Thread: XinXing Measuring Tools Factory Granite Surface Plate Vs HP Laser Interferometer

Originally Posted by .RC.

Be difficult to measure something like a gauge block, unless you have a room at 20C...

You can check gauge blocks if you have a known one with a micron indicator used as a comparator...

The auto compensator takes care of the error for humidity, air pressure, air temperature and materiel temperature. The materiel temperature sensor takes care of that error if the part is not at 20C, well almost; it only goes to 10ths of parts per million per degrees C for example the 10.5 ppm/C for grey cast iron.

Sure send me a couple of gauge block without the certificates and I'll will give you a number back. The bigger the better as the materiel sensor is about 1" dia.

-Josh

Originally Posted by Stustoys

Hi Ray, Josh,

I have a feeling mine maybe worse than that. Rays numbers would put it on the limit of detection with a 300mm vernier. Joshs numbers would be below my limit of worry. Of course that assumes my Mitutoyo vernier is better than my DRO. I know which one I'd be betting on. Of course it could have been me. Mill is set up ATM. I'll try and check it again tomorrow.
How do you feel about getting up early and running the tests again when things have cooled off a little?
If its the aluminium that has the greatest effect on the scale?? 10C should do nicely

Stuart

If you have gauge blocks set them up on the mill table and use a dial indicator. If you don't have gauge blocks use a Mic standard instead.
I think you know how to set them up so I wont go into detail, I did this on mine and it checked out fine.

Dave

Hi Dave,
No gauge blocks. The longest standard I have is 3". So I figured the vernier was better.
I do have a 12" master height guage but that could be a little tricky to setup on its back.
I now have a 600mm height gauge. Wouldnt exactly be to R & J standards but I'd have a number. I'll have a bit of a think about how to mount it.

Stuart

Well I checked my DRO this morning.
Set up parallel to the bed in both plans, getting a repeatable 0 within +/-0.005mm(no bad considering I'm using my $10 knock 0.01mm DTI)
moved the height gauge 550mm, took four readings(all within +/- 0.005mm). return to check 0. back to 550mm and four more readings.
The number. drum roll please. 549.337mm

Now I could repeat it with a 0.0001" DTI but as the error is so large by comparison I dont think it would change things much?

Stuart

What brand of DRO is this Stuart and how old is it?

Lex.

Originally Posted by Stustoys

The longest standard I have is 3".

I heard you only had 3 "

I've got some 300 or 350mm mitutoyo standards out there. I bought for a rainy day. Guess what it rained today.

You can borrow them next time you are over, I'll even lend you some little vee blocks for them to go in.

Phil.

Hi Techo,
Its a no name one. The scales are made by Ditron if that means anything to anyone.

Hi Phil,
Indeed it did rain, big nasty drops to. All techos fault I got wet going to the shed.
Well I could dodge this question "when I only had 3" ". but how do I accurately measure mic standard on a mill? I could use my wiggler but then I have to subtract my ball diameter and I dont even want to go there
pressing it up against a ground block sounds a little rough as I'd have to move in Z or Y.

I could test the height gauge against the master as I guess it just has to be right(to this level)

Which beings up something I'd never given much thought before. Just how accurate is a height gauge?(I am assuming way more accurate than my DRO lol)

Stuart

Originally Posted by Stustoys

Which beings up something I'd never given much thought before. Just how accurate is a height gauge?(I am assuming way more accurate than my DRO lol)

Stuart

Hi Stuart, I'll ignore the obvious comments that I could make regarding subtracting ball diameter... and instead concentrate on the height gauge, I'd expect the DRO scale to be more accurate than the height gauge. The DRO would be a glass scale, where the height gauge would most likely be an inductive type scale ( like digital calipers I guess )

So, wouldn't be too quick to conclude the error is in the DRO only.

I seem to remember you picking up a height standard? Or is my memory failing.... In any event Phil says has the required larger equipment...


Regards
Ray

Originally Posted by Stustoys

but how do I accurately measure mic standard on a mill? I could use my wiggler but then I have to subtract my ball diameter and I dont even want to go there
pressing it up against a ground block sounds a little rough as I'd have to move in Z or Y.

You would have to trust your Z with in reason. Or at least you can check that with a trammel test or by clocking a square. If there's an error you can calculate it out.

If you were to lay a standard, parallel, butt it against a stop block. Zero an indicator on one end, lift the quill a pooftenth then move to your stop block. That would have to be close enough, or are you looking to split the atom also?

