Starrett Micrometer Ratchet Spring

Having coming into possession of some older Starrett micrometers recently, I found one rather impossible to calibrate. The barrel seemed to be frozen, and wouldn’t adjust to zero-out with the thimble.

I took it apart by removing the ratchet, pulling out the spindle, taking the lock ring out, etc. I did the mineral spirits/PB stuff routine (no Kroil oil in my area – apparently people have forgotten how good it is), and eventually got it to move. I had the variable heat gun ready as a back-up, but wanted to see if I could leach some gunk out first, which apparently I was able to do.

The problem was when I went to put it all back together: In my quest to fix the barrel being frozen, I didn’t pay attention to the little ratchet stop-pin and the teeny little ratchet stop-pin spring that pushes the ratchet-stop against the little ratchet-teeth in the ratchet stop proper. <insert expletive of your choice here> They must have fallen out when I was bathing the thimble/spindle in mineral spirits, shooting it with PB, etc. I had taken a victory and turned it into a resounding defeat by ignoring what should have been obvious. I was not a happy camper.

Oddly enough, the next day I just happened to step on the ratchet stop-pin. After pulling it out of my foot, I placed it in the stop-pin hole on top of the thimble, and indeed, it was the girl I’d been lookin’ for. Joy! But still no spring.

Starrett never returned an email, and I found conflicting information about parts availability on the normal suggested micrometer repair folks’ websites. On top of that, I wasn’t really excited about shelling out money for a spring (what, seven or eight bucks?) and then a shipping charge to send me something the size of a baby’s nail-clipping (another seven or eight bucks?). I paid about ten for the micrometer to begin with, and it was just something cool to play with and see how close it was to a digital – not an investment.

On a side note, I’ll have to say in comparison to the digital, it’s spot-on. Pretty incredible. Let’s just say I’m rather impressed. Some things just work, period.

Anyway, I’m depressed about the spring, so I plop into my chair, and start brooding. As I’m brooding, I’m looking around on the table/shelves next to my chair, and I spy a watchband spring-pin. I had been changing a watch band and shooting spring-pins all over the living room a couple days before. Don’t ask.

I thought, “Say….those spring-pins have little teeny-tiny springs inside them…I wonder…” Sure enough, they fit inside the ratchet stop-pin spring-hole on top of the thimble. I used some nice wire stripper-cutters to slice a little bit off, to see if it would work. It sure as <expletive> did.

The other thing I realized is that if people don’t like the amount of tension that the ratchet stop places against an object being measured, you could vary it by putting in a different length spring from a watchband spring-pin; a lot of folks like the “three-clicks-and-you’re-good” way of measuring, and others say, “It’s a feeling…an acquired skill. I can do it better than any ratchet after years of ‘feeling’ the right pressure.” I’ve found that both work well, and I like the ones that don’t have ratchets, and I like the ratchets on the ones that have them.

This way, if you have a ratchet stop, you can adjust the amount of pressure that causes the spindle to stop moving when it’s in contact with an object being measured to be whatever you want it to be.

If you thought the ratchet stop provided a "ham-fisted neophyte" measurement, you could change it to a lighter spring for that "sensitive, intuitive amount of pressure garnered from years of experience" feel.

Thought that might come in handy for some folks some time, so I thought I’d share it. Watchband spring-pins are cheap, plentiful, and come apart rather easily. With a decent set of cutter/strippers, they can be cut cleanly and neatly into whatever length (with its representative amount of force) that feels comfortable to the operator if they choose to use the ratchet stop when measuring.

Now I just need to find a shade-tree micrometer mechanic substitute for a ratchet stop-pin in case I ever do something stupid like this again…