I am quite certain that this problem does not occur a lot. However, for me, it was the second time with two different rackets... Time to make an Instructable about it!
I have no pictures of the first broken handle from which I felt the wood was breaking. Gluing it was of course only good as a temporary solution. After it broke beyond "glue"-repair, I bought a new racket but I felt sad that I could not use this racket anymore that I've enjoyed for years. After all, the frame was still perfect. So I repaired it and almost 2 years later I'm still playing with this racket!
As I play with both rackets, the same happened with this other racket. I felt the wood was cracking so very slightly. If you swung the racket you could feel the backlash from the shaft in the handle. So I just went for a repair again!
Step 1: Buy a Handle or Make One Yourself!
The first time I could not find where to buy a handle, so I made one myself. It was fun but it was not that easy as my woodworking skills and woodworking tools are limited. I will include some pictures about it but I will not describe the process because it is way easier to buy one for 4,95 dollar including shipping!
I must have overlooked it the first time but you can buy handles on My Badminton Store. The advantage is that you can choose the right size (handle and shaft dimensions) and the plastic cone (front cap) and bottom (end cap) are included so you don't have to recover this from your broken racket (which is not easy).
The front cap just above the handle holds a sticker with the shaft size on it. Mine says it's a Yonex G3 handle size, so go for the G4 handle size. Indeed Yonex uses other sizes than other racket manufacturers but My Badminton Store informs you about this. If you want a bigger or smaller handle, this is the moment, choose your favorite.
Also measure the diameter of the shaft and choose the correct one on the site. Mine was 7,12mm so I went for the 7mm version.
It took almost 2 weeks to arrive (China to Belgium). So you have a lot of time to follow another Instructable in the mean time ;-).
Step 2: Remove the Old Handle and Salvage Most (non Wood) Parts
Okay the new handle is arrived. Time to remove the old one.
First of all you have to remove the grip. Just pull it loose. You can throw it away and use a new one (buy one at your local badminton store) or you could reuse it on your new handle in combination with your favorite overgrip (like I did). It's up to you.
I also recovered the plastic end cap. The one that came with the new handle is just plain black while the original one is green with the Yonex logo on it. Once again it's up to you to choose. You just have to remove 4 U-shaped nails with a small screwdriver (the wood is very soft so it's very easy). Underneath this end cap, there is another plastic cap located in the hole that makes the handle less heavy. You could also recover this if your racket have this (only one of my two rackets had this), it's not critical. It pops out very easy, no glue involved. Just split the wood with a hammer and a chisel or screwdriver (remember the soft wood, very easy).
Next step is to remove a small screw just below the front cap. Use a small screwdriver.
At this point I also discovered why my handles break. I dare to say it's a bad production step/mistake. After the grip is applied, the excess is cut of just below the front cap, this is done too deep and left a cut in the wood. The force on the racket whilst playing made this crack go deeper resulting in a loosening handle and ultimately in a broken handle.
Remove the handle by just twisting it a bit. Use just a little force, no tools. It breaks very easy. The shaft is only 6 cm deep into the handle, there is only about 3 cm left beyond the front cap.
Step 3: Remove the Plastic Cone Front Cap
Removing this front cap might be a little bit harder. You could use a hammer to break the wood a little, be very gentle, you don't want to damage the shaft. You could also use a small chisel or screwdriver to prie some wood from under it and some long nose pliers to pull it out. Twist it a little until it let loose. You may use some force while twisting it, there is some glue used in production.
Step 4: Sand the Shaft and Make It Fit Into the New Handle
As you would have seen, there is some glue and wood left on the shaft. Sand this until the shaft is clean again. I used some fine sanding paper in combination with a vise to sand it equally over the length. Your racket is probably made of carbon fibre composite, this is easy to sand. A bit to easy actually so be careful to sand it equally and not to much.
You should sand it until the shaft fits into the handle. Do not force it! The wood will break/split! A tight fit is possible, you may twist-slide it in but use no force!
Alternatively you may make the hole from the handle a little bit bigger by using a 7 mm drill. Rotate it a few times yourself, do not use a drilling machine.
Step 5: Make the Hole for the Screw
This hole has two functions. The first one is to make sure that the shaft is secured in the handle, a mechanical protection aside from the glue we will use later. The second function is that this hole allows that the air can go out if we will glue the shaft in later on. This screw has nothing to do with the alignment from the top of the racket, the frame to the handle.
Mark where the hole has to come. Measure it from the top or align the shaft next to it (see picture). This hole has to come on one of the two wider sides from the handle.
Use a 2 mm drill and use a drilling machine. Carefully drill the hole until you feel that you reached the middle of the handle (the space where the shaft fits in). Make sure that this hole is aligned correct by inserting the shaft, I used a nail to verify this. If this is not good, have a second (and last!) chance on the other side of the handle. If it is okay, use a 4 mm drill and drill just a few millimeters into the wood so that the head of the screw will be countersunk in the handle.
Step 6: Glue the Shaft in the Handle
First of all, slide the plastic cone front cap over the shaft, we will use it later. Do not forget this!
Clean the shaft so that the dirt from sanding it is gone.
Prepare your glue, I used two-component adhesive. Apply it around the shaft for the whole length that fits in the handle (+- 6 cm), the part that you sanded. And slide/twist it in the handle. Keep track of the hole in the shaft so that you can align it with the hole in the handle. Once again use a nail to verify this. If this is okay, screw the screw back in.
Also make sure that the frame is aligned perpendicular to the handle while the glue is still not dry.
Apply some glue on top of the handle where the front cap has to come. After that, slide the front cap down from the shaft over the top from the handle. Use some force, the front cap may show some curvature as a result from forcing it over the handle.
Step 7: Finish the Handle
Make sure that the glue has dried a little bit and be careful not to twist the frame in the handle until the glue has dried complete.
Put the plastic cap back in the hole in the underside from the handle. Next put the end cap (the original one or the new one) over the end of the handle and hammer the U-shaped nails in.
Apply the new or used grip over the handle and possibly also the overgrip.
Admire your work! Well done! Now make sure the glue dried enough before you jump on the field with this racket!
Go win some games!