I would like to make a rounding hammer in the next couple months but have no cupping tool. I've seen videos online showing the process of making one but the videos I saw showed using a rounding hammer to help refine the inside. The reason I want to make a rounding hammer is simply because I do not have a rounding hammer. That said I could use suggestions for finished the cupping tool.

I have seen an almost perfectly shaped convex I could use to help make my first rounding hammer except that I know it would be unable to withstand the abuse. If there was a way to support the bottom of one of those mapp cylinders to the point of it being useful I'd give that a shot. I also have a 4" malleable iron dome cap for use on chain link fencing I've been trying to figure out if I could use. The dome cap is roughly .25" thick if I had to guess but I doubt I could use it as is. I thought about polishing up the outside and casting lead in enough quantity to fill the underside to make it more robust so I could finish the cupping tool with it. However since steel forging temps are so much higher than the melting point of lead I don't think that's a good option. I could use other filler metals but it's going to be the same problem forging temps compared to melting temps. 

I have a feeling I'm overthinking again and there's a simple enough solution. If anyone cares to point me in the right direction I'd really appreciate it. 

It's a ball fuller rather then another rounding hammer used to refine the cup. You can get some cupping from hammering the sides of the tool. That will start cupping when the force of the hammer blows do not reach to center. If your dome cap is enough use it to planish the inside of the cupping tool after hammering the sides up a little.

 

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Thank you Rashelle. I knew there had to be an easier way to go about it. I have a ball joint from either a forklift or a truck that would probably work a treat. 

Now I'll just need to find a large enough piece of steel. I just don't think a 1" diameter axle will cut it for this project lol.

Mine of these days I might finally get myself out of this box in stuck in. 

I have hardened and polished ball bearings up to 4" diameter, if it were me I would start the cup by raising the edge of a round section by hammering all round it at one end as mentioned earlier then reheat it to orange and put it under my press with the ball on top, bring down the press and you have a cup, the bigger the press the bigger ball you can use

That's another idea I haven't thought of. Unfortunately I don't have a press of a 4" ball. 

I do have plans on building a press and actually just got a lead on less expensive material not far from work the other day. 

I did mine by hammering the edges as mentioned then took a cheap 4# hammer that had been ground to the shape I wanted and used it as a die to hammer in the cup further. Turned out well.  Keep it clean of scale as you finish it up as its a pain to clean the scale out of the bottom of the cup. 

Made from 2.5" axle. 

24 minutes ago, Jasent said:

I did mine by hammering the edges as mentioned then took a cheap 4# hammer that had been ground to the shape I wanted and used it as a die to hammer in the cup further. Turned out well.  Keep it clean of scale as you finish it up as its a pain to clean the scale out of the bottom of the cup. 

Made from 2.5" axle. 

I did much the same as this, except that I already had a 3 pounder I'd ground into a rounding hammer. Struck with a soft (wrought iron) hammer, it made a great fuller. 

Mine was 1.5" axle, upset and flattened with a *lot* of sledgehammer work. 

Thanks Jasent and JHCC. Looks like I need to source larger vehicles getting parted out for scrap. My 1" axle came from an old car, if I want larger I'm guessing I need to find a pickup or dump truck. The county school district has the bus maintenance department about 8 miles from where I live. I need to give those guys a call and see what kind of treasures they might have lying around. 

Don't over look old sway away trailer load leveling hitches, the bars are neirly 1 1/2 square spring stock. 

Thanks for the suggestion Charles, I'll keep my eye open for that too. 

I need to get back to my scrap yard, they had some useful stuff last time I went. I just wasn't able to bring any back with me.

Don't forget that the head of train rail is 1 1/2x3" steel as well. The flange is 7/8. Almost an instant hardy tool. 

2 hours ago, Michael Cochran said:

I might finally get myself out of this box in stuck in.

The best way to think outside the box, is don't get into one in the first place.

6 minutes ago, Irondragon Forge & Clay said:

The best way to think outside the box, is don't get into one in the first place.

Glenn has been trying to drill that in my head for quite a while. Maybe one day he'll manage to break through that rock in my head and that wisdom will be able to sink in. 

 

38 minutes ago, Charles R. Stevens said:

Don't forget that the head of train rail is 1 1/2x3" steel as well. The flange is 7/8. Almost an instant Harry tool. 

I have some rail head set aside for a couple projects but I might have enough for a couple other things. I'll have to double check what I have/what I need. Most all the flange and web will be used for other projects including some hardy tools. I remember you making that suggestion shortly after I joined here and I haven't forgotten. 

Once you start looking at it, it's a very useful peice of scrap

14 hours ago, Charles R. Stevens said:

Once you start looking at it, it's a very useful peice of scrap

Definitely a valuable piece if you can legally acquire large pieces. Which reminds me I need to call my local CSX office and ask them about some of the rail they just tore up down the road from me. 

7 hours ago, Lars_ said:

Since I assume this will be your first hammer you are going to use many heats to forge it anyway. Therefore it's even better to grind of a little bit more in the end. 

Not my first hammer just the first large hammer. Even if it does only save 5% of grinding as you say that's a good bit when grinding when you don't have access to grinding equipment that'll move lots of material quickly and consistently. 

Yes sir, it's always good to remind the uninitiated to contact the rail companies. I have pretty good luck with the maintinance yards. Sheffield has a plant up buy Tulsa that recycles rail into fence posts, so don't expect to get a full rail, but drops are generally abtainible for the asking. 

Fyi, Sheffield also makes spikes up that way as well. 

I didn't grind mine what so ever. Little clean up with the wire cup was all I needed

I have a cupping tool. A Swedge Block with round die (ladle/bowl) will do the same thing. Don't over think it 

Now what would be the fun in that, Francis?

10 hours ago, Francis Trez Cole said:

I have a cupping tool. A Swedge Block with round die (ladle/bowl) will do the same thing. Don't over think it 

If I had a swage block that would work I'd most certainly use it.  I do appreciate the suggestion, I might can find one to borrow or make my hammer in that shop. 

10 hours ago, Michael Cochran said:

If I had a swage block that would work I'd most certainly use it.  I do appreciate the suggestion, I might can find one to borrow or make my hammer in that shop. 

I have to ask.

Why do you think it takes a cupping tool to make a rounding hammer?

That's the only way I've seen them made. Well not the only way. You could always forge flat and grind round. 

A friend of mine uses various sizes of ring for making bowls, in lieu of having a ladle / cupping tool on a sewage block. 

That works pretty well. The rings are made from suitable sizes of round stock. 

Greetings Michael,

       Forming rings not so much .,. I have used half round bottom swages to form rounded ends with great success.  You just keep rotating the forge stock in the form and than finish grind...  Worth a try.. 

Forge on and make beautiful things 

Jim

18 minutes ago, Jim Coke said:

Greetings Michael,

       Forming rings not so much .,. I have used half round bottom swages to form rounded ends with great success.  You just keep rotating the forge stock in the form and than finish grind...  Worth a try.. 

Forge on and make beautiful things 

Jim

I didn't think about using a half round swage either. I'll see if I have anything large enough to make one with a close enough radius to be usable. 

 

1 hour ago, Ratel10mm said:

A friend of mine uses various sizes of ring for making bowls, in lieu of having a ladle / cupping tool on a sewage block. 

That works pretty well. The rings are made from suitable sizes of round stock. 

I'm not real sure how that'll help forge a rounding hammer. I've tried that trick before when dishing sheet metal and it works a treat for that.