Adair

Little Giant Sow Block tooling

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Hello all,

 

I've been designing a power hammer forever to dish steel plate 1/8" and heavier.  I don't think I'll ever tackle the project.  It occured to me that I might have some level of success by reconfiguring my 100# Little Giant.  I could remove the sow block and design a lower female die with a corresponding top male die extension devetailed into the ram.  Has any one tried something like this or seen something similar?  I never see any tooling designed for the sow block position and I wonder what's been done. 

 

-Adair

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Hi Adair, I'm so glad that you have brought this up as I would like to know how to make dishes out of plate up to 5mm thick. I tried with apposing forms in a press without any luck. I have seen it done with a foot operated treadle hammer at MOONY'S place. It has opposing forms fitted to it.

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Beg borrow or steal the Clifton Ralpf films.  He shows/talks about some tooling that goes in place of the sow block IIRC.  Aside from that the only advise I have is don't bottom out any moving parts on the ram guides if you run a mechanical without a bottom die or sow block.  

 

When you do it please post pics, without pics it didn't happen!

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I know an armourer who uses a spring swage under his air hammer to rough out his armour.   I second the Clifton Ralph video suggestion there is a TON of good information in them.  They are a sure fire insomnia cure though.

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Well Adair if you are near central NM I can introduce you to a fellow who took a LG with a damaged sowblock and made a carousel or tools for it that are mounted on a rotating disk and so can be shifted in as needed.

 

If you are in Australia I can't help you.

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It's been fifteen years or so since I watched the Clifton Ralph videos.  I have a vague recollection of a mandrel lower die.  Must borrow them again. 

 

For my needs, I may purchase the interchangeable upper die from the Little Giant company and fabricate a sinking hammer head long enough to reach as deep enough to reach the female lower die set in the sowblock dovetail.  Yes,  I'll be cautious to maintain clearances of the toggle arms and the wrap around guide.  I'll try to put an image together to clarify my idea.  Thomas, that fellow sounds like quite the innovator.  I only do those kind of things on paper. 

 

LGdie_zps881ee119.jpg

 

LGDieII_zpsb88a2446.jpg

 

-Adair

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I just took a picture of a top die that I made for shaping 1/8" thick 4 stainless bowls I had to make and have to make about every 16 months.  It is similar to what you have drawn but bolt on and a little crude.  The bowls have to end up with the sides vertical.  The hammer die did not work well for the deep bowl.    It did beat me up quite a bit when I tried to do it cold and was tricky for the sides as the opposite side of the bowl is in the way as you are trying to work the  inside sides.    I have used a flypress to sink bowls which has the advantage that the slower motion does not jerk the bowl around like a hammer does. 

 

I will try to post pictures of the die tonight

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I believe the heavier the material, the less sense it makes to attempt raising.  I noticed in the Big Blu video they misuse the term, since they are 'dishing' the shallow vessel.  Their tooling is interesting,  but it looks like press work.  Too slow for what I'd like to try. 

 

I am convinced there are faster means to shaping deep vessels.  I have a strategy, but it always involves specific tooling that I don't have time or money to make. 

 

I am also considering inverting the male-female die arrangement so that the male is on the bottom, similar to how the metalshapers configure their dies.  This would give more clearance around the dies,  allow for greater control of the workpiece so that gravity always has it resting on the contact point,  and keep ones hands clear of the moving parts of the ram.  The lower die could be held or clamped in a socket receiver so that dies of different radii could be changed easily. 

 

LGDieIII_zpsefa9ed2f.jpg

 

This arrangement would also allow the use of a mandrel for a lower die if one were working the sides of a deep vessel.  It would have to be one heck of a mandrel.  Of course that is purely theoretical since I have that giant cast iron base in the way with my Little Giant. 

 

-Adair

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This is a good job for a mechanical nibbler like a Trumpf or a Pullmax. They are much easier to control and have more predictable results.

This is not the example I was looking for if I find it I will post it. It was made from 18 ga with a Pullmax  P5.

post-2703-0-94635700-1396481645_thumb.jp

 

I now have a much larger machine (a Trumpf cn900) which could easily handle 1/4.

 

brad

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LGDieIV_zps457932e5.jpg

Neat Guy,

The Pullmax type machine is awesome, but limited by their long, skinny throats. I'd also like to design this for hot forging with the intent to move the thickness of the material quite a bit more than a nibbler would. A purpose made power hammer would be ideal, I'm just trying to work with the Little Giant that I have to see what kind of sculptural applications I can explore.

-Adair

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The taller/higher the tooling the less stroke that your power hammer will have available.  A diminished stroke will result in reduced power.    There could also be control issues.   I suppose that for thinner material, loss of power, and stroke can be tolerated up to a point.  That point is likely specific to each hammer.  I somehow think that this application will be easier to use sucessfully with an air hammer rather than a mechanical hammer.   Very interesting thread.

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Knots,
 
Agreed.  As I tried to show in the last series of sketches,  the tooling never exceeds the height of the standard die.  That was the reasoning for removing the sow block in the first place.  I think my 100# hammer may be a bit too much oomph to test this idea.  A 50# ram would be ideal.  I can cycle my Little Giant very consistently right now without any erratic blows.  That makes me feel confident that I can feather my blows enough to try this out. 
 
-A.

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Cool, Adair.

 

A shaper and a lathe could do most of what you want here.  Burning Specialties in South Seattle has some large round cut-out drops for cheap.  We could turn your dishing die on the lathe and shape the dovetails.  Same goes for a low-profile option you could bolt male tooling onto.  I used bolt on dies for my 100lb kinyon and they held up fine.

