TOOL REQUIREMENTS:

• KIRMSER BOW REHAIRING JIG (Plans available)
• HAIR GAUGE
• POINTED AWL
• WEDGE DRIVER
• 5 mm MORTISE CHISEL
• 18 mm STRAIGHT CHISEL
• PUTTY KNIFE (1" Blade)
• TABLESPOON
• SLIP-JOINT PLIER
• SMALL DIAGONAL PLIER
• SCISSORS
• FINE-TOOTHED COMB (i.e. Metal Dog-Grooming Comb)
• ALCOHOL LAMP
• HARDWOOD CUTTING BLOCK (4" X 4")
• SMALL RAT-TAIL FILE
• WEDGE DRESSING WHEEL ON ARBOR

MATERIAL REQUIREMENTS:

• GOOD QUALITY BOW HAIR (min. 31")
• BOW WEDGE MATERIAL (Basswood)
• DARK SHELLAC STICKS
• * FINE (00) STEEL BINDING WIRE
• * NO. 40 HEAVY COTTON THREAD
• * WAXED DENTAL FLOSS
• * #25 LINEN THREAD
• CONTAINER OF FRESH WATER
• ALIPHATIC RESIN GLUE (Carpenter's Yellow Glue)
• POWDERED ROSIN
• 000 STEEL WOOL
• BEE'S WAX
• TUNG OIL

* Any of these wrapping materials may be used (your preference)

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I. INITIAL INSPECTION

It is very important that you evaluate the precise state of the bow at the time the customer presents it to you for rehairing (or repairing). It is at this time that you must determine any and all conditions that must be corrected prior to the rehairing process, so that you may advise the client of possible additional charges. Following, is a list of some of the problems that may have to be corrected before you proceed with the rehairing of the bow.

• *CLEANING THE BOW STICK
• *RE-CAMBERING THE BOW STICK
• *STRAIGHTENING THE BOW STICK
• REFINISHING THE BOW STICK
• CLEANING AND RE-CUTTING (DRESSING-UP) THE TIP WEDGE MORTISE
• REPAIRING A FRACTURED TIP WEDGE MORTISE
• RE- BUSHING A BADLY WORN OR DAMAGED TIP WEDGE MORTISE
• *THE REPLACEMENT OF A MISSING OR BROKEN IVORY (BONE, SILVER) TIP
• REPAIRING A FRACTURED TIP
• GRAFTING A TIP WHICH HAS BEEN COMPLETELY SEPARATED FROM THE STICK
• REPAIRING A FRACTURED STICK
• REPAIRING A STICK WHICH HAS BEEN BROKEN IN TWO
• *REPLACING A MISSING OR DAMAGED WRAPPING (WIRE, WHALEBONE, TINSEL, ETC.)
• *REPLACING A MISSING OR DAMAGED LEATHER GRIP
• RE-BUSHING A DAMAGED OR BADLY WORN FROG MORTISE (ON THE STICK)
• REPAIRING A STICK WHICH HAS BEEN CRACKED AT THE FROG END
• GRAFTING ON A REPLACEMENT FROG MORTISE SECTION TO THE STICK
• *CLEANING AND RE-CUTTING (DRESSING-UP) THE FROG WEDGE MORTISE
• REPAIRING A DAMAGED FROG (i.e. CRACKS ALONG THE SLIDE RAILS)
• REPLACING A DAMAGED OR BADLY WORN PEARL SLIDE
• *REPLACING OR REFITTING THE BRASS EYELET
• REPLACING OR REFITTING THE FERRULE
• REPLACING A SCREW AND/OR SCREW BUTTON
• REPLACING A FROG HEAL
• REPLACING A FROG LINER
• REPLACING A PEARL INLAY (EYE)

* Repairs Commonly Required

II. PRELIMINARY STEPS

A. "SNIP" THE OLD HAIR OFF IN FRONT OF THE CUSTOMER

This will assure the customer that you will, in fact, replace the hair. (Save the old hair and make brushes with it later!)

