Most professional framebuilders are one man shops and their only source of income is from building frames for customers. If they are not building a frame for a customer, they are not making money. Developing an efficient process and workflow allows them to make the most of their available shop time. Adding an apprentice into that mix throws off the workflow and also takes away some of the control that the builder has over every part of the process.

Some framebuilders take on students who want to learn to build frames or just want to build a frame for themselves. Those builders charge a fee for for those classes, in order to make up for the income lost from not building customer frames during the classes.

The only framebuilder that I have recently seen take in a apprentice was Sean Burns of Oddity Cycles.