setting up for metal spinning

[werowance]

not sure if this should be in the "machine modifications" section but here goes.

i am making a tool post for metal spinning on my lathe. the type that has the drop in pins accross a flat piece of steel so you can use your "tool" which is a round shaft with a sort of ball nosed end on it. like a steady would be on a wood lathe for the tools.

my first question is - should the top of this steady rest be centerline with chuck / tailstock? or just a tad lower to compensate for the thickness of the "tool" i will be using?

and if anyone has any recomendations / things i need to be thinking of let me know. ive watched tons of videos and totorials and have seen many failures as well as much success. seems one of the key things is when applying preasure to the stock, you spin it away from the base but just as important you spin it back toward the base and work the metal in both directions.

anyway thanks in advance for any suggestions / help.

 

[stevehuckss396]

I have never tried it but hope to some day. My friend has a setup and makes parts to restore old motorcycles. He uses wood forms to shape the parts. Best of luck finding the information you need. Sorry I wasn't able to help.

 

[goldstar31]

Perhaps Googling a video on how brass musical instruents are made.

It gets addictive and a complete change frpm turning instruments using exotic hardwoods

 

[Brian Hutchings]

I have only tried this once, in steel, to make the gear cover for a 3" Marshall road roller. The cover looks like a British soldiers WW2 helmet.
I used a piece of scrap aluminum as a former to produce the dome. I left it on the lathe because I wasn't sure how to proceed but had a stroke of luck when I had to oversee the spinning of some aircract air intakes at a factory in Leeds. I took the oportunity to question the operator as to how I might produce the 'rim' and he told me to cut a slit in a piece of wood, locate the unfinished brim in the slot and just move the rim where i wanted it.
I was quite skeptical but it worked just as he said it would.
On a return visit I had a word the operator to report on progress and he said that many jobs didn't require a former if you could pull the metal into shape with a couple of pieces of polished and greased pieces of wood or metal.
The ideal position of the tool is with the centre of the tool to be on the centreline of the lathe.
Brian

 

[werowance]

The ideal position of the tool is with the centre of the tool to be on the centreline of the lathe.
Brian

ok, that is sort of what i was thinking so ill make the tool post a tad shorter to compensate for the dia of the rod i use as the spinning tool.

last night i cut up a piece of plate steel using band saw and in the end i had to plasma cut a corner off to be able to make the full band saw cut. plate was to large to fit the saw. i then took some box tubing and cut some pieces off and stuck each one in the lathe chuck to square off one end to be welded to that plate. i will then mount the plate to my cross slide and since my lathe is a combo mill/lathe i will mill the 2 vertical box tubes to final length then remove that and weld on horizontal piece of box tube. once that top horizontle box tube is in place i will then drill holes in the top to drop in fulcrum pins in.

when im done i hope it will look something like this crude "paint" drawing i did

 

[bikr7549]

There was a 3 part series on metal spinning in The Home Shop Machinist magazine in 2002. I have the September/October issue and while the author has drawings for the tool post parts, the height aspect is not addressed in this issue. It might be talked about in the other 2 articles however. Back copies may be available from Village Press-they don't list them for this far back but I did request an old one a number of years back, they were able to photo copy what I needed.

 

[werowance]

thats good to know, i have several issue of the home shop machinist magazine at home. dont know if mine go back that far but ill take a look and see. i may already have a copy.

 

[Brian Hutchings]

For the job I did, I pushed 2 pins of 1/2" dia steel into holes driled in a piece of 1/2" X 1 1/2" bar held in the toolpost in place of a lathe tool. This worked fine for the thinish material I waas spinning.
Brian

 

[Robsmith]

Ha Ha I tried to spin a bit of aluminium. Had it all set up and spinning. Started to push the tool onto it and my Lathes' bearings screamed for mercy . I then realised they were straight bearings not cone race ! That project is waiting for a major bearing overhaul.

 

[clockworkcheval]

About 50 years ago we often did some spinning in my first machineshop. I remember that it really required quite some force. So it was done on heavy lathes, the instrumentmakers type of lathe just is not strong and stiff enough. And the operator attached himself with a heavy leather belt to the machine to withstand the push-back forces. Spectacular operation.

