Flaking on straight edge?

Was looking at pics of an older SE and saw flaking on the working surface. Was a 60" long SE. Why? Any original makers do this?

Lucky7

Could it be some dealers idea to make it look newly refreshed? I have seen this done on older milling machines to try and fool the unknowing into thinking it had been rebuilt.

Charles

Carries blue better.

Gbent, thanks for comment, and I'd wondered about that. I've also noticed that I can get many more prints from granite than from equal bluing on cast iron SE or plate. My iron references are not flaked.

L7

Unfortunately it'll smear the blue as well. Which makes it a very bad idea.

I have a 48" straight edge which has no wear from new - actually looks unused, and whilst I wouldn't call it 'flaked' the scraping is very deep. It does give a good print though.

I don't know that I'll ever agree about granite printing better than a scraped iron plate. Maybe you can get more prints from the granite but the iron plate prints so much better IMO. I know which I prefer to use for sure.

If you mean flaked as in your typical half moon biax job, then im thinking along the same lines as Charles.
Im with Peter in preferring a reference scraped a decent depth, its far easier to use in that it carries more blue, is less smeary and most important imo, it wont suck down to a granite reference or shallow finely scraped work.

Cheers
D

I've met many scrapers who flake everything regardless. Their method is to scrape for contact, say 75% contact. Then use the flaker to break up the contact area. The result gives you maybe 40% contact area and the number of contact points depends on how you flake it.

I know there is a highly opinionated member of the forum who will call that butchery, but that was a factory scraping method for many storied machine tool builders. I've met factory trained master scrapers from Bridgeport, Mattison, Devlieg, and Blanchard who all scrape using this method.

In fact I have some factory scraping literature from Mattison that refers to flaking as "spotting". I've also heard this term used by several master scrapers to describe what we commonly call flaking on the forum.

[OPINIONATED]
Only the manufacturers who were more interested in looks than longevity would allow flaking on horizontal exposed surfaces
[/OPINIONATED]

Biax Germany purchased a brand new ground surface plate from a Germany mfg. The plate was also Biax 1/2 moon flaked. We blued it up against a AA grade Granite plate and it blued up all over and the percentage was about 50%. The points of that contact was approx. 15 PPI. That is the only new plate Ihave ever seen flaked for use. I have been making and scraping straight-edges for 50+ years and have never seen a precision straight-edge flaked. Also when properly 1/2 mooned oil flaked surfaces they measure about .002" deep. I also prefer to blue up on a cast iron surface plate, but with the cost of big cast iron plates (plus who makes plate anymore? Bash in India maybe))compared to Granite most use granite now-a-days. Also the time it takes to re-scrape a 4 x 8 foot cast iron plate and back aches most call a surface plate lapper to get it qualified. I believe in 1/2 mooning all unexposed to the air way surfaces. I have discussed with Bridgeport Engineers who say they know 1/2 mooned flaked surface collect dirt, but they also recommend you replace the way wipers every year. LOL... I laughed when he said that as I have rebuilt Bridgeport mills that were 20 years old and the ways were scored up and they wipers looked like they were never replaces.

I also have worked with new machine builders who 1/2 moon flake ways more for cosmetics then lubrication. I want everyone to know Wes is not talking about me by the way! Many machine rebuilders do not have surface grinders who can grind 60" straight-edges so they scrape them and don't flake them. When I taught classes at Puget Sound Naval Shipyard where one of our longtime members worked and he showed me a scraped and 1/2 moon flaked his supervisor insisted on doing. I can see it working if the plate was used for production machine shop testing as it would last longer when parts were rubbed on it after machining. I have never 1/2 mooned precision straight-edges as I prefer 40 PPI scraped ones. The more points you can transfer bluing onto a precision way IMHO. So some 1/2 moon them and some don't. I am going to email Cash Masters to comment as he has Mattison trained Journeymen working for him and Cash also has super long surface and way grinders plus he is a Journeyman Machinist and rebuilder. I - 1/2 moon flaked a Landis Cylindrical Grinder exposed ways one time but I sharpened the blade so it didn't flake deep. It was .0005" to .001" Because the customer only wanted it "cut and flaked" for better lubrication. It was when I had a sore back and did not want to bend over the base ways for hours compared to 45 minutes.

Seems discussing 2 things here??

Flaking on a straightedge- seems pretty useless to me. Messes up your point contact.

Flaking on a machine tool way- moving surface only.

a lot of cast iron and steel sitting around months / years gets rusty eventually and maybe ?? scraping and flaking was done after rust removed ??
.
even stuff sitting in a rack will get rusty unless some sort of rust preventative was applied. simple spray of oil doesnt last long
.
or minor wear, warapage after years noticed and it was "repaired"

I bought a used 72" Brown & Sharpe camel back a couple years ago that looked like the working surface was "decent" in the pictures. It looked like it had broad criss-cross scrapes evenly over the whole surface. Upon arrival I found that it had in fact been flaked and that just behind the flaking you could see the darker surface with some pitting, scratches, etc.

I was still happy with it as it was a good price for a "core" and it won't take too long to bring it back. If I bought a used straight edge again though, I'll just assume it'll need some work from the get-go. Flaking from a distance gives "the look," so it can be deceiving.