Any ideas please for shaping a piece of oak to an elliptical cross-section (it's a replacement handle for my garden roller)? The wood will be about 18" long and I want the cross-section to be about 2" major axis x 1½" minor axis.
If I had access to a Holtzapffel or similar lathe the job would be trivial.... :-(
Drawknife.
If you have access to any lathe you can approximate an ellipse by offsetting the work in the chuck and turning the minor axes. You can offset by using a
4 jaw chuck or shims in a 3 jaw chuck. Finish with some emery paper and Bob's your aunty's husband. The calculations are rather horrendous though. I did it once to work out how to machine elliptical engine pistons on a normal lathe but I wouldn't want to try and repeat the calculations or remember how I did them. I did end up with satisfactory pistons and a running engine though.
Considering the application I reckon that a belt sander would be more appropriate than a Holtzapffel, assuming IK Brunels block making machinery isn't available !
AWEM
Well, I do have a Myford metalwork lathe, but the calculations and setting up, as you say, would take excessive time. In actual fact the lathe bed (a Speed 10) is barely long enough for this, so that's my excuse!
I might just go for Dom's drawknife idea - actually I think I have a spokeshave somewhere, although I haven't seen it for ca. 20 years!
Thanks both...
A Drawknife! that will take some practice? what circumference is a wooden curtain pole? or brush pole?
...Or a piece of bannister rail
Two questions spring to mind
MBQ
You don't, you have a round dowl already formed making it more easy to mold the oval shape required.
ps did I say he should use the dowl as a shaper? :-P
personally I'd just keep to a round handle,saves the hassle.
spoke shave and sandpaper.
honestly, it doesn't take THAT long.
Honestly, they're easier than you think. Ok it's not press-button automation, but I practised once on scrap before using it to rough out an oar and subsequently some of the work on a mast.
I prefer the London pattern (handles at right angles to the blade). Use it with the bevel face down to the work, starting on the corners and drawing the knife towards you with the handles pointing down at about 30 degrees. If it starts to bite too deep, lift the handles so the blade rolls on the bevel and rises out of the cut. Go for lots of thin-ish cuts, so that you can sustain a rapid back and forth motion. Aim to rough out the longest area you can comfortably draw, frequently moving round the others to reduce them all evenly.
Will an oak stair spindle suffice as the handle? :-)
Possibly - I'll see what's available. Elliptical or otherwise :-)
Spokeshave is more a tool for interior curves. An ordinary plane can be used to cut curved sections, by planing longitudinally around the desired section. I suggested a drawknife for roughing out the shape (as it's much quicker), a plane would then be good for levelling up the surface along the section, followed by using a sandpaper belt wrapped around the section (by hand in a pull left/pull right motion). However it could be done albeit slowly by plane and paper alone.
Personally I found the spokeshave a more difficult tool to master than the plane or drawknife.
Pickaxe handles are usually elliptical of about that section. Unlikely to be oak, but should be a decent quality wood to take the bashing. They're usually contoured to non-uniform cross-section down part of their length, but you might find one with 18"-worth of starting point.
Chris
No more than I said that you said it. I asked you how you couold, since that was your implicit suggestion.
MBQ
Yep. That's how I made a replacement handle for a garden roller many years ago, although I don't recall much sandpapering being needed after using the spokeshave.
Colin Bignell
Perfect :-)
Hickory or ash usually. Both arguably better than oak for the job in hand.
Locate the Holtzapffel and ask its user to shape it. Where is it now?
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