Replacement tuning peg

Q: I have enjoyed viewing you website and I have a question for you. I was wondering what the best way is to replace a single ivory knob on my classical guitar. I have the right size replacement, but I'm not sure if there is a special glue needed or special procedure.
Thanks!
John 

A: To install an ivory knob you would drill out the hole until the tuner just presses on and then epoxy it to the shaft, using color powders to match the epoxy to the ivory. However, since ivory is illegal, and you seem to have a commercially available replacement button, I presume that you mean ivoroid, a breed of plastic. The official instructions for replacing a plastic button are: remove the tuners from the guitar and clamp them in a vise. Heat the shaft with a blow torch. Press the button into place.  It sounds easy. I find that it is hard to get the shaft to just the right temperature; hot enough to sizzle the plastic but not discolor the shaft. And it can be hard to push the button into place. The first time you try it it might be good to have a couple of buttons in case you wreck one or two.
Sometimes the old cellulose buttons on vintage instruments just crumble and fall off. The more common reason for the button to come off is that the tuner is bad. The gears lock up and the stress exceeds the grip of the button on the shaft. With vintage tuners, you can clean and adjust and find replacement parts. If you are paying a professional luthier, the cost of restoring tuners quickly exceeds the cost of replacing them. 
 
Steve Mason