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Problem: Powerhammer turns steel into rhombus shape


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Hey guys,

 

I've been getting a lot more shop time recently and been putting my Sahinler SM50 to good use. And the title says it all, when I'm forging out billets or barstock I wind up getting rhombus shaped bars.

 

This issues is especially annoying when forging damascus or three layer billets on the edge. As this leads to some welds shearing of as the layers are pushed differently.

 

I pulled the dies out at least 20 times trying to get things right. Also made a set of new keys (as the top die tended to come loose or wander to the left).

 

First I thought the dies weren't parallel to each other. But today I put them on the surface grinder and took of like 0,5 mm. So now they are perfectly parallel in itself. And after putting a shim under the left side of the upper die, both are perfectly level when in place (checked with a water level).

 

Of course this was checked while the wood block was holding up the ram. But I assume the level doesn't change when the hammer is idling or actually hitting.

 

So after all this the issue is still the same. When putting a piece of steel under the hammer it just takes a few blows and piece is shifting in a rhombus form :(.

 

What else could be the issue? The ram guide, the way I mounted the hammer (bolted down wooden base with rubber mats)... ?

 

Or is it just me ? Am I unconsciously holding my work in such a way that it lends to hammer to turn it into a diamond shape ?

 

If anyone of the more experienced powerhammer users has any thoughts on this problem, I'd really appreciate it. Would make for a nice birthday present to find a solution :).

 

Looking forward to your answers.

 

Best regards

 

Marcus

 

P.S.: Obviously "Oben" means top and "Unten" means bottom :D.

 

P.P.S.: The dies I'm using are combination dies, as it might not be that clear from the photos. And the rhombus shape is mostly an issue when I'm working on the flat part of the dies.

IMGP5850.JPG

IMGP5849.JPG

Edited by Marcus
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Hey guys,

 

I've been getting a lot more shop time recently and been putting my Sahinler SM50 to good use. And the title says it all, when I'm forging out billets or barstock I wind up getting rhombus shaped bars.

 

This issues is especially annoying when forging damascus or three layer billets on the edge. As this leads to some welds shearing of as the layers are pushed differently.

 

I pulled the dies out at least 20 times trying to get things right. Also made a set of new keys (as the top die tended to come loose or wander to the left).

 

First I thought the dies weren't parallel to each other. But today I put them on the surface grinder and took of like 0,5 mm. So now they are perfectly parallel in itself. And after putting a shim under the left side of the upper die, both are perfectly level when in place (checked with a water level).

 

Of course this was checked while the wood block was holding up the ram. But I assume the level doesn't change when the hammer is idling or actually hitting.

 

So after all this the issue is still the same. When putting a piece of steel under the hammer it just takes a few blows and piece is shifting in a rhombus form :(.

 

What else could be the issue? The ram guide, the way I mounted the hammer (bolted down wooden base with rubber mats)... ?

 

Or is it just me ? Am I unconsciously holding my work in such a way that it lends to hammer to turn it into a diamond shape ?

 

If anyone of the more experienced powerhammer users has any thoughts on this problem, I'd really appreciate it. Would make for a nice birthday present to find a solution :).

 

Looking forward to your answers.

 

Best regards

 

Marcus

 

P.S.: Obviously "Oben" means top and "Unten" means bottom :D.

 

 

well your useing rounded dies not flat this has a tendancey to push the steel sideways and i think you may be gripping the billet so tight your actualy twisting it and as you turn it over you doing the same again you have to be very consious of the way you present the steel to the hammer,because the hammer will only exagerate any twist you give the steel , i found i was twisting the billet without even realising it and the hammer only makes it worse try flatter dies and dont hold the steel overly tight but not slack enugh so it can shoot out of your hands it takes practice

 

hope this helps happy birthday

tell

Terence.........(today started off perfect now --- watch sombody come and stuff it up ]

 

if it aint broke dont fix it

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Like Tell said, takes practice. I can forge billets very square on my 100 lb LG but let someone else use it and they can't, at first. Your biggest problem is you're forging on the ends of the dies (combo dies), Get a set of flat, and or a set of drawing and work your billet in the center of the dies, should have no more problems.

Don Hanson lll My Webpage

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I've been thinking about doing the same for mine in getting some drawing dies.

Mine does the same, but last time I used it after some adjustments, seemed to be doing it less.

Did some shimming myself.

Edited by EdgarFigaro

Beau Erwin

www.ErwinKnives.com

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Don't break it down too fast and be sure to work both sides evenly. This is a common and frustrating mistake and not the fault of the dies.

Don Fogg

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Don Fogg brings up a god point, a long time smith told me years ago, after working the top side of a billet, flip it 180 deg.s and work the bottom. This will push the side out, then when working the sides down, just hold the flats of bottom and top square with dies.

 

I do find it easier to keep square when working in the center of the dies, but it can be done on the ends of combo dies.

Don Hanson lll My Webpage

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Also, when drawing down (and this was a huge problem for me at first) you have to make sure your bulged bar is square in the dies. I drew an illustration, read left to right:

squaring up.JPG

Edited by Sam Salvati

Let not the swords of good and free men be reforged into plowshares, but may they rest in a place of honor; ready, well oiled and God willing unused. For if the price of peace becomes licking the boots of tyrants, then "To Arms!" I say, and may the fortunes of war smile upon patriots

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[First make sure that your guides are tight. My 3B Nazel has VERY flat matting dies and I have this out of square issue as well...its the guides.