 

[werowance]

Clockworkcheval, what gauge metal were they spinning? im just going to learn on 24 gauge aluminum that i can easily bend by hand. then if i learn to do that then it will be roughly the same guage but in brass for the customer.

 

[clockworkcheval]

Long time ago, but it seems to me anywhere between 0,5 and 1,0 mm (24 to 18 gauge) aluminiumsheet made into 30 to 60 mm parabolic discs. Mind you that the deformation by full material displacement in spinning is not really comparable with bending.

 

[mcjustis]

Werowance,
Terry Tynan did a series of videos on spinning several years ago. I used to buy my material from him until he moved back to the UK. He has a website:

Metal Spinning Workshop – Successfully helping the hobbyist and commercial clients with their metal spinning

I make spinners for 1/4 and 1/3 scale model airplanes. Years ago I was building a plane that needed a spinner that nobody sold. I thought I'd have a go at it. I have made quite a lot of money spinning spinners for other guys planes. The ones I do are around 6" small, and 8" large diameters. They are aluminum (1100 series) and I've been using .05" thick with good success. The videos go into everything from lathe selection, tool making, lubricating, material choice, to finished products. It's like anything else, you will need to practice to become good at it. And it takes awhile. You will trash some material. Just don't get frustrated. I don't know what kind of machine you are using, but I have a spinning lathe I do my work on. I used to do it on a Leblond Makino engine lathe. I wouldn't recommend that, as the chuck jaws kind of get in the way. With a spinning specific lathe or a converted wood lathe, you don't have chucks to worry about. As far as your original question, the height of the rest isn't really that important as you will be moving the tool in and out, up and down to get what you are looking for. Kind of like a wood lathe, the rest height isn't very critical.

I would recommend using 1100 series pure aluminum. Don't mess with any alloys (6061, 2024, etc. ) as they will harden very quickly and you'll have a bad time of it. The 1100 aluminum is quite soft so works easily. You're correct on spinning both ways. If you just go from the center out the material will stretch a lot on the outside and you will have a much thinner material thickness at the edges. That also makes it crack and break (not fun). Be sure your lathe and tailstock are up to the task. You don't want the material flying out because your tailstock is weak. If you have a small machine it's just not going to be robust enough to get the job done.

So have fun and be careful!. It is quite dangerous if you don't feel like paying attention.

Martin

 

[Peter Twissell]

I have successfully spun some relatively small (3" diameter) brass parts for a motorcycle, using my Drummond Roundbed lathe. I had to re-anneal the brass several times to produce a 'cup' approx. 1/2" deep.
For the tool, I fitted an old ballrace to the end of a 2 foot length of steel bar, so that the tool was rolling rather than sliding on the material. This, combined with the regular annealing, kept the loads down to a level I was happy with on the old lathe.
Pete.

 

[dazz]

Hi
I made a spinning tool for my small Denford lathe you can see here: Metal Spinning Tool
You do not need such a complex tool. Spinning can be done with a waxed stick.

It is really important to get the right grade of metal, especially aluminium.
Mild steel, brass and copper is formable, but the average aluminium sheet is not. You need untempered, unalloyed 00 (zero-zero) grade that is soft and formable.

You can see the output here: Spun motor end cover.

Metal spinning is not something you can learn from YouTube or a book. Ask me how I know.
Common beginners mistakes:

• moving the metal in one direction only. The metal will get thinner and thinner until it breaks through.
• Allowing the lip near the out edge of the metal to roll towards the tailstock. Difficult to recover from.
• Over working the metal so it cracks with fatigue.

A lot of practice is required. If possible, video your attempts so you can do post-disaster analysis looking for lessons learned.

 

[cds4byu]

The shop wisdom of Philip Duclos has an article on spinning brass to make an oil can.

I did spinning when I was in high school. As I recall, I wasn't very successful.

