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Ad de Crom
30th July 2009, 06:24 PM
Last year I made a prototype, with a rollerchain transmission.
The running speed of this protype was okay, but the rollerchain transmission spoiled my fun. Turned than a couple of picture frames, these frames came out with quite a bit of irregularity's, so not what I wanted to see, so I put this prototype away.
But I never give up, it stays all the time in the back of my head, with the thoughts to find another solution without a rollerchain or a timingbelt transmission, and I found another solution.
Here is the new design. The oval is based on a excentricity of 17.5mm.
Maybe many of you are thinking why I put so much effort in this, the answer is very simple, that's the way I am. Try always to improve my turnings, by making as much as possible my own stuff, if it's a tool or a device.
Anyway I like it to share it with you all.
Cheers Ad

rsser
30th July 2009, 10:37 PM
A nice challenge you've set yourself there Ad.

Keep us posted on your progress.

hughie
31st July 2009, 01:04 AM
Ad I am following your interest in oval turning as I have often thought about doing the same. Except to make a bit more interesting to make a device that has a variable oval set up say 20mm to 75mm or maybe more

Its interesting, oval turning really has not been explored much, except by a few. I think it has potential. I see a few of them around from time to time for sale, I think Teknatool had one for around $2,500 some time back.


and for the curious. http://www.volmer---ovaldrehen.de/englisch.htm

Ad de Crom
31st July 2009, 02:11 AM
Ad I am following your interest in oval turning as I have often thought about doing the same. Except to make a bit more interesting to make a device that has a variable oval set up say 20mm to 75mm or maybe more

Its interesting, oval turning really has not been explored much, except by a few. I think it has potential. I see a few of them around from time to time for sale, I think Teknatool had one for around $2,500 some time back.


and for the curious. http://www.volmer---ovaldrehen.de/englisch.htm
Hughie, it's from of the first oval turning I saw, that I'm interested in this technic.
But only for small low profiled objects, like lidded oval shaped lidded boxes, and such kind of stuff. The device I'm busy with has a adjustable excenter in the range from zero till 17,5mm. This means an oval with a different in the axes of max.35mm. So for smaller objects just fine, anyway I find.
Had for a half year ago contact with a German, about this issue. He made a device for oval objects made out of metal, promised me to share with me his experience, got only a note from him with the message that he made a big mistake, and after that I heard nothing from him. Actually a pity, because there is not much to find on the internet about this subject. The Vicmarc, Steiner, Volmer and Bollenger are to complicated, so nothing for a do it yourself guy like me. If I'm able to make a couple of small oval objects a year, I'm satisfied.
Teknatool? Have to take a look to see if they have something.
Thanks Hughie.

Daniel.
31st July 2009, 03:28 AM
Very complicated:?

Ed Reiss
31st July 2009, 03:46 AM
Very complicated:?

...for those of us that are mathematically challenged, that would be a definite YES :(


Really neat Ad...I'm impressed.

Ad de Crom
31st July 2009, 03:50 AM
A nice challenge you've set yourself there Ad.

Keep us posted on your progress.
I'll do that Ern
Ad

hughie
31st July 2009, 11:16 AM
Ad,
I have always wondered about doing oval hollow vessels and have played around with a simple device design. But the list of things to have a go at grows and I have noticed I am not immortal.

So aged based selection :U takes over, although your post caused me to haul out some old ideas and sketches.

wheelinround
31st July 2009, 01:23 PM
Ad the Ornamental Turners here have their own design, Tom makes and sell them a simple attachment for the lathe $390.00. I don't have a photo got to take one but have video one day I hope to upload it somewhere.

It does an excellent job.

joe greiner
31st July 2009, 09:43 PM
I guess this is why retired engineers don't take up golf. Who has time to chase a pebble around a cow pasture, when the ideas come so thick and fast?

Something like this is depicted in "Lathes and Turning Techniques - The Best of Fine Woodworking," ISBN 1-56158-021-X, pp. 52 ff., regarding the Old Schwamb Mill in Massachusetts, with diagrams of the innards.

One thing that makes this kind of turning "interesting," is the varying angle of presentment as the workpiece rotates past the toolrest (See the envelope cartoon on Volmer's website). Roughly half the time cutting downhill, and half uphill.

Your perseverance is legendary, Ad.

All the best,
Joe

Happy amateur
2nd August 2009, 05:35 AM
In 2002 David Springett gave a demonstration, of an oval chuck, at our club.
He published the details of how to make one in "Adventures in Woodturning"

The book is out of print but there are some copies available on Amazon.co.uk

He can be contacted at http://www.davidspringett.fws1.com/

Hope this may be of some interest.

