Through spindle stick out...

Hi folks.

How much, how often, and for what sort of jobs, do you find yourself having a lot of stick out at the rear of the headstock?

I'm mostly going to be doing stationary and model traction engines.

Due to an annoying drain pipe, I have a situation where I need to limit myself to about 18" rear stickout, or move the lathe down in front of said pipe and potentially have a spot with a limited cross-slide travel. I haven't measured exactly how much of an issue this limit could be yet, as I just happened to notice it as a possibility while I was doing something else. But Sod's Law would suggest it'll be exactly where it's most constantly inconvenient...

Cheers, Jay

Unless the stock is of reasonable thickness then try to avoid having that much out the back as it can vibrate at the very least or whip round and bend .

When I buy 1m lengths of stock I'll cut them in half unless there is a very rare need for longer and I've not yet had to drill a hole in the shed wall which is about 500mm from the headstock

I doubt you will need it on stationary engine models but a large traction engine may do.

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

Quite often, because keeping stock in one piece reduces waste. I can manage just over a metre, but it has to be carefully controlled because of the danger of whipping - a bent rod flailing at 2000rpm is no joke! Working with long items 'Oil Country' style is important in some workshops, not mine.

And I often cut stock into shorter lengths despite the waste because not having to guard against whipping saves time.

18" stick-out is probably OK most of the time and I'd rather put up with that than limit the cross-slide.

Dave

...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.

When our factory was in Guildford, there was a large early type cnc lathe and the guy operating it put an 6 foot length of 2" diameter aluminium in it without a bar feed and turned up the speed. The 4 feet overhanging the headstock bent and hit his toolbox and everything in it embeded in the ceiling about 25 feet above. Just as well the lathe weighed about 5 tons, it survived the hilarious incident. When the building was demolished, somebody might have found some tools. The lathe was sold and ended up in India.

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.

Mount a plumber block at a suitable distance from the headstock to contain the overhang say a30mm bore. OR keep the revs down. Noel.

Ok, thanks for that guys. Martin has solved it though. I didn't think about the hole in the wall option, and I bloody should have as I've seen it done!

I wouldn't dream of having any sort of excessive stick out on either side without the use of a steady, and in this case I'll just bolt one to the wall if needs be. In all other regards it means I can move the lathe even further into that corner and give myself a half decent size 'dirty bench' at the other end...

This place is by far the most valuable tool in the kit!

All the best, Jay

Just for clarity, the wall in question will be a stud wall separating the rest of the garage...

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.

I also use wooden bushes at the end of the spindle bore. When the stock is thick and heavy, I use bushes to reduce the load on the spindle bearings, even if the stick out is minor.

Edited By Huub on 06/10/2022 23:19:16

Edited By Huub on 06/10/2022 23:19:41

Edited By Huub on 06/10/2022 23:20:07

Edited By Huub on 06/10/2022 23:21:00

Good shout!

Very similar here, but use spirit/port bottle corks. They live on the barstock which effectively colour codes it.
To the left of the Myford, I have a heavy cabinet, on which I can add a length of weighted/clamped down down steel tube, appropriate to the extending workpiece.

I've not got round to doing it yet, but my larger GH 1330 is to the right of the Myford.
I could do with raising the smaller lathe a bit and moving it away from the wall slightly to line up the two machines.
That way I could use the fixed steady on the Myford to constrain longer barstock in the bigger Warco.
Just a shame it would only work for round bar, rather than square or hex, though again I could use the steady to support a tube poking into the larger spindle.

Here's an example I saw a while ago about how not to do it.



Bill

Edited By peak4 on 06/10/2022 23:39:52

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.

Should be easy enough to make up a support unit to deal with the overhang, I use a length of timber with two or three blocks screwed to it, drilled to suit the stock. The unit can be as long as required. Never had any trouble with it so far.

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 forgot to mention J A Radford's neat design for the Myford in his book Improvements and Accessories for your Lathe.

He shows a bush holder clamped to the tail end of the spindle. Mine lives there permanently and is useful for other purposes. Here it is supporting an impromptu draw bar:

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.

Good idea as it would positively grip the work; however, it would also likely foul the gear cover when closed.

Incidentally, another advantage of the JAR holder is that chips from boring are less likely to be deposited on the gears.