Horsehair and Wood: Re-hairing a Violin Bow

The idea for producing musical sounds using a bow fitted with horsehair is thought to go back at least a thousand years to the nomadic horse cultures of Central Asia, while the modern violin bow was perfected in the mid-to-late 1700′s. With this rich history, bows are a fascinating mix of engineering, material, and refined craftsmanship and an essential element in bringing any great violin to life.  And why this interest in bows? With two dedicated teenage violinists in the house, bows are just a part of my life. From replacing or repairing the protective bone tips, to re-gripping the leather holds, to regular re-hairing, I’ve gotten to know and appreciate the intricate beauty and engineering of this amazing bit of of woodworking.  Anyhow, I recently re-haired both girls bows and thought you might enjoy a peek into what this is about.

Update 10/3/2013: It should be said that bow work is rather tricky and quite delicate and if you are interested in trying this yourself, be certain your bow is a cheap one — you could easily suffer a complete fail until you have gained experience! (Thanks to Andrew Bellis’ comment for pushing this point). The following is not meant as a tutorial, simply a chronicle of some of the work that I do.

Well, here’s a bow  and a very handy fixture for securely holding the bow while it’s being worked on.   It’s made to gently clamp the bow at the tip and frog end (the ebony grip is called the frog) and accommodate various length bows.

After inspecting the bow, I remove the frog from the stick and fold back the hair at the tip end in order to remove the small wooden plug that secures the hair to the bow tip.  The plug should not be glued in. It’s unique compound wedged shape allows it to lock in place due to the pulling action of the hair. Sometimes, however, it takes a bit of digging to remove the plug.  If it stays intact then I may reuse it.

The plug is quite small as you can appreciate in this picture!

Once the plug is removed the bundled hairs are pulled out of the mortise.  Now it is time to remove the old hairs from the frog.

The metal ferrule is a tight fit and needs to be pulled off carefully. I use a piece of rubber and a small vise.

 

The small triangle of wood is called the spreader — it serves to do just that — spread the hairs into an even band.  A drop of glue holds it in place and as a result they often get ruined during removal. I always replace these anyhow to ensure a proper fit with the new bundle of hair.

Next the abalone slide is removed.  It has angled edges that fit into the channel creating  a dovetailed way. These also can be recalcitrant due to tight fits and rosin buildups!

 

Fold back the hairs and the frog-end plug can be seen and then removed.

The frog is carefully cleaned, metal parts polished, and the channels for the slide are lubricated with graphite (pencil). After selecting and measuring a new hank of hair I tie the end off tightly with very strong thread. I use three clove hitches — a self binding knot – finished off with a reef knot.

 

The end is then dipped in powdered rosin.

Then the rosin is melted into the hair, using an alcohol lamp, while the heat also serves to swell the hair ends, locking them firmly in place.  All of these efforts are taken to prevent hairs from pulling out while the bow is in use.

You can start attaching the hair at either end, but I prefer to begin at the tip.  Insert the hair so the knot is settled at the bottom of the mortise and then takes a bend to come up the back wall.

Then insert the plug to capture the hair bundle.  I reused the old one which was  made of hard maple and still seemed serviceable despite the small chip in the corner. I always give firm pressure on the hank of hair at this point, simulating use, to be sure that the plug is working properly and will hold the hair in place.

After a bit of preliminary combing to straighten and spread the hairs evenly, I use a rubber band to pull the hairs down tightly at the tip.

Next, I wet the hairs, comb and tension them and tie off the frog end. Now is the time to thread the ferrule onto the hank. Slide it up out of the way.  Then the plug is inserted to capture the hank in the frog.

The frog is installed on the stick. The abalone slide is slipped into place and the ferrule is put back on — it goes on easily without the pressure of the spreader clamping it. Here is some mahogany that has been shaped for a spreader. I insert it as is and mark and score it a little oversize for length.

Finally, a dot of glue goes on the tip that will be against the ebony of the frog. the spreader is inserted into the ferrule, separated at the score mark and the hairs carefully fanned out and evenly distributed.  Then the spreader is pushed all the way home.

It’s a good job if the bow hairs all tighten up evenly when the bow is tensioned and all the hairs are properly aligned.

Until next time!

dF

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47 Responses to Horsehair and Wood: Re-hairing a Violin Bow

  1. Rob says:

    This procedure resembles a delicate surgical operation. Thanks David.

  2. Jerry Rice says:

    Very informative. Great pictures. Would like to have dimensions for the bow holding jig. Thanks, Jerry

  3. Hello David,
    Bravo, well done! As a full time bow maker I must admit to cringing when I see posts regarding the bow. Often times the information given is not well thought out and can cause problems down the road for players and their bows. Not so with your post. If you want to make a frog someday check out my blog and follow along.
    Nice work, site, and books.
    All the best,
    Robert

  4. John says:

    Superb pictures and explanation.