Fred

Ad de Crom
2nd August 2009, 06:59 AM
In 2002 David Springett gave a demonstration, of an oval chuck, at our club.
He published the details of how to make one in "Adventures in Woodturning"

The book is out of print but there are some copies available on Amazon.co.uk

He can be contacted at http://www.davidspringett.fws1.com/

Hope this may be of some interest.

Fred
Thanks Fred for pointing me on that.
I have a drawing of David's device, so I know how his device works.
What I not knew is that he did some turnings on his device, probably he did when I read that he gaves a demonstration at your club.
In fact my new design is based more or less on his device, it's in fact very simple, with the less thinkable parts, the less parts, the better.
Thanks again, Ad

powderpost
5th August 2009, 09:42 PM
Interesting Ad. A couple of years ago I played with oval turning. The concept intrigued me. I bought a copy of David's book and began the journey. I built a chuck based on David's design using cooktown hardwood. The first one wore badly after only two jobs and didn't have a ny means of adjusting as a result of wear. The second model I built in adjustment on the slides as well as soaking them in lanolin oil. The second chuck stood up much better. The third model was made incorporating a ball bearing, that one is still in use now. I have a fourth prototype, but lately I have been spending a lot of time laminating. I will have to get back to oval turning.
Jim

Ad de Crom
6th August 2009, 01:26 AM
Interesting Ad. A couple of years ago I played with oval turning. The concept intrigued me. I bought a copy of David's book and began the journey. I built a chuck based on David's design using cooktown hardwood. The first one wore badly after only two jobs and didn't have a ny means of adjusting as a result of wear. The second model I built in adjustment on the slides as well as soaking them in lanolin oil. The second chuck stood up much better. The third model was made incorporating a ball bearing, that one is still in use now. I have a fourth prototype, but lately I have been spending a lot of time laminating. I will have to get back to oval turning.
Jim
Very nice oval objects Jim. Is it a low profile lidded box, probably it is.
This is just my second try, after the first prototype based on a rockin headstock principle. Well this concept intrigued me too, still I have to build up my own experience :)
Ad

powderpost
6th August 2009, 10:27 PM
Yes Ad it is a low profile box. I found that it is important to have cutting height of the tool, or the point of contact if you like, consistent throughout the job. Otherwise you will get a "twisting" of the pattern. If you look closely at the inside of the lid (on the right of the photo) you will see what I mean.
Jim

Ad de Crom
7th August 2009, 01:17 AM
Yes Ad it is a low profile box. I found that it is important to have cutting height of the tool, or the point of contact if you like, consistent throughout the job. Otherwise you will get a "twisting" of the pattern. If you look closely at the inside of the lid (on the right of the photo) you will see what I mean.
Jim
Yes Jim, you're right, I saw it.
Ad

Ad de Crom
21st August 2009, 02:15 AM
A lot of WIP pictures showing the different parts.
The cam and the beares are made of Merbau, the most wear-resistant wood I have.
The slider and runners moves smoothly. A drip of motoroil for lubrication.
Made black nylon bushes for the polished rods.
Cheers, Ad

Ad de Crom
21st August 2009, 02:22 AM
Put this afternoon everything together, have still to do fine tuning.
Mounted a wooden sheet on the device for seeing the result and draw with a pencil an oval on this sheet with the dimensions 180x145mm. Running speed about 300 rpm.
Looks good sofar.
Cheers Ad

Ed Reiss
21st August 2009, 12:24 PM
ambitious project, my friend...looks like it's coming along swimmingly :2tsup:

bobsreturn2003
21st August 2009, 02:41 PM
several years ago bought one from a guy in nsw . had a tie up with the leady lathe. well made metal machine with bearings , a delight to use ,when i have the time . could be adjusted for centre height . but slow speed only . and had to keep tool top on centre . . cheers Bob

Ad de Crom
28th August 2009, 04:09 AM
Put on youtube this week a video of the running device after assembling.
Runs with a speed of 328 rpm.
See video YouTube - 100 1284
Did today the first turning with turning a prepaired piece of yellow pine diam 200 x 30mm.
Here some pictures of this first turning, the size of the oval is 190x155mm.
Lateron a picture of the finished low profile oval bowl.
Cheers, Ad

Ed Reiss
28th August 2009, 12:13 PM
vurrrry interesting :2tsup:

wheelinround
29th August 2009, 12:26 PM
Ad I have video of OTGA's oval turning device but would need permission to load it to YT first.

Ad de Crom
29th August 2009, 06:35 PM
Ad I have video of OTGA's oval turning device but would need permission to load it to YT first.
Ray, would be nice to see it on youtube, at least if you get permission....)))
Ad