My ever inventive mate (sadly deceased) had his Myford in a corner with enough space to open the gear change cover. However he had the forsight to bore a 3 inch hole in the wall in line with the spindle bore and then fitted a bung. In extremis he could remove the bung and feed the stock through from the outside. The garden was about 300 feet long so space was practically unlimited.

regards Martin

…unless you install something to contain it. (e.g. the nearest size seamless pipe to your spindle bore).

It is not the having it sticking out as such that is the problem, it is the unsupported nature of it that causes issues. Bar feeders have been working with 12' lengths since forever but they contain it within a tube.

Another option to help stabilise really floppy stuff that is barely longer than the spindle is a cathead at on the outboard end of the spindle.

The length will depend greatly on the spindle bore, surely? And at what speed you intend to turn the piece?

There is no ‘universal’ length that can be stated for all scenarios. Even a huge spindle bore would have different requirements if using a tiny rod.

I have a selection of wooden bushes, OD to fit the spindle bore and ID the stock, the bush a push fit and located at the end away from the spindle nose.

Chap at work was seriously injured by bar sticking out the wrong end whipping when the lathe was switched on. Not worth the risk. You could probably work out the whirling speed if you were really keen. Starting slow and winding it up won't necessarily work, onset of whirl could be sudden.

Even a secured bit of wood with a hole in it and some oil squirted in will do the job, it only has to stop the whipping from starting up, metal pipe is probbly best

I wonder if there is any danger with a single point of support (as opposed to an enveloping tube) of the bar vibrating between the supports like a string. And will it ever vibrate at one of its higher harmonics?

See: https://en.wikipedia.org/wiki/String_vibration

We need some brave soul to perform an experiment.

—

I wonder if a modern update of the Radford bush would be to mount a ER collet holder (of a different series to the one in the headstock) in the same place.

I too went for solid bushes bored to size to support bars hanging out of the spindle.

But mine is a bit more high tech.

A clear out in the plumbing department shortly after doing a batch of long overhang jobs unearthed a brass internally flanged nut whose bore was a little bigger than that of the 1024 spindle. As the S&B 1024 has a native 5C collet fitting spindle nose and I have full sets of 5C in both metric and imperial my habit is to use the collets for slender materials. I made an adapter to go on the hand wheel of my collet drawbar to take standardised nylon or delrin bushes made as needed. Black for imperial, white for metric.

Having made the beast after that batch of slender jobs convinced me that simply shoving a wadded up rag in the end was a bit too bodgy it sees very little use. I just don't seem to get jobs needing lots of slim parts these days so cut first, turn next is fine.

I think the suggestion of using ER collets made by DC31k is probably our gold standard for this sort of thing given that folk like us are generally concerned with relatively modest stick out.

The dangers of single point support where long bars are concerned are well known in industrial practice. There are rules of thumb for manual machines a relatively low speeds. Factory set ups with fast running CNC, Swiss or hard worked capstans tend to be sorted a but more seriously

Clive

Edited By Clive Foster on 07/10/2022 14:07:04