B. REMOVE THE TIP WEDGE AND REMAINING HAIR

Carefully pry the old wedge up from the back-side of the wedge mortise. This may be done with your mortise chisel or sharp awl. If the wedge does not want to come out easily, you may have to carefully remove the old wedge one sliver at a time. Be very careful not to damage the mortise or change its dimensions! Occasionally the previous technician will have glued the wedges, in which case you should be careful not to damage the tip or mortise while removing the dried glue and wedge chards.

C. DISASSEMBLE THE FROG

This process should be performed while the frog remains firmly clamped, and the whole bow assembly is held firmly in your rehairing jig. This will help to avoid damage to the frog.

Carefully remove the ferrule with your ferrule-removing plier. I use a converted 6" channel-lock plier, that I have shaped each jaw to fit perfectly around each side of the ferrule. After the jaws are shaped to perfectly match the outline of each side of the ferrule, I polish each face to be absolutely smooth, so that it doesn't scratch or damage the ferrule. After you grasp the ferrule with the plier, gently 'walk' it off the frog tongue by gently 'wobbling' it back-and-forth, until it may be easily removed. Do not force the ferrule too much, as you may permanently damage the tongue of the frog. Again, avoid putting plier marks on the side of the ferrule. If the ferrule will not come off with reasonable force, you will then have to carefully cut-away the ferrule wedge with a small chisel or awl.

Once the ferrule is free, remove the ferrule wedge, by lifting the remaining hair and then carefully paring the wedge material away with your violin knife. The thin ferrule wedge is often glued when installed, so be very careful to avoid removing any of the frog material (traditionally ebony, other exotic hardwoods, ivory, and rarely, tortoise shell).

Remove the pearl slide by first gently tapping the slide on its front edge with your small nylon faced hammer. You may then proceed to firmly push the pearl slide out with your thumb. Do not hit the slide too hard with your hammer, as this may cause the pearl to become jarred loose or to chip. If you are still unable to push the slide off with thumb pressure alone, you may use the sharp flat edge of a mortise chisel by carefully wedging it between the back edge of the pearl slide, and the end of the slide channel (heal). You are then usually able to get your thumb nail in-between the slide and heal to work the pearl slide out. If the pearl slide still refuses to slide out, then warm the frog a bit with a heat gun (dry - flameless heat) being careful not to overdo it.

Remove the frog wedge by lifting up the remaining hair and carefully prying the leading edge of the wedge out with your mortise chisel or sharp awl. Again, if the wedge does not come up easily, you may have to remove it sliver-by-sliver, being careful not to damage the mortise or change its dimensions.

Remove the stick from the rehairing jig.

Remove the frog from the stick.

Check the overall condition of the frog and all of its parts:

• Is the ferrule distorted or marred-up?
• Are the frog's slide rails or the liner cracked?
• Is the brass eyelet stripped or showing excessive wear?
• Is the liner loose, bent, or corroded?
• Is the button screw in good condition?
• Is the metal heal (if present) unglued, un-tracked?
• Is the pearl-eye chipped; missing?

D. CLEAN THE STICK AND ALL PARTS

Use an appropriate varnish cleaner (i.e. xylene). DO NOT use alcohol on varnished surfaces, unless, of course, you wish to remove the entire finish.
If the frog ferrule is blemished, you may burnish out any visible plier marks or scratches, and buff it lightly with white compound, however, on student bows (nickel ferrules) it makes more sense to just replace the part, if you have it in stock.

