The wear will though be most rapid when the arms have been used previously on a different
diameter. Then, when the arms have bedded into the diameter being supported wear
will occur much less slowly. Because of this, resetting the arms should be carried
out quite soon after the work commences.
To minimise the wear, and the heat generated, the workpiece should be lubricated.
However, if the temperature of the arms appears excessive do stop and check that
the workpiece is running freely and not being gripped. If gripped, then the heat
generated will expand the arms with the problem then being progressive, do check
their temperature frequently.
Above I commented that when using the travelling steady that the feed should be continuous,
the reason being that the steady relies on the cut to keep the workpiece in contact
with its arms. If therefore the feed is stopped the workpiece may leave the arms
and a shallow grove produced, Photograph 12. Photograph 10 showed a similar situation
occurs when starting the final cut on a part where the initial few millimetres have
been pre made to allow the steady to be set.
Do take particular care when large diameters are being held in the chuck's reverse
jaws as, due to the limited depth of grip, the material will work out of the jaws
with only the slightest error in concentricity of the material with the lathe's spindle's
Whilst I have used steadies frequently in the past and mostly without any problem
I was finding using the travelling steady not as I would have expected. However,
the problem caused me to investigate the situation and I found that the arms were
only wearing over a short portion of the end, not surprising as I had left them when
made as they came off my band saw rather than finishing them on the milling machine.
The ends were not therefore accurately square though this caused no problem in the
case of the fixed steady. To overcome this I placed a rather old and large reamer
in the chuck and closed the arms very lightly onto this and then turned the chuck
by hand. Then repeating the task with the arms closed a little more. This resulted
in them being machined across the whole width. With that done and a few other minor
adjustments the problems were eliminated. Photograph 13 showing the process.
If you would like to see a very old article from the Model Engineer magazine regarding
machining the ends of the arms to suit the item being supported then see this web
site page. Some of the ideas in this are rather excessive in my estimation but it
makes interesting reading, if only as a look into the past.