03-30-2018, 09:19 AM
Got lucky recently. Found a new Starrett 81 piece rectangular set of gage blocks with certs, where each gage block was checked for size and flatness. They were certified to the old Starrett A1 specification. They were calibrated in 2003. They have never been used! Still have the petroleum jelly coating on them. No scratches either! I'm afraid to use them. I gave less than $100 for them, too, from a local pawn shop.
I have two other sets of square gage blocks I use as my shop blocks. One of the sets was from a dumpster dive at one of my past jobs. I missed getting the accessory set that went with the square gage block set. Now enough for the bragging.
I have successfully recondition gage blocks removing rust and some scratches. My method uses two abrasive stones, one a new fine grit Norton indian stone such as a 1/4" x 1 x 4" lg. Second stone is a broken piece of a 1/2" square norton hard arkansas "white" stone. Use the indian stone to stone off any rust large burrs and such. Use a little honing oil or as Starrett mention, a little kerosene. Use light pressure to remove rust or burrs. It don't take much rubbing. When it get's where the stone feels like it stops cutting, stop. Clean the surface of the gage block. Next, take the hard Arkansas stone, rub it against the indian stone to make it flat against the indian stone. Now, stone the gage against the Arkansas stone, again light pressure. You'll feel when it stops cutting. Rub the Arkansas stone against the indian stone to clean and repeat rubbing the gage block. Two, three times doing this will restore the some of the mirror finish on a gage block. Won't be factory perfect or stick together when you wring blocks together, but will be close. Like others said coat the with oil or petroleum jelly for storage. I do not recommend using any general purpose grease. It can leave permanent stains from long term storage.
Ken
I have two other sets of square gage blocks I use as my shop blocks. One of the sets was from a dumpster dive at one of my past jobs. I missed getting the accessory set that went with the square gage block set. Now enough for the bragging.
I have successfully recondition gage blocks removing rust and some scratches. My method uses two abrasive stones, one a new fine grit Norton indian stone such as a 1/4" x 1 x 4" lg. Second stone is a broken piece of a 1/2" square norton hard arkansas "white" stone. Use the indian stone to stone off any rust large burrs and such. Use a little honing oil or as Starrett mention, a little kerosene. Use light pressure to remove rust or burrs. It don't take much rubbing. When it get's where the stone feels like it stops cutting, stop. Clean the surface of the gage block. Next, take the hard Arkansas stone, rub it against the indian stone to make it flat against the indian stone. Now, stone the gage against the Arkansas stone, again light pressure. You'll feel when it stops cutting. Rub the Arkansas stone against the indian stone to clean and repeat rubbing the gage block. Two, three times doing this will restore the some of the mirror finish on a gage block. Won't be factory perfect or stick together when you wring blocks together, but will be close. Like others said coat the with oil or petroleum jelly for storage. I do not recommend using any general purpose grease. It can leave permanent stains from long term storage.
Ken