DRO Linear correction

[James GlindemannParticipant @jamesglindemann57712]

I have finally found the time to fit a Chinese "Tech" brand DRO-L2 DRO with Glass scales to my Colchester Master 2500 Lathe. Every thing is now working fine after I replaced a "D" connector on one of the scales that had pins that were loose in the housing, causing the pins to not mate correctly resulting in intermittant operation.

My current problem is my inability to input a linear correction factor. I do have the manual for this DRO but it is written in chinglish and I am unsure if I am using the correct method.

Does any one on this forum have experience with this operation and if they have had succes or otherwise.

thanks in advance from the other Jim G from Australia (Victoria)

[James GlindemannParticipant @jamesglindemann57712]

how to set linear correction on Chinese “Tech” brand DRO

[mgjParticipant @mgj]

I don't know about all of them, but on mine there is a set up menu, (you press 9 longtime to get in but others makes will be similarish )and you add corrections in millionths of a metre (.001mm) or parts per million. ie 100 is .1mm and 1000 would be !!! 1mm.

I think the ppm system is fairly common. Remember to work out which way is + and – depending on which way you have the sign on that axis set, .

Technically one should work out the distance applied – I used 1"" off a long travel DTI, and then you work out the error as a %, convert that into .001ths of a mm. and that gives the correction.

Or you could just work carefully against the DTI a bit at a time, and then when its all about right, fine tune off the micrometer as you go along. I find that works well and is a great deal less stressful!

Edited By mgj on 19/02/2012 13:06:06

Edited By mgj on 19/02/2012 13:06:38

[James GlindemannParticipant @jamesglindemann57712]

I use a 5 inch (127mm) standard from a 6 inch micrometer. I don't think the figure that I am using is the problem

((actual length – measured length) divided by actual length) X 1000 = error over 1000 mm

(( 127 – 127.027) / 127) X 1000 = -0.2125mm correction

When I am in the setup mode there is provision for setting the scale type, increment, direction and a couple of other parameters but no scale linear correction.

The manual says to press x to select the axis then press the mm/inch key and enter the correction figure via the keypad then press enter . These actions do not seem to be achieving the results I expect

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