Part of my business is machining restoration parts for antique H/D bikes. 1905-1920 to be specific. the 1909 engine uses an atmospheric intake valve. meaning there's no camshaft to actuate it. It opens soley on the vacuum created by the piston as it moves to BTC after the exhaust stroke.
Well, these engines are ULTRA rare. There's less than 10 in the world that run. A cylinder (one cylinder) is worth over $20K if its servicable. "We" spent some big money having cylinders cast from scratch to put a few of these engines together. I'm making the valve pockets for them out of 4140 aerospace certified 2" bar stock and I almost screwed up about $5k worth of parts.
YEASH!! Luckily I caught the woops and we were able to make a slight mudderfication and save the parts.
Nothing like enginidioting on the fly!!
Thanks again for the kind words. Feels really good to be washing coolant and saw dust off my hands again and not middle eastern sand!