I have made a musical instrument part I have made that sort of resembles a patented part. Am I guilty of patent infringement?

The below does not constitute legal advice, does not form an attorney-client relationship, and should not be relied upon to take or refrain from taking any action.

This question cannot be answered with the information provided. In order to determine whether a particular product infringes a patent, the claims of the patent, its prosecution history (the written record of proceedings at the Patent Office), and the part that may infringe must be analyzed by an attorney experienced in such matters.

While it is potentially good that you state your part "is minus a few of the patented part features," this is not necessarily conclusive. The patent owner's commercial product is not relevant to the question, because the coverage of a patent is often broader than just the specific design or characteristics of the patent owner's product. If your part is missing at least one of the elements of the claims of the patent, you are more likely to be in the clear, but there may still be an issue of infringement under the doctrine of equivalents, which arises when a part in the accused devices is not exactly as claimed in a patent, but the differences are insubstantial, or it performs the same function in the same way to get the same result as the corresponding part in the patent.

You need to discuss the issue with a patent attorney who can undertake the necessary review.