EL JUEGO Y LA FORMACION DE DISPOSITIVOS

1/4” length. Tool hole 1/8” diameter. Tool bit 1/8” drill rod. Hole drilled at 15 degree angle.

There are many clarinets that seem to break more readily than others. This is espe- cially true of the plastic variety and the hard rubber or Ebonite. Although wood clarinets do crack, they are rarely broken but this state- ment does not mean that it cannot happen.

There are three tenons that we are usually confronted with. They are the following:

Male Tenon on the lower joint (to fit the bell) Male tenon on the upper joint (to fit lower joint) Female tenon on the lower joint to fit male tenon on the upper joint.

There may be many methods of doing these specific types of repair jobs. However, we shall describe the two types of methods that are most commonly used. This does not mean that if any repairman has another method, that we frown upon it. In fact, we are always open to new suggestions from any- one. It merely means that we know that these two methods do work to good advantage. The first method is that which calls for boring out the body, and the tenon is inserted and glued in place, with or without safety pins to lock it.

The second method is that which calls for the threading of the parts, gluing and allowing the posts to act as the pins. The boring tool, con- sists of a 6” length of drill rod, 1/2” diameter, with a 1/4” hole through the side of the rod. The front edge of the rod is cut down to 3/8” for 1/2” from the end. This under cut is for the pilot which is made of brass. To hold this pilot in place, a 1/2” washer and an Allen screw

(8x32 thread) are used. The front end of the boring rod is: drilled out to 1/2” depth with a 28 drill and’ the hole ‘is threaded with an 8x32 tap. The cutting, tool is 1/4” drill rod, sharp- ened and hardened so that the .tool has the cutting edge. This tool bit is inserted in the 1/4” hole -and locked in place by means of a headless Allen- screw. The resulting tool is’ a pedect fly cutter. The pilot used on this tool’ must ‘have its outside diameter a perfect fit to the bore of the body of the clarinet. The length of the cutting bit is dependent upon the size of the cut desired. If the method of repair used is ‘that of threading the tenon and the body, we recommend the use of 27/32x20 tap and die. To bore the body out the bit should be set .152” extended from the boring bar. This will the bore out the clarinet to a diameter .804”. Since the decimal equivalent of 27/32” is .84375 or .844”, this will allow .040” for threads, This procedure is used to repair the male tenon on the upper joint. The depth of the cut should be past the open C tone hole. Thread the body, making certain that the threads are cut true and straight and using a cutting oil with a sulphur base. To cut these threads true to the center, the tap should have a pilot end. Replacement tenons can be pur- chased. If you prefer making the tenon, the outside length should be the length of the pre- pared bore plus the length of the tenon. The diameter of the end to be threaded should be .844”. If this repair is performed on a wood joint, we recommend the use of plastic steel for the gluing agent. Cut the diameter of the tenon to fit the female socket of the lower joint, then cut the recess for the cork. Since even a bottom tap has a lead on its starting thread, we must allow for that lead on the threaded tenon by under-cutting the first thread on the tenon. This will assure you of the fact that the tenon will screw in to match the opposite end. By the same token, a die has a lead as well. Therefore we must under- stand the last thread.

If this tenon is not to be threaded in place, we must bear in mind that we need more length to the gluing service. Therefore, the internal cut should be made past the Bb or Eb tone hole.

After the tenon is set in place, the tone holes must be rebored and the post holes redrilled slightly, since the boring out of the

Tap and die for upper tenon 27/32” x 20” for bell tenon - 1” x 20” bore drill

body interferes with the post hole. It is for this reson that all the posts must be removed from the body if they are in the length of the cut. In both methods of repair, the posts upon reset- ting, will act as pins for the tenon.

If the tenon is made on a rubber clar- inet, we must use plastic steel. Rubber

cements will seal any leak, but they never fully

harden. The best glue I have found for this purpose is plastic-steel. It comes in wet pow- der form with a small bottle of liquid. After mix- ing, it does a terrific job of holding.

On clarinets made with plastic materials such as Resonite (Bundy, etc.,) I suggest that you do not attempt to use the threaded

method.

If the tenon is threaded and glued in place, we can proceed with the finish cutting immedi- ately since the threads, being right hand, will hold the part firmly. If the tenon is merely glued in place without the use of threads, it is wise to let the glue set for twenty-four (24) hours before making the finish cut.

The above description is merely for the replacement or repair of broken male tenons on the upper joint that fit the female tenon of the lower joint.

MALE TENON LOWER JOINT