    Wonderful.

  5. Janet says:

    I am having work done on a violin and bow which I was recently given. The “store” said that the case would have to be replaced because of the “bugs” which have eaten the horse hair on the bow. I have never heard of this nor did I see anything resembling exoskeletons. Am I being lied to?

    • David Finck says:

      There is most definitely an insect that will eat through bow hairs. It is called a demestid or “museum bug”. Infestations seem to be prevalent in cases that are rarely opened (I am not commenting on your practicing habits!) as the insects like it dark. Likewise, it also seems that the case can be cleared of the infestation by exposure to several days of bright sunlight (while protecting the violin elsewhere of course). This seems like a good course of action to me. I would follow the music shop’s advice though and replace the case if you continue to lose hairs after airing it out.

  6. apple juice says:

    This is really interesting i bet i can do it to. =)

  7. Isla says:

    I am glad I have found this tutorial with very clear photographs. Would you please advise where the frog is positioned in the bow slot for measuring the length of the hair, would it be the closest to the grip? and where to cut the hairs off in relation to the frog’s mortise.
    Any help would much appreciated. Thank you so much.

    • David Finck says:

      Hello Isla — keep in mind that although I am sharing my work here, it is not intended as a tutorial. The treatment is in no way comprehensive. If you are diving in to this I hope you will practice well on student, or inconsequential bows. To answer your questions though — yes, the frog must be forward in the slot, closest to the grip. I make a mark on the hairs past the back end of the mortise, plus the thickness of the plug, towards the button, as the point to start tying the knot. The knot is tied and then the hairs cut off close to the knot.

      Hope this helps and good luck.

      David

  8. Kay says:

    Is there a particular kind of wood (or woods) used in making the plugs? You mentioned this one was maple (and mahogany for the spreader), but are other types of woods acceptable? Thanks for this site. Very clear information.

  9. Andrea says:

    Hello, David.
    I’m trying myself to rehair a bow of mine. I was thighting the hair once, when the wood plug popped from the head of the bow, going where no man has gone before!
    It is the first rehair try and I’m almost shure the last, because things become really difficult when those little parts are to tight! I already have removed ferrule and the spreader wood from the frog, but the abalone slide is absolutely tight!
    Any tips to make its removal a little easier?
    Thanks in advance!

    • David Finck says:

      There are a lot of things that can go wrong with a bow rehair! To remove a tight slide try cutting two narrow strips of duct tape, about 1″ longer and slightly less than the width of the slide, and doubling them up for strength, then stick them down onto the slide. Pull on the excess tape while holding some pressure on the portion that is taped down to the slide — see if this give’s you enough purchase to loosen the slide. Failing that, remove the frog from he stick and dropper some alcohol or turpentine onto the margins of the slide where it meets the ebony of the frog — built up rosin dust is probably the culprit for your sticky situation and the solvents may loosen the deposit enough for the tape trick to work. There shouldn’t be much if any finish on the frog but do be aware that alcohol will damage a shellac finish. Turpentine is preferable as it won’t damage any normal finishes and is a pretty good solvent for the rosin. Clean the slide area well once it is off and graphite the dovetailed channels with a sharp pencil to keeps things sliding easily the next time around. Good luck!

      • Andrea says:

        Thanks a lot, David! Great tips, indeed!
        Unfortunately, turpentine had no effect to an absolutely GLUED slide! :-( Ended up broke.
        Nonetheless, frog is now clean and with graphited channels. Will buy another inlined abalone slide any soon and will keep playing the violin with the other bow that I have! No problem at all!
        Thx again!

  10. scott says:

    Great information.
    My question is which alcohol lamp to buy? Is the glass based lamp with a 3/16″ wick the one to buy?
    Thanks

    • David Finck says:

      That sounds like what I have — it does the job. A larger wick might be nice for more heat output if you were to perhaps try recambering a warped bow with heat from an alcohol lamp…

  11. mike meyers says:

    what kind of wood do you use for the plugs??? my wife is a fiddle player of 32 years and can not find a good rehair place so we are trying to learn the craft. any advice wood help thank you

    • David Finck says:

      I would use fairly hard wood with very fine grain that pares nicely for the plugs and something fairly soft for the spreader. There are many woods that fit this general criteria. I’ve used, pearwood and maple or cherry.

  12. Gilbert Gia says:

    Very pleased to see your work and encouraged to give a try on three old bows I inherited. Thank you.

