Actually, services are not usually subject to sales tax. Doctors, lawyers, accountants, none of those people are required to charge sales tax for their services.

Sales of products are subject to sales tax.

If you have ever had any repair work done (on a car, an instrument, etc.), look at the invoice. Sales tax is charged on the parts, but not on the labor.

When someone builds and sells an accordion, at least from a tax standpoint, he is not providing a service, he is selling a product, therefore the sales tax.