Help required with decorative turning

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Bogstandard

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I am looking to expand my repertoire and need a bit of assistance.
I want to do some 'barley twist' turning, either concave or convex, can anyone point me in the general direction or has anyone seen it done, just to give me a starter.
I know that normally it is done by heating and twisting, but surely it must be able to be done on a lathe, like multi start screwcutting.

John
 
I never cease to be amazed by what one can find with Google. This

http://homepages.ihug.co.nz/~rhaslip/Rex/workshop/projects/barleytwist/barley.htm

was the second entry returned on a search with the phrase 'barley twist'.

He's talking about making one of wood, (You didn't say what material you intended to use.) so I'm not sure if it will be of help.

Could it be done, at least to roughing stage, with a form tool and the spindle hand-cranked with the lathe set to cut a truly humungous pitch?

When you get that all sorted out, try cutting a wood screw - the type that has coninuous threads all the way down the conical shaft to a hard point. Might also be fun to try to turn a corkscrew.
 
John, some time ago I read a article on a "Rose Engine Lathe" that was used to make some real fancy work. Are you familiar with it? I think you might could use something like it or at least it’s principal to make the type of turnings you want. There is some information on Google for it.
Mel
 
Marv,
I saw this one on google, unfortunately I want to work with brass and do it mechanically, also I want the solid barley twist rather than the open. I have a lot of trouble nowadays holding my graver to do hand turned metalwork, although I still do simple things like funnel caps and spinners.
I think I may have cracked it though, I went thru the old 1930's manual for my lathe, and have decided that a 4 multistart thread with a pitch of 4 teeth per inch will do it, and I can use either a round nose tool for concave or a half round form tool will give me the convex, I will be trying it out sometime this week when I feel up to changing the gears on my lathe.

Mel,
I am familiar with a rose lathe, I have in fact seen one running, absolutely fascinating, unfortunately they are not made any more and to buy a second hand one would require a second mortgage, unless of course you have one in your garage, then it is worth scrap value only and I will give you $50 for it, and I won't charge you for taking it away.
They were mainly used by jewelery and watch manufacturers to engine turn or engrave very intricate patterns onto metal, using cams and gears to give different patterns. The most famous of which were the Faberge studios in Russia, he used to use coloured glass enamel over the top of his engravings.

Thanks for the info lads.

John
 
Mel

If you do a search on the PM forum on Rose lathes, they talked about a guy in Washington State, making a Rose lathe kit for sale.

I think (rivett608) posted the info. There was also a clip of it running.



Hal
 
This is the sort of thing a rose engine produces.

roseturning.jpg


A little over the top on bling for flywheels I think.
This sort of thing for jewellers is now done by 4 axis CNC, so unless you are a sadist and want to do it the hard way, the rose engine is out of business.

John
 
My mate came round today and I persuaded him (only gently, a one pound rather than two pound hammer) to do the change gears on my lathe for me.
I ended up with a 5 tpi pitch, then 2.5 tpi, something I could work with. So these are the results, from left to right.

barleytwist.jpg


The three top pieces are 1/4" diameter and about 5" long, the one across them is 8mm.
5tpi two start screw thread, small round nosed tool. Looks too tight, hardly notice any twist.
5tpi single screw, 5mm round nose, not quite the right angle.
2.5tpi two start screw, 5mm round nose. The best one so far and I think at this small scale looks ok.
The one across the bottom is nearly Marv's corkscrew, but the metal gave up and snapped off.
What I am trying to simulate are the uprights used on early machinery and traction engines, and was usually formed by heating square bar and twisting it, so really it needs to be a four start thread at about 1 tpi, but at this small size it looks just like threaded rod. This is where artistic license comes into its own.

