If you haven't sorted this out already by reference to CHJ's useful link, they will be changewheels which allow you to change the gearing between the main spindle and the leadscrew, thus allowing to to cut screw threads of various pitches. The range of threads you can cut will depend on which wheels you have and whether it is an imperial or metric machine.flintandsteel":2etz1dmf said:I've got 920, maybe from the 1980s
Just checking the box of bits that came with it and found a set of gear cogs.
Are these an optional extra for altering the gearing on the machine
The various clones may also be perverse in having a mix of Imperial and metric, or maybe it's a case of second hand ones have had a incorrect replacements* fitted but it's not been unknown in the various forum references.chaoticbob":21148nri said:... The range of threads you can cut will depend on which wheels you have and whether it is an imperial or metric machine.
Quite normal practice AES, in the above mentioned links is the chart for my machine without any fudging.View attachment Gears.pdfAES":2o31jh1c said:... I read on one of the "Mini Lathe" web sites that with a bit of "fiddling" with ratios it's possible to cut Metric threads on an Imperial machine (and vice-versa). T..
I is my understanding that the 'format' was widely circulated as generic pattern in far eastern climbs much like several others such as the common reeves drive wood lathe, as a means of speeding up engineering uptake in the area, this resulted in numerous sources spread around producing parts to varying degrees of finesse eventually coming together with whoever was finally assembling them.AES":hi8c9prw said:...
Thanks for the lathe pix too. Mine's the smaller Mini Lathe (nominally it's 7 x 14) and just as you say, although all seem to be basically "the same" (apart from colour!) when looking closely there are differences between the various "badges".