forging hexagon

[fciron]

I've heard (and read) form a number of reputable sources that drawing out can be done to a hex rather than a square. I've got a couple of jobs coming up that call for long round tapers from 3/4" and 1" round bar (about 18mm and 25mm?). I thought I'd try drawing them out hex, since that would be closer to the final round than a square.

I tried to take my time on the first heat and get a well define and accurate hexagon, then started drawing with the second heat. The bar seems to twist when I hit the second side of the hex; for the first side everything is symmetrical and I can get a nice squish, but when I turn it 60 degrees then the blow twists the bar. I rotate again and hammer on the third side to put it back to a symmetrical hex, but now it's got the twist. I can keep it all tidy if I use a real light foot on the treadle (25lb. Little Giant, just cleaned and tuned, new bushings, the new dies are flat and parallel) but then I am going really slowly, which is the opposite of what I'm looking for.

Are my angles still off or is this technique only appropriate for larger material? (Running the hammer hard on larger material would have the same effect as me using lighter blows, it wouldn't deform the hex enough to start twisting. So larger proportional to the hammer. )

Any thoughts or suggestions appreciated.

Lewis

[mike-hr]

Lets back up. Are you talking Hexagon(6 sides) or Octagon(8 sides)? I do a lot of octagon forging on the hammer, go to square, and knock the diamonds down until the facets all match.

[thingmaker3]

What follows is speculation, so salt as needed.

Material being forged follows the path of least resistance. When forging square from round or octagonal from square, those resistances are symmetrical.

When forging second side of hexagon from round-with-flat-sides-at-sixty-degree-angle, I don't think those resistances would be symmetrical.

Have you considered using a hex-shaped swage for the first step?

[fciron]

Mike, I do indeed mean hexagonal, having six sides. I've heard Clifton Ralph and other industrial smiths talk about drawing out hex, then round instead of square, octagon and round.

Thingmaker, it is not necessary for things to be symmetrical, but to keep from twisting most of the material needs to be in a vertical line with the contact points of the hammer and anvil. (Just think how boring it would be if we could only forge symmetrical stuff.) When the hexagon is 1 inch across it does not distort enough to start twisting (although it would under a larger hammer). When it gets down to about a 5/8 inch hex, then hammer blows deform it enough to cause trouble on the next side. My question is whether there is a way to prevent this and still draw quickly or if this a limitation of hexagonal drawing.

[Dave Hammer]

Control.

[mike-hr]

The watch word of all traditional smithing is S,O,R square, octagon, round. It's easy to juxtaposition hexa for octa in conversation. I love the work CRalph does, and modeled my PHammer tooling from his video. If you want to get to round, then SOR is your friend. If you want to generate Hex shapes, I'd reccomend a bottom swedge.

[fciron]

Let me rephrase the question. I want to make some very long round tapers for a paying job. I want them quick and I want them decent. Should I try to draw a hex all the way to the pointy end bit or would it be faster to switch to square/octagon/round when the hex starts to distort?

The more time I can spend with my foot down hard on the treadle the more metal I can move and the quicker the whole job gets done and the sooner I get paid the exact same amount. My test pieces suggests I can put more whammy into a square than I can into a hex, experienced industrial smiths never miss an opportunity to talk about drawing hex. Which should I go with?

You know what? I just told someone in another thread that the little giant is not an industrial grade tool. I should go with my test piece and worry about hex later.

Good Night.

Lewis

[mike-hr]

Sounds like you're frustrated. A 25# LG won't thunk steel like a Nazel 4B. All you can do is get good at running flat out. My opinion, use a long gas forge, get a 20 inch heat, and make a pull taper, start at the fat end of the bar, and pull it toward you, all the way to the end. Next heat, index 90 degrees, same thing. I learned a great trick from a friend a couple weeks ago. If the taper is 3/4 to 1/4 in 2 feet, for example, lay that taper out on some sheet metal, and band saw it out, for a comparison jig. It's real easy to cheat the taper and leave thick spots laying there. The sheet metal comparitor will show the thick spots. If you get 4 sides laying true to the sheet metal jig, then go to octagon, then round. Accuracy should come first, time and money come after that. You dance with who brung ya. If the LG is taking 10 minutes longer than you feelit should, it's nobody's fault. Eat the time, or gear up.

