Jagged metal on farm wrenches

[skylab]

Was wondering what caused the jagged metal on the casting line of most farm wrenches?   One person told me it's left over from the casting where the metal flows into the mold.   Just was never cut or filed off.  Another person said it's from the forging process when the wrench is hammered down into a mold and metal escapes in pockets in the mold.   I believe it's left over from casting.
What do you think?
I put a pic pointing to this jagged metal on a wrench.
Thanks
Skylab

[rusty]

It is left over from casting in most cases, the thing being made (the wrench) is cast into a sand mold, 2 holes are made nextr to it, one, the sprue, lets the molten metal in, the other , the vent, lets the air out. The two are jouned via a 'gate' which is a thin section connected to the mold pattern ( where the wrench will be). That part gets snapped or cut off after the casting cools...
That is the piece you are seeing...

[skylab]

Thanks Rusty!

I wonder what type time period wrenches where made this way?

[Wrenchmensch]

Rusty:

Sounds like you know the difference between a cope and a drag half.

[Branson]

Rusty:

Sounds like you know the difference between a cope and a drag half.

And he's not alone in that.

[Stoney]

You have to remember that the wenches that we hold so dear were, just tools made to get a job done, to manufacturers, made by lots.  That is why they didn't take the time to file or grind off the rough edges while blacksmiths made tools one at a time and took personal pride in their work.

[rusty]

> a cope and a drag half

'Top' and 'bottom' seems so much simpler ; P

I wonder where these terms came from? England? earlier?

As an aside, some of the scythe wrenches I have seen appear to have been surface cast, which makes sense, it is easier to do, and is consistant with an even earlier era of metal working, but I have never seen anyone discuss this much....

[Wrenchmensch]

I was an engineering student at an Upstate New York University, and a course in metallurgy was a mandate.  The course included casting and machine shop work,e.g. cutting a gear that worked.  The terminology "cope and drag half" was in use in 1956 in Ithaca, New York.  Nothing British about it.

[rusty]

The terms are much older than that tho, they appear in articles about brass founding in the 1800's....

http://books.google.com/books?id=JPMJAAAAIAAJ&pg=PA375&dq=%22cope+and+drag%22&hl=en&ei=hiOiTpG5I-rr0gHchuGLBQ&sa=X&oi=book_result&ct=result&resnum=10&ved=0CF8Q6AEwCQ#v=onepage&q=%22cope%20and%20drag%22&f=false

[anglesmith]

I agree With rusty.
Charnock's Mechanical Technology (1915) and the I.C. S. text book on founding (1903) both British and both talk about cope & drag for top and bottom core boxes.
Graeme

[Branson]

> a cope and a drag half

'Top' and 'bottom' seems so much simpler ; P
I wonder where these terms came from? England? earlier?

As far as I know, they're standard terms for casting, just peculiar to the trade, like kerf.

[leg17]

Thanks Rusty!

I wonder what type time period wrenches where made this way?

Could be well into the 1900's
Castings are cheaper and are somewhat close to final size right out of the mold
Being less expensive, they tend to be more likely to have some cut corners, such as simple functional de-gating.

Forgings often need relatively more "second operations" than castings accounting for some of the higher cost.
(Forgings are stronger as well)
Being more expensive, there is usually more effort put into "second operations" and various parting line defects are usually not as apparent.
Forging is as old as blacksmithing and still popular today.