  13. Very good photography, but PLEASE don’t carry out work like this unless you have been shown how to do it by a bow maker. Remember, the bow may be worth much more than you think, and the slightest slip with a tool could harm it. Bows are very delicate items. For instance, I see from the speckles in the wood use for the spreader wedge that it is the wrong wood – far too hard. Use lime (basswood). The reason there isn’t much written material on bow work is because it has to be seen ‘live’.

    • David Finck says:

      Thank you for your comments Andrew. You spurred me to update and and include thoughts along your lines. With this bow, I simply replaced the spreader with the type of wood that was used previously — a softish mahogany. An even softer wood, such as basswood as you suggest, would be a better choice for its compressibility. However, if the fit is good and the purpose served without harm to the bow, then there is nothing terribly wrong. I also feel that there are a vast number of junky bows out there needing work that a person could safely build their skills on!

  14. Anita Sterling says:

    I recently got back into playing the violin after a 55 year hiatus. I had been given an old violin that has been sitting around my house for @20 years. The bow hairs were eaten away when I recently opened the case. I learned about the bug that does that from my instructor and we are in the process of cleaning the case. I really appreciated your response about the demestid bugs and how to treat the case after cleaning it. We will put it in the sun (of course, without the violin). Thank you so much!

    • David Finck says:

      Let’s hope the sunning does the trick. My dad started in with the violin after 60 year vacation. Best of luck to you getting started. He eventually shifted over to viola

  15. josh says:

    I acquired some horse hair from a friend and was planning to rehair a cheap bow. Should I wash the hair first? Would the natural oils in the hair inhibit the hair from taking rosin?

  16. Max says:

    Great guide, David! I apprenticed to a luthier for nearly four years and could not have done a better job myself. My only recommendation is to notch a small block of wood then line that with a bit of soft leather to hold the head of the bow instead of just clamps – many a good bow has been lost by the head snapping off accidentally and this will help alleviate the pressure.

  17. Ken Roach says:

    Wonderful Article! and many thanks. I have one question. Does the little wooden plug that holds the hair on the bow’s tip have a name? Mine was lost and I wondered if it’s possible to order a new one or should I try to make it? Thanks so much.
    Sincerely, Ken

    • David Finck says:

      That would typically be called (surprise!) the “tip plug”. Plug material is sold, but every plug must be accurately fitted to the mortise of the particular bow.

  18. Rod says:

    Could you please clarify how much hair to use for a violin and viola. The hank I have looks like it might be too much.

    • David Finck says:

      Pre-measured hanks typically oversupply the amount of hair required. Once your tip plug is fitted you should end up with a gap where the hair will exit from the tip — it should be about 1 mm wide and, of course, the width of the mortice. You should select just enough hair to fill that gap. Herdim makes a handy little metal gauge (available from luthier supply shops) that is simply a flat tab with an open-ended 1 mm slot milled in it that corresponds to the gap I described above. One would mark the width of the mortice on the gauge then fill up the slot in the gauge with horsehair until you hit the mark on the gauge — that’s how much hair is needed. Let me know if you need a photo or two.

  19. Melvin Gilhaus says:

    This is the best information I have seen on bow rehairing. It is full of good information. Here are a couple of observations:

    I have been re-hairing student and professional violinists bows for 20+ years and it never ceases to amaze me how many bows come to me with the hair glued in. I have often thought of charging extra (I don’t, I just mutter unrepeatable things under my breath) for the labor involved. The half-lined frogs seem to be the worst.

    If you have old cello bridges in your shop, they make very good frog and tip plugs. Just make sure that the grain is going in the same direction as the hair.

    Removing abalone or mother-of-pearl slides, I have a sized mounting base with a clamp to hold the frog and I use a large rubber eraser and a mallet to gently tap the slide. Once started, I finish the job with my thumbnail.

  20. I play my fiddle outside, like to take fiddle for walks and lose hair so much hair. Need to figure out how to do this. Find rosin and hair less effected by humidity. Thanks for the post and fine set of pictures.

  21. A. H. Miceli says:

    I am having difficulties combing the hair properly without having a lot of loose hairs after I tie off the frog end. Dampening the hair seemed to help and combing it from the tip end, but we still end up with a lot of looses hair. How can I maintain an even bundle by the time I get to the frog end?

    • David Finck says:

      If the trouble is with your combing technique you must learn from anyone with long hair — start combing at the free end and work your way back towards the knot. If you are already doing that and hairs are pulling out then your ties are not tight enough. It’s a little hard to say though without knowing precisely what you are doing.