[maddog]

I've never forged hex but I have several times come across descriptions of a method using a small hex jig at the end of a round bar. If, for example you were to mount a hex nut on the end of a round bar, it would sit on the anvil and hold the orientation for each face so you could start the flat with y our hammer and keep it true until it was well formed enough to be stable. The drawings I remember show a sheet metal jig with a collar in the center. The jig is considerably wider than a nut would be for that size bar.

I dont know how this would be applied to power hammer work but I think the key is the initial stage where the flats are established with the right orientation. After that the piece will guide itself like square or octagon. I dont see how one could do this going from square or octagon.

Like I said, I've never tried it. Just seen it described in smithing texts.

[monstermetal]

Its not the answer your looking for but If I needed to move a lot of material with a small hammer the first thing I would do is try to reduce the working area of the die... If you can build a small fixture to hold a tool on the lower die rig it up with a chunk of half round ... or better yet a double fuller spring swage.... run a forge full of bars through the swage to draw to size and forge rough octagonal, pull the tool and run the whole lot back through the hammer with no sawge to planish... If its a very long taper I think concentrating the force in the direction of flow will increase overall efficiency and more than make up for the extra step in SOR vs trying to learn to forge it hex... (all that is only true if you already where taking two heats to make the part of course)

BTW I have forged round to hex and then drawn in large sections (3"+ bar)...Because I wanted tapered Hex.... but never the other way around.... If the end goal was round taper Id do SOR, just because that's what feels natural.... When I was doing the hex I had a fairly hard time controlling the taper... I found you had to take real small steps on each face or it got out of wack... Unlike forging SOR you can get crazy and still pull it back together at the end.... Of course like I said my goal was not to end up with a round taper, I did end up rounding some up and then forging back to hex because it seemed easier than maintaining the hex...

[SGropp]

Part of the problem with forging a tapered square or hex on a LG style hammer is that the top die is actually making a sideways sweep as it hits. This is a result of the fact that the rotational motion of the of the fly wheel is transferred to the up and down stroke of the ram., even though it is mostly restrained by the guides. This is worse if there is a lot of wear in the guides, but even with clean, straight, well machined guide ways there has to be enough clearance for the ram to slide up and down , particularly once things warm up.

This effect can be greatly minimized by forging corner to corner across the dies. [ flats with a slight crown and rounded corners ] I forge the tip down close to finish on the first heat so I have a target to aim for. I then work up to the fat end and then finish the taper going back down to the tip, running close to full speed and rolling the bar at a steady rate if I want a round profile.

This also works for making long hollow tapers in pipe although you need to slow down a bit and ease off on the treadle,and let the hammer lope along a steady pace.

[forgemaster]

Square octogon round is the way you must go, there are times to use hex but this is not one of them. Fastest way to reduce anything is in a swage or some sort of die as the metal is contained and can not bulge out sideways. But even if we are using taper swages we will still rough the job to shape before sticking it in the swages.

Phil

[fciron]

Thanks for some informative replies.

I guess I'll be going back to square, octagon, round but I have to say that the hex draw was pretty cool for the small area where it worked. I'm gonna need to design an excuse to play with it some more.

I also need to remember to let things percolate through the internet a little longer. Mike-hr, I think we posted simultaneously, my frustrated comment was not aimed at you.

[JNewman]

I have been told about forging hex when you want to finish round as well by an old industrial smith. I have done it a little but normally taper square. I didn't notice rotation any worse than square. Leo also tells me of making 6'long 1/4" allen keys without swages. He is still frustrated that they wanted the whole bar forged hex rather than just the ends.

[fciron]

JNewman, the fact that I always hear about it but never see it should have been a big clue. ;)

[thingmaker3]

One thing I'm a little fuzzy on...

If the finished product is a round taper, then why is the twist a problem?

[fciron]

One thing I'm a little fuzzy on...

If the finished product is a round taper, then why is the twist a problem?

It's not just the twist, it's that the bar is twisting instead of drawing and I spend a lot of time fixing it. Time I would rather use drawing the taper. I've reached the conclusion that drawing hex is not suitable for this job, maybe sometime in the future with bigger stock.

