The 90 degree Boogie

[macbruce]

I've often watched smiths turn their work on the anvil and the power hammer (sometimes at mind boggling speed) 90 deg each time they strike the bar they're forging. I rarely do this prefering to work down one side and then the other.....What if any is the advantage of this?

[ciladog]

Keeps the stock square.

[Maillemaker]

reduces risk of over-flattening.

[Timothy Miller]

It looks cooler

[Pault17]

Develops that muscle for the "original" cordless screwdriver?

[781]

keeps it hotter as you are working the material more

[Francis Trez Cole]

Hit turn is a power hammer skill that is promoted by lots of smiths for one Toby Hickman. In hammer and anvil it is important to isolate and areas of work. I know for some items it is not used but for other things it is a good skill to have. I like using it when I make Leaves. 

[billyO]

keeps it hotter as you are working the material more

I agree, with all of the above, and when drawing larger (1 1/2"+) stock, you can see the color change (get hotter) with each strike moreso than when not doing the "Boogie". 

But I am by no means an expert on this matter.  Or many others now that I think about it...

[Jeff Seelye]

I used to wonder the same question. I also wondered why Dr. J could hang so long in the air. (still wonder about that one). I tried turning stock and found that (like 781 "keeps it hotter as you are working the material more") that when my stock is not always touching the anvil, that I keep more heat in the stock and I can forge longer. When you push a piece of steel into an anvil with a hammer and don't turn it, all the heat is being sucked away each time. So if I hit 4 times on one side and turn it, then hit 4 times and turn, more heat is sucked out than if I turned each time (less contact with cold anvil) I have a gas forge so it is easier to get the same heat, on each time at the anvil, I seem to get further with each heat.

Last year I did 3 things different. 1. Put my thumb on the side (lets not hash this one out, it's personal) 2. When drawing out stock, I started using the horn more. And 3. Did the 90⁰ twist. I think my overall technique has improved.

[nonjic]

It might keep the internal deformation (grain flow, and percentage reduction from each side) of the bar more even. Just a guess.  I can also see it reducing the possibility of 'fishlipping' the faces you are working (in exageration, a flat bar could look like an ' I ' beam if constantly worked on one face)

 

sure look cool. Sadly I just end up with a mess when I do it !

 

I shot this quick vid at one of my customers factories, its a titanium alloy hip joint preform. I think you get the moves and make it look easy if you do it 8 hours  a day :D

 

http://www.youtube.com/watch?v=euV2pc7CPdM

[SoCal Dave]

I found that on my LG hammer, my technique was bad and found the square going towards the diamond after a period of hammering.   So, I went back to hammering like MacBruce.  That style of hammering has worked well for me as I can concentrate better/more on the hammer blows and have a little bit better control. I try to hit each side the same number of times as I'm drawing it threw, and also look at the size of each side.     

[macbruce]

25 LG's for instance go way faster than most can keep in time with. The one guy I've seen do it is Peacock and I was impressed..... B)

[Frank Turley]

No matter what method, you want to turn 90 degrees not, say, 87.5, or if the latter, you'll get a parallelogram section. Same thing with hand hammering.

[bigfootnampa]

I would say that it depends quite a bit on your hammer.  The big Nazels that I have seen hit like a ton of bricks but give enough time to flip if you are quick.  My little 20 pound Anyang is so gentle when I want it to be that I can do about 75% of the forging to make nails with it... but you'd have to be way faster than me to flip between each blow!

[brianbrazealblacksmith]

Turning your material after each hit is one of the most important things to know and understand about forging. Reason alone can tell you why. The very first thing that I talk about in a class has to do with this very subject. Think about a piece of round stock. What happens when you strike it between a hammer and anvil at a forgeable heat? It will form a pill shape. You would not want to strike it again on the same side and form a thinner and longer pill shape if you are trying to draw it out. If you turn it 90 degrees after each hit it will maintain a smaller surface area contact with both hammer and anvil and come back to a more square shape. If it is struck properly, it will actually bulge the previous sides and therefore keep the surface area contact down to a minimum every time you turn it. It will put energy into the material with each strike instead of wicking heat away with the larger surface area contact with hammer and anvil.

[basher]

Turning your material after each hit is one of the most important things to know and understand about forging. Reason alone can tell you why. The very first thing that I talk about in a class has to do with this very subject. Think about a piece of round stock. What happens when you strike it between a hammer and anvil at a forgeable heat? It will form a pill shape. You would not want to strike it again on the same side and form a thinner and longer pill shape if you are trying to draw it out. If you turn it 90 degrees after each hit it will maintain a smaller surface area contact with both hammer and anvil and come back to a more square shape. If it is struck properly, it will actually bulge the previous sides and therefore keep the surface area contact down to a minimum every time you turn it. It will put energy into the material with each strike instead of wicking heat away with the larger surface area contact with hammer and anvil.

 

 interesting 

 I have never previously understood this, it makes sense for a hand hammer.

 I always forge past final dimension in one plane and then thicken back to final dimension whilst forging the other. of course I am using a power hammer and fuller dies . it is defiantly quicker to do it this way than in a more controlled turning manner . not the most efficient way in number of blows or energy used but the fastest which is what counts when power is not a problem .

