My set of Class B precision gage blocks (0.050 to 4.00 inches) is three or
four years old, and most of the mirror-finish blocks are still perfect.
However, a couple of them are showing minor evidence of corrosion - probably
from human fingerprints. I keep them slightly wetted with a spray coat of
WD40 but not sure if that is the best protection. Any suggestions? Please
don't tell me I have to use cotton gloves! Dave
LPS 3 works a lot better for corrosion protection than WD-40, but as
expected its also harder to clean off.
Anything that has better protection than WD-40 is going to have a slightly
waxy feeling until you take it off.
Get Lano-Lube. That's what's called out by Starrett and others. It's a
sticky lanolin gel you smear on. It washes off very well indeed in solvent,
but when it's on it is a real good rust protector and it doesn't hurt your
This isn't a "for sure" thing, but if these came from an economical
source, there may be some problem with the wooden box. I think some
woods are either "wet', or out-gas something that causes oxidation.
I think I'd bake the box in the oven or a few hours, and then I'd do
as someone else has suggested about LPS3, but spray the box instead,
and re-heat it again.
As an aside, I used some unknown liquid which I thought was oil, but
may have been either tapping fluid or brake fluid, as an "oil" for a
stone to sharpen something. I then placed the stone back in the
corner of a drawer of the tool chest, where it had resided with other
stones for years. It was a week of so before I went back into that
drawer, and there was oxidation of a "funny" kind forming on the shiny
surface of a bunch of stuff in that drawer. Closer the stuff was
located to the stone, the heavier the oxidation. I removed all the
stones to an outside-the-box storage, and have had no further
I >My set of Class B precision gage blocks (0.050 to 4.00 inches) is three or
Thanks for all who contributed some very good ideas on corrosion prevention
for precision gage blocks. Brian Lawson's response may have hit on an
unsuspected source: the wood box itself, since the individual gages are
fitted to narrow rectangular compartments. On a slightly different
application, I have several home-made wooden storage holders for small end
mills with 0.500 and 0.375 inch shanks. Some of these that are not used
very much now show minor to moderate corrosion where the shank has been in
long-time contact with the raw wood. A few quick passes with #600 grit
aluminum oxide paper cleans them up ok, but obviously this is not
recommended for gage blocks. Thanks to all. I am buying a tube of
WD-40 is a water displacement agent.
It is lousy at lubrication and rust prevention.
||My set of Class B precision gage blocks (0.050 to 4.00 inches) is three or
||four years old, and most of the mirror-finish blocks are still perfect.
||However, a couple of them are showing minor evidence of corrosion - probably
||from human fingerprints. I keep them slightly wetted with a spray coat of
||WD40 but not sure if that is the best protection. Any suggestions? Please
||don't tell me I have to use cotton gloves! Dave
Texas Parts Guy
First off, for quite a while, I've been wiping Starrett
"instrument oil" onto the ends of the gauge blocks before putting them
away. More recently, I've been sprying with CRC 5-56 (or is that 3-56? --
something which sounds like a very fine pitched thread, but isn't.
As an example, at work, I had an old set of collets for the
Unimat SL-1000, which were all rusted. They were in a fitted wood case,
with a sliding clear plastic lid. (Well -- sort of yellow clear. :-)
I got a new set of collets, and put them in that case, after
spraying the inside with oil. They started to rust right away (a day or
two). I finally pulled the plastic lid, and made a new one from
Plexiglas, and the problems went away. I *think* that it was a
cellulose nitrate which was starting to break down, and emit a gas which
combined with moisture to become nitric acid.
I've since inherited the case, sans collets, and put my own
collets in them, and again I have had no problems since the plastic lid
I've got two sets of gauge blocks -- a smaller Chinese import
set (used for rough-and-ready tasks), and a larger set of real "Jo"
(Johansen) blocks, and with my treatment, I have had no problems with
A good warning. Thanks.
David Anderson wrote in article
My experience has been that WD-40 tends to evaporate in a fairly short time
- leaving your tool with no protection.
An old machinist acquaintance told me to use something along the line of
Liquid Wrench to both clean up rust/corrosion and to leave an oily
protectant film on the metal.
If the oily residue presents a problem, you can always clean the tool up
with spray carburetor/choke or brake cleaner, then re-coat the tool with LW
upon placing it back into storage.
That's what works for me.....
I use a light coat of CRC 3-36. I wipe with a lint free cloth before
use anyway and I tested a stack of a bunch of the thinner ones. Any
error due to residue was less than a tenth which is good enough for me.
I have not the facilities nor (so far) the need to get down to