forging hexagon

[fciron]

Caleb,

I made it sound sarcastic, but the 'if you're good' bit is my addition. It's usually like that thing Phil just did, he said this wasn't the job for hex but never said what makes the right job for forging hex. Confirming that it exists, but not explaining it.

(As I said before, I appreciate the input. Phil and some other folks on here are very gracious in sharing their hard-won knowledge with others.)

Southy,

I do a lot more at the octagon stage than just rounding up, but I hadn't really considered sticking with octagon the whole way. I think I would probably treat it as forging two different squares, rotate 90 degrees a couple of times, one 45 degree rotation, back to ninety degree rotations again. I would worry about piping in the center of the bar and getting too oval if only rotating one side at a time while doing any significant reduction. (I think Grant described a similar process in a discussion of forging titanium.)

[fciron]

Ooops, missed one.

David, one can forge hexagonal shapes by rotating the bar in 60 degree increments instead of 90 decrees. KISS

I made a 120 degree v-block forging pipe. Some how I wound up forging heptagon! :blink:

[Frank Turley]

We tease each other in the shop about hand hammering a triangular cross-section. Can anybody do that? I have a "cartoon" bird's head forged of 1" square by Tom Joyce where the large bill is a tapered triangular section with a slight downward curve. In studying the shape, it appears that Tom may have forged it to a round taper and then run it upside-down through a specifically made vee-swage. When turned over, the central ridge is upward. It is not equilateral; the hammered side is a little wider than either of the swaged flats.

As you might imagine, it is a fine forged piece, and I had Tom put his initials on it.

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

[JNewman]

I forged an equilateral triangle so that I could make a 60" v block. I forged it by hand without a swage. I then cut it off the end of the bar and used it to forge the swage. The trick is to forge the angle into the end of the bar :D

[fciron]

I forged an equilateral triangle so that I could make a 60" v block. I forged it by hand without a swage. I then cut it off the end of the bar and used it to forge the swage. The trick is to forge the angle into the end of the bar

That's thinking outside the box. I'll save that for when I want to make a 60 degree block, which would be the correct shape for forging hex.

I found a rejected piece of the hex-pipe forging and I apparently was able to forge hex right down to a point ten years ago. I welded a piece of solid stock in the end of the pipe once it was drawn down to a manageable size. It came out quite well, I'll take a picture later.

[fciron]

I took some pics in the yard and there is some yard art that I also forged hexagon. I must have been more patient that day. I would seem that several years ago I had no problem drawing hex from 3/4" down to a point. I even used it for yard arts which means it was either easy or I didn't care that day.

Does this mean I've forgotten things that people want to know? Where do I apply for my old geezer card?


More hex tapers by fciron, on Flickr

Close up of the end of the hex taper by fciron, on Flickr

Hex forged pipe rail finial by fciron, on Flickr

[peacock]

I forge hex on a 25LG alot. SGROPP posted above about lataral ram movement. If you can feel ANY side to side or front to back of the ram with it extended out the bottom of the guides you will have these kinds of problems. You will also get along better with drawing die than flat. But the biggest cause of twisting while drawing hex tapers for me is improper heating ( or lack of it). after you forge the first pair of flats we tend to turn the part 60 degrees and start the second set of flats. Now the flat that was on the bottom die is cooler than the one 180 from it, as a result the hot side moves faster than the other we also have a round cross section 60 degrees the other side and that will move differently from the tapered flat sides. As you can see things get out of whack real quick. My fix is to forge all 6 sides as close as possible at the same time. This usualy means one blow turn 60 one more blow turn 60 one more blow and so on. If your hammer will not hit one hard controled blow is is very difficult.

