differential expansion

[paul gough]

I have a little workspace in a shipping container that has a seasonal internal  temperature range from approximately 10 degrees C. to 50 degrees C. over the course of the seasons. Temperatures when I would wish to do any work with a machine would be approximate 20 C. to 30 C. and wondering if secure fastening of the machines or not is the most satisfactory.

Question:1) With a Sherline lathe and mill which are constructed of aluminium and steel and are of necessity very low in mass and section, (bed), will there be any temperature induced distortion of consequence within this temperature range?

Question:2) I have seen a few different base materials used by Sherline owners to secure their lathe or mill onto. Most seem to use a wood sheet of one sort or another or directly to a wooden bench. Others seem to claim the need for a heavy support, such as a piece of steel 12mm or 1/2 or so thick to get rigidity and absorb vibration. Is securing the lathe rigidly, given its dissimilar material construction and the added dissimilarity of the supporting structures material going to induce detrimental forces or distortion.
Regards, Paul Gough.

[steamer]

The difference between steel and aluminum is about 20 x 10-6 m/m degC    If they were assembled at 20 C , and was then subjected to 30 C   the delta of 30-20 or 10 C would exist.

over approximate 0.6 m  ( the full length of the sherline lathe....eyeball ametrically....I don't have one in front of me...but you can substitute.

Delta L   =  L0  x 20 x 10-6 x 10   or 0.6 x 20x 10-6 x 10  or 20x 10-5 x 0.6 or 12 x 10-5 m or .0012 mm.......or 1.2 microns.

I would not worry about that for one minute........

Dave