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I've been thinking about this one for a while and finally got started on it. It will be a steel, 4 sided box with concrete as a filler. It's going to be about 12 inches square and 3 inches wide. I have one end completed and another side mostly there. I have still to make a 60 degree V swage and I would like to make some dishing swages too, although I don't have any steel in that shape . The rest of it is just pipes and angle iron so far.

The strength in this design will be mostly dependant on the rebar configuration I have planned. The concrete will provide stiffness and support.

If it works, it may provide an economical alternative to all steel units. We'll see how it goes...

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That's a good question. I plan on using plain high strength concrete unless things start getting crowded. Then I may pre mortar the tight spots and crevices, and fill the rest in with regular concrete. 

I don't think adding small steel reinforcing pins will buy me anything. 

I may do a custom mix if warreted. 

The aggregate size in the high strength is pretty small which is good. It should work fine. 

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I got both the ends finished, and assembled the unit. It was difficult to keep everything square and flat with so many different pieces having to be welded together. I did the best I could and it's functional anyway. I added a 60 degree V swage, and a block containing 1/2", 3/8" and 1/4" slots. 

I reinforced the inside of the block with lots of rebar. The load is distributed both laterally and linearly for all the different dies. 

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I managed to make one side of the block flat and level so it would sit in the pan during pouring with minor leakage. Since it's fairly small, I decided to use mortar instead of concrete. I didn't see where concrete would buy me anything, and the mortar fills the little voids better. I mixed the mortar pretty thin and did a lot of tapping on the outside of the block to settle and pack the sand. I found that this produces a very dense final product. You can see how much water it displaces. I also use more cement in the mix to compensate for losses.

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I'll let it set for a couple of weeks or so to harden sufficiently. I'm pretty confident with all the rebar that it should work just fine.

 

Ted

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  • 2 weeks later...

I finally got around to testing this thing and it worked well. The mortar didn't crack and the dies didn't deform. 

Here I formed a simple arc

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Here is a 60 degree bend

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And here I just beat a 3/8" square bar round on the end dies. 

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All in all it should suit my moderate needs. I did need to put a hardie bar on it because it likes to dance around. Should I form anything else in it, or should it fail, I'll post it.

 

Ted

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  • 1 month later...

I think a lot will depend on how much you use it and how hard you pound on it.  If you used a heavy 4 pound hammer or even a sledge I'm not sure how long it would last.  Then again, such a small swage block isn't make for that really.  I think with things like this you need to see how they perform years down the road.  A solid steel swage block will last hundreds of years and probably a lot longer than that.  I hope it works well for you.  

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Interested in the type of mortar you used.  Was it a masonry type mortar?  They make some high strength non-shrink grout that can get up to 10,000 psi compressive strength. We use that type of grout under equipment bases such as pumps, exhaust fans, compressors, turbines, etc.

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MC... I don't do any heavy forging, and don't even own a hammer larger than 3 lbs. I just wanted to see if it would work more than anything else. It's fine for what I need it to do. 

Joe... I mixed my own mortar so I couldn't tell you exactly how strong it is. The internal steel bracing takes most of the shock while the mortar stiffens things up and helps distribute off center stresses. 

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  • 1 year later...

Neat idea for a roll yer own. If anyone else builds one ine this way I would definitely recomend following jeepinjoe's suggestion and use a non shrink mix. I have years of experience in concrete and I also would add that the less water you use the stronger the cure will be. Basically the more water you use the more you thin the portland cement. To ensure it's free of voids use a power tool to vibrate the "mold", in this case you swage. Sanders will work, a sawsall with no blade and the foot pressed against the side. Largest aggregate you can get in the mix that doesn't impede flow through the rebar will also make it stronger. 

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  • 2 months later...

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