III. PERFORM ALL NECESSARY REPAIRS AND ADJUSTMENTS

• *CLEANING THE BOW STICK
• *RECAMBERING THE BOW STICK
• *STRAIGHTENING THE BOW STICK
• REFINISHING THE BOW STICK
• CLEANING AND RE-CUTTING (DRESSING-UP) THE TIP WEDGE MORTISE
• REPAIRING A FRACTURED TIP WEDGE MORTISE
• RE-BUSHING A BADLY WORN OR DAMAGED TIP WEDGE MORTISE
• *THE REPLACEMENT OF A MISSING OR BROKEN IVORY (BONE, SILVER) TIP
• REPAIRING A FRACTURED TIP
• GRAFTING A TIP WHICH HAS BEEN COMPLETELY SEPARATED FROM THE STICK
• REPAIRING A FRACTURED STICK
• REPAIRING A STICK WHICH HAS BEEN BROKEN IN TWO
• *REPLACING A MISSING OR DAMAGED WRAPPING (WIRE, WHALEBONE, TINSEL, ETC.)
• *REPLACING A MISSING OR DAMAGED LEATHER GRIP
• RE-BUSHING A DAMAGED OR BADLY WORN FROG MORTISE (ON THE STICK)
• REPAIRING A STICK WHICH HAS BEEN CRACKED AT THE FROG END
• GRAFTING ON A REPLACEMENT FROG MORTISE SECTION TO THE STICK
• *CLEANING AND RE-CUTTING (DRESSING-UP) THE FROG WEDGE MORTISE
• REPAIRING A DAMAGED FROG (i.e. CRACKS ALONG THE SLIDE RAILS)
• REPLACING A DAMAGED OR BADLY WORN PEARL SLIDE
• *REPLACING OR REFITTING THE BRASS EYELET
• REPLACING OR REFITTING THE FERRULE
• REPLACING A SCREW AND/OR SCREW BUTTON
• REPLACING A FROG HEAL
• REPLACING A FROG LINER
• REPLACING A PEARL INLAY (EYE)

* Repairs Commonly Required

IV. THE REHAIR PROCESS

A. PLACE THE BOW (WITH FROG ATTACHED) INTO YOUR REHAIRING JIG

Lubricate the frog liner with a small amount of paraffin.

Make sure that the assembled frog slides back and forth on the stick smoothly and easily. There should be a minimum of side-to-side wobble, which would indicate a badly worn slide mortise (on inexpensive plastic bows, this consideration is mute).

Adjust the frog's relative position is such that after the screw comes into contact with the eyelet, make 5 or 6 complete turns to fully stabilize the frog on the stick.

With the partially assembled bow firmly in place in the bow jig, carefully clean and "dress" the tip wedge mortise and the frog wedge mortise at this time. Refer to the graphic showing the correct shapes for each mortise.

Fabricate the tip and frog wedges with precision. If you have dressed the mortises, you will have to make new wedges.
These wedges MUST fit their respective mortises exactly, like pieces of a puzzle! I never reuse the old wedges as they are generally spent after each use. There can be no short cuts here, because if the wedges are over-sized, they will likely split-out the frog or tip; if they are too under-sized, they will fail to hold the hair sufficiently. (See illustrations)

Validate the fit of the pearl slide and the ferrule; re-fabricate a new slide or ferrule if necessary.

Lubricate the slide with paraffin, and work it back-and-forth

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V. BOW HAIR SPECIFICATIONS

A. BULK

I recommend that you purchase your bow hair in bulk, from a reputable wholesaler. There are several companies which qualify. Currently, I buy my hair from Wagman - Grenamyer, Inc., 10 Strawberry St., Philadelphia, PA 19106 (800) 229-5059. Generally, I purchase 33" Black hair for student bows, and some Cello and Dbl. Bass bows. The cost of this black hair is very reasonable, and the quality is often nearly as good as the premium white hair. In the shop we are able to use black hair only on Dbl. Bass bows, and an occasional Cello bow, as most advanced violinists and violists strongly prefer the white hair only. I do not recommend that you buy hair in the single coil form. They are rarely the correct size (number of hairs per hank), and the price/per is usually prohibitive. If you ever do use a single coil, be advised that the ends are only temporarily sealed with sealing wax, and must be re-wrapped and prepared as follows:

VI. PREPARE THE HAIR HANK

A. SELECT THE APPROPRIATE NUMBER OF HAIRS FOR THE BOW

Use the violin hole on your hair gauge to pull your first dozen violin hanks. If you end up with too many or too few hairs (for a specific bow) you will be able to adjust as is necessary later on. This process consists of packing as many hairs as will fit into the violin hole on your gauge. Proceed by trimming-off the bundle of hairs as close to the top of the bulk tail as is possible, with an end-nipper. Once the bundle is separated from the tail, temporarily secure the hank with a short length of iron binding wire and wrap into a neat coil for the time being; we will secure it permanently later on. The actual number of hairs which makeup a hank will depend upon the specific instrument bow type and size you will be rehairing. In addition, you will find that the relative sizes of the mortises will vary slightly from one specific bow to another. Generally, a 4/4 Violin bow will require approximately 150 hairs, Viola bows around 175 hairs, Cello bows approximately 200 hairs, and Dbl. Bass bows somewhere in the neighborhood of 225 hairs (there is a wide variation among Dbl. Bass bows). When you make your Hair Gauge, you will use a #33 drill for the violin slot, #30 drill for the Viola slot, #29 drill for the Cello, and a #27 drill for the Dbl. Bass bow.

