Ditron vs Sino...wich is better in your opinion

[rwm]

That is the menu I am using. What I am saying is that I can only select a 1 or a 2 in that box. I cannot select a 4 or a 5. Keep in mind, you do not enter using a number key. You press SET and it toggles through the available options. I tried changing the DRO to MILL and GRINDER but I still can only select 2 axes. Clearly they are limiting the DRO display capabilities since more axes are more expensive. I'm sure it just a software limit with identical hardware.

 

[rwm]

Now I am seeing that my cross slide scale is not accurate! It is randomly off by up to .0015 on each turn of the handwheel (.100.) I have checked it against a DTI and the DRO is definitely off. I cannot apply linear comp because it is not a linear error. This will be a major issue when trying to hit a diameter. I am wondering if I need to go to a 1um scale? I hate to throw good money after bad, but I can't trust it the way it is.

 

[Gaffer]

That's a drag. I haven't had a chance to work on my installation or to get the lathe reassembled. If I recall, you bought magnetic scales, both 5um. I bought glass scales, 1um for the cross slide and 5um for the carriage. I wonder if the error concerns the brain box or the scale's resolution. The random part is concerning. Either way, it sucks.

 

[rwm]

I think its the scale. It seems to repeat at the same part of the scale. 0 is still 0 when I come back. The scale seems non uniform. For example

0=0
.1=.100
.2=.202
.3=.301
.4=.400
.6=.602

These are pretty consistent. My mounts are totally solid.

 

[pontiac428]

I have 5 micron scales, they are working fine.

I would check the read head alignment and clearance and make sure everything is tracking straight and consistent before moving straight on to panic. Also make sure you are gounded to the head unit using the included grn/yel wire. My unit isn't grounded and works fine, but I have heard of others fixing jumpy numbers by doing so- and it makes sense.

Edit- You're not one of those VFD people, are you? If so, it would explain my lack of issues.

 

[mksj]

You need to use a 1uM scale if you are planning on using diameter mode on a cross slide. The issue is with a 5uM scale reads in 0.0004" increments and you also have the inherent error of the scale as well as the conversion error from metric to inch. The accuracy is often +/- the last digit if not more. On my current lathe I had specified a 1uM cross slide scale but the company sent a 5uM, I could not figure out why I couldn't get reproducible readings in the 0.001" range until I realized that they had sent the wrong resolution scale. It also has to do with the DRO software and how it interpolates or rounds calculations. On your DRO if you bought it as a two axis, even though it comes in 3 and 4 axis and/or has the sockets installed, the additional ports are either not connected on the board or deactivated through firmware.

 

[rwm]

No VFD. Alignment is good with solid mounts. Even if I grab the read head it is hard to change the reading. Units is grounded.
MSKJ- thanks, I did not know any of that when I bought this. OK, I'm gonna spring for the 1um scale. I want to be able to use diameter mode and hit within a thou.
Fingers crossed.

 

[pontiac428]

I don't think I understand conversion error, since the conversion is 1mm=0.040 in and 25.4mm=1 inch, no repeating digits, no infinite fractions.

The only type of rounding error that I am aware of occurs when rounding is done either incorrectly (too early), or across significant figures, both are avoidable in script.

For cross slide, .0004 isn't awful, but if you do sine transform on the combination slide, I can really see the need for more resolution.

 

[mksj]

It has to do with the chip/software calculations/conversions and the decimal places it is accurate to when you are reading in microns, you will often note that you can enter in one value on the keypad, hit enter and your screen shows a different value based on how it interpolates the position and rounds the calculations. I have had this happen on multiple lathes using 5uM scales in diameter mode, and almost impossible to get accuracy at the 0.001" or below level. When you talk about reading 0.0004" increments that is resolution that is seen on the display, but it is not accuracy of the measurement. I also agree that proper alignment, in particular with glass scales is very important. Quality of the scale is also another issue.

 

[rwm]

I have ordered the 1 um scale for $150. I will report back if this fixes the problem.