Okedo Construction, part 2

[If you’re looking for part one, go backward here.]

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STEP 4: LACE THE TENSIONING STRING
STEP 5: STRETCH THE HIDE
STEP 6: MARK ROPE HOLES
STEP 7: STITCH THE HIDE
STEP 8: TRIM THE HIDE
STEP 9: CUT ROPE HOLES

STEP 4: Lace the Tensioning String

Now it’s time to thread the string through the holes. Before tightening the strings it is a good idea to lubricate the ring so the head will slide over the hide as it is tensioned. This step isn’t usually necessary for okedo, but if the hides are thick and you desire a good stretch it will be very helpful.

The string is threaded in from the opposite side that the ring is resting on. Make sure that the ring is resting on the inside of the hide (i.e. the rough side) and the smooth side is opposite the ring. This order will insure that the proper playing surface faces out when the head is complete.

When the string is threaded through all the holes tie a BIGknot in the end to prevent it from passing through the hole where the pattern started. The final end stays loose and is clamped with the spring clamp as the hide is tightened around the ring.

A close-up of a completed 29 hole pattern is shown below, before it has been tightened. The holes have been marked with chalk using the template and punched approximately 3/4″ in from the edge of the head with the leather punch.

VIDEO: LACING THE STRING

STEP 5: Stretch the Hide

It’s time to tighten the strings to stretch the hide around the ring. Work around the perimeter starting at the first chord, taking the slack out of the strings. Each pass will pull the head more snugly around the ring until the excess hide is completely folded over against the back side of the playing surface. Make sure the head stays centered during this process.

VIDEO: TIGHTENING THE STRING

Once the head is snug around the ring it can be stretched by pressing on the playing surface and re-tightening the string. This can be done a number of ways – using the heel of your hands, or getting someone to stand on the head. Note that in the picture below the hide is turning white around the perimeter indicating a good stretch has been achieved. The stretch is important for thick hides like cowhide but should be done cautiously for thin hides such as calfskin of horse hides due to the possibility of tearing.

VIDEO: STRETCHING THE HIDE

STEP 6: Mark Rope Holes

After the stretching is complete and there is no more slack in the strings, the holes for the ropes can be marked with the chalk using the appropriate template. Keep in mind that the holes need to be marked along the edge of the ring and that they need to be large enough to accept the rope.

STEP 7: Stitch the Hide

There are two lines of stitching required for an okedo head. The Outer Stitch is the stitch that runs along the ring. This is the important stitch. The Outer Stitch isn’t a continuous line, it deviates around the rope holes that were marked in the last step. The inner stitch is continuous and does nothing more than hold the two sides of the hide together in the space between the ring and the shell.

• The Outer Stitch should have at least twice the stitch density as the Inner Stitch.
• The Outer Stitch should be right up against the ring.
• The Inner Stitch should be very close to the shell, with enough space for the trimmed hide to be bent up and out of the way of the shell.

The stitching is done with synthetic sinew and either a larger leather needle and awl or a leather stitching tool. If you are using a plain needle, measure about 150% of the circumference of the head worth of synthetic sinew. Tie a knot in the end of the sinew, leaving enough extra length to tie it to the other end after the stitch is completed. Use the awl to punch the holes in the leather and perform a simple straight stitch around the circumference. Periodically tighten the stitches. Do not tie the end of the sinew to the needle. Once complete, tie off the two ends of the sinew and trim the excess.

If you have a leather stitching tool like the Speedy Stitcher Sewing Awl, it will make your work much faster. Read the directions for the sewing awl and then straight stitch around the circumference of the head. Keep in mind that when using the sewing awl it isn’t necessary to make it all the way around the head in one go, you can do it in segments and simply overlap the stitches. It is a good idea to back stitch before tying off.

