The short warranty version:

All electrical parts are tested for proper operation and mechanical parts inspected before I ship them to you. I cannot accept the wasted time and expense of shipping parts back and forth for you to test what is wrong with your machine. If you you destroy a new part during installation or order a new part for the sole purpose of testing it on your machine to see if that part is the reason the machine is not working, I will not refund and you will own the part.

The long warranty version:

 Due to a very few customers who attempt to take advantage of our past refund policy, there has been a 600% increase in returned items since 2008. These parts were obviously ordered by customers only for the sole purpose to test diagnose the problem with their machine, then return it if that part didn't solve the problem. Those items were the correct new part or a used part ordered by the customer that I tested and inspected before shipping, so I know it was not a defective part. Mechanical parts have been returned damaged by amateur installation and electrical parts fried because the "mechanic" incorrectly connected the wiring, or the customer simply changed their mind and decided to not repair the machine after ordering the parts.

  As you are probably aware, other companies have pages of warranty legalese to avoid honoring most any warranty claim. Just read the fine print in that wonderful 25 year warranty on your new sewing machine. It is actually a one year warranty and does not cover labor, which is often jacked up to cover the cost of warranty parts. I refuse to mislead customers by writing pages of warranty legalese. However, I must protect my business from accepting returns for parts destroyed by amateur repairs or uninformed operators, then returning the parts for a refund.

 I will accept returns and offer an exchange for new parts, if you ordered the correct part number and I shipped the wrong part. (my error).

I will offer an exchange part, less a 25% restocking charge if you ordered the wrong mechanical part. (your error).

The part must be returned in new, unused condition.

Electrical parts will not be refunded or exchanged.

Motors and electronic parts warranty:
We test all motors and electronic parts for proper operation before shipping, so we know they are working before we ship them. I refunded the last new $400.00 circuit board after the customer connected the wires incorrectly and returned a fried piece of junk. Another circuit board was returned for refund when the customer installed our new board, then returned their old board for a refund. Never again. Yes, I have used a secret mark and other methods to identify many parts to assure the returned part was the same part I shipped.

  A new motor or circuit board may be fried instantly when connected to other malfunctioning components that may be in your machine. We cannot guarantee you won't ignore advice to unplug your machine from the wall outlet, as recommended by all manufacturers, and will allow lightning to strike your home and fry the new circuit board. We can no longer assume responsibility for untrained mechanics or replace or refund circuit boards, motors and other electronic parts that are damaged by improper installation or any other circumstances beyond our control. Therefore, I can no longer offer any refund or guarantee on any electrical product after I ship it. You break it or burn it up, and you own it.

Mechanical parts warranty:
I have no control how you use your machine. I cannot guarantee the new pinion gear I shipped will be broken because you abused your machine trying to sew over a zipper or forced your household machine to sew 1/2" thick upholstery. I search for the highest quality parts available and they will last for years if the machine is operated as the manufacturer intended. Therefore, I do not warranty mechanical parts for years, months, or even days after it has been installed.
                                                Updated 06/15/21