Some do, some don't…

As I understand it, the Americans tend to use the "total reduction in diameter" whereas here in the UK we use "tool distance". Other countries just seem to have picked whichever they prefer.

I may be wrong.

Rob

Hello Paul,

I think I prefer the actual tool movement, although I'm getting used to the total reduction WM250.

What I am struggling with though, is the 0.04mm graduations.

Interesting, my somewhat elderly WM250 has a similar arrangement which I am now used to but the graduations are in 0.05mm which is slightly more useful. The dial also lets you know it is referring to diameter by the ⌀ symbol.

John

To Paul W – When I was training, thousands of years ago it seems, a very experienced and smart workshop instructor said "assume nothing – when you walk up to a machine you don't know, set up a dial indicator and check distance moved vs the handwheel graduations on every axis" and then "check it in both directions you lazy ba%6^%ds to see what the backlash is like". Words to live by. I've remembered that and have done it since. Just food for thought.

I have a Boxford and a Colchester. They differ. Keeps me on my toes!

It freaked me a bit at first on my Warco, but you can get used to anything. If I'm milling or co-ordinate drilling using the crossslide I double the metric offset I dial in. What complicates it more is that my vertical slide's a Myford Imperial.

I know I could buy a DRO set, but (a) I'm a cheapskate, (b) too lazy to want to go through the learning curve to fit and calibrate the things, and (c) believe in maintaining the mental calculation exercise.

I've had it 8 years and so far I've coped.

My first lathes were Myfords, all with "tool movement" calibrations. Made a lot of sense when the lathe plus vertical slide was also used for milling. Current lathe is an old-but-good Smart and Brown 1024 which is calibrated in diameter. However, the transition was significantly eased by the fact that it came with a DRO which, like many, has a radius/diameter button. It means that I work in diameter – take a cut, measure, set DRO to that diameter, and then machine down to required diameter. Yes, you still have to do the right thing with depth of cut, but the sums are easy enough (and simpler than the imperial DoC to metric equivalent for which I still have little feel). Can't remember the last time I read a feedscrew dial…

Odd graduations on the habdwheel dials drove me nuts when I first got my Chinese lathe – so much so that one of the first jobs was to make some new ones!

Edited By Andy_G on 18/04/2023 21:19:49

If using an unfamiliar tool then checking these things is essential before cutting metal. It is not always obvious if a machine is metric or imperial so make some checks. The cross slide being calibrated for diameter or radius is a classic area of confusion, I would hesitate to attribute the convention to an Atlantic divide as British machines are not consistently one way or the other.

Mike

Something that just ocurred to me – tool movement would be preferable to diameter reduction if you were screwcutting and wanted a specific thread depth i.e. "working to the book".

I just keep cutting and testing until a nut goes on…

Rob