Eccentric turning?

[Anonymous]

Hello all, I've been working on a bowl and I would like some advice. What I'd like to do is have it so that the hollow (?) is slightly offset in the bowl blank. The "hole" would be slightly off centre is probably a clearer statement. The reason being it is a very angular bowl, no curves whatsoever in profile, and I thought offsetting the opening would be a way off introducing some variety into a very geometrical turning.

Now, how can I do this? I thought of mounting the bowl sightly off-centre in a jaw chuck, but that doesn't seem too exact, or more to the point, very safe. I could be wrong though, being rather new at this turning business (this is my 3rd bowl, I burnt the first as it was better the world never saw such an abomination )

 

[trevtheturner]

:shock: Blimey, Regan, you're ambitious! :shock:

I haven't quite got the picture of what you mean by "angular....in profile." Anyway, if you are looking to mount the piece on a chuck, you will first have to mount it off-centre the other way round to turn an off-centre spigot or a recess for the chuck (sorry if I'm stating the obvious). Alternatively, you could use a 'glue chuck', i.e. a piece of wood or thick MDF attached to your chuck and turned to the round. You then attach your workpiece, offset from centre, to this using a glue-gun and hot-melt glue. When you have finished the turning you split apart the glue joint and clean up that surface. To make the separation easier some use a piece of paper in the joint, i.e. glue the paper to the chuck, then the workpiece to the paper.

What size is the piece you want to turn? In any case, you should run your lathe at a very slow speed, because the workpiece will be very much out of balance, and be extremely careful to avoid any aggressive cutting but use only very light cuts.

Not wishing to dampen your enthusiasm in any way at all I do, nevertheless, suggest that a lot more practice developing your skills with your tools on 'normal' bowls will be time very well spent. If you do this your angular piece is much more likely to be a success :wink: . If I have read it right, you have only made two bowls previously - and one of those went on the fire. Only someone of a lot more experience would attempt what you are suggesting, I think.

Cheers,

Trev.
(not trying to put a dampener on things - just trying to be helpful) :wink:

 

[cd]

Regan,
I'd agree with all of what Trev said, My first couple of eccentric turning ended up where your first bowl went , I found it much harder than books and video's suggested. There are a few chucks about that will hold the work but there not cheap if its a one off (try axminster). I would reccomend the glue block method and suggest you practice a couple of times first. Main problem I had was in wanting to move the turning too far off centre what looks like a small amount when stationary looks a lot bigger when its spinning around. :shock:

All that said if you get it right its adds a great effect to some pieces.

cd

 

[Anonymous]

Thanks for the advice!

The bowl is only about 5 inches in diameter, maybe a little more (I could run and check, but then I'd have to move....).It is a little ambitious, but I tend to learn best by leaping in, and I do have another "normal" bowl on the go at the moment. I just thought I'd try something a little different, change of pace, etc.

Besides, its getting cold and I can always use mroe firewood... :lol: