow hair tension Reply with quote

Quote:
="ctviolin....(the only real variable is the amount of hair - which can often dictate playing qualities.

Again, an ability that arises from practice only.

From fully and evenly loose at the forward position, toa fully tight ribbon quickly enough, is what you are looking for on just about any bow.

all hair tension matters, have more to do with how large the gap is between the stick and the hair ribbon at playing tension, and the amount of screw left, to adjust for (if needed) to either add additional tension to the ribbon amount chosen, or retract for less playing tension in the chosen ribbon... which is not calculated before the rehair, as far as I know - other than getting used to rehairing in general.

it's simply an adjustment of the bow screw.


Suppose ( because I don't know at the moment) a single hair has a capacity of 1 ounce to straighten fully without distorting, so a hank of 200 hairs will be stretched with a tension of 200 ounces (12.5lbs) but some bows may not be able to pull that amount of tension to produce the correct amount of gap between the ribbon and the shaft, leaving some hairs still loose... so less hair is the solution... but how much less? The bows ability to tension should be measurable. In fact it is measurable, I've done it (awkwardly) and the range so far is from 5.95 lbs on a professional Dodd bow, to 20.1 lbs on a chinese student bow. The better bows range 5-10lbs
How to measure it quickly and easily is my quest.
Cheers, Mat
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ctviolin
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Joined: 07 May 2009
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Location: Roswell

PostPosted: Thu Oct 11, 2012 12:30 pm    Post subject: Reply with quote

Mat Roop wrote:
ctviolin wrote:
... and seat the actual knot itself at the bottom of the mortice. then cut and glue the knot on the ribbon, and place and wedge it in the frog....

Thanks CT... I get most of your method except the slight piece in the quote above... why would you seat the knot in the frog mortice before cutting the end off? In my knots, there would not be enough room in the bottom of the mortise for the uncut hairs to curl back up and out of the mortise on the front side. Maybe I am not quite understanding.
My method is to locate the position of the knot, cut the end, seal the end & knot , kink the hair between my fingers to get a nice 90 degree bend in the hair at the knot, then set with a plug... always remembering (sometimes Shocked ) to thread the ferrule onto the ribbon first!

My point of asking the original question was how best to determine the amount of hair for a given bow. Like you, I work primarily on student and medium quality bows, and some of the student bows are way too stiff so more hair is needed and some are soft needing less hair.
Using my sense of feel tends to vary from day to day depending on the quality of my breakfsast.
Cheers!... Mat


Mat,

Gret questions and thank you for taking me literally, because I did write the instruction a bit incorrectly. (Ahhh, English! So often I must accept that I use it acording to what I am thinking, and it is not exactly what I intended to say!)
I meant that when rehairing from the tip first, the LAST knot is at the frog end, and before inserting THAT knot into the mortice on the frog, in my method, where it is tied compleately in front of the frog to begin with, it must be lenghtened, or slid back towards the frog on the ribbon, so that the final knot (after cutting and glueing it, must be able to travel over the frog wedge (plug?), twist over at the end of the frog wedge, turn upside down, and wind up under the frog wedge - the knot is glued and trimmed so that it winds up under the frog wedge - where there is an adequate amount of hair - allowing the frog to be in the full foreward position on the bow, with the bow screw in, with the hairs all loose still.
- and the ribbon will begin to tighten all of the hairs quickly - so that there is plenty of room both to loosen all of the hairs, and to put as much tension as you would like into the ribbon. The amount of tensioning up should be available at whatever tension you would like, so that placement of the knot in the ribbon is critical right from the start...

Even before it is put under the frog wedge - there's the "experience" or "feel" part of what makes a good rehair a skill, and not really a matter of chance or of using some sort of a guage or scientific measurement.

Grrr.

Does that make sense? It's difficult to say, which is why I have ended up with a rehair guide - it's easier to just show it on film or in illustrated guide.

Also - the way I look at how much hair is necessry for a particular bow is this;
A bow may have large (or perhaps tiny) mortice openings, but this may not be an indication that indicates how much hair is required for that particular bow.
Tension of the stick, and an examination of the sticks straightness and camber, for me, is the only real indicator of how much hair is the best for a particular bow.
Then, when the bow is rehaired the correct tension needed for that particular bow is arrived at, by the bow screw - so, for me the amount of hair is simply dependant on a feel one acquires by examining the indepent indiviual bow.

