Hi Gene you can buy Prussian Blue oil paint tube from an art store or internet you can get a pretty good surface plate from a cutout of a kitchen sink granite top you can measure the flatness with this old trick takes 2 123 blocks a mag indicator stand and an indicator mount indicator to stand and clamp stand onto large surface of 123 place both 123's on surface to check. You can 0 indicator onto the plain 123. as you move the pair over the surface you are measuring the avg 123 area height to the other 123 area height. You make a map of the results on paper. This will show you how flat the surface is. this is an independent measure ( the surface may not be parallel to the x or y rails but it is important to be able to what element is contributing what part of error to the wkpc.
stay safe, god bless america tomp On Thu, Jan 7, 2021 at 7:08 AM Gene Heskett <ghesk...@shentel.net> wrote: > > On Wednesday 06 January 2021 18:45:11 Jon Elson wrote: > > > On 01/06/2021 04:30 PM, Gene Heskett wrote: > > > On Wednesday 06 January 2021 06:08:23 andy pugh wrote: > > >> How far out of true is it? > > > > > > A good mm in some of the places I have checked. But now I need to > > > stay at or below .1mm over a foot of travel for this box mod. I > > > could reclamp it, and survey it with my throw away renasys(sp?), but > > > am trying to get enough data I don't have to do it over for each > > > piece I make. > > > > Well, there is always hand scraping. I've never done it on > > aluminum, but I'd guess it might > > be very similar to cast iron. But, of course, if putting > > clamps anywhere distorts it more, then > > it is kind of a losing battle. > > > > All you need is a known-flat reference surface like a > > granite surface plate, some blue dye > > and a scraping tool. You can make scrapers out of large > > carbide cutting inserts. While > > Dy-Kem Prussian Blue dye is the best, it is very messy, so I > > recommend Canode spotting dye. > > That is water-soluble. > > Never heard of Canode till now. Msg marked, thanks Jon > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