When in the down position can you wiggle the ram side/side? Lifting it with a lever can you jack one end up and have the dies tilt?

if so then you need to shim the guides or use a squaring swage to get back to square.

 

I am not a fan of half/half dies they seem like a good idea, but what they actually do is force the guides out of true as you are working only off center...not good practice.

I suggest a good set of oversized flat dies and use tolling for drawing or a dedicated drawing dies set.

 

To verify take a bit of large square hot and lay it on the flat dies side and let the hammer eat. If you are not moving it other than forward and back and it still goes out of square rather than a squished rounded side rectangle than you know its the guides.

I suggest six inches of 1" square for the test.

 

Ric

Richard Furrer

Door County Forgeworks

Sturgeon Bay, WI

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Thanks a lot guys for all the info.

 

I cant really wiggle the ram side by side. I can only wobble it a tiny little bit around it's own axis. Is that just as bad?

 

The hammer is from 1996 and hasn't really seen any use with the previous owner, so I hope the guides are still ok. With the Sahinler it's just one on the inside I think. The guide is the piece of metall, that's inserted in the hub on the side where the ram is flattened, right? Just want to make sure I'm not confused here ;).

 

Looks like I'm going to put my dies back on the surface grinder and carefully turn them into flat dies. Got like 1,5 cm wiggle room left before it get's critical.

 

And then it's practice, practice, practice :).

 

Gonna let you know if all this helped fix the issue.

 

Regards

 

Marcus

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Marcus

 

I don't disagree with any of the above advice.

But

Get in the habit of watching the squareness as you forge and correct immediately.

That bulge that Sam has drawn a few posts earlier allows you to hold the flats(bulges on the dies) a little off vertical to correct.

Do it at the beginning of the heat when the billet is really hot and it only works well when you have those "bulges" available to allow you to hold the billet with the flats a few degrees off vertical to compensate.

Tough to describe but soon becomes automatic.

 

Hank

henry knickmeyer

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Looks like I'm going to put my dies back on the surface grinder and carefully turn them into flat dies. Got like 1,5 cm wiggle room left before it get's critical.

Don't go completely flat. Grind a good flat across the middle, and carry that slight bevel on the drawing side all the way across. This way with light blows you can get a flat surface on the billet, but with heavier blows these dies will draw very good. My dies are set up this way and they do it all very well.

Don Hanson lll My Webpage

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Thanks for the tips guys. Actually ground them down this afternoon, and did just what you suggested Don :).

 

One of the reasons was the same concern you have Greg. According to the manual the dies can be undersized by 2 cm. Since I wanted to be on the safe side I just took of about 5 mm of each die. And then put a phase along the full sides. I hope the specs in the manual hold true. According to my first few attempts this afternoon they are. I hope it stays that way in the long run.

 

Put the dies back in and worked the billet of Damascus the combination dies messed up two days ago. The billet is no good anymore since some of the open welds couldn't be properly closed.

 

But the difference between forging on the combination dies and the full dies is astonishing. Feels like the hammer has quite a bit more "Ooomph" in the middle and sounds more solid now (but maybe I'm just imagining things ;)). Welding the billet the long way under the dies is also a pretty nice feature.

 

And finally no more slipping of of one side and ending up mashing the piece right on the ridge in the middle.

 

So thanks again guys. Two days ago, I thought that I had to put my hot work on hold for the next few weeks, now I'm already in full swing again :).

 

Regards

 

Marcus

Edited by Marcus
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if your dies are undersized by grinding.. will the extra travel damage your air hammer? .. i'm concerned about the upper parts of the ram ?

 

is there a spec for minimum die size

YES if the dies are too short they will not stop the ram before it bottoms out inside the housing and it will break. ..sometimes shooting the ram through the base of the housing...I have heard of this, but never seen it.

There should be a hack line on the ram somewhere when it is fully down..without the bottom die. If not then let it down all the way and measure it..then make the dies taller than that length by a bit...mine is about 2" of extra space on my 3B Nazel..this allows for dressing the dies over the years and still gives me a lot of throw.

The smaller the hammer the less the extra room as it has less throw and you may need it at some point.

 

Ric

Richard Furrer

Door County Forgeworks

Sturgeon Bay, WI

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I find its pretty good practice to forge the rhombiod bars back square. It helps to have a sturdy handle welded on so you can control the billet much better.

 

When Im welding on a hammer (setting the first weld) I have much more consistent results biting into the billet about 1/8" of per hammer blow. If I try and set the whole weld at once, like you do on a press, I find I get blisters forming.

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Seriously considering ordering a pair of drawing dies to swap out my combination dies with.

The rhombus thing is driving me nuts.

 

I have noticed that while my hammer (50# LG) is not running if i grab the top die i can give it a slight wiggle (side to side). Very little but it does wiggle some. Wondering if something can be done to remove that wiggle.

Beau Erwin

www.ErwinKnives.com

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Beau, do you mean JUST the top die wiggles in its dovetail, or the whole tup assembly is a little loose in the guides? The first is a little more serious with combo dies, but should be fixable with a brass hammer upside the wedges. As Don said, a little wiggle in the guides is okay.

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I'd go for flat dies with radiused edges, kinda like you'd find of a regular hand hammer. True flat for a bit in the center, then slowly curving away like the crystal of a very thin pocketwatch, if you know what I mean. I'd think the dedicated drawing dies would be too "nippy" to leave a good flat finish if that's what you're after.

 

One of these days I'm gonna redo the dies in my hammer because they're slightly dished in the center, but the thought of pulling the wedges makes me shake in my boots. :ph34r:

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