Carl

 

[werowance]

well, after a week at the beach then a week catching back up from being off i managed to do my first attempt at metal spinning. 1 caveat is i only had 6061 sheet aluminum to try with. i have ordered 1100 aluminum and should be here in a few days.

i sooted my sheet with the acetaline torch then burned that back off as this is how i was taught to anneal alumuminum sheet. it was a bout a 6 inch dia circle.
started out really good. doesnt take much force and it starts rolling really good. i got to the point to where it was shaped to look about like one of those styrofoam bowls you get in the paper plate section at the grocery store.

but at this point is where it started going down hill (and from the videos and tutorials i have seen - this is where it goes bad for alot of others as well). one thing i was thinking is i never stopped to re-aneal the sheet. the outer lip kept wanting to roll back in on itself so i had to keep working that alot. eventually i started getting a few small wrinkles then it started to crack.

as this was my first and only attempt i was pretty happy to see what it feels like and watch how the metal behaved with different directions and preasure applied so all is not lost with the test.

for the form i used a piece of oak firewood and turned it down on the lathe, the photo of the disk is before i sooted and anealed it.

 

[mcjustis]

I wouldn't waste your time on the 6061. Just wait until the 1100 comes in. When you get out to the edge, you will need to use a back stick. At least that's how I do it. It takes some practice, but you are basically spinning the material with the tool and using the back stick as the "buck" or form. This will keep it from creasing on you, also it will move the metal down (toward the headstock) much easier. If you don't have something for the material to work against it will just roll up and crack or crease. I use a piece of hardwood cut in to maybe 3/4" x 2" x 6" or so that is coated in the lube I use for spinning. You can buy some good lube for spinning, but mostly they are beeswax. I use beeswax and it works well for me. It's easy to clean off when you're done. I tried some other stuff when I first started that was more of a goopy paste. I didn't like that as it just slung off all over me when I started spinning. The more you do spinning, the better you'll know on how much to lube and where/when to lube the metal. Too much just makes a mess and too little you will start to remove metal from your material.

If it does crease on you, take the material out and start another because you won't be able to save it. It will just frustrate you. Just another point, looking at your picture, you might want to do a little better job of marking the center of your blank. That looks way out of center. If you get it too far off and out of balance the part may fly out when you turn it on. I use the center finder of my combination square to make a couple of cross hairs that show the center. This is really easy if you buy blanks that are already cut into a circle.

Like I said earlier, there are videos that are available and are chock full of information that will help you. I'm sure you're finding that there isn't a wealth of knowledge that you can tap into on this subject as it's kind of becoming a lost art. The videos by Terry Tynan gave me the knowledge I needed to get started making things I wanted. I must add in here that while the knowledge from the videos makes a great starting point, there was still a considerable amount to learn just by doing. There is no substitute for experience.

I have sold quite a few parts that I have spun. It's a fun and different aspect of metalworking that very few people really know much about.

Here is a picture of the spinner I made that's on a friends 1/3 scale Siemens Schukert WWI airplane. I didn't make the cowling, it was done by a professional, not a meager amateur like me.

Here's a good shot of using a back stick. Keep in mind, he's a professional so your results may vary. They sure make it look easy. Also, I've never found it necessary to strap myself to my lathe.




Good luck and be careful,
Martin

 

[werowance]

Thanks MCJustis, last night i did try the last piece of scrap 6061 so no more trying till i get the 1100 since im out of material anyway. that spinner looks GREAT!

and thanks for the video as welll.

 

[werowance]

well im right happy about now. this 1100 spins wonderfuly. i used bees wax and i did aneal it but i dont know if i needed to or not (someone let me know please).

now a few things

1. the oak form over the few days has started splitting. its been dry for about a year now so would think it would be done splitting. how do form/mold makers keep their forms from splitting? should i use a different wood? in one of the photos you will see line in the ali thats where one of the splits was

2. it wasnt a big test, but it was a right angle and i think more stress buildup because of it. the piece i need to make in brass will be about 50 to 60 degrees i think. have to wait until he gets the glass r ceramic cups that sit in the brass cups because the origial ones are missing so he wants me to make to fit whatever replacement he comes up with

3. this was around .030 thick and after spinning it is super thin. lesson learned is must have thicker material as it gets thin quck

4. i forgot to make the rolled over lip but will try another test with a different form as soon as i figure out what wood to use so it dont split. but hey i was just going for a cup or ash tray anyway just for learning.

5. im not about to order brass just yet but what alloy would you recomend? saw something about yellow and red brass being good? but that just doesnt tell me the alloy. and then i read along time ago about a horror storry of red brass being radio active from way back in the day. is that really still an issue these days?

other than that i am right pleased with my new ash tray lol.