Regards Phil.

I just occured to me, you could use it with out moving any thing other than the axis you are checking. Zero your clock on the stop block, right where the master will touch, wind your table a foot left, then insert the master back into its Vee blocks, and wind back until you get indicator zero. The difference between your DRO and the master is your error.

Hi Ray,
I'm not sure wich one I want to be wrong ATM. I'd hate to think my Mitutoyo height gauge was not much better than a rule and at least there is a chance of entering a correction on the DRO(Dave sent me some instructions a while back for a different DRO but I couldnt seem to make it "fit" my DRO, though another look would be in order)

I do in fact have a 12" master height guage. Now while I likely cant set it up correctly to take an absolute measuremeant, as they are really just a row of gauge blocks it shouldnt be any trouble to cheak the height guage over 11" (well apart from the whole inch/mm thing). Its stopped raining so I'll had back to the shed and drag it out.

Stuart

**Hi Phil I think I might have been on the verge of working that out myself. So easy once someone else has worked it out for you thank you

Not trying to split the atom just yet but something a little better than 0.001" an inch would be nice.

I set-up to do the straightness of travel on the HM52 today according to the instructions in the manual. I ran the test and realised I did not really know what I was measuring on the display...... :S

*insert coffee break*
*re-read manual*
*insert coffee break*
*light bulb*

I was not until that I realised that it is the straightness reflector axis that is my "laser" straight edge then it all made sense, so all I had to do was change the mountings so that the micrometer adjustments on the reflector would make the adjustments to the right axis and it should all work. I had not realised I had been dialling in on the wrong axis, it had previously set-up in an alternate configuration, and there where 4 hidden screw that needed to be taken out so that I could change the mountings so it would allow for a proper alignment to the axis of travel. I was having all sorts of problems trying to figure that out....
With every thing dialled in as close as I could get it with out X36 resolution extender, I put that in and dialled it in the last little bit. Not perfect but good enough to take a measurement. But I decided that a video would give me better results if I could tie it into the DRO and get a data points every 0.5mm. So I removed the DRO from the mill and moved to over to the laser display and took a video.

The Camera stopped working after a 100mm due to a memory card error, so I'm clearing some space and should have a video up in the next couple of hours.

-Josh

edit the error is somewhere in the order of 3-4 microns per 300mm

Well the good news is the Height gauge looks pretty good.
Checked it against 11" on the master height gauge and it came out at 279.3mm. So while not perfect its at least closer. Down to 0.00036" an inch.
I'll check it a couple more times later, hopefully the numbers will come out the same.

Though I guess thats not good news for the DRO.

Stuart

Hi Stuart,
If using gauge blocks you can zero the dial gauge then slip it out, and then move that axis down to you other block that is held.

Your DRO might have the linear compensation but it might not be in the manual. My book describes it being measured in PPM (parts per million) so 100 PPM is 1 micron, which can be added or subtracted.

Dave

Originally Posted by Brobdingnagian

I set-up to do the straightness of travel on the HM52 today according to the instructions in the manual. I ran the test and realised I did not really know what I was measuring on the display...... :S

*insert coffee break*
*re-read manual*
*insert coffee break*
*light bulb*

I was not until that I realised that it is the straightness reflector axis that is my "laser" straight edge then it all made sense, so all I had to do was change the mountings so that the micrometer adjustments on the reflector would make the adjustments to the right axis and it should all work. I had not realised I had been dialling in on the wrong axis, it had previously set-up in an alternate configuration, and there where 4 hidden screw that needed to be taken out so that I could change the mountings so it would allow for a proper alignment to the axis of travel. I was having all sorts of problems trying to figure that out....
With every thing dialled in as close as I could get it with out X36 resolution extender, I put that in and dialled it in the last little bit. Not perfect but good enough to take a measurement. But I decided that a video would give me better results if I could tie it into the DRO and get a data points every 0.5mm. So I removed the DRO from the mill and moved to over to the laser display and took a video.

The Camera stopped working after a 100mm due to a memory card error, so I'm clearing some space and should have a video up in the next couple of hours.

-Josh

edit the error is somewhere in the order of 3-4 microns per 300mm

Thats far better than i expected from the HM52, it has such a short saddle and such bad scraping (well mine does anyway). I'm guessing thats powerfeed only? Feeding by hand it would be flopping around all over the place no doubt.