First oval turning

Started yesterday with the first try out to create oval shapes.
After searching for the right gripping point of the tool, I found the shape in the middle of picture 1000049 acceptable, the device was running with a speed of 733rpm.
Today the first real try out to make a oval shape 180mm x 155mm, running this time with a speed of 430rpm. See picture 1000057.
You can see the completed oval turning device running with a speed of 733rpm, on youtube, http://nl.youtube.com/adecrom


Cheers, and thanks for looking
Ad

Hi Ad, looks very interesting. I was not able to open the link though.

Mohammad Madha said:

Hi Ad, looks very interesting. I was not able to open the link though.

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Now you can Mohammad, I did something wrong.
Ad

Ad I have to say that looks very interesting. Link worked for me.

Thanks Ad, It worked for me now.

I don't know what is more impressive. The fact that you can turn an oval object, or the fact that you designed and built the device to do it.
Very cool, Ad.

This certainly is a long process, but it is also very interesting Ad, thanks for keeping us updated!

First try to turn something real

Spend the whole last week with doing refining work.
This was needed to reduce margins, in different connection points, and rollerchains.
Made a more sturdy connection between the swivelarm and the rockin headstock, complete with new linear bearings and 10mm steel rods.
Reduced by doing this the margins with 90%.
Having to much margins in the mechanical parts, have a negative effect on the oval you try to turn, I noticed this already with the first test run.
Anyway after all this refining work time for trying to do some real turning.
I had in my mind to turn a low profile bowl 30mm in hight, hollowed on the inside. For that I had a rectangular piece of oak glued on a round piece of wood, and fasten on the faceplate with 4 screws.
As it is a new learning process, and there is not much information about this issue available, I decided to use a parting tool and a cutter/scraper tool.
Turning the outside is not so difficult, but the hollowing job on the inside is not so easy, for sure not in the center area. It's something like a ride on the back of a jumping horse. Running with a speed of 600rpm a bit scary.
So I created little hills in the center area, which I could flatten with the scraper tool. I found out very soon that it was better to drill or turn first a hole in the center area, before I started with the hollowing job. I was able to reach a depth of about 15mm, not enough, but I saw a couple of other points in the mechanism who needs my attention, so I'm going to work to solve this, before I continue with my turnings.
For now some pictures of the refining work and the turning results till now.
At last you can talk about turning an ellipse or an oval. An ellipse is a mathematical shape, an oval a more free style shape, the last is what I'm trying to turn.

Cheers. Ad (still in one piece)

Glad to see you survived the test drive in one piece. I'm still amazed each time I see your machine. I could not imagine designing something like that. Very cool.

Turning results after a lot of refining work

Did the last couple of weeks a lot of refining work on the oval turning device.
All my hard work paid off, in a nice oval shape I turned this afternoon.
Figured out that it's not possible to use a bowl gouge in the first place, only possible to use a gouge when I reach almost the oval shape.
Using scrapers and a parting tool is the best you can do.
Also I think to develop profiled scrapers, for finishing surfaces.
This is something I saw with visiting the site of the Old Schwamb Mill, furter is not much information available about this issue, so I have to figure it out by myself, as it is a complete new kind of turning, anyway for me.
Next I'm going to try to turn something usable.
For now a few pictures to show the last turning results.
Thanks for looking, comments are very wellcome.
Cheers. Ad

Ad - very impressive engineering! I think you are on to something! Looking forward to reading the next chapter!

Steve Schlumpf said:

Ad - very impressive engineering! I think you are on to something! Looking forward to reading the next chapter!

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Thanks Steve, I was an engineer from my profession, and still I love my old profession. This project was and still is a big challenge for me.
Building something new is one, but getting it properly running is something else. So I have to spend lots of time, on refining work, making improvements and so on. This oval was the first step, so I'm not down the road yet. Still a long way to go.
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