B. SECURE THE HAIRS WITH YOUR CHOICE OF WRAPPING

Note: Each type of wrapping material requires its own specific technique for holding the hair properly. Refer to your notes outlining the appropriate methods for using each material (i.e. wire, waxed floss, linen thread, etc.). If one end of your (white) hank is noticeably darker than the other, then this darker end should be placed at the tip of the bow.

When you first "pulled" the bow hank from the large tail, you secured it temporarily with wire or thread approximately 1" from the end nearest the top. Now, to secure this end permanently, we must saturate the end hairs with liquefied (hot) dark shellac. This may be accomplished by carefully fanning the hairs out so that you may saturate them with the molten shellac in your spoon (or putty knife) while holding over the alcohol lamp. While the shellac is still liquefied, secure the hairs firmly with your chosen wrapping material. This will insure that the hairs are sufficiently bound together and will be less likely to pull out. Secure the wrap before the shellac cools and hardens.

Next, snip the extra hair off (beyond the wire wrap) to allow only 1 to 1 1/2 mm of hair to protrude beyond the wire.

Singe (burn) the ends of your freshly wrapped hank to form a slightly bulbous enlargement on the end. Avoid getting the wire overly hot, and be careful not to burn the hairs behind the wire wrapping.

Flatten the bulbous shellacked-end slightly with the warmed jaws of your flat nosed plier to reduce the overall thickness of the wrap.

The entire wrapping (wire plus "bulb") should be able to fit comfortably inside the mortise; this means that the wrapping plus the thickness of the hair (as it turns upwards) will fit comfortably into the length of the mortise. (see illustration)

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VII. INSTALL THE HAIR INTO THE FROG MORTISE

Pre-shape your frog wedge so that it will fit perfectly into its mortise.

Cause the shellacked-end to conform to the contours of the frog mortise by heating the brass wedge driver, and carefully packing the shellacked-hair into the mortise. Do not get the driver so hot that it will singe the hairs.

Secure the hair into the mortise with the wedge. When pressed in fully, the top surface of the wedge should be level with the adjacent edges of the frog mortise (with the hair confined to the back of the wedge). (see illustration)

Draw the hair into a ribbon and pull it as you lay it into its channel; carefully slip the pearl slide over the hair. The fit should not be overly snug, such that the hair is forced up against the slide, causing it bulge out when push all the way in.

Draw the hank of hair through the ferrule, such that the correct side of the ferrule end up against the frog. (Note: The outside corners of the ferrule, that is those facing away from the frog, are usually slightly rounded).

Place the ferrule into position on the tongue and over the ribbon of hair.
Pre-shape your ferrule wedge so that it will fit snugly into place. Prior to placing it into position on the frog, trim its length with an X-Acto saw so that you end up with a flat, evenly trimmed surface, when fully pressed into position. Note that one side (the side that contacts the hair) will be flat; the other side will reflect the angel of the frog's tongue; the wedge will fill the entire space snugly.

Place a small dab of aliphatic resin (yellow carpenter's glue) on the flat side of the wedge facing the hair, and then press firmly into place such that the hair is spread into an even ribbon between the flat side of the ferrule and the ferrule wedge. Pull the hair firmly as you drive the wedge in, and do not allow the hair to slip back into the frog. If this does happen, the hair will work itself out later when the finished bow is drawn up to tension. Also, be careful not to let any hairs slip around the sides of he wedge; the wedge should fill the entire ferrule cavity.

You may find it helpful to rest the heal of the frog on the edge of your bench as you drive the ferrule wedge firmly into place with a pre-shaped screwdriver blade. I can't stress the importance of the "snug factor " here. The ferrule wedge is the first line of defense against the hair pulling loose.

Grasp the frog firmly and test the hair by trying to pull the hair out of the frog (use significant force) this will test the "holding power" of your new wedge. . . . .pull hard, as it is better to discover any weakness in your handiwork now, rather than later.