John
 
This must be the type of turning your looking to do.
DSC_8026.jpg

I saw some posts like those in the photo a few weeks ago at a craft fair. The guy that made them said that he had heated and then twisted some angle iron to make them. But you want to turn them on a lathe, right?
Seems to me that Sears (Craftsman) some year’s back had a wood turning machine that produced spiraled spindles. They used a router that was moved down the bed of a lathe with some cable setup. the lathe turned the work piece while the router cut the spirals.
Looks like you might already have it.
Mel
 
Hi Mel,
Thanks for posting the pic, it shows exactly what I wanted to produce and it looks like I have got it almost spot on with the one on the right. Good enough for what I want to do with them
I was talking to a friend tonight on the phone about this decoration on showmans engines, and he was told that they were in fact hollow, beaten to shape from flat plate by skilled metal beaters, puts my information into the garbage bin. I suppose made like how the old gun barrels were made.

Many thanks

John
 
Kevin,
It is nice to get the info straight from the horses mouth, is the one on the right a fair enough simulation, or was it a single screw like the one in the middle.

Don,
No problems encountered on turning these, all done within an hour or so. Also because I have a fairly old lathe I can get a very slow spindle speed.

I had this discussion with Rick a little while back. Learning how to screwcut on a lathe, things like this are just another turning project, and it is very easy to do once you get the basics under your belt. On this one the only probs encountered were finding the correct marks for 'dropping' into. It is about 25 years since I have cut multistart threads in anger.

Thank for all the info

John
 
HI John
The middle one looks the closest of all of them just short three starts.
Most engines Burrell scenics and Fowlers always had handed Olivers so the helix pointed into the middle of teh tractor. Looks more in keeping but its a real sod to polish!

I have to say thats a nice bit of turning, You could try twisting from square section just anneal to cherry red and hold for a few seconds.
Im making some olivers for a full size engine late next month so il post the pictures. Again these will be twisted I use a 6 foot bar with a square hole in the middle its a two man job. Trick is keeping the twist even and the shoulders smooth. The ball trims on the ends of the Olivers were always separate parts and in general cast.

All said and done I do this for a living and the middle one impressed me a lot!

Cheers Kevin
 
Many thanks Kevin, good info all round.
I think I will give the hot twist a miss, I think I would end up with more scrap than good.
I am only trying to get a fairly good representation, and as I said, to do it in any smaller scale it just looks like screw threads, so an exagerated 'twist' has to be done for it to be seen in the context of simulation.
I really look forward to seeing it done by 'professionals' in a dying trade.
I think we are lucky in the UK because we were an engineering nation and still have a lot of examples of our past, and dedicated people like yourself are just managing to keep it all going. The only other place that comes to mind is India, but theirs is through necessity, trying to keep an obsolete rail system going, they work wonders with their steam locos, but that is now starting to fade as they are now becoming a major producing nation and gradually updating their old colonial rail system.
Keep up the good work

John
 
Hi John
I tend to agree with you it is only a matter of time before most of this has gone for good.
My friend owns five full size engines and we struggle to keep them running. Between the cost and the work involved it has to be a labor of love and nothing else.
In the last three years i have seen a few engine men give up partly due to huge costs and also partly down to trying to find place to get jobs done.
later this year im starting a full restoration on a portable engine. The boiler is reasonable as is the firebox but i still see myself replacing maybe 50% of teh boiler plates and firebox just to make it viable to steam. its daunting for me and i do it for a living so how the owners that dont do it for work feel I dont know Theres no way round it these engines and the people that keep them running are getting older and less able to take the strain.
With no real engineering left in the UK its only a matter of time before we run out of decent engineers. The guys coming from UNI are great at ideas but little or no use at making the parts required. I took a degree in mechanical engineering many years ago and in truth little or none of it helps in everyday work. The job has to be learnt hands on and not from a book or computer.
This i think is why this forum is so good it keeps alive some of the old skills and that im all for.

Cheers kevin
 
almost looks like a rifle barrel turned inside out.
 
You guys might want to check out

www.smokstak.com

forums if you haven't already. There's a LOT of old iron guys over there who might be able to give some input. :)

Mike
 
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