Cross slide calibration

[modeng2000]

Are there any views on the different calibrations of the cross slide travel called I believe American and English?

My new lathe has the cross slide calibrated so that 1mm of slide travel is indicated as 2mm on the collar. I have always been used to the travel and collar readings being the same and so I first thought that the lathe had been fitted with the wrong collar. As it happens, a second top slide collar would probably fit in place of the present cross slide one so making the calibration English.

I could probably adapt to the American version if there are advantages to it but I feel that having the collar calibrated with the slide travel makes more sense.

John

[Tel]

Probably only advantages to it if you happen to be American and used to it. Personally I'd fit a direct reading dial, the small amount of mental arithmetic you have to do is nothing.

[modeng2000]

Thanks Tel, that is the way I was thinking. I wanted to sound out the oppinions of the folk on the forum in case I had mised something.

John

[steamjohn248]

Thats funny, on my Colchester Mascot 1600, if you set 25 thou on the collar, thats the amount by which the diameter of the piece is reduced, (in other words it only moves the crosslide 12 1/2 thou) but on the Bantam and the Harrison 25 will dig off a twenty five thou cut, reducing the diameter by 50 thou. Does this mean my Mascot was built for the American Market? I actually prefer the way the Mascot is callibrated. I have a little "aid memoir" painted on the other two after a few expensive "senior moments".

John

[Jo]

I recall converting my Myford to metric: As an imperial machine the cross slide cut twice the collar reading. As a metric machine the collar is graduated for the actual cut. I know which I prefer.

Jo

[Tony K]

I know which I prefer.

Go on then Jo - tell us!

Regards, Tony

[ron]

It probably doesn't matter all that much because you'll quickly adapt to whatever you have, the problem could be when you use one that's different. The Warco I have reduces the dia by twice the dial reading but it helpfully has a little logo on the dial that tells you that [if you have a magnifying glass!]
Ron

[modeng2000]

Having been used to the calibration being the same as the slide travel, have ordered a replacement Collar calibrated 1mm per turn rather than the 2mm as at present.

I had not noticed the Dia symbol

John

[Jo]

Tony,

Simple: I prefer it cuts the same amount off the job as on the dial. The advantage is if you get it wrong you are still over, not undersized!.

Jo

[John Lee]

I have fitted DRO's now, which is another matter (well worth it though and cheap these days)

But what I used to do was more or less ignore the calibrations on the axis anyway. As I get close I start (ed) measuring after every cut and advance by "a tad", and then "half a tad" and then less if you see what I mean. The only reading to be believed is what is on your micrometer or perhaps vernier. You can still get to half a thou without peering at dials providing you are thinking about backlash. If you believe the dials you are trusting in the total accuracy of your screws and the dials themselves.

The advantage of the DRO is know for sure, from a zero position where I am at, and when I am very close without mental arithmatic or zero setting dials, so its quicker.

Does this sound crude?? I don't know but it works. Still I am as amazed as many when the bits actually fit together as they should ;D

John

[GeorgeRay]

The slight problem with the American type dial is if you use the cross slide for milling work, then you have to remember to wind on twice as much to get the right result. Its sort of the reverse of the diameter turning problem.

[steammadman]

GOOD
JOB SOME OF YOU GUYS WERE NOT AROUND IN THE GOOD OLD DAYS
WHEN WE HAD NO CALIBRATIONS ON MANY LATHES ETC,ONLY THE TOP MACHINISTS HAD THAT LUXURY, WE LESSER MORTALS HAD TO RELY ON FEEL, AND A VERY QUICKLY AQUIRED SKILL

[chameleonrob]

steammadman said:

GOOD
JOB SOME OF YOU GUYS WERE NOT AROUND IN THE GOOD OLD DAYS
WHEN WE HAD NO CALIBRATIONS ON MANY LATHES ETC,ONLY THE TOP MACHINISTS HAD THAT LUXURY, WE LESSER MORTALS HAD TO RELY ON FEEL, AND A VERY QUICKLY AQUIRED SKILL

will the younger of us be saying something similar in a few years time to model engineers that have only know CNC?

rob

[John Lee]

steammadman said:

GOOD
JOB SOME OF YOU GUYS WERE NOT AROUND IN THE GOOD OLD DAYS
WHEN WE HAD NO CALIBRATIONS ON MANY LATHES ETC,ONLY THE TOP MACHINISTS HAD THAT LUXURY, WE LESSER MORTALS HAD TO RELY ON FEEL, AND A VERY QUICKLY AQUIRED SKILL

Were these the good old days? I doubt it except in a social cohesion sense.

Hmmm CNC again... if you do not understand about how to run a machine tool; feeds, speeds, climbing cuts, accurate zeros, backlash compensation, how to hold it, etc etc then you cannot do CNC either. The skills are not being lost, just transferred into a quicker and faster way of producing repeatable bits.

The old rifle companies, and after that Henry Ford pioneered exchangable bits. Model Engineers cannot generally do this yet, nor should they because there is no need, usually. My cross over point is about 4 complicated bits and then I will sit down and use time drawing it out, and let the machine cut it.

But heading into old fart territory myself (50 in 2 weeks time) I will still say that engineering is about progression, not looking back with rose tinted specs about how things were better in "my day"... whenever that was ;D

[Tel]

I tried that once - and got me face slapped

steammadman said:

, WE LESSER MORTALS HAD TO RELY ON FEEL, AND A VERY QUICKLY AQUIRED SKILL

[spurley]

Was it just before that picture of you was taken? ;D ;D ;D

I actually think you're a handsome beast!

Cheers

Brian