Say hello to my new little square friends

dcsipo · Mar 16, 2019

I just scored two cast iron squares in excellent surface conditions. They need just new paint and that is it.

If I scrape them they will be only "flaked" for better ink retention. The Bush is 4x21.5x8 the challenge is 12x10x8

dee
;-D

dcsipo · Mar 17, 2019

You knew there was a question in this, Both of these pieces are in pretty good condition, the critical surfaces are not rusted, and have no deep machining marks on them, both have some very superficial circular scratches, and other scratches, nothing measurable. The surface has an almost polished appearance like these were originally lapped. but as you can see on the pictures they have a dark coloration almost like a cyanide heat treated steel would have. I want to clean the surface well without destroying any of the alignment.

Is there anything that would either safely remove this dark surface, or make it more uniform? Since it is all dark the scratches that are on the surface really stand out. Ok ok ok, I know this nitpicking, and goes back to the joke I told a few times here about one being lower than the other.... but once I clean them and paint them, I guess you can relate

dee
;-D

dcsipo · Mar 17, 2019

one painted...the other one needs a strip

Sláinte

dee
;-D

TDegenhart · Mar 17, 2019

The copper colored paint is really sharp! Not sure about #2

Tom

Mark Rand · Mar 17, 2019

Too much Icing...

Whysosharp · Mar 17, 2019

And green none the less

dcsipo · Mar 18, 2019

TDegenhart said:
The copper colored paint is really sharp! Not sure about #2

Tom

Bailey's Irish cream

dee
;-D

dcsipo · Mar 20, 2019

minor update...

measured both of them. The Challenge is spot on the Bush is out about 4 tenths. I also stripped off the paint from the Challenge.

dee
;-D

dcsipo · Mar 22, 2019

Had a crazy idea this morning. What if I tried to lap them on the surface plate? Would I risk screwing up the geometry? I know I could scrape them in but for these two pieces, I think I want ground or lapped surface. I can wait till I fix the surface grinder, or I can try to lap them, the challenge just needs polish, the Bush needs a couple of tenths shaved off its sole. If I screw them up I can always fix when I have the grinder fixed. Am I just chasing my tail? Any good pointers on lapping a square?

dee
;-D

Hbjj · Mar 22, 2019

I assume by lapping on your surface plate you are talking about using sandpaper taped or glued down
I do this on occasion but the paper will form sort of a wave in front as you push your parts across removing more material right at the edges

A true lapping plate with abrasive embedded in it is alot easier to use and super handy to have around

I'm no pro lapper but I think it would be difficult to remove a few tenths and not make the surface convex in one way or the other

Ember · Mar 23, 2019

I wouldn't try it, unless you have a jig to hold them square, it will wear down more at the heavy end

TedinNorfolk · Mar 23, 2019

Why not just scrape the Bush to the Challenge?

cash · Mar 23, 2019

If the tall section of the Busch is within .0004" you could cheat and use some superfine sandpaper, 240, 320 grit to take a bit off the bottom.

This could be enough to get you home.

If you are going to scrap for retention for your spotting compound you could work it to get another tenth or 2 if needed.

Nice score!

michiganbuck · Mar 23, 2019

If abrasive paper is to be used you might consider automotive wet paper as it stays clean and often takes more stock than dry paper. The wetting solution having a bit of baking powder to help avoid rusting. One can use such paper like a hone stone and count passes to gauge stock removal in various areas. Yes baking soda and laundry washing soda works as well.

I guess one could use spindle oil for wetting but have never done that.

dcsipo · Mar 25, 2019

TedinNorfolk said:
Why not just scrape the Bush to the Challenge?

Wanted to keep the lapped surface. If I scrape it then I scrape it to the granite....

dee
;-D

Fal Grunt · Mar 25, 2019

It probably wouldn't be worth the shipping to borrow, but I have a nice lapping plate...

morsetaper2 · Mar 25, 2019

dcsipo said:
....<snip> they have a dark coloration almost like a cyanide heat treated steel would have. I want to clean the surface well without destroying any of the alignment.

Is there anything that would either safely remove this dark surface....<snip>

dee
;-D

You might try "Never Dull". It is a mild polish impregnated fiber wadding. Sold at motorcyle shops, auto parts stores, etc. Its not aggressive at all, but will cleanup cast iron, aluminum, and other metal surfaces nicely. Will remove the mildest surface rust. But if the rust is into the metal at all it won't help you. You could use this on a scraped surface and be confident you wouldn't effect that surface, but for the appearance. Its a polish, not an abrasive.

Around here in MD, Advance Auto stocks it. The blue can is the original. But is also packaged and sold by Eagle One. Either can is the same stuff.

dcsipo · Mar 25, 2019

Fal Grunt said:
It probably wouldn't be worth the shipping to borrow, but I have a nice lapping plate...

appreciate the offer, but agree it is not worth the shipping cost.

BTW I painted the Challenge

...

dee
;-D

Say hello to my new little square friends

Diamond

Diamond

Diamond

Diamond

Diamond

Cast Iron

Diamond

Diamond

Diamond

Cast Iron

Aluminum

Stainless

Titanium

Diamond

Diamond

Titanium

Diamond

Diamond

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