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Mitutoyo dro display
- Thread starter Tom O
- Start date
I like it....
Nice and bright. Not touch screen though. I could sure do with out the 0.0000 resolution LOL.
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I would think that would be a language choice. Lol
cDetailBottomMoreOtherSeller,scm-url:1007.33416.213724.0,pvid:72a09d9f-4f01-4074-89b7-539c56cab573,tpp_buckets:668#0#131923#17_668#888#3325#11_23416#0#213724#0_23416#4721#21967#485_23416#4722#21972#7_668#2846#8116#2002_668#5811#27188#84_668#2717#7564#677_668#1000022185#1000066059#0_668#3422#15392#953_4452#0#226710#0_4452#3474#16498#897_4452#4862#24463#309_4452#3098#9599#32_4452#5108#23442#707_4452#3564#16062#813Don't have LCD but to my eye looks crisper & better overall light balance. I'm not sure how they perform in cooler or variable shop temperatures. On some other equipment I have experience with, that separates the good stuff from the wanna-bees. My fingers are almost always oily or dirty so would prefer they stay on dedicated, tougher keypad buttons vs the screen.
Tom Kitta
Ultra Member
So now I am going to go to the shop and see how accurate is my DRO really. Checking the 5um will be a bit difficult. I have no idea how to check 1um. 5um is about 2 tenth.
I am thinking of a test indicator in a collet and gage block in the vise.
I also wonder what distance is the accuracy over - 30cm?
How accurate are class 3 (or grade B) gauge blocks - supposedly quite accurate at +0.25 um and -0.15um BUT they are made a bit smaller to account for "film" However, this is just 0.25um or so. All at 20C.
I am thinking of a test indicator in a collet and gage block in the vise.
I also wonder what distance is the accuracy over - 30cm?
How accurate are class 3 (or grade B) gauge blocks - supposedly quite accurate at +0.25 um and -0.15um BUT they are made a bit smaller to account for "film" However, this is just 0.25um or so. All at 20C.
Its hard to say if the encoder/readout would progressively get worse over distance. You could just as well have an accurate or inaccurate localized section of windings but one would assume consistency.
The way I've tested DRO (more of a sanity check than anything else) is
- make up a block assembly from your most accurate gage blocks, In cartoon, black is the the backstop block wrung on blue length block. You could try a 4, 3, 2, 1" length for example
- attach to table ensuring its perpendicular. Lock the table Y-axis
- orange ball represents you most sensitive DTI ball in quill chuck or whatever. Lock spindle or select lowest gear (to mitigate quill rotation)
- bring DTI ball to edge of block, lightly load, get a needle reading, zero DRO. Raise quill & re-lock (this is where we potentially introduce error). Displace table to stop block until same DTI position. Record DRO reading vs block length. Rinse & repeat with other blocks.
The way I've tested DRO (more of a sanity check than anything else) is
- make up a block assembly from your most accurate gage blocks, In cartoon, black is the the backstop block wrung on blue length block. You could try a 4, 3, 2, 1" length for example
- attach to table ensuring its perpendicular. Lock the table Y-axis
- orange ball represents you most sensitive DTI ball in quill chuck or whatever. Lock spindle or select lowest gear (to mitigate quill rotation)
- bring DTI ball to edge of block, lightly load, get a needle reading, zero DRO. Raise quill & re-lock (this is where we potentially introduce error). Displace table to stop block until same DTI position. Record DRO reading vs block length. Rinse & repeat with other blocks.
Tom Kitta
Ultra Member
I try above. I tried two blocks to test against each other but could not get the aligned perfectly. I wonder whatever above setup will be better.
The main issue is that the BP machine is meant to do thous not tenths or even less then that. I placed half tenth indicator and touching the machine moves it. It feels my own breath moves it. Locking the quill moves it up to a tenth or so - even lightly. There is no way to move Y axis - it has to be blocked.
I did check the DRO for sanity when I installed it vs. dials over long distance & either it is accurate over like 20 inches or the dials have same error.
Incidentally I learned today why cheap Chinese dial indicators are cheap. They do not measure even remotely accurately! Distance of 1 inch can show as 1003 or even 1005. Starret does not seem to have an issue - 1in shows as 1in.
I plan on making a little video, Starret vs. China (Busy Bee) and maybe one of the above orange ball method - if I manage to get it working.
The main issue is that the BP machine is meant to do thous not tenths or even less then that. I placed half tenth indicator and touching the machine moves it. It feels my own breath moves it. Locking the quill moves it up to a tenth or so - even lightly. There is no way to move Y axis - it has to be blocked.
I did check the DRO for sanity when I installed it vs. dials over long distance & either it is accurate over like 20 inches or the dials have same error.
Incidentally I learned today why cheap Chinese dial indicators are cheap. They do not measure even remotely accurately! Distance of 1 inch can show as 1003 or even 1005. Starret does not seem to have an issue - 1in shows as 1in.
I plan on making a little video, Starret vs. China (Busy Bee) and maybe one of the above orange ball method - if I manage to get it working.