VIII. COMB THE HAIR AND TIE IT OFF

A. PLACE THE HAIR (ONLY) IN A JAR OF WATER FOR A MINUTE OR TWO

You must remove the frog from the stick and coil the hair into the jar of water and hook the frog over the edge of the jar (allow 1" between the frog and the water so the moisture won't wick-up into the frog ferrule wedge).

B. REPLACE THE FROG BACK ONTO THE STICK AND SECURE IT INTO THE JIG

Adjust the frog's position (relative to the stick) so that after the screw comes into contact with the eyelet, make 3 or 4 complete turns to allow for the adjustment of the new hair after it shrinks overnight from drying. Be sure that the frog is pushed completely forward in its mortise while secure in the rehairing jig.

C. COMB THE HAIR AND SECURE WITH THE WRAPPING

Comb the wet hair into an even ribbon by squeezing firmly between your thumb and fore finger; excess water will be removed during this step. Make every effort to get the hairs running exactly straight-and-even prior to clamping the ribbon in place with your securing clamp. Try to avoid breaking hairs off during this process. You can use your fingers to squeeze the hairs into a flat ribbon --- pulling too hard at this point will result in making the hairs too short (after drying) and generally uneven in tension, so don't overdo the pulling.

Place a small drop or two of liquid shellac at the tie off point; avoid using cyano-acrilate adhesives.

Tie off the hair beyond the edge of the mortise. The tie-off point is exactly one length of the mortise, beyond the edge of the mortise (see illus.).

Unclamp the hair and trim off the excess (again, 1 to 1 1/2 mm beyond the wrapping. Hold the hair firmly at this point so that it doesn't shift in the tie-off.

D. PREPARE THE WRAPPED HANK

Trim and singe the end of the hank identically as before.

Apply the hot shellac so that it penetrates well into the end of the tie-off . This may be accomplished by heating up shellac in a spoon over your alcohol lamp, and dipping the end of the hair into the pool of liquid shellac, and working it well into the bulb.

Flatten the bulbous end (only slightly) with the warmed jaws of your flat nosed plier.

IX. INSTALL THE HAIR INTO THE TIP

A. UNCLAMP THE FROG FROM THE JIG AND REMOVE IT FROM THE JIG

At this point you have to be very careful to keep the ribbon of hair flat and correctly referenced with respect to the tip mortise (as you remove the frog and place it off to the side in preparation to press the hair into the tip mortise).

Press in the tip wedge. When fully pressed in, the top surface of the wedge should be level with the adjacent edges of the bow tip, and the hair should be drawn over the wedge such that it completely covers the wedge. There should be no evidence of a bulge. If too much wood remains after pressing fully in the mortise, you may trim the excess by paring it away with your violin knife (don't cut any of the hairs!). I will place a dull single edge razor blade between the violin knife and the hair to avoid loosing hairs.

Proceed by placing the frog back on the stick, such that the hairs run in an exact even ribbon from tip to frog. You may establish the ribbon's alignment by running a medium comb through the hair.

Loosen-up the hair (back off the screw) and allow it to dry thoroughly over night. Prior to drying, the hair should not be tight, as it will shorten considerably as it drys. If you do not allow sufficiently for this shrinkage, it will probably result in a popped-loose hank, or worse yet, a snapped-off tip!

X. MAKE FINAL ADJUSTMENTS

A. DRAW UP ANY LOOSE HAIRS (STRAGGLERS) WITH THE HOT AIR GUN

At this point you should not have more than 6 or 7 "danglers". You will shrink these stragglers by running the hair carefully over a hot air gun (flameless heat) until they draw up evenly with the rest of the ribbon. Be very careful not to overheat the hairs as this will make them very brittle, causing them to break easily as the bow is drawn across the strings. Don't hold the hair too close to the hot air. . . . go at it slowly until you feel comfortable with this step.

Remove any hairs which are exceptionally long or have broken off. Never pull the hairs out, as this will loosen the bundle inside the frog and tip. Instead, snip the hairs off at either end.

XI. FINAL INSPECTION

A. THE HAIR SHOULD BE VERY SECURE AT THE TIP AND AT THE FROG.

B. ALL HAIRS ARE EVEN AND RUN A STRAIGHT LINE FROM FROG TO TIP.

The ribbon should cover the tip wedge fully.

