View Full Version : lapping with emory paper and a surface plate

06-09-2013, 03:58 AM
Shouldn't this work? I realize there are variations in the thickness of the paper (can't be much, guessing .0001 -.0002"), and variations in the grit deposition (again shouldn't the combined peaks come close to a flat plane?). But after the
rub down especially shouldn't even the (by my estimation) tiny discrepancies become even less?

I'd also like to tie this into my other query about making a gib. I don't have a grinder so it behooves me to find a way to put an acceptable finish on whatever I come up with.

06-09-2013, 08:14 AM
It should come out pretty well. It depends of course on how good it needs to be, but it's certainly an accepted technique. Tape the paper to the surface plate and have at it! The problem I've found is that the paper tends to load up quickly because the dust can't fall off it.

06-09-2013, 09:04 AM
Dont tape the paper down. Assuming wet/dry paper, (1000-1200 grit,) spray the plate liberally with WD40, lay the paper in it and spray the paper again. It will stick like glue!

06-09-2013, 09:16 AM
It's pretty hard to keep something as small as your gib strip from tipping as you lap it, and the surface ends up slightly convex.

You could blue the strip to a flat surface (the ways of your lathe perhaps), and scrape it flat. It can be held for scraping on the cleanly cut end grain of a block of hardwood held in the vise. Two small nails at each of two opposing corners will hold it in place. Drive the heads a little below the top of the gib strip. A scraper made from a flat file will do OK for a small job like this.

Dr Stan
06-09-2013, 09:40 AM
I've done this very thing multiple times. Just recently I needed to rework the top & bottom of a sewing machine needle plate that I filled a hole with sliver solder. I filed it close and then finished it with abrasive cloth on top of a flat surface in this case a large bench block as it was the only thing I had available.

06-10-2013, 02:03 AM
Something related was a manual metallurgical sample prep station we had in a lab, it consisted of an inclined plate glass sheet, to this a sheet of abrasive paper was clipped with a couple of bulldog clips, a plastic container on a shelf above with a plastic tube to the top of the sheet where water or soluble oil dripped onto the sheet to flush the paper, it did not take long with successive grades of paper to get to a mirror finish.