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metalmagpie
05-06-2013, 06:59 PM
I picked up a small cast iron surface plate today. It's old. Patinaed but not pitted, it will clean up perfectly. I wished I'd had one like this in a recent scraping class, to avoid the line at the big surface plate.

Question is, how much is it worth as is? Cleaned, painted, scraped flat and with a plywood cover?

metalmagpie

http://tinyisland.com/images/temp/15side.jpg
http://tinyisland.com/images/temp/13side.jpg
http://tinyisland.com/images/temp/bottom.jpg

oxford
05-06-2013, 09:12 PM
Honestly, my opinion is with import surface plates being so cheap, it won't be worth very much. Judging by the gloves in the picture it looks like it is a 12x18, you can get a new one for under $50 from enco, just over $30 if you order today with 30% off.

beckley23
05-06-2013, 09:49 PM
The cast iron surface plates I've seen have a 3 point support, and are thicker and more heavily braced. I think what you have is a layout plate.
Harry

gdavis2265
05-06-2013, 09:56 PM
Would make one hell of a table for some cool project. Drill press, h-press, tapping machine, etc....

Buy a cheap surface plate from Enco, and save this one for a project - or ship it to me!

Glenn

lakeside53
05-06-2013, 10:13 PM
Clean, painted, scraped and in a cute box - $50, maybe (you'll earn maybe 10c an hour).

I gave the last one I had (set up as a lapping plate) away for free :) It was much heavier and more cross braced than the one pictured. Old cast iron plates are an interesting piece of the past that has been superceded by granite.

Use it for a welding table.

garyhlucas
05-06-2013, 10:28 PM
I just built my CNC mill on an old Navy spotting plate I picked up at a junkyard. $98 for a hand scraped 24" x 24" plate with handles that is 6" high with the webs on the bottom, and 205 lbs! It was evenly rusted and I carefully removed all the rust and a couple of dings. I knew it was flat when I set my 9" x 9" x 9" granite angle plate down and it slid on a cushion of air. Picking it up again involves breaking the suction! Over the weekend I drilled and tapped 121 5/16-18 holes on 40mm centers to clamp down parts. The mill drilled all the holes, but didn't have the torque to do the tapping so I tapped them all by hand, using a small V-block against the tap to make sure it was square. Big job, glad it is done.

Gary H. Lucas

Forrest Addy
05-07-2013, 12:19 AM
It's not really a surface plate within the meaning of a scraping reference. The casting in the images is shallow, probably 1 1/2" top to feet. A 12 x 18 cast iron surface plate would be stiffened with triangual arrangements of ribs three inches high and it would have three cast in feet.

What you have is a bench plate used in a bench man's asssembly area for small layout or any other non-fussy operation where a flat surface comes in handy. They are typically ground but can be scraped. They are not a flatness reference.

So, what the hell: scrape it.

metalmagpie
05-07-2013, 11:38 PM
What you have is a bench plate used in a bench man's assembly area for small layout or any other non-fussy operation where a flat surface comes in handy. They are typically ground but can be scraped.

Cool. I'll put it on my bench!

metalmagpie

SGW
05-08-2013, 06:28 AM
FWIW, Moore Special Tool Co. preferred cast iron surface plates to granite. (See "Foundations of Mechanical Accuracy" by Wayne. R. Moore.) Of course, they also employed some of the most skilled scrapers in world for whom re-truing a CI plate would have been routine.