The ribbon should be evenly distributed beneath the frog ferrule with none of the hairs slipping around the sides of the ferrule wedge.

C. CHECK THE HAIR RIBBON WHEN THE SCREW IS FULLY LOOSENED

When you loosen the hair fully, the hair should just begin to show evidence of a loose bundle. It should not be so loose that it falls limply around the stick, nor should it be so tight that you can not fully remove the tension on the bow. A delicate balance must be met here.

D. BRING THE TENSION OF THE HAIR UP TO PLAYING STRENGTH

As you slowly tighten the hair, it should "rise" slowly off the stick to form an even flat ribbon. If the sides of the ribbon come up to tension before its' center becomes taught, then your hair is uneven. If the center becomes taught before either side, then again, your hair is not drawing evenly. If either of these conditions, or variations are allowed to persist, then the bow stick will likely begin to warp over time. There should be equal tension on all the hairs across the ribbon of hair. This can be determined by bringing the bow up to tension and drawing you thumb across the ribbon, checking for an even resistance across the hair.

E. CHECK THE HAIR FOR SIDE-TO-SIDE MOVEMENT AT THE FERRULE WEDGE

The ferrule wedge must fill the entire space between the hair and the ferrule, it should be secured tightly, and reinforced with aliphatic resin (carpenter's glue). You may check for this by first bringing the bow up to tension, then grasping the hair in front of the ferrule and try to physically move it back-and-forth in the ferrule. Movement generally suggests that the ferrule wedge is too loose, or has slipped.

F. CHECK THE PEARL SLIDE

There should be no evidence of a "bulge" at the pearl slide, indicating that the hair has dislodged from its' wedge inside the frog.

G. CHECK THE FROG FOR ADJUSTMENT

Make sure that the screw-to-eyelet alignment is in adjustment. If this adjustment is out of alignment, the frog will not adjust smoothly, back and forth when tightening and loosening. You may improve a sluggish frog somewhat by applying some cork grease (or other paste lubricant) to the threads of the screw and the frog liner.

When adjusted correctly, there should be an absence of side-to-side wobble of the frog on a superior bow. This is a mute issue on the inexpensive plastic bows, however, even these less expensive bows may be adjusted to be fairly secure.

H. TREAT THE BOW HAIR WITH POWDERED ROSIN

This is normally done by drawing the bow up to tension and dusting the hair with some powered rosin (in a long trough). Work the rosin into the hairs and follow this step by applying a cake of rosin in the manner that is in common use by the player.

I. WIPE THE BOW - CLEAN AND SHIP IT!

BIBLIOGRAPHY

AMATEUR FIDDLE MAKERS Q AND A ---Harry S. Wake Published by the author 1980
BOW MAKING - 1000 BOWS AND A TRIBUTE --- John Alfred Bolander Booklet
BOWS AND BOW MAKERS --- Wm. C. Retford --- Pub. Novello & Co. Limited Edition 1972
AN ENCYCLOPEDIA OF THE VIOLIN --- Alberto Bachmann Da Capo Press, New York 1966
HOW TO MAKE A VIOLIN BOW --- Frank V. Henderson Murray Publishing Co. Seattle 1977
HOW TO REHAIR BOWS --- J. P. McKinney University Press Fresno, CA 1970
HOW TO SELECT A BOW FOR VIOLIN FAMILY INSTRUMENTS --- Balthasar Planta Zurich
A LUTHIER'S SCRAPBOOK --- Harry S. Wake Published by the author at San Diego, CA 1979
THE RETFORD CENTENARY EXHIBITION --- Ealing Strings London 1975
SOME NOTES ON THE REHAIRING OF BOWS --- Max Moller Reprint: Violins & Violinist 1959
VIOLIN BOW MAKING --- John Alfred Bolander Published by Boyd Poulsen, San Mateo, CA 1981
VIOLIN BOW REHAIR AND REPAIR --- Harry S. Wake Published by the author at San Diego 1975
VIOLIN MAKING AS IT WAS AND IS --- Ed Heron - Allen Ward Lock Ltd. London 1885

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January 2011
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