disk probe

[gage guru]

I calibrated a disk probe(25mm X 2.5) and have a couple of questions.

Can it be used for height as it has near the end of the diameter like a little pin through it that it a little higher than the top and bottom of the disk or do you have to thread a probe into the bottom of it.

If the answer is use another probe - then on the part I am measuring the bottom probe will not allow the disk to get at the diameter to be measured as there is another surface below it that interferes.

Also the calibration I was only off by .001mm on the diameter of the cal sphere and stnd dev was .002. I then checked a ring gage and was off by .020mm and it was done with auto circle after I manually aligned it.

Please help and I will look at posts after my meeting I have to run to.....

Thanks in advance.......

[Underspec]

The metal stud is called a "roller". I'm told it's supposed to be used for plane hits, but I never use it. Actually on mine I took it off and actually use the bottom edge of the disk probe to take plane hits if I can.

For your .020mm deviation, I would double check the ring gage against another measuring tool, maybe an optical? It could be also that if you are using TP20 modules you are not using the correct force module. You said you had a 25mm disc probe?

I would also check to make sure your calibration check/move/touch speed is the same as your measurement speeds.

[craiger_ny]

I use the discs infrequently but find Underspec's advise to pretty much follow my practice. Use a higher force module and go dcc on your measurements. I too removed the roller but at this point would recommend NOT using it to establish planes if you have removed yours as well. The reason I say this is if you take plane hits with the X side of the disc over hanging the edge of the part and then take hits with the Y edge (or even the edge 180 degrees from the other hits) over hanging the part then you may be contacting the disc at different Z depths (because it is not perfectly parallel to your workplane) giving you an inaccurate plane.

I thread in a ruby for most accuracy, but I know you said you can't so hopfully you have the roller intact.

Craig

[gage guru]

ok looks like I found a probe tip that will work for being under the disk(as it has threads to put a tip into the bottom) but how do I construct it as once I get the disk probe selected as a tip I do not get another connection line for more tips.....ahhhhhhhh

I also have reverified the calibration of the disk on the sphere at same speeds etc. and the ring gage is still off by .040mm the last time I ran it.

Called B&S help line and got 'new guy' and pretty muchso have to come up with a way to do this - kinda at a brick wall.

If I use the disk to measure for the Z direction won't I be off by the radius of the disk?? Do I offset the z then in an alignment by 1/2 of the calibrated diameter of the disk?

Ok I am done venting.....sorry - jsut frustrating that when you call for help you end up with none!!! I will check back for some better help as I know this group is a better source as they do it - not like the B&S help where they try to simulate it????

thanks in advance!!!

[gage guru]

OK B&S called back and they are sending me some info on how you modify a file to a special tip and then you can call that when you create it.

They had no idea as to why the size is off by sooooo much.

I will try some more to get better results, but just frustrating......any other help is appreciated......thanks.....

[craiger_ny]

Did you measure the ring gage as a cylinder? If not try that.