Yes its a tough thing to measure if the quill has any side action that might influence the DTI by raising or re-clamping.
Another quasi-repeatability test for DRO is run up to the stop block at a predetermined DTI position (aim for about 1/2 clock turn needle for DTI spring loading consistency). Don't touch anything but note the DRO readout at that position. Then back up & repeat a few times. Tell us how many of those trailing DRO 0.00000 digits stay the same. This should have no leadscrew backlash mechanical implications as long as you only turn the handle one direction only. Its testing encoder / scale assembly on an arbitrary but fixed distance. But this assumes your scales & head are installed per spec. If there is tension or scale bending or misalignment, that's not the DROs fault. It will happily measure an arc segment or triangle hypotenuse as best it can LoL
Another quasi-repeatability test for DRO is run up to the stop block at a predetermined DTI position (aim for about 1/2 clock turn needle for DTI spring loading consistency). Don't touch anything but note the DRO readout at that position. Then back up & repeat a few times. Tell us how many of those trailing DRO 0.00000 digits stay the same. This should have no leadscrew backlash mechanical implications as long as you only turn the handle one direction only. Its testing encoder / scale assembly on an arbitrary but fixed distance. But this assumes your scales & head are installed per spec. If there is tension or scale bending or misalignment, that's not the DROs fault. It will happily measure an arc segment or triangle hypotenuse as best it can LoL
Tom Kitta
Ultra Member
So I did the ball test with a 4" gauge block. Surprise - gauge blocks are well made. The DRO measured 4" gage block as 4.0000
I made sure the clamping action on the quill is feather lite. I watched the test indicator.
I think the hardest part is getting test indicator exactly at the same spot. Or you have to compute the difference.
Test indicator is very precise - half tenth. It gets a bit strange to have to count all these zeros - 0.00005
I made sure the clamping action on the quill is feather lite. I watched the test indicator.
I think the hardest part is getting test indicator exactly at the same spot. Or you have to compute the difference.
Test indicator is very precise - half tenth. It gets a bit strange to have to count all these zeros - 0.00005
Tom Kitta
Ultra Member
Here made a video about DRO
1 tenth is so little that the machine was at 4.0000 when I left it in the evening, then went to 4.0001 in the morning and then back to 4.0000 in the afternoon.
Interesting find about dial indicators. I did not know cheap Chinese stuff is so inaccurate.
Interesting find about dial indicators. I did not know cheap Chinese stuff is so inaccurate.
Interesting. Well gives you confidence of the DRO encoder & your DRO installation to the extent of your gage blocks. You could repeat at different positions of the table & the Y-axis. Actually I got thinking that raising./lowering knee might have been better that adjusting quill but anyways. Now you will sleep better knowing 'theoretically' you can machine to within a tenth haha
Re the dial test, the results could have been influenced a little bit by a back plate (influencing case orientation) or how accurate the stem holes are drilled relative to back plate datum despite mounting body on parallels. But plunger axis would have to be canted pretty noticeable to get 2-3 thou delta on that plunger displacement.
Re the dial test, the results could have been influenced a little bit by a back plate (influencing case orientation) or how accurate the stem holes are drilled relative to back plate datum despite mounting body on parallels. But plunger axis would have to be canted pretty noticeable to get 2-3 thou delta on that plunger displacement.
Tom Kitta
Ultra Member
Yes I thought about it making a triangle in order to get it off by few thou - but I also realized it had to be crooked a lot to get such a delta. I was actually quite surprised - Chinese dial calipers have to be more accurate or on measuring something that is 5'' they would give and error of like 15 thou - at this point you would probably be better off with a steel ruler. I guess I could use a right angle to make sure the indicator is straight and measure against surface plate and blocks.
Temperature fluctuations does the same for me. I can level my lathe w/machinist level, and have it fluctuate 1/4 bubble by turning my furnace on. I'll never machine to 10ths, so I'm ok
Tom, if you are now confident of your DRO accuracy/resolution as you seem to be, you can perform similarly tests on other items.
Open the jaws of offshore calipers to some arbitrary display value & check against DRO length. Install a 123 or 456 block in the vise. Etc.
Open the jaws of offshore calipers to some arbitrary display value & check against DRO length. Install a 123 or 456 block in the vise. Etc.
Tom Kitta
Ultra Member
I actually had machine move few tenths all by itself. I made a movement. Stopped. After about a minute I noticed DRO moved by 3 tenths. I still had my test indicator in and it also showed a movement! There may be some "metal relaxation" or some "lead screw tension" being released. It was in the direction of a movement of the table, so no backlash.
It almost feels like the surface tension of oil held the table back a bit under slow movement and then suddenly released its hold. Magic.
I am almost scared of measuring a lot of other things - I am sure to find out a lot of things are junk.
It almost feels like the surface tension of oil held the table back a bit under slow movement and then suddenly released its hold. Magic.
I am almost scared of measuring a lot of other things - I am sure to find out a lot of things are junk.