Little Giant Sow Block tooling

[littlemilligan]

I'm totally rapt in this thread, the last two video's, wow

[BIGGUNDOCTOR]

I was told that the large welding cylinders are made out of 3/4" plate. Check to see if Coyne has any videos.

Drawing is the fastest way to do deep sections like a cylinder. Spinning has also been done on some rather large, and thick sections. IIRC I saw a picture of a spun tank head that was 10' in dia, and 2" thick.

There is a cool video of making train wheels that may offer some hot working options.

Good luck!

[John McPherson]

*The following is a personal recommendation, and not a paid endorsement or ad. I just happen to know and respect the guy.*

 

Dean Curfman of Oak Hill Iron makes a line of vanity sinks (among other things) on his Big Blu hammers, no special dies needed. I have seen him do a 8" deep bowl in copper in just a few minutes from a flat disk. I know that he sells videos of power hammer uses, and specialty dies as well. Check out his websites, and if you don't see what you need, give him a call.

[knots]

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. 

 

 

Check out  this modern build for forming sheet metal :

 

http://metalshapers.org/101/mcglynn/history.html

[metalmangeler]

In the drawing of the proposed purpose built hammer above. I think your support is way to far from the blow. This would put a lot of stress on your machine. If you can not support your blow with a direct collomn you would want to be as close as possible, so that you don't have a long lever you are pounding on.

[metalmangeler]

I would think along the lines of a very short throw helve with a solid anvil under the blow but the top of the stroke not hitting the top side of my bowl.

[knots]

Well yes, the details of this build concept would need to be adjusted for hot forging bowls.  The referenced machine was for sheet metal and therefore for cold work and is designed for short fast blows.      This thread is focused on hot work for heavier walled containers however it seems that there may be a middle ground between the 100 pound helve and these sheet metal machines.

 

I am particularly taken by the idea of using a pneumatic powered drive with a simple pneumatic foot valve for control.  However I suppose that 3 phase and a VFD speed control would work as well.  The benefit of the helve concept is that the tooling can be designed for all around clearance of deep forged shapes.  The tooling can be cupped form on top or bottom.  The anvil can be designed to be raised or lowered according to the stroke and speed.  The linkage could even be designed to be interchangable for different stroke lengths and tooling weights.  The tooling could be light but supplimented by variable ballast weights mounted helve arm.  Seems to me that forging 3/16th" or 1/4" thick plate (hot) for bowls would not require a particularly heavy machine.

 

If I were doing a lot of bowls I would have a serious look at this concept.

[Adair]

I finally have my little giant in condition where I can make good use of it.  I'm revisiting this idea I hatched while the machine sat.  It looks like all my previous image links are broken,  I wish I could go back and correct the links.  I just had to organize the images I had in Photobucket and that messed everything up.  

I'd like to make a tool holder that replaces the sow block similar to the attached sketch I made (the image on the right in the first photo, the image in the center in the second sketch). 

The die height would match the normal bottom die and would not affect the performance of the machine.  

I have a piece of 1-1/2" plate burned to the outside diameter of the hammer base where the sow block mounts.  I would like advise on two things:

1.  How can I best attach a male dovetail to my baseplate? I don't want a weak connection here, but I can't afford to machine this from solid.  

2.  Should the base of the dovetail "bottom out" in the casting, or should the "shoulder" of the base plate bear on the machined surface from which the dovetail is inset? 

Cheers, Adair

[Adair]

Here is a better sketch of what I would like to build.  Would drilling and counter-boring for large machine screws be sufficient to attach the male dovetail? 

-A

[Adair]

I wanted to revive this thread in hope of receiving some input on one question:

Is it wise to bolt on a dovetail on a 100# little giant per the lower right drawing in the above post?   I'm imagining (4) 3/4" socket head cap screws up from the lower part of the dovetail 

[Frosty]

Are you asking about the bowl making bottom die that's at such an angle? If so I'd never put that kind of  leverage against my power hammer. 

When I'm looking at doing hollow forms I like a round top die over a ring bottom die. 

If I really needed to work at an angle inside a hollow form I'd make a spring die and not put impact stresses on a lever against my hammer. Much better to risk a spring tool than the LG don't you think?

Frosty The Lucky.

[Adair]

Frosty, 

Negative.  Please ignore those images.  I am referring to the last image posted.  The  one with the note identifying "cylindrical forming die".  (It's photobucket, I don't know if everyone can still see it). 

I just want to make a shallow sow block but don't want to machine it all from solid.  I'd like to use 2" plate with a male dovetail bolted on.  

-Adair

[Frosty]

That's workable though I don't know if it'll work that way. I'm not familiar enough with the forces nor how much that much steel will deform. It'll probably be fine but what I envision going wrong is vibration loosening the screws and then hammering them to ruin. Or compression forces turning them into rivets.

I think I'd drill from the top of the 1 1/2" plate and tap the male dovetail piece more deeply than the screws. Recess the Allan cap screws on top of course. You could screw various dies right over them. 

That would put impact deformation and rebound effects on the screws in tension which screws are designed for. Screwed from below impact forces will be in compression and may deform the bolts beyond it's rebound limits. 

I have no, ZERO engineering nor math to back that opinion it's just a gut feeling and could be way wrong.

Frosty The Lucky.

[Jim Coke]

Greetings Adair, 

        Your LJ does not have the control to form things on your proposed dies. Dishing requires depth control. I do dishing on a fly press . 
Just this ol boys 2c . 
 

Forge on and make beautiful things 

Jim

[Adair]

Frosty, 

Bolting from the top does make sense for various reasons.  Thank you for the suggestion.

Jim Coke, I strongly disagree with your assertion and find your conclusion pretty limiting.  Finding terminology to describe the processes for forging plate into vessels seems elusive sometimes (as evidenced by this meandering discussion thread).  I suspect we are just visualizing something different.  I do this work already (though inverted) with both sledge on anvil and set tool on my Litle Giant. I posted earlier on this thread of the same process done with a water powered tilt hammer. I just need more room to move the work around on the Little Giant.  No shortage of control with the machine.

-A.

[anvil]

I agree with Jim. You can make a bottom die by rolling a ring and pressing into it.

[Goods]

Adair, I cannot speak to technique, but have a recommendation for the dovetail. Bolting from above will limit problems if something goes wrong. (That way you always have access to them.) I would torque them tightly then put a small dot of mig or tig weld to be very sure they don’t back off. Much more secure under heavy vibration and can be visually inspected unlike locktite or lock washer. (“I” marks work for inspection purposes, but may not stay very visible in a blacksmith’s shop.)

The other step I would take would be to either leave a tenon on the dovetail to key into the plate. This would make the machining more difficult, but at the least put a key grove in both the dovetail and plate and key the together also. That way you eliminate all side loading and shifting from the bolts.

David

[Adair]

Goods, 

Very constructive suggestions, thank you.  The keyway is a great idea, it need not be deep to be effective.

-Adair