On the other hand, what a player gets used to, only REALLY depends on who originally haired or who rehaird their bow last. They may be used to anything - which only makes life *interesting* for the rehairer.
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Last edited by ctviolin on Thu Oct 11, 2012 7:58 pm; edited 1 time in total
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ctviolin
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PostPosted: Thu Oct 11, 2012 2:23 pm    Post subject: Re: Bow hair tension Reply with quote

Mat Roop wrote:


Suppose ( because I don't know at the moment) a single hair has a capacity of 1 ounce to straighten fully without distorting, so a hank of 200 hairs will be stretched with a tension of 200 ounces (12.5lbs) but some bows may not be able to pull that amount of tension to produce the correct amount of gap between the ribbon and the shaft, leaving some hairs still loose... so less hair is the solution... but how much less? The bows ability to tension should be measurable. In fact it is measurable, I've done it (awkwardly) and the range so far is from 5.95 lbs on a professional Dodd bow, to 20.1 lbs on a chinese student bow. The better bows range 5-10lbs
How to measure it quickly and easily is my quest.
Cheers, Mat


Less hair - more hair - looser hair, tighter hair, whatever - the correct rehairing process takes these questiions and negates them during the normal process, in my opinion.

Perhaps you're looking for something (a measurement?) that isn't all that different (or difficult) per individual bow and that accounts for each individual hair...?

In fact, as the reality exists, regarding professional reharing - all of the hair for a rehair, doesn't come, nor is it at the same degree of "streatch" or "tension" in the hank, ever - at the beginning.
No matter what anybody says about rheairing, in theory, or how they may quess what is important - the actual steaps are understood and practiced by rehairers of today. In particular, non rehairers are often worried over technalities that are only theoretical. The individual hairs ARE all different, directly from ANY hair supplier, and it is part of the mechanics of a normal rehair, to attend to these details accordingly, as a part of the NORMAL, TYPICAL rehairing process.

In a standard, normal, rehair process, continual attention to detail must be a continuous part of the process at every steap - in order for the ribbon to tighten or loosen as much like a single unit as possible at the end of the rehair.

This is part of the technique of a normal rehair.

Perhaps you are over thinking some particular difficult parts of the process a tiny bit?

Or, to simplifi things;
After rehairing some thousands of bows professionally, I am not familiar with such needs as you and some others are thinking of here.

I am saying that doing and practiceing of traditional methods, works as well for me, as it did for my teacher (who has rehaired bows for twenty years in a large corperate setting, where he has rehaired for many well known violin players and thousand upon thousands of ameture bows) (in fact he is still rehairing bows)

Something to consider?

My apologies if I come across as a "know it all", or something like that, But the fact is, that I rehair still, almost every week I still rehair a few, I rehair and have NEVER had a single complaint - even from the pros I work with.
Except for; if one of the wedges comes loose during play - I will re position it for free. This happens about every thousandth bow rehair. Or perhaps once every couple of years.
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Mat Roop
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Joined: 24 Mar 2007
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Location: Wyoming Ontario

PostPosted: Thu Oct 11, 2012 3:51 pm    Post subject: Reply with quote

Thanks for sharing all your experience, CT !..
I have not rehaired thousands of bows like you have, but certainly hundreds. My past 22 year career in managing the maintenance and restoration of 35 schools in a school system that was chronically underfunded has left me with the mindset that there is always a better and more efficient way to accomplish whatever. The challenge is finding that better way. In some cases, that pursuit has been futile, but in others successful. Your experience and advice helps in that regard and it is appreciated!
I do have another bow quandry that I am curious to hear your thoughts, but will start another thgread.
Thanks CT... and all the best, Mat
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ctviolin
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Joined: 07 May 2009
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Location: Roswell

PostPosted: Thu Oct 11, 2012 5:50 pm    Post subject: Reply with quote

Mat Roop wrote:
Thanks for sharing all your experience, CT !..
I do have another bow quandry that I am curious to hear your thoughts, but will start another thgread.
Thanks CT... and all the best, Mat


Thanks Mat - your opinions are a real treat for me to respond to.

I think I'd love to meet you in person, where we could compare these things firsthand!
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Mat Roop
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PostPosted: Thu Oct 11, 2012 11:13 pm    Post subject: Reply with quote

Thanks Ct... I'm looking, listening and hopefully learning!
Cheers, Mat
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