[forgemaster]

Ok ok ok one time I would use hex is when forging a sleeve on a mandrel ie you take a billet punch a hole all the way through it to the size of the mandrel then insert the mandrel and draw the billet along the mandrel. If you forge the billet hex it tends to stop it going square on the mandrel (obviously) and when you have to get it off the bar(mandrel) to get another heat and before it has lost to much heat you knock the corners of the hex in. This increases the dia and allows you to withdraw the mandrel. It is harder to forge a taper by going hex as you tend to flare out the steel as you go towards the point. We almost never use hex when tapering. Another time that you could use hex to an advantage is when you have necked a shaft off a bar and you need to forge it down and keep it central to the bar, going square can sometimes cause the shaft to go to one side especially in the first 2 turns. We also tend to use a hex tool to fix the angles if we are making a large no. of items such as rivet, railbolt or anvil punches.

I'll post some more on this later tonight.

Phil

[fciron]

Phil,

I really was just taking the mickey. Don't put yourself out over a technique that we both now agree is inappropriate for the job at hand.

If you do write something I'll read it with interest. I had kind of figured out that in might be good for work on a mandrel, but the bit about keeping necked forms centered is a new and valuable bit of info. Thanks.

Peacock, I just did a minor rebuild of my LG. One thing I did discover (before my hex tapering adventures) was that you can pull the ram out of plumb with the guides. So not only do they have to be adjusted to a tight sliding fit, but also to make sure they remain at right angles to the lower die right to left. (I don't measure this with a square but by checking that the faces of the dies remain parallel while I tighten the guides.)

Lewis

[forgemaster]

Nah thats cool FC,

I've taken some photos of a hex tool and an application for forging a shaft hex from a necked head.

[fciron]

Ooooh, I love the way the hex tool is the finished depth so it acts as it's own stop block. Every hex swage I've ever seen is only the lower half of the hex, so they are just a finishing tool rather than a forging tool.

Thanks,

Lewis

[forgemaster]

Ooooh, I love the way the hex tool is the finished depth so it acts as it's own stop block. Every hex swage I've ever seen is only the lower half of the hex, so they are just a finishing tool rather than a forging tool.

Thanks,

Lewis

We normally rough forge the hex to near size otherwise it will tend to stick/wedge its self into the tool.

Phil

[fciron]

I see, it's just a better finishing tool. I still like it better than the half a hexagon version.

See what you've done. I had talked myself out of worrying about hex and now I'm gonna be looking for an excuse to make one of those cool tools. Is that one cast?

Thanks.

Lewis

[pkrankow]

I am sure it can be cut using a sine vise an a straight end mill. I am also sure that a set of offset blocks and clamps can do the same as a sine vise. Cut a trench the required depth, then set your angles and cut those in.

Phil

[fciron]

If I had a mill, Phil K.

I'll probably make a block, grind on it a little to refine the angle and sink it into a big hot hunk of steel. I asked if that one was cast because it has a weird looking bit on the end that could be a sprue mark. It could also be where a porter bar was welded on, now that I think a little harder.

[monstermetal]

did you happen to notice the blue tapered hex things in the back of the swage pic?

[monstermetal]

mmm... Well in the second pic you can see what they are and look octagonal.... I guess its easy to see what you want ;)

[fciron]

mmm... Well in the second pic you can see what they are and look octagonal.... I guess its easy to see what you want

I knew it! There is a conspiracy to keep this secret smithing knowledge from me. Don't try to backtrack now, Mr. Monster, you've let the cat out of the bag.

Can't loose them with that blue color. Back to the shop to draw more tapers, lunch is over.

[forgemaster]

We would normally make that kind of tool by sinking a bar close to the size into a block,(to cut down on machining, then when its cooled down machine it on the shaper,(shapers are great tools for making a host of forging tools) this tool used to have a long handle on it, but it was cut off so as one bloke can use it. If you have the long handle on it it just tends to bounce up and down if you use it without an offsider. The tapered OCTAGONAL things are the small ends of combination dogging hammers, used for driving dog spikes into railway sleepers.