VIDEO: STITCHING THE HIDE, PART 1

VIDEO: STITCHING THE HIDE, PART 2

STEP 8: Trim the Hide

Trim the extra skin on the bottom away so that it doesn’t vibrate against the shell. A large X-Acto knife works well for this. Keep the shaft of the X-Acto in contact with the ring, being careful never to let the knife edge get anywhere near the head. The last thing you need is to put a hole in the head at this point.

Fold the inner edges of the leftover hide up and place the shell where it will eventually go. You can put some cardboard shims in to keep the hide away from the drum body to prevent any contact. As the hide dries it will pull away from the shell and the cardboard shims will fall right out.

STEP 9: Cut Rope Holes

The best tool to use for hole cutting is an X-Acto knife. In the video below we used a sharpened pipe instead of a knife, but it dulled too easily so we recommend a knife. Be careful not to get to close to the stitching. The holes are much easier to cut while the hides are wet, so test that the rope fits through the hole after they are cut. The holes will get a little larger as the hide dries. It’s helpful to put a short dowel in the hole to keep it round as it dries.

If you prefer to not cut the holes while the hide is wet, you can let the hide dry and then cut the holes later on a drill press with a forstner bit.

VIDEO: CUTTING THE ROPE HOLES AND TRIMMING THE EXCESS

STEP 10: Repeat all steps with the second head! 🙂

Okedo Construction, part 1

This tutorial will walk you through the process of making an okedo head, from determining the dimensions of your head to stretching it over the ring, sewing the double stitching, and punching holes for the rope. Keep in mind that you will need to make two heads, one for each side of your okedo, so you’ll repeat this whole process twice. Making a head is also quite a time-consuming process, so be prepared to devote a full day or at least an afternoon (3-10 hours, depending on your skill level) to it. Since the head must be stretched and sewed before the hide dries, it’s important to make sure that your cowhide stays moist at all times. Keep moist towels handy to refresh the hide if necessary.

PAGE MENU

TOOLS AND MATERIALS REQUIRED
STEP 1: DETERMINE HIDE DIMENSION
STEP 2: PREP RINGS AND HIDES
STEP 3: CREATE TEMPLATES
MATH TO FIND STRETCHING HOLE MARKS SPACING

Tools and Materials Required:

• hide cut to proper dimensions
• steel ring (made from 5/16″ dia. rod)
• leather punch
• razor blade or X-Acto knife
• spring clamp (2″ is a good size)
• white rust-inhibiting primer
• lubricant (e.g. K-Y Jelly)
• heavy leather sewing needle or leather sewing tool
• synthetic sinew
• nylon string (do not use cotton)
• chalk

STEP 1: Determine the Hide Dimension

The hide dimensions are determined by two things: the size of the ring and the size of the shell. The hide needs to fold over the ring and stretch well past where the shell will be placed. As the hide is stretched over the ring there will be a region where the hide folds over on itself. The majority of this section should fall within the shell diameter so that it will be trimmed off.

The hide will also have holes punched the whole way around for the rope. These holes are located approximately 3/4″ away from the outer diameter of the folded over hide before it is trimmed.

Calculations:
For example, a drum with a 15 1/4″ OD ring and a shell with a diameter of 12″ would need a hide with a diameter of at least twice the difference between the ring and shell diameters plus twice the tensioning rope distance added to the ring diameter. This would be:

15 1/4″ + 2(15 1/4″ – 12″) + 23/4″ = 23 1/4″

Note that using a smaller shell with the same size ring requires a larger diameter hide (or more of a stretch). Keep in mind that depending on the thickness of the hide the amount of stretch will potentially vary quite a bit. If you cut the hide too small, there is no going back, if you cut it a little large to start then you can always trim it down if necessary.

STEP 2: Prep Rings And Hides

Prepare your rings in advance by doing the following:

1. file down any protrusions or burrs from the weld
2. sand the rings completely (~100 grit sandpaper)
3. clean the rings by washing and wiping it dry
4. painting the rings with a few coats of rust-resistant white primer
5. allow adequate time for the primer coats to dry and sand finish smooth with fine sandpaper (220+ grit). Focus on sanding down any protrusions, be careful not to sand through the finish.