[JNewman]

Turning your material after each hit is one of the most important things to know and understand about forging. Reason alone can tell you why. The very first thing that I talk about in a class has to do with this very subject. Think about a piece of round stock. What happens when you strike it between a hammer and anvil at a forgeable heat? It will form a pill shape. You would not want to strike it again on the same side and form a thinner and longer pill shape if you are trying to draw it out. If you turn it 90 degrees after each hit it will maintain a smaller surface area contact with both hammer and anvil and come back to a more square shape. If it is struck properly, it will actually bulge the previous sides and therefore keep the surface area contact down to a minimum every time you turn it. It will put energy into the material with each strike instead of wicking heat away with the larger surface area contact with hammer and anvil.

This assumes you are hitting it in the same place if you are not turning it.  If you hit it move it in or out then hit again you are not forging the flattened pill shaped section you are forging another pill beside the first and so on.  I do agree you need to move the material every blow if you are drawing out. 

 

That being said I have heard that forging too much on one side then going on edge and forging too much on that edge can cause piping like forging round to round can do. However I don't  believe if you keep things moving and flip before the bar gets flattened much that problem will not manifest.  I usually forge like Macbruce does because I am not yet fast enough but I do keep things moving all the time. and am trying to get faster and faster with my flips.  A lot of the things I forge need a 180 degree flip to keep things centered which can be hard to do with out letting off the treadle for a blow or two.  I have forged 4" round down to 1.5" round using Macbruce;s method and cut off the end for testing  and the bar was MPI tested so there was no piping as it would have been exposed by the end being cut off. 

[macbruce]

When I'm doing points for leaves and finishing tapers I always do the boogie in the power hammer or by hand. When power is not an issue like Basher says I rarely bother and I get good results......On an off day I can make ''diamonds'' from rounds no matter which way I try.....

I think size does matter here because once a bar gets above a certian size it's alot more work to do. Trying to flip say a 3'' bar back and forth in time even with a bigger slower hammer is not easy.......

[Timothy Miller]

I did a semi-scientific test.  I took 2-1/2 square bars of hot rolled steel.  I heated them up in my induction heater for 25 seconds to a welding heat so I know I got the same exact heat.  I allowed my self 30 hammer blows on each piece.  I drew out over the horn like I normally do with a mildly crowned 2 3/4 lb cross peen hammer.  One piece I did the hit turn hit turn the other I did my normal hit hit hit turn.   I did both tapers wile feeding it about 1/8" towards myself after each blow so each blow is hitting in a new place.  The results are that the one where I did the hit turn ended up 1/8" shorter.  I still had plenty of heat to go and could have drawn out much more and finished hammered the pieces but I set my self at 30 blows.  I did this because I wanted to do the test pieces in quick succession and not be worn out on the second one.  A better test would be average of 5 of each type. with a few different smiths each tring.  It could also be that I am just more efficient at hammering in my normal way and could strike harder more sure blows.  I do some times do the hit turn boogie when I am drawing out very small stock where the work is getting cold fast and more thane one blow will make it too thin to forge back.  I also think It may for some people easier for them to keep the stock square because each turn is has a slightly different angle and the average of these angles is more equal to 90 degrees than any one individual grip they take.   Also on many power hammers especially mechanical hammers with a crank stroke that are worn there is some side to side motion of the dies at the bottom of the stroke.  This can result in the metal being slightly smeared  in the direction of the lateral motion of the dies. 

 

 

 

And lastly how many angels can dance on the head of a pin?

[JNewman]

 

And lastly how many angels can dance on the head of a pin?

 

I clicked on your picture because I thought you had the answer in the picture :)

[macbruce]

I keep turning the bar 90 degrees because that is how I was taught to do it, many years ago.............never thought about the alternative, though..........interesting!

DANG! I thought this one would really fire your rockets Stu, you're getting mellow in your old age...... B)

[metalmangeler]

I am in the camp of, it helps with keeping or adding heat. I doubt tha you will ever see someone heat a peice of steel to red by hand hammering without doing the hit turn.

[macbruce]

I am in the camp of, it helps with keeping or adding heat. I doubt tha you will ever see someone heat a peice of steel to red by hand hammering without doing the hit turn.

Good Point..... :)

[basher]

I keep turning the bar 90 degrees because that is how I was taught to do it, many years ago.............never thought about the alternative, though..........interesting!

 

I was kind of the opposite , and in fact i have almost never seen this  untill recently, I always worked down one side and then the next ,working two sides which is kind of the same thing or is it?

 its a good thing that everybody does this stuff differently.

[billyO]

I did a semi-scientific test. . . .  A better test would be average of 5 of each type with a few different smiths each tring. . .

I'm glad you added the "semi", because, as you no doubt realize, you were only able to control 3 out of many variables (1) number of heats, (2) number of blows, and (3) to boogie or not to boogie (which is the question).  There were no adequate controls for: force of impact, speed/rate of blows, accuracy of blows, accuracy of the boogie, consistent placement of piece on horn, temperature of steel, among others I may not be grouping in these generalizations.  So 'semi' may be too generous.  You started to apply the scientific method, for sure, and controlled what you could to the extent you could, but nowhere near scientific quality, so perhaps a better wording would have been "semi, scientific-ish" test.

 

I only bring this up because of numerous comments over the years on this site of how this is an educational site, and I would not want an uninformed individual to read this thread and then think that this is a representative test of how the material behaves. 

 

 

PS - I hope this isn't just one more step in my turning into a crumudgeon.....