  22. John Cockman says:

    Hi David, when you receive the hank, is the root or tip end of the hair specified? Can you distinguish root from tip? If so, do luthiers have a preference of hair direction? I have read that some will start with the root end of the hair at the bow tip, so that the tip end of the hair gets trimmed off at the frog. I have also read that some luthiers used to alternate hair directions. Does anyone still do this? Thanks! John

    • David Finck says:

      Hi John — That’s a great question. Every hank I have received is knotted at the root end. The tips of the hair are identifiable because they taper to a point (they usually darken towards the tip as well). There are two premises for making a choice of which way to orient the hairs or to jumble them. Horsehair is seen to have a scale structure (like shingles on a roof) going from the root to the tip). Some have thought that this accounts for the “grippiness” of horsehair on the string and would be a good argument for jumbling the direction of the scales so you get similar grip in both bowing directions. However, the scales are so small (.5um) in relation to the hair diameter that they present a flat surface to the hair. It is the chemical nature of the hair protein that attracts and holds the rosin, and it is the stickiness of the rosin that gives the bow hairs grip on the string. The other consideration is strength. As mentioned, the bow hairs taper to the tip, especially over the last couple of inches, so for the strongest hair it is best to trim off (waste) hair more from the tip than from the root. Since players can exert more force on the frog end of the bow than out at the tip of the bow I orient the root of the the hair all at the frog end of the bow. This scientific article by Francoise Rocaboy has an excellent discussion of these points along with some (not very helpful) electron micrographs. Here’s a link to an excellent micrograph of a horse mane hair: http://www.psmicrographs.co.uk/horse-hair-mane–equus-caballus-/science-image/80019138. I actually had trouble finding micrographs of horse tail hair, but almost all micrographs of mammal hair seem to show this same scale structure. Finally, I have an instructional DVD on bow rehairing and the presenter divides the hank and reverses half the hairs, so there a probably a fair amount of people doing this if they follow his lead.

  23. Nita Kinney says:

    I have two baroque bows. Both lacking hair. Because we are on SS, bow rehairs are out of our budget and my husband is rehairing my modern composite bow but is defeated by the difficulty of making a wooden plug for the baroque bows. They just won’t stay in. I had one professionally rehaired and the plug fell out after a month. What is the secret?

    • David Finck says:

      Well, of course, accuracy of fit is everything. Properly done, the plug will sit in the mortise with no gaps at the sides or the face nearest the frog and no force is required to have it sit level with the bow tip — just a slight push. The gap at the opposite end must correspond to the correct amount of hair and then the correct amount of hair must be used so that too much hair does not create a jammed fit for the plug. Finally, the details of the mortise itself must be correct — nice flat walls correctly angled and undercut sufficiently at the tip. Takes some practice to get this all right! When it is right, the slightest tension on the bow hairs will serve to lock the plug in the mortise due to the undercut wall at the tip.

  24. Daniel Wise says:

    Hi, a big thank you for this, I found very useful! A question: what about flaming the hair after a rehair? I’ve heard many suggest this operation as a must do, is there really a need to do it? In order to obtain what? Another question comes from my issues on obtaining a good tip plug, when I press it down to capture hair it either holds too weak (and as I twist the button to tighten hair, it comes out) or eventually I break it for applying too much pressure… Don’t know if this happens because of wood I’m using (I tried with willow, now I turned into much harder juniper, but stil having problems) or because of too short thickness of the plug I realized, or even uncorrect grain direction (I keep it parallel to direction of hair, but it breaks in two when I press it…) What’s your suggestion about it? Again, many many thanks!

    • David Finck says:

      Hi Daniel — I believe most people rehair with wet hair as it is easier to handle. Flaming is usually done to to help tighten stray hairs that are looser than the rest of the bundle, after the bow is initially tightened. Some folks rehair with dry hair, then wet the hair and flame it to get the hairs tightened up. Here’s a decent video on that approach:
      https://www.youtube.com/watch?v=5CLnvVKn_VQ Caution! It is easy to overdo it and weaken the hair or even burn the stick so practice on your own cheapo bows if you want to give this a try!

      The plug problems you describe just sound like poor fit (sorry) to me. When all the angles are cut correctly (not easy!) and sized correctly, the plug will fit easily and stay in place. It is also very important that the gap for the hair be correctly sized to the amount of hair you are using — if the gap is undersized or you are using too much hair, the wedge won’t fit because of the extra hair. If the plug is breaking from pressure — beware! — you got lucky — it is just as easy to rupture the walls of the bow tip. On the other hand, your plug may be excessively weak because it is too thin (perhaps the mortise is also not deep enough — inexpensive bows can have many ills). Plugs can be made from hard wood, even brass, so it is the fit that defines its functionality not so much its material. Hope this helps a bit.

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