Chinse DRO accuracy

[pacifica]

Hey Guys

Ok so I got a chance to dig into this some more. I cleaned up the 123 blocks and things were closer. I checked it again over 8" and its about .002 difference.

The brand name of this DRO is Ditron D80 with 5um scales. One thing I could not figure out was how to do Linear compensation.
They show a screen shot on page 11 But I cant seem to find that on the DRO. I will play with this some more tomorrow.

Thanks everyone

Using a little trig:
If your 8" of scales are tilted at 2 degrees, the difference in measurement between the slope and straight line distance would be .0058".

 

[Asm109]

A little more trig. Tangent 1 degree = .017. tan 2= .034.
So the rise is .034 *8 = .272 OR over a 1/4 inch out of line with the direction of travel. Bound to be noticeable.

 

[pacifica]

So if your reading is .002" off at 8", that could be a 1.28 degree tilt, first thing I would check are your scales and the holder. At 8" the height difference would be .1789",maybe not so noticeable?

 

[Knick]

So if your reading is .002" off at 8", that could be a 1.28 degree tilt, first thing I would check are your scales and the holder. At 8" the height difference would be .1789",maybe not so noticeable?

Hi guys

Ok you guys are way way over my head here!
I went back and read my original post and think I left some things out, This is how I checked it yesterday.

I mounted a indicator in the spindle and laid a 123 block on the table and squared it up with indicator. I then clamped it down and zeroed my indicator and the DRO.

I then ran table in the X axis down 6" and checked with the indicator and compared to the DRO I was neg maybe .0008
I then went 8" and was Pos .0014.

I take it, it was good to have it read back and forth as this could be rounding issues and other things that a old mill could interduce into the readings.

I am brand new to machining and have a real hard time understanding instructions that are written, I do much better with visual aids.

So tell me does the tilt of the blocks still play into it? I am thinking at this point what I am getting now is pretty good for a old mill and old man.

I really do appreciate all the time you guys spend help me and everyone else on this site.
One thing I still have not been able to find was how to get into linear compensation on the DRO. Not that I think I need to change it anyways.
Thank you again

 

[Winegrower]

There is another thread about linear compensation. I have a Ditron 80, and yes it was hard to figure out the compensation, but I gave the steps that worked for me quite successfully. Another poster apparently could not figure out how to do it, so who knows?

I think that the 1 micron scale on my cross slide is now the most accurate way I have to measure any distance over 1”.

 

[Knick]

There is another thread about linear compensation. I have a Ditron 80, and yes it was hard to figure out the compensation, but I gave the steps that worked for me quite successfully. Another poster apparently could not figure out how to do it, so who knows?

I think that the 1 micron scale on my cross slide is now the most accurate way I have to measure any distance over 1”.

Hi winegrower,

I looked for that tread but all I found was where you said everything had to be in metric.
I played around with it for quite awhile and have given up. I dont think I am off enough to make much difference.
linear compensation

 

[Winegrower]

If that’s the thread, I tried to state exactly what I did. There are only a few steps, but they all have to be there. Sorry it didn’t work for you.

Perhaps the firmware changed, who knows?