question, hammer / anvil weight?

[The Iron Dwarf]

OK
am working on a power hammer and am wondering if there is a formula for the relative weights of the top tool / hammer in relation to the bottom tool and heavy block under it.

the answer may be as much as possible but I dont want to go too far as it increases costs and makes delivery of these harder.

am working on a system using variations in motor speed to control the blows and the compression of coil springs and am aiming for a hammer weight of 10 to 15 Kg ( 22 to 33 lbs maybe ) and a working speed of maybe 200 BPM.

cant show you much as at the moment it is mostly in my head and I want to start making a prototype to get the tuning sorted and unveil the finished one only

[wcallen]

I don't know what the real answer is.

The formula for the Tire Hammer - which uses a 50 pound hammer - is to use an anvil that is solid, about 32 inches tall and at least 5 1/2 inches in diameter. This is by no means portable. It is definitely designed for "blacksmithing" not "armouring" so I expect it needs the weight. I know that mine is about 6 inches in diameter and in playing with it before it is bolted down it can walk around the shop by itself. Lighter would be worse. I haven't been doing any really abusive bashing, just playing with scrap metal. We had to use tractors, engine hoists, heavy duty carts and come-alongs to move them.

Wade

[The Iron Dwarf]

I can work out the weight from the sizes you have given me thank you.
6" 43.59 Kg per foot =3.6325 Kg per 1" x 32 = 116.2Kg x 2.2
= 255.72 Lbs on your 6" one
your hammer is about 22.7Kg

so with mine at 10Kg maybe 112 lbs or 50kg or
15Kg maybe 162lbs or 75Kg making a ratio of about 5 to 1.
will try as a starting point 5 - 1 and see how it goes

[wcallen]

I actually checked mine. I was off a bit.

35" high
mine is 6.5 in. in diameter. We did some at 6 1/4, and some with 6" square, and some up to 7.5 inch round.

So mine appears to be ~330 pounds. Then there is the 2x2 sheet of 1/2 inch plate on the bottom, and all of the other steel that holds the thing together.

And in our case the 50 pound hammer is without the actual hammer end - that is a 3.5" square of 1/2" plate with a piece of 2x2x3 S7 welded to it. I did some other hammers with the plate and ground down 3x3x1.5 4145.

I don't know what my whole hammer weighs... estimates seem to be 900-1100 pounds. No fun to move.

Anyway, good luck. I think we need some more power hammers to play with.

FYI - mine is one of these:

http://www.bladeforums.com/forums/showt ... ay-Spencer

Wade

[The Iron Dwarf]

seen a thread about these here a while ago, looks good

will work it out again, want to keep this down in weight a bit due to cost but also to make it easier for people to collect or have it shipped to them.
am aiming for one that is versatile enough for planishing, dishing and forging too without costing too much.
will weigh mine by removing a linkage and putting bathroom scales under the hammer and will have a recommended weight for tooling as well as height for it ( mine will rely on the alternate compression of 2 coil springs to throw the hammer so controlling the motor speed should give me what I need, can get springs made to my specs easily enough ).
we have a modern 50Kg air hammer at work ( 220lb ) for heavy stuff but I want to make something to do the lighter tasks to help prevent injuries to smiths and armourers

[The Iron Dwarf]

150kg for yours then which would mean mine may be 75kg.
thought about doing mine from heavy box section with a plate on top and lots of rebar inside welded to the top then filled with concrete.
dont know if I can work out the weight on that though so may have to guess and see what it comes out at.
this piece will be separate and bolted on so that in 2 or three pieces the machine will be easier to move.
on our air hammer the anvil is bolted on the front with springs on the bolts to allow a little movement

[Thomas Powers]

15 to 1 for professionally built systems is generally suggested though 10 to 1 for "cheaper" ones is know. Much above 18 to 1 the you don't gain much.

It usually comes out to how big a single piece of steel you can source/afford/find, though one maker assembles his anvil from several pieces of heavy plate laminated so they are vertical.

[wcallen]

15 to 1 for professionally built systems is generally suggested though 10 to 1 for "cheaper" ones is know. Much above 18 to 1 the you don't gain much.

It usually comes out to how big a single piece of steel you can source/afford/find, though one maker assembles his anvil from several pieces of heavy plate laminated so they are vertical.

We actually did that on our hammer build. They ran out of round "bars" so had to make the last couple from (I think) 6"x2" flat stock welded together vertically to form a 6" square. The welders had fun filling the bevels to make sure the result really was pretty solid.

Wade

[The Iron Dwarf]

the new one we bought a few years ago is a sahindler (sp) 50kg air hammer the thing weighs just over 1 ton in total and the hammer is about 1 cwt, at a guess the anvil on that is not much more than 1/4 of the total weight of the machine making that one maybe 7 to 1.
I will see what weight I can get without it costing too much ( and the anvil weight can easily be changed if a customer needs it to be ) .
I will try 6" by 4" heavy wall box section filled with reinforced concrete first, this could be replaced with 6" square

[Thomas Powers]

Concrete is a heck of a lot lighter than steel. Check out the differential and you might get the same weight with a smaller chunk of steel and still get the one solid mass effect then.

[wcallen]

And I don't know this for sure.. but my hammer appears to have enough shock transmitted through it that there is a decent chance that over time concrete inside an anvil would break down. It isn't the best "shock" material.

When Clay talks about adding weight to our hammers he talks about just pouring sand into the back tubes.

Please, if you try, tell us how it works.

Wade

[The Iron Dwarf]

I will, I intend to weld very thick rebar to the top plate that will go most of the way to the bottom so there will be a lot of steel inside the box too before the concrete is added and maybe after some use I will cut away the casing to see what it is like inside.
if it turns out it needs to be steel a steel one can be fitted easily as it will just bolt on.
at the moment am waiting for a friend who is doing some machining to make a plate to mount the 1hp 415 volt 3 phase motor to the 7 to 1 gearbox, this will be run off an inverter to control the speed and means it can run from our 240 volt mains supply.
the countershaft and crank are being made and bearings ordered, by the time the machining is done I should have most of the bottom half of the machine done

[Cap'n Atli]

Some useful information here: http://www.anvilfire.com/power/

The Catalog of User Built & JYH Hammers link shows the wide (and weird) varieties that people have put together.

[RandallMoffett]

WANT POWER HAMMER.

I got to use a few different hammers over the last 15 years and I only wish I had the know how or cash to have one now. Talk about a time saver. I was dishing helmet tops, carpal plates, breastplates, cops and such in fractions of the time it takes to do it by hand.

I keep hoping to make friends with some one that has one up here

RPM