This item listing is for a set of 4 cylinder barrel base nuts to fit the Douglas 2 3/4 hp models in stainless steel with washers. These nuts are 5/16" x 25 tpi Douglas thread and have more depth than standard. CNC manufactured in stainless steel.
As can be seen from the last photo, an original Douglas 2 3/4hp barrel nut was used as the pattern to manufacture these nuts, and we have had custom taps made with the correct thread. These nuts are CNC manufactured by us in stainless steel and are the correct depth as originals (to fit on the special floating crankcase studs fitted to this engine type). We also linish the flats of our stainless bar before machining, so the nuts look pretty as well.
Sorry these are more expensive than normal nut sets, but the cost of Douglas 25 tpi taps means we have to take great care in the CNC setup, to ensure we dont break one! We also perform a post-CNC op to chase the thread again, ensuring their is no thread burrs after the parting off/countersinking.