Anvil sizing

[hillsideshortleg]

I am going to start building my homemade hammer and I am starting with the anvil first. This may be backward or wrong but I specialize in backward or wrong so it will be nothing new. My choices are: 24" dia x 3" thick base with a 7" solid round stock welded to it how ever tall you all recomend. I could also double up the base and make it 2- 3" x 24" disc on top of each other with the 7" solid round welded to the top. My other choice is to use the 24" dia. disc (1 or 2) and weld a 8" od x 4 1/2" id tube to the disc and make it however tall you all recomend. I like the idea of the tube so I could drop differant fixtures in the hole and have it rest on the tube wall. The weight of the tube per foot is very close to the weight of the 7" round, around 120 lbs per foot. Looking for any help you all will offer
Thanks
Rick Nelson

[Dave Hammer]

How heavy is the ram (falling weight) going to be? The weight ratio between the anvil and ram should be at least 10 to 1. The higher the ratio, the more efficient the hammer will be (at least up to 25-1).

Personally, I would recommend a solid anvil.

[Nakedanvil - Grant Sarver]

While technically a tube, it feels more like a solid with a hole in it. I like the tube, could be very useful.

[ThomasPowers]

take a piece of steel and hold it at a comfortable horizontal position. That should be the height of the top of the lower die on your powerhammer. Size your anvil accordingly.

Try to avoid adding more horizontal interfaces in the anvil column---ie don't double stack the base plates if you can avoid it.

[hillsideshortleg]

Can I include the 3" x 24" diameter base plate or plates for figuring the ratio" I also have some other heavy round stock I can through in just to build up the weight. Also will it take a lot of welding to attach these properly or can just a pass or two around the differant pieces work.
What is an ideal heigth of the anvil. While I was down at the Mall today I noticed some peices of 4" square solid that was 3' long. Would this make a nice hammer?
Thanks for the replies.
Rick Nelson

[hillsideshortleg]

Just so I know, what is the results of having too much horizontal interface.
Thanks for the help
Rick

[ThomasPowers]

Loss of energy that could have been put into deforming metal. Unless you do a full penetration weld there will be gaps in any stack that will waste energy---why if you want to do a build up anvil you want the pieces going top to bottom rather than stacked up.

[hillsideshortleg]

So dang it im a bull headed Norwegian. I have found a 28" dia. x 6" tall plate that I would like to BOLT the 2- 24"dia. x 3" tall plates to using a nice circular bolt pattern. I would be up 12" and would use a smaller taller round stock till I get to a good height. Question is? If the plates are bolted and torqued tight would I loose energy. I also like the idea of a larger footprint and having something substantial to attach my vertical column to.

[Nakedanvil - Grant Sarver]

Everything will help, bolted, welded or glued. Solid is just a little better. 10:1 is good, 15:1 is great and past 20:1 the return is small. The KA75 works surprisingly well with 5 or 6 to 1.

[John Larson]

I think you will find a 36" height for the bottom die about right. If a little taller or shorter no big deal, but you want to work comfortably and not be bent over. As for the horizontal lamination approach, don't let it bother you. Bolted or welded will work fine, but not stacked loose. True, a one piece anvil is supposed to be the cat's meow, but for centuries dies and sow blocks have been wedged in place (a form of horizontal lamination) and have worked quite well and no one ever talks about that fact. You can include the base plate weight to the anvil weight when looking for your magic number provisded they are solidly attached together.

Here is one way to figure out the number you want. If you had an ordinary anvil weighing 100 pounds and you used a guy striking with a 10 pound sledge do you suppose the anvil would seem a bit too small? I would and suspect you would, too. That's 10 to 1. You don't need fancy theory. Just use your manual blacksmithing experience as a guide and you'll get things the way you like them.

4" square stock can make a real nice hammer head.

Have fun! :-)

[clang]

Eric Chang; One very smart smith, is writing an article on the physics of anvils and popular beliefs.
He said that well welded horizontal joints suck up less energy than generally believed.

I think you will find a 36" height for the bottom die about right. If a little taller or shorter no big deal, but you want to work comfortably and not be bent over. As for the horizontal lamination approach, don't let it bother you. Bolted or welded will work fine, but not stacked loose. True, a one piece anvil is supposed to be the cat's meow, but for centuries dies and sow blocks have been wedged in place (a form of horizontal lamination) and have worked quite well and no one ever talks about that fact. You can include the base plate weight to the anvil weight when looking for your magic number provisded they are solidly attached together.

Here is one way to figure out the number you want. If you had an ordinary anvil weighing 100 pounds and you used a guy striking with a 10 pound sledge do you suppose the anvil would seem a bit too small? I would and suspect you would, too. That's 10 to 1. You don't need fancy theory. Just use your manual blacksmithing experience as a guide and you'll get things the way you like them.

4" square stock can make a real nice hammer head.

Have fun! :-)