How to read micrometer (ASM o-ring)

[Lyscer]

I'm trying to figure out how thick the o-ring on my asm g4 skimmer is so I can get a slightly thicker one because it is starting to leak. Does anyone know how to read these things? It started at the 0 did one full rotation and stopped at 40. What would that reading be?

 

[Anemonebuff]

I just make sure the O-ring is flush with the base of the cone. I also push down on the cup as I turn the cup. It rarely ever leaks.

 

[der Riff-Konig]

that reading is 143 thousands. 250 is a quarter of an inch. 125 is 1/8 of an inch.

 

[dne63]

agree with the last post .0143 is correct

 

[narow37]

actually dne63 it would be .143 not .0143.

 

[Dubbin1]

Yup .143 I think you can figure out how to read it now

 

[rayjay]

Shouldn't really nit-pick I guess, but the picture shows measurement with a vernier caliper, not a micrometer.

 

[Amphiprion]

It should read in millimeters (mm), not micrometers (lowercase mu and then an m). for reference, a micrometer is roughly the size of a bacterium.

 

[Lyscer]

so would .143 of an inch be correct? Where is a good place to buy an o-ring?

 

[rayjay]

Looking at the scale in the picture, the scale is in .001" increments, that's thousands of an inch.
Metric ones DO read in mm.

 

[rayjay]

Try a hardware store or an automotive supply shop.
You need to know the inside diameter of the O ring as well as the thickness. You never mentioned the the diameter, only the thickness.
.143" is approximately 9/64 ths of an inch.
I don't remember the common thicknesses that O rings come in but something should be close to that.
Another problem is that the manufacture possibly had special size ones made, to stop people from using generic sized rings so you have to order the special ones from them.