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Brown and Sharpe 30x20x6 cast-iron surface plate - Is it? And what is it worth?

torinwalker

Aluminum
Joined
Nov 28, 2010
Location
Oakville, Ontario
Picked up a new (to me) milling machine and a few of the accessories that came with include a 10x11x12 t-slotted shaper table (so far, looks like Elliott), and this Brown and Sharpe cast-iron surface plate covered in a thick layer of grease. Table measures 30x20x6, has a 1/2" top surface thickness, webs are 7/16" thick, and so far no maker's mark that I can find. There is a casted impression of "239" over ". 29", and it has brass stamped tags with M-1046 (serial number, likely).

I surmise it is Brown and Sharpe because the web pattern is identical to many other Brown and Sharpe cast-iron surface plates across the Internet.

So, question - Do you think this is a Brown and Sharpe? what is this plate worth? I know that granite is the current choice, but some might appreciate cast iron because of its heritage, or that they might one day scrape it, or use its handles to print a machine, etc., not sure.

Any suggestions?

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Those are swirls from a paper towel I used to redistribute the grease after handling the plate with my hands, plus a few swipe marks from the same paper towel to brush away bits of fluff in preparation for taking photos. I would never do that to a surface plate.

I just learned that this plate is indeed a Brown and Sharpe model 740-86 (page 93 of the '57 Precision Tools and Gages Catalog, courtesy of Vintage Machinery.org: http://vintagemachinery.org/pubs/2185/22926.pdf

Agreed, I should probably remove the cosmoline and take a look at the surface.


Torin...
 
I don't know what the broader market value is for something like this but i bought a 24 x 36 x 6 inch grade A granite plate for $50 in upstate NY. I certainly consider myself lucky but then again, there's not a huge market for these.

Good luck
Mark
 
On the other hand, a cast iron plate will be somewhat lighter (and with those lifting studs considerably easier to manipulate) if you want to bring the plate to the work, rather than the work to the plate.
 
Grade A for $50 is a good deal. I paid about the same for a grade B (indicated by a shop-made sticker after the original placard was removed - had to take the guy's word for it.)

Not even sure what the grade is on this cast iron plate is. Catalog doesn't list grades at all. Just says it's hand-scraped and has 14~18 bearing spots per inch.
 
New raw cast iron castings going for around $1.00-1.25 pound. So if it weighs 100 pounds, $125 at max. Cast iron scrap maybe $10 per thousand pounds or thereabouts. You don't have a gold mind there!!!! Not even close.... I would offer you $100 for it, but shipping would be a killer to get it to Texas!!!
 
Thanks 4GSR - not expecting a lot, but hoping to learn fair market value. Good idea and will take that into consideration. I'll have a look at Fireball Tools and see what they sell their raw castings for.
 
The handles suggest it might have been used for a spotting plate. If so, its accuracy may be better than average. Really, it all comes down to the appearance of the surface. I say appearance, as few (almost no one) can actually check the accuracy, and ever fewer can check the accuracy and actually correct any errors. If the plate has a beautiful scraping job, its usage may well be a showpiece in some home shop. Very little value to a commercial shop.
 
The handles suggest it might have been used for a spotting plate. If so, its accuracy may be better than average. Really, it all comes down to the appearance of the surface. I say appearance, as few (almost no one) can actually check the accuracy, and ever fewer can check the accuracy and actually correct any errors. If the plate has a beautiful scraping job, its usage may well be a showpiece in some home shop. Very little value to a commercial shop.

Agreed. I've settled on a price of $250 (about $187 USD) based on a variety of factors, particularly because of the previous suggestion of selling it for as-cast value, that it came from Brown and Sharpe, its calibre/size, etc. I have two people interested within a day of posting. Now that I've settled on a price, I have one interested buyer coming to look at it.

I also uncovered a small area at the center of the surface - according to this same fella, the scraping "appears to be in good condition" (seems a little faded to me, but still present and smooth to the touch)

I agree with this being a colletor's piece, or for an apprentice of the scraping arts to use/admire/practice upon, but as far as a tool, it still has an intrintic value as a fixture plate, lapping surface (with water-paper adhered to its surface, of course). I believe the price to be a fair starting point, until no one offers, then I will drop it until someone does.

Appreciate everyone's help. You guys have supplied a lot of good suggestions for which I am grateful.


Torin...
 
The handles suggest it might have been used for a spotting plate. If so, its accuracy may be better than average. Really, it all comes down to the appearance of the surface. I say appearance, as few (almost no one) can actually check the accuracy, and ever fewer can check the accuracy and actually correct any errors. If the plate has a beautiful scraping job, its usage may well be a showpiece in some home shop. Very little value to a commercial shop.

So I’m the guy who bought it. This is what it looks lime after a bit of cleaning. I actually have an autocollimator (just for the fun of having it) and will report back once I take some measurements. I did do an initial check on it though and it appears to be within .0001 to .0004 over the entire surface. The handles cleaned up really well too. I just picked up a Biax power scraper and was going to try my hand at scraping it expecting that it would be in rough shape, but I would make the argument that it has either never been used, or was used so little that it appears unused. It is stamped Brown & Sharpe MFG CO Providence R.I. USA. Pretty good deal for $150 Canadian ($112.33 USD).


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Thanks!! I’m a Starrett addict..... In fact, this plate is the only B & S piece in my shop, but I’m very impressed with it. Cheers.


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