- Joined
- Dec 8, 2013
- Messages
- 2,648
Wouldn't the ratchet or friction mechanism in the thimble relieve any force due to thermal expansion? But isn't the entire device made of the same material anyway?
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Tubular Micrometer Co. Micrometer
- Thread starter Strtspdlx
- Start date
- Joined
- Feb 8, 2014
- Messages
- 11,187
The ratchet only controls the thimble tension as you tighten to measure. The threads are directly connected.
It's good practice to leave mics open a bit. This was drummed into my head about 50 years ago by my high school shop instructor.
Actually I'm just repeating what I've been told. Corrosion is caused from a reaction in chemicals but I don't know which is acidic & which is caustic. Is assume the brass is the caustic & leather is the acidic. I have been told Law Enforcement went to the nickel platted brass because their leather cases caused the brass to corrode. I know the brass does corrode in leather. I also know there is several reloaders that swear by lanolin as a lube to run brass through a press & these guys should know brass better then most people.
Now with that said all brass isn't equal.
- Joined
- Dec 8, 2013
- Messages
- 2,648
Neither is all leather. There are different tanning processes.
True.
I have to admit I probably know less about leather then I do about brass. I'm sure that conditioners for the leather could have an affect as well. I have some leather tact but I don't believe there is any brass on mine. My favorite is the stuff made from synthics. I believe it was called "new (something)".
To the op I was going to mention something earlier & forgot. You should always wipe you anvils of every time you measure even if you just measured & your going to again. Unseen dust is huge when your measuring to the ten thousandths of a inch. So dry wipe every time.
- Joined
- Jul 10, 2013
- Messages
- 1,224
I hope that I'm not beating this subject to death, but George you got me thinking. You live in Williamsburg, Virginia, aren't you pretty close to the ocean? I live in eastern Oregon, as they say the dry side. I'm 300 miles east of the Pacific Ocean. I went down to my shop and pulled out my rarely used machinist toolbox. The outside has rust, but the felt lined drawers loaded with steel, iron, and brass tools are just fine. Go figure. Mark
- Joined
- Jul 10, 2013
- Messages
- 1,224
Darn! I forgot to mention, that box is over 35 yrs old. Mark
- Joined
- Jul 26, 2011
- Messages
- 4,139
I am not that close to the ocean. About leather: here are differently tanned leathers. I carry 2 carbon steel pocket knives in an oak tanned double sheath. I do this to keep them outside of my pocket and any sweat,etc. that invariably darkens carbon steel that is kept in the pocket. I've been carrying these knives for over 20 years. They are left in the sheath day and night. Somehow my blades are still perfectly bright.
There's oak tanned,chrome tanned,sumac tanned,and I don't know what else. Oh,I have a 19th. C. ship maker's adze that has always been in its original old,nearly starting to fall apart leather blade guard. The bright bevel on the adze is still bright,though I'd have thought the tannin is certainly freely available to rust it.
So,another "go figure".
There's oak tanned,chrome tanned,sumac tanned,and I don't know what else. Oh,I have a 19th. C. ship maker's adze that has always been in its original old,nearly starting to fall apart leather blade guard. The bright bevel on the adze is still bright,though I'd have thought the tannin is certainly freely available to rust it.
So,another "go figure".