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I Forge Iron

More metal spinning questions- How do I stop doing this?


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This has been a re-curing problem for me in Copper and Steel, this would be an exaggerated example. I saw using a knob tool (best way to describe it) its about a 1" to 1 1/4" Diameter knob made of brass on a 5/8" steel shaft, Sorry no picture for now. I'm hand spinning and as you can tell from the inside shot, I'm using a back stick.

Any and all suggestions will be greatly appreciated :D

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  • 1 year later...
I like it, could be a happy accident?


Why not put it into words and photos so we can bring the thread to a logical conclusion?


Michael-
It defiantly was an accident but not a happy one. At that point in my learning to spin it was a major stumbling block and frustrating. I did make a few that had the wrinkle only on the edge. I liked those but have not learned how to reproduce that effect on purpose.

Glenn-
I will be writing an article for the California Blacksmiths Associations Magazine in the next year or so and it might include a followup article or just another section on some of the things to watch out for while spinning metal and how to correct mistakes. At this point, I don't see the interest here. If a few (4 or more) people really have an interest it what was the cause and how to avoid it, I would be happy to share what I know. I had a nice dialogue going with Frosty until his accident and a few people jumped into the conversation. That was great! I love talking about spinning, I'm fairly addicted to it. But I'm not interested in just hearing myself speak. Consider this an invitation looking for interest in the conversation. The explanation will take some time and be fairly involved.
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Yes! Notice my original post date and the first reply date almost exactly 1 year.
Its an involved process Glenn. Its really simple in a very complex way. Kinda like drawing a really smooth, flat and nice taper on a power hammer in one heat using the hit-turn method.

I can't say who looked and why over the last year. How many people here spin metal, would like to learn to spin metal or would like to discuss the process? It this a topic for a thread? If it is I'm in!

As I'm sure you have seen, I have posted a lot of work and discussion about metal spinning over the years and I have receive great support for the work but not allot of interest in the process. If that could be changing, I would love that! I have been looking for a place to learn and share metal spinning. I have sent hundreds of emails to countless people looking for knowledge on spinning. I have receive some real gems but mostly, I don't hear back . Those gems have kept me going and furthered my knowledge and ability. Metal Spinning seems to be a dying art. Somewhat like Blacksmithing was 20-30 years ago.

I think I will begin that thread....

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i am glad i looked through old posts and replied, as i would like to know more, definately, i have had an interest in spinning for a while, having done a small amount whilst working for a silversmith. but i would like to learn more about it, and any advice on corrections of errors would be a great deal of help before i get started.
is it a special spinning lathe you are using? or a converted lathe? homemade tools or bought?

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. Metal Spinning seems to be a dying art. Somewhat like Blacksmithing was 20-30 years ago. I think I will begin that thread....


not dead...

http://www.stupidvideos.com/video/science_technology/Metal_Spinning_Magic/#348307
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I have a question (which will expose my ignorance on spinning). When machining on a lathe, it is important to stay on centerline with the cutting tool and maintain rigidity - so if I was starting to spin with no training or background, I would put the tool on a pivot so it stays on center without having to fight it. Wood turning is typically all done off a tool rest and the operator regulates the gouge - but I would think the resistance in spinning could be enough that any vertical bouncing of the tool might cause variations in surface finish. If this theory has any merit, then a cure might be to build a tool post with a vertical bolt attached to the compound or cross-slide to match a corresponding hole in the spinning tool. It would have to fit tightly enough so there is no chatter during use (like a bearing).

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IMHO, That guy has some of the best videos showing a variety of techniques used for spinning. I suggest looking at all his video's. Notice the different cutters he uses for cut quality and were he is cutting, the different tips on the hand tools (wood on the one). Varying rpms for finish and how he moves various parts of the piece. Step mandrels (two different ones) that allow him to move the material in incraments to the final shape. All of that makes a difference. Note that he is spinning a 3000 series aluminum. It is like butter to work.

HWoolridge-
Metal spinning is a craft or art that requires all the things you know about material movement, including removal and combining it in ways you have never tried or even thought of. Take the conventional wisdom, turn it on it head then apply to spinning. At least that is how it has been for me. Thats kinda why I am so addicted to it. Try everything, watch the result. (use your own judgement as to whether it is dangerous or not. I am assuming a good solid skill level here) To answer your question about wood turning techniques used for spinning. I have found for hand spinning it is better to position the tool well below center line (at 7 or 8 o'clock). This allows a greater force to be applied to the movement of the metal. I put the handle of the hand tool in my Arm Pit and use my body weight rather than pure muscle. When trimming I tend to come in at 9 o'clock and then very that slightly depending on how it is cutting. I also rotate the tool (roll it) from left to right again looking for good cut quality. Scissor tools are different.

From what I have seen, there are 3 types of spinning- Hand spinning which is using a long handled tool (mine are about 32" long). Scissor tool spinning which is using two tools to add compound leverage for greater pressure. Mechanical Spinning which would be all the CNC and memory machines used or put simply, were hydraulics run the tool.

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Looks a lot like wood turning with regard to technique. My suggestion would be to put a hole in the tools and swing it over the pin but that doesn't look necessary based on the video. And that old boy sure knows what he's doing...


Surely that would limit the range to a radius from the pivot point, and not be versatile enough to produce the variations needed when spinning shapes without a fixed radius
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Surely that would limit the range to a radius from the pivot point, and not be versatile enough to produce the variations needed when spinning shapes without a fixed radius


You would have adjustment on the cross slide and carriage to adjust the radius - and you could have different length tools; but it would be much slower than the type of work being done in the video.
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