Branson, Now I understand why your after a smaller anvil, I had not read anyting about the " portable Forge"  concept and kept picturing the larger civil war traveling forge set up. Were their many of these porable set ups used or was it just a one off? Though I guess that if Captain Morecai drew up plans, more than one set must have been made.
Graeme

Presumably, every unit with the 1841 mountain howitzer would have had one of these portable forges.  These howitzers were made to travel where cannon with carriages could not go, and therefore where no travelling forge could go.   It doesn't look a lot different from the nave forge pictured in an earlier post here.  That one is also a "portable" forge, just a lot bigger.   The military seems to have liked portable, and there were later portable forges well into the 20th Century.

Branson,

Would this anvil be anything which would help you? Here is Old world anvil's website which is where this picture came from.

http://www.oldworldanvils.com/anvils/anvilstake_55.html

Bill D.

There's a photo of one of the drawings for building a mountain howitzer portable forge at:

http://www.facebook.com/photo.php?fbid=289941254386291&set=a.289928167720933.63430.146477635399321&type=1&theater

It shows the anvil we need to construct -- a stake anvil.

Curiously, the drawing shows hex nuts.  A photo of an original (pretty bad photo) included with the plans does have hex nuts. 
Now to research hex nuts and see if this is possible in 1862 or so.  There's also, in the plans, reference to a "wrench for nuts
No. 1 and 4."

> hex nuts and see if this is possible in 1862 or so

hehe...you are suffering from excessive focus ;P

Look at pre civil war locomotive photographs and you will see honking big hex bolts holding the  drivers to the wheels...

I suspect that they are much much older than that tho...

Mass production is a different question tho, and you are close to the timeframe for mass producing hex head bolts cheaply...

Branson,,,here is a blacksmith forge vise you are looking for:

http://www.ebay.com/itm/Antique-Blacksmith-6-Leg-Vice-Old-Tinsmith-Farrier-Vintage-Farm-Anvil-/200811324028?pt=LH_DefaultDomain_0&hash=item2ec149a27c

Thanks MrChuck.  But thankfully, I found mine locally and a long time ago.  But if you see one of those stake anvils in the drawings,  I'll be on it in a short New York second.

In a local museum, are the items dug from the cargo hold of a steamboat, that went down in 1868.   Stuff went to the bottom and got covered with clay, sealed out the oxygen.  Dug up in 1968, and on display is a shaft with arbor bearings, ten inch saw blade, set up to cut lumber to size.  The bolts holding it together look machine made and are 1.5 inch hex.