 

I like your thinking- I've been wanting to do something similar on my little Beaudry for taller and more specialized tooling like bolt and rivet heading, etc.

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depending on what type of bowl you want if you just draw the center portion and not the rim say using a flat ball fuller oposing a flat die the drawing action will produce a bowl shape with the rim having thicker material than the rest of the bowl.

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If you were to combine forging the bowl bottom/dome under the power hammer, then manually shrink the rim,  interesting forms could be developed .  Maybe even some sort of shrinking fixture ( they shrink rims under the pullmax machines with special dies).

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I can see that your fixture could/will allow deeper bowl forms to be forged on a power hammer.  However even your fixture will impose limitations on the depth of your vessels.  What comes to mind as a next step, after your innovation, is to forge and fit dished bowl forms together in three dimensional plated constuctions.  Think about the old leather ball technology.   Think about examples in nature such as the evolution of skull structure - sutured plates .   Think Geodesics.  Container forms fabricated from smaller dished elements sutured edge to edge, or over lapped and rivited could be a present a furtile opportunity .

 

Where your fixture could really make a difference is forging long narrow asymetric blanks into bowl forms.  

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LGDieIV_zps457932e5.jpg

Neat Guy,

The Pullmax type machine is awesome, but limited by their long, skinny throats. I'd also like to design this for hot forging with the intent to move the thickness of the material quite a bit more than a nibbler would. A purpose made power hammer would be ideal, I'm just trying to work with the Little Giant that I have to see what kind of sculptural applications I can explore.

-Adair

 

 

 

 

 

 

 

 

 

 

 

 

I think the third drawing is innovative but you are making a big lever to destroy whatever mounting system is in place.  Fact is I think you can do some shallow dishing with a hammer but as you approach the 1/2 hemispehere things get tricky.  I would be very wary of doing handheld stuff, especially as the radii gets smaller, and especially cold.  I would have an eye towards working bigger (thicker) material hot and shallow.

 

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I want to try to keep this topic on track,  there have been some really good points made.  I'll try and move this forward.  For what my ultimate goal is, I really need to make a purpose built hammer.  For the time being I'd like to experiment with my Little Giant.  As Nuge pointed out,  the last lower mandrel arrangement I showed puts a lot of overturning force on the die.  I'm probably pushing the idea too far.  The intent is to do hot work on these dies, hands well clear of the moving parts.  I'd like to start with at least 1/4" material, probably thicker and see where I can go.  The ideal progression is shown below where I would dish the center portion as Metal Mangeler described, leaving the rim unforged to contain the stretching.  From there (and this would involve a purpose built hammer) I would try to draw down the rim with fullering dies to try to minimize the spreading of the overall circumference.  (See diagram below)

 

Progression_zps2c92c8a3.jpg

 

A purpose built hammer to work the rim of a deeply dished form might look something like this crude sketch:

 

HammerI_zpsfca89e01.jpg

 

Knots mentioned a shrinking fixture for a pulmax.  I believe he was referring to a thumbnail shrinking die as used originally on sheetmetal power hammers like this patent:

 

1stshrinkdies02_zps56df62b7.jpg

 

This is effective at drawing in or gathering the edge of sheetmetal to shrink the material.  I've often imagined if there was an application for this in forging plate,  but in my experience this type of die requires uniform behavior in the material, in other words the die works because cold sheetmetal resists and contains the portion of the "tuck" that is being compressed or shrunk. 

 

Still brainstorming.  May not build anything anytime soon, but it is fun to plan for it. 

 

-A.

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If I were looking to build a "purpose built hammer"  I think I would probably base the build on raising techniques and the tuck and shrink principle.  Seems to me that "power hammer" might not be the the proper word to describe the direction that I would most likely take.   I think I would be looking at a pneumatic machine.  Built as a two in one or three in one machine, with multiple hammers mounted front and back or radially on a common column.   One to make the tuck and another to shrink the tuck .  Possibly a third to draw the rim out in order to maintain a uniform wall thickness and deepen the bowl . 

 

The reason for pneumatics is that what you really will be doing is raising the bowl.  The only way that I can think of that this might be done in hot iron efficiently would be to mimic the raising process used for non ferrous metals but with a bit more power.  Hand raising substitutes a lot of low power blows for a few heavy ones.  Thus pneumatics is a good option.  Using pneumatics would also solve the the structural problem of the need to cantilever the anvil.  Since the work is thin a short strike is the best choice as well. The reason for two or three in one is that you will need to constantly move from one process to another and frequent tooling changes could be a a big major barrier to productivity . 

 

If I were to undertake this design I would sit down and raise a copper bowl manually so that I would really understand the process.  Could be that you are way ahead of me there.   There is a huge selection of pneumatic hammers available so you could taylor your machine to whatever power you think you may need.

 

This is indeed a very interesting thread, keep it going.

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Knots,

 

I can see that our minds travel similar paths.  However,  I need to stress that what I am trying to explore here is heavy dishing and not raising.  My goal is to get away from raising which to me is neither enjoyable nor efficient.  I've raised copper, I've raised up to 12 ga. sheetmetal with heat.  I am trying to find a way to draw deep vessels from heavy stock,  not gather deep vessels from sheet.  The video below (one of many on the Maglio of Bienno, Italy) is what first got my imagination going.

 

 

I know I can get hung up on an idea, particularly if there is a cool machine involved.  For that reason I'm not trying to fixate on a very specific outcome (though I have plenty of sculptural applications in my sketchbook). I do know that deep vessels were forged in the past and I am skeptical that a flat sheet was the point of origin. 

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