Dwell tool. As defined by Automotive Dictionary. Org
The number of degrees the breaker cam rotates from the time the breaker points close until they open again. Also called the “dwell angle ” or “dwell period”.
This little funny looking screwdriver “like” tool was made for only one purpose. That’s for adjusting the old ignition points systems used on the older cars before electronic ignition systems were invented.
I used to watch my father use these on our family cars. But at that young age, I didn’t know yet what he was doing with the strange tool that can twist like a snake! As I got older in my mid-teens I learned what it was for and what it did but still, it took me time to understand the exact purpose for this tool and where it fits into. My father would say, the points is one of the reasons that brings the car to life! With the other parts that accompany them like the rotor cap, capacitor, and the distributor cap, with all of them together it helps. One time I asked him what the silver square was on the distributor was for? He said so he could adjust it to the measurement or settings. I learned many years later from working on one of my own cars with feeler gauges and a new set of points for a tune-up what the point setting was for my car. But at this time my father wasn’t around, but I kept on advancing my mechanic knowledge while still making fast-food wages.
But this is about the Dwell tool and this is about learning to make adjustments simple if your old car may be running rough. If you have this weird tool and know someone who does then it may help you help your car or truck by opening the points or closing them slowly or if you don’t want to go through the headache of taking it all apart or don’t have the feeler gauges.
This tool was my fathers favorite. I use it only to set my points plus my feeler gauges so there isn’t any guesswork if I’m close to the right settings or not. I also bought mine for the memories it brings back to me of watching my father work on our family cars and what gave me the “inspired love” I have for this passion of mine for cars, mechanics, tools, restoration of vintage vehicles or like my loving wife says, “my car sickness anyway you look at it.” It’s a wonderful thing, I love it always! Now I posted here my distributor cap for a point to be aware if you ever get a misfiring engine look for a hairline crack between the contact points in the cap. Maybe a cause from past experience this has been some of the cause just something for you to look at if you’re stumped on your own project.