[fciron]

Shapers do seem like the thing for the blacksmith shop. I need to do a lot of cleaning and organizing before I consider bringing more stuff into the shop. Bought a new (to me) lathe six months ago and I'm still using the old one.

There's a spike driving hammer in the sample bin in my shop, which is quite impressive when you consider the biggest hammer is a 50 lb. Little Giant. Now I wouldn't mind getting some of the other old jobs back, but that one looks like a lot of work under the little hammer.

[pkrankow]

Shapers do seem like the thing for the blacksmith shop. I need to do a lot of cleaning and organizing before I consider bringing more stuff into the shop. Bought a new (to me) lathe six months ago and I'm still using the old one.

There's a spike driving hammer in the sample bin in my shop, which is quite impressive when you consider the biggest hammer is a 50 lb. Little Giant. Now I wouldn't mind getting some of the other old jobs back, but that one looks like a lot of work under the little hammer.

A lathe can be used as a mill with some creativity (not much needed really). Less if you have a mill attachment. The work envelope is rather small though. I do understand that paying jobs come before making a machine do something it generally does not do.

Phil

[fciron]

I have done some milling on my lathe with an angle plate. Since almost all of my machine work is one-off, repair or tooling for the shop I don't get too upset about having to take light cuts or complex set-ups. A shaper is actually ahead of a mill on my wish-list, almost all of my best/worst ideas can be done on a shaper faster and cheaper than on a mill: Cutting dovetails for hammer dies, making trough-type profiling dies for the hammer, dove-tail slides for all kinds of fabulous tools that don't work like I imagine. That kind of stuff. :D

[brianbrazealblacksmith]

I've been busy lately, so I just got around to trying out the hex taper this morning. Now I only have my hand hammer, but you could do the same thing on a power hammer with the appropriate dies. The dies I used were the far side of the anvil with a 1/2" radius and the flat side of my hammer. Starting with round stock hold the appropriate amount of material off the anvil at the appropriate angle of the taper desired. Strike once with half-hammer faced blows and turn 60 degrees with every blow. This will give you the base of your hexagon taper. After that, move the appropriate amount of material onto the anvil, rotating the same direction as you continue to turn 60 degrees, and strike with the same dies using the near portion of your flat die as a stop on the already hex forging on the anvil. Continue to desired point.

Under a power hammer I would use a tapered die instead of holding the angle of the taper, of course.

Hex bars are no problem either, just start on the near side, holding straight and feed into the flat dies with little bites using the forged material on the anvil as a stop.

[fciron]

Thanks for weighing in Brian. Taking little bites every sixty degrees is my approach too. I do like the finished look of the hex tapers.

What happened with the power hammer was that it was too easy to 'overpower' the small section of the bar and instead of drawing my second side the bar would twist over and the first side would get flattened some more. This made it impractical to use for a piece that I wanted to finish round. (If I wanted hex as a finished piece it would have been worth the effort to slow down and make a nice hexagon, but I was having to do finishing work in what should have been an intermediate step.)

[forgemaster]

Hi all I have come back to this post as we have been trying forging down shafts by going hex at the earliest point we can and just seeing if there is any benefit. We have been taking the shaft to square till about 3/4 inch above our finishing size then taking off a corner as for oct but then going to hex to forge the rest of the way. what I am seeming to find is that the bar is staying hotter longer, or gaining heat from the metal moving, and we get to rough round with less forging then by going oct, we have not as of yet had any pipes appearing in the ends etc so it would seem that it is not to detrimental to the stock re splitting and it does seem quicker to go square,then hex, take the corners off the hex and then round (polyhedral). We have experimented with sizes to 30mm dia up to 105mm dia and all sizes seem to me to forge hotter, easier, and quicker when forging to square, then hex (instead of oct) then rough round, then swaging. I'll try to get some footage of it and post it to you tube then nail it into IFI.
Phil

But I'll add that this is all forging to parallel shaft not forging tapers. If we have to forge a taper where ever we will rough forge it to oct tapered then use a set of taper swages