[Frank Turley]

I'm a hand hammer and LG smith. Clifton Ralph notwithstanding, I can't fathom the methodology of forging a hex section with flat dies. If you flatten round stock somewhat, you obtain a capsule section (like an RX pill). If you turn it 60º, there is no solid anvil support under the tup blow. Earlier responses have already talked about symmetry and vertical point to point contact. That is lost with the 60º turn. You may not only get a twist, but an internal rupture called "pipe" which can't be seen from the outside. One of my books talks about this briefly, Schwarzkopf I believe.

My old swage block has large hex swages on one side.

Nobody know 10% of anything. If someone has an answer, I'm open to hearing it.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

[fciron]

Mr. Turley.

I think you're assessment is right on, that's what I was trying to describe in my first post. I was only able to work with the hex when the stock was proportionally large for my hammer capacity (so I had a very fat lozenge), once I got down to efficient forging sizes then the bar deformed too much with each blow (normal lozenge). I think that if I wanted to draw a round tenon that was larger than the inscribed square on a large bar it might be useful. Put another way, if drawing to a sharp square would make the part too small, then I might find drawing hexagonally useful.

Clifton Ralph notwithstanding

somehow, I see him withstanding just about anything. :lol:

[Frank Turley]

Mr. Turley.

I think you're assessment is right on, that's what I was trying to describe in my first post. I was only able to work with the hex when the stock was proportionally large for my hammer capacity (so I had a very fat lozenge), once I got down to efficient forging sizes then the bar deformed too much with each blow (normal lozenge). I think that if I wanted to draw a round tenon that was larger than the inscribed square on a large bar it might be useful. Put another way, if drawing to a sharp square would make the part too small, then I might find drawing hexagonally useful.

somehow, I see him withstanding just about anything.

There is nothing wrong with forging a "soft cornered" square cross-section. It's more like an octagon with chamfers, but the chamfers remain from the native material; they are not directly forged. That way, you've saved the reduction needed for a sharp cornered square.

[maddog]

The six sided analogy of square to octagonal would be triangular to hexaganol

[fciron]

There is nothing wrong with forging a "soft cornered" square cross-section. It's more like an octagon with chamfers, but the chamfers remain from the native material; they are not directly forged. That way, you've saved the reduction needed for a sharp cornered square.

It's almost like you get a free octagon! That's why I only said it might be useful, in theory if you want to finish round the smaller the flats you make, the less rounding up there is to do later. This may not be true in practice. I have found forging to a hex very useful for working with pipe, the corners don't get as sharp, and you're already using light careful blows.

It's just one of those tantalizing hints I always hear industrial smiths toss out without any additional explanation. A little throw-away sentence at the end of an explanation, "...Oh, and if you're really good, you can draw hex too."

(Phil said that this was not the job to use hex for, but he didn't clarify when to use hex, I think it's some kind of industrial smithing conspiracy. I'm not really complaining about Phil, the first batch of commenters thought that drawing hex was a figment of my imagination. These tantalizing hints are kind of like a challenge.)

So I tried it and it seemed to be a fairly limited technique. I brought it up here because I thought there might be something really obvious that I was missing or some special trick that had been left out. Since no one has volunteered the secret to drawing hex shapes to needle sharp points I'm going to stop worrying about it.

[Ramsberg]

Hey Fciron,

If that context of usage you described, "...Oh, and if you're really good, you can draw hex too.", is the one in which it is usually used I believe that it may have been sarcasm.

Sort of like saying that a really good pilot can fly without wings.

Kinda like the old car shops sending a guy around to their friends shops since they were out of muffler bearings.

Caleb Ramsby

[Timothy Miller]

I draw a lot of tappers to fairly precise sizes. When I need them to be super clean I draw out octagonal and not square. It helps me hold to tolerance better as it is nearer to finished size before you start to round it up. As for forging hex I find it hard to index it properly and keep all of the faces the same width and the corners all at 120 degrees. Unless you are drawing hex to begin with from a hexagonal bar. Some may be better than me I'm sure.

[David E.]

Are tapered V-blocks used for drawing hex??