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Wednesday, September 9, 2009

Multicenter Lathe Statue: A Experimental Test Project

Some time ago I decided to try Multicenter Wood Turning or as some write Multi-Center Turning. I'm not good with hyphens... I think If I ever get around to blogging about English Grammar it would definitely be filed in complaints. Anyway I wanted to try multicenter turning because it looked like a fun thing to do and figuring out how to turn something on a lathe using multiple set ups so the axis of rotation changes with each set up seemed fun. Especially considering that the work is off balance the entire time. Another thing I like to do is not spend money so rather than buying a nice big piece of wood that didn't have any knots I cut op various pieces of scrap and glued them together to make a bigger piece. I use this lamination technique often because it tends to create interesting patterns in the wood. So I glued it all up into a relatively flat piece then cut that piece at odd angles, drilled holes into the lamination and inserted wood dowel pins with more glue.
  
  
Cut and Glued Wood on Mandrel


  
After letting it dry overnight I mounted it onto my home made lathe mandrel. I thought that the piece was a little short so I glued a couple more pieces of scrap wood on the end (right side in picture). The wood is a mix of redwood from a deck my neighbor cut up and shipping pallets from work. I had no particular shape in mind when cutting the wood and gluing it up because I wasn't even sure that this was going to work. Sometimes when you try to make something look a particular way it becomes obvious that you have produced a crappy piece of work when it doesn't look right. If you start out with the intention of creating 'beautiful free form art' you can end up with pure crap when you are done but it's 'art' so no matter how crappy it is that's OK - takes the pressure off!
  
Beginning to turn the project
  
I got the piece mounted in my Homemade Lathe (click the link to see my DIY Lathe) and started turning it slow at first then increased the speed until the lathe was jumping all over the garage due to the lopsided part. Backing off on the speed I roughed out the part and then did some finishing sanding on the portion that I had just turned. Usually with a more traditional balanced part I would save all the sanding and finishing until the end but in this case that wasn't as easy because of the multiple set ups. Since each center has a different axis I would have has to rough it out, change set ups, rough the next portion, change set ups etc... then go back to the first set up and sanded, changed set ups, sand, change etc...
  
Changed centers
  
So I got to the second set up (picture above) and the part was behaving OK... even being lopsided and shaking the lathe to pieces. Getting a smooth cut with all the vibration required me to sharpen all my gouges and chisels (they needed it anyway) and putting some weight against the lathe to help dampen the vibration. At this point I decided that I had gone as far as I wanted to go toward the tailstock end of the piece and it was time to go for another set up on a different axis of rotation. This next set up turned out to be tricky with the piece mounted to the mandrel so I flipped it around. Taking the end that was on the tailstock side and mounting it to the mandrel headstock with some screws.
  
Work flipped around

  
This worked out well but because the first portion that I turned was on a different center I couldn't easily get the tailstock support  on the end that was previously the headstock. So I had to finish out this portion of turning with the piece cantilevered  - and of course lopsided. This increased the vibration and made is even more fun because I was in constant fear that the lopsided cantilevered piece of wood spinning around in front of me was going to break off at high velocity.
  
Sanding
 
After some time and some close calls I got it roughed down and sanded relatively smooth. Because the cutting was being done near the headstock it wasn't all that bad. 
  
  
I cut the piece off the mandrel and sanded the saw cut. I'm note really sure what it looks like now that it is done but because it's "beautiful free form art" that is OK.
Finished Lathe Statue - front?
  
Everyone that sees it asks me what it is and I just say it's a statue. If they ask the obvious next question "a statue of what?" then I tell them its "just an experimental piece to see how hard multicenter turning is and what the challenges to that form of turning might be"
  
Finished Lathe Statue - back?
  
At least now I can tell them to go read this Blog post and maybe despite my lack of grammar knowledge and boring writing style they will get the idea!

4 comments:

  1. hi sir
    first thanks for this explained
    we want to do this projects for high diploma in Oman . it is very nice lathe Mahican .

    ReplyDelete
  2. Anonymous,

    Thanks for checking out my blog! I'm glad that you found it useful. If you have any questions please leave a comment and I'll be happy to answer you!
    - Otto

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  3. Are the plans for the lathe available?

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    Replies
    1. Hello,

      Thanks for checking out my blog. The only 'plans' that I have are posted on my blog up in the right sidebar at the top. Look under Lathe Stuff and Woodworking.

      Thanks,

      Otto

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