View Full Version : best way to clean Ref. Blocks?

02-07-2005, 07:58 PM
I recently unearthed these Reference blocks. They were my Grandfathers and have been tucked away in a damp place since he died in 1961. As you can see they have some surface rust. What is the best way to clean off the rust without changing their size very much? Note these are not "gage" blocks, just reference blocks that I believe he made. For my use, +/- .001 would be more than good enough. Thanks, Buzzer John

02-07-2005, 08:02 PM
Lapping maybe


02-07-2005, 08:12 PM
First of all, if they are reference blocks, a good objective would be to not remove any metal http://bbs.homeshopmachinist.net//wink.gif

If they are steel, you could use a chemical approach which will not touch the base metal. Brownells Blue & Rust remover from gun shops and wwwwal-mart, applied with a Q-tip, will either remove the stuff or tell you that you need to get more aggressive.

Next step, I'd try Nev'rDul wadding which is a wool batting with a light solvent and very light (they call it non-abrasive) abrasive. Rub the wadding back and forth and in circular motions.

If these don't touch it, go for the lapping with #600 or so wet/dry paper on a surface plate and a light lube (WD40 for instance). At this point you'll end up with flat surface and pits. Depending on how numerous the pits are, they may not impact your use of the blocks.


[This message has been edited by nheng (edited 02-07-2005).]

02-07-2005, 08:32 PM
I've had good luck with this type of problem using an Arkansas hard stone with WD-40. You can feel it knocking off the high spots, quit when you feel it floating over the surface and not hitting anything. You won't take enough steel off to measure. You can use 400-600 wet or dry paper if you have a true flat surface to lay your paper on. Spray your flat surface with WD-40 then lay down your paper. Spray your paper with WD-40. Work your blocks on it in a figure 8 pattern. You will never be able to get out any pits without getting "into" your blocks. Just take off all the high spots and they will be good.

02-07-2005, 09:30 PM
Starrett sent me a bit of slightly oiled and very sticky as a result chamois for my new block set many years back. Seeing it worked well for the new blocks, i took a chance and used it on some old rusted blocks. Worked like a charm. the pitting is still there, but there were never any real high spots but for the small specks of rust this removed. had this set approved or calibration last year at a local shop, they passed in the .0001 range.

charlie coghill
02-07-2005, 09:56 PM
Would the washing soda and electricty work on this problem?

Dave Opincarne
02-07-2005, 10:31 PM
Yes. Then try steel wool then try muratic acid and electricity. (clean well, oil imeadietly and keep fumes away from anything you don't want to develop rust.) Only then would I try anything abrasive.

Forrest Addy
02-07-2005, 11:28 PM
First do not abrade or etch the gaging surface. The rust on the non-reference surface can be removed by any convenient means. Rust on the gaging surface can be reduced locally at the pit sites by means of acid or electrolysis taking pains not to attack any bare gaging surface metal.

Once the gaging surface is cleaned up you can give it a light rub with a worn smooth hard Arkansas stone or the surface of a granite flat. This is only to remove any high metal, not to reduce the size.

By the way, there is nothing magic about a reference block being right exactly on the niminal size. So long as the block is accurately calibrated and the actual size inscribed on it, that's all you need for checking your mikes, setting stops, or adjusting a bore gage. The common calculator makes it easy to add 1.9993 + 0.4998 + 0.2487 etc and so on until you build the gage to the length you desire.

[This message has been edited by Forrest Addy (edited 02-07-2005).]

02-08-2005, 08:27 AM
Thanks to all the replies. I'm not sure which method I'll try first, but am leaning touard the electrolitic method. I'll try to post pics of the results. Also I'll try just one first. One of the odder sizes.

Paul Alciatore
02-08-2005, 12:23 PM
Some excellent advise above. In addition, I think I would dip them in oil and let them set for a week or so first. That may help loosen the rust and ease it's removal.

I have a few tools I inherited from my grandfather and I treasure them. And I use them too.

Paul A.