Use of a weighted cord for bullwheel indexing.

[GreensandsParticipant @greensands]

Can anyone suggest a neat way of anchoring a length of cord around a standard lathe chuck as recommended as a means of eliminating backlash  In a bull wheel indexing.set up. Any hints and tips most welcome.

[Martin ConnellyParticipant @martinconnelly55370]

Large jubilee clip.

Martin C

[duncan webster 1Participant @duncanwebster1]

Peg in the chuck key hole with a notch in the outer end. Tie the cord to the peg, then wrap it round the chuck a couple of times over the notch do the cord holds the peg in

[DiogenesParticipant @diogenes]

A Timber Hitch & three more turns

[John PurdyParticipant @johnpurdy78347]

I use the end of one of the jaws if the work is large enough that it protrudes out beyond the chuck body, otherwise, like Duncan says, something in one of the chuck key holes (chuck key?). BUT I ALWAYS remove the primary drive belt (Myford) when indexing by any means (bull wheel or change gears).  Prevents some nasty surprises.

John

[GreensandsParticipant @greensands]

The method would appear to be dependent upon there being sufficient height available along the side of the chuck for the deadweight to make the drop. For a 4ins dia chuck this would be typically a 12ins drop. Are there ways around this issue?

[Greensands]

On Greensands Said:

Are there ways around this issue?

Larger weight, smaller diameter (e.g. around workpiece in picture).

Reset weight to next jaw after 120 degrees of rotation.

Use tautline (or any friction) hitch on line and reset after each index (similar to adjusting the guyline on a tent).

Bungee cord pulling horizontally (technically not constant force).

Tie dog to chuck and put bone 14″ from its jaws.

There are not so many lathes that would be within less than 12″ of the floor. You only need drill a hole in the bench the diameter of the string.

[Nigel Graham 2Participant @nigelgraham2]

One way would be to arrange the drop to be completely behind the cabinet if there is space there.

Alternatively, down in front though that may be a bit in the way.

A third way would be to put a small pulley on the weight, reeve the cord down through it and back up to the anchorage. That would halve the drop for the given length of cord paid out from the chuck, but at cost of needing double the mass for the same torque.

Or just shape half the divisions then move the cord round to a new belay on the chuck!

[JasonBModerator @jasonb]

Does not even need to be vertical, just let the string run against the edge of the swarf tray.

Or screweye in the shed ceiling to take the string upto and then you have a long drop. Looks like John has done similar

[John PurdyParticipant @johnpurdy78347]

As Jason says I run the string up to a small pulley fastened to the bottom of a shelf on the wall behind the lathe, loop the cord over it, and the weight hangs down the face of the wall. The pulley is out of the top of the picture above but you can see the cord and the weight (an old sash weight) hanging down the wall. Barring a handy shelf just a small bracket on the wall with the pulley attached would do just as well.

John

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