Prep Hides

Prepare your hides in advance by soaking them. If they are thick hides, such as cowhide, soak for ~ 8 hours, if the hides are thinner such as calfskin or horse hides, a 2-4 hour soak is adequate. Your hides may vary a lot, if it is not completely flexible then continue to soak.  Inadequately soaked hides are very difficult to stretch. You can add a little bleach to the water to prevent anything from growing…a weak solution of 2% bleach is sufficient to sanitize a surface, but isn’t necessary.

STEP 3: Create Templates

ROPE TENSIONING HOLE TEMPLATE

Preparing a template for the rope tensioning holes should also be done in advance. Put your ring on a piece of tagboard and trace the inner and outer circumference on the tag board. Now place the shell on the tag board centered in the ring and trace the outer diameter of the shell.

If you are using 5/16″ diameter rope  then you will want to cut 3/8″ holes. Decide on the number of holes to use, 10-12 holes is common. Draw the 3/8″ diameter holes at equal distances around the inner diameter of the ring. There will be two stitch lines, the first along the ID of the ring and around the rope holes and a second one closer to the outer diameter of the drum shell. There needs to be enough space between the second stitch and the shell to accommodate the leftover hide after trimming.

STRETCHING LINE HOLE TEMPLATE

It is also very helpful to prepare a template for the stretching line in advance. The template is prepared by first deciding how many stretching holes you want around your perimeter. The more stretching holes you have, the less strain there will be on any particular hole and the less chance there is for a tear. Larger heads need more holes for an even stretch.

Cut out the stretching holes with a leather hole punch (one like this)

Below is an example template for a 21 hole pattern with the string order marked. Use a compass with the appropriate distance measured from a ruler and mark the circumference of the circle, if you don’t end right at the mark you started on split the difference and and mark backward until the marks line up again and use those in the same way you would when marking for byou when heading a nagado-daiko.

(click on the template below for a full-size version)

The number of holes chosen is important. The string will be run around the perimeter of the head in such a way that it skips over a fixed number of holes each time and after completing each lap of the circumference it will line up with the next hole. The following patterns are viable options:

• 17 Holes: String Order is 1, 6, 11, 16, 4, 9, 14, 2, 7, 12, 17, 5, 10, 15, 3, 8, 13
• 21 Holes: String Order is 1, 6, 11, 16, 21, 5, 10, 15, 20, 4, 9, 14, 19, 3, 8, 13, 18, 2, 7, 12, 17
• 29 Holes: String Order is 1, 6, 11, 16, 21, 26, 2, 7, 12, 17, 22, 27, 3, 8, 13, 18, 23, 28, 4, 9, 14, 19, 24, 29, 5, 10, 15, 20, 25

The spacing between the marks along the outer edge can be determined with some simple trig. If you don’t care about the details of the math, skip to step 4.

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MATH!! 

The chord between each hole along the perimeter is the base of an inscribed isosceles triangle which can be split into two right triangles. The radius (r) of the circle is then related to half the chord length (c/2) by the sine of half the angle (theta/2) inscribed by the isosceles triangle.  If a 21 hole pattern is desired, then 360 degrees needs to be split up into 21 isosceles triangles. The angle theta is then 360°/21 = 17.14°. The chord length (c) is given by the following: c = 2rsin(theta/2). A less exact method would simply be to divide the circumference on the circle by 21. The error between the two methods is ~0.57% for 17 holes, ~0.37% for 21 holes, and 0.20% for 29 holes.

So, for the three patterns above the chord length is related to the radius by:

• 17 Holes: c = 0.3675*r
• 21 Holes: c = 0.2981*r
• 29 Holes: c = 0.2162*r

Head to PART 2 to find the next steps!