TIL from a retired machinist that my tool height offsets were all wrong

I was at a local shop supply place in Akron last month picking up some end mills when an old timer named Gene saw me setting up a tool in the back of my truck. He asked if I used a touch probe or paper method, and I told him paper. He shook his head and showed me a 0.001 inch shim trick he learned back in the 80s. Turns out I had been averaging around 0.003 to 0.005 inches off on every offset for the past two years because paper compresses too much. Has anyone else had a random stranger straighten out their whole process like that?

2 comments

2 Comments

hollym8225d ago

Honestly my buddy Kevin had something similar happen at a car meet. Some retired mechanic watched him adjusting his timing by ear and just walked over and handed him a vacuum gauge he had in his trunk. Told him to hook it up and tune for highest steady reading at idle. Kevin had been guessing his timing for like five years and the gauge showed he was off by almost 10 degrees across the whole RPM range. Fixed his stumble and got better gas mileage in like ten minutes.

robinson.leo25d ago

Read somewhere that older mechanics swear by vacuum gauges for more than just timing. They can also spot a burned valve or a vacuum leak just by watching the needle bounce at idle. My buddy tried using one after reading about it on a forum and found out his carb was running lean on one barrel. Took him maybe 20 minutes to dial it in after that. Funny how some of that old school stuff still works better than the fancy digital tools half the time.