Hi
I was asked at work to duplicate a 35″ baluster that a customer brought in. The S4S post is 2.350″ and at its thinest part it is about 1.125″. The detail on the baluster does not begin untill 10″ from either end. We turn everything at the shop on a Nova 2446 (i think) and the part to duplicate goes into a Vega Duplicator. My problem is that the part begins to violently vibrate in the machine as i start to get down near an inch. I have turned three posts, poplar, hard maple, and mahogany, and they all did the same thing. I tried taking off about 1/32’s at a time, i tried speeding up and slowing the machine down. Nothing is working. The part is being ruined during the vibration and i feel bad because i told my boss i thought i could do this in 2.5 hours. I watched a video of a man turning by hand and he gently rested his hand against the piece while he turned. I don’t fell comfortable doing that with the duplicator. Is there something I can do to turn this piece successfully?
Replies
Look up, woodturning steady rest. There are different styles and types but they keep your work piece from whipping. Turn the speed of the lathe down, too.
thanks
Thanks to both of you. I'll give the steady rest a try.
Matt
matt,
I don't know the Vega duplicator, but as noted, a steady rest is traditionally the solution to turning whippy spindles. The rest (variously a pair of ball-bearings backing up the spindle, a trio of bearings capturing the spindle, or a pair of waxed wooden blocks with concave ends that capture the turning) is fitted up to a (ideally large diameter) section near the center of the spindle that has been turned to a smooth cylinder first off, then the remainder of the turning is done. The question is whether this will interfere with the use of the duplicator.
If it does get in the way of the duplicator, then you must consider turning the spindle by hand (horrors!) using the backrest, or possibly making a backrest that incorporates a disc with a square hole in its center that is a friction fit over the square. Position one of these as near the beginning of the turned section as possible, on each end. This will provide support on each side of the 15" long turned section.
Finally, reduce the pressure of the tailstock as much as possible. Too much endwise pressure will add to whip as the diameter is reduced, making it easier for the spindle to bow.
Ray
I know for nothing about duplicators but I do know that 35" is not too long to turn on a lathe. As has been suggested, reduce the tailstock pressure. And proceed very slowly. Possibly you have been trying to cut too much at once.... the stock goes loopy then causes the cut to worsen. Its all downhill from there. Using your hand to steady the turning stock is rather standard practice. Take your rings off first and do not wear a glove.
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