It looks like, if that's a round feature and all things given were nominal, you would have +/- .0004 on the diameter at the end of the cone. Yea, kinda tight.
My company checks a lot of gages that incorporate all types of angles. 0.02° converts to 0°1'12", which in the gage industry is not considered overly critical. I have done a comparison check between checking the angle on the CMM and checking the angle on a surface plate a number of times. On the surface plate I use a sine plate build up and indicator attached to a height stand. The results have been very comparable. I would suggest, if possible, you do the same thing. With the part you have shown, you will need to use a vee block on the sine plate to hold your part. Rotate the part to a few different position to ensure that you are checking the form of the taper as well.
It looks like, if that's a round feature and all things given were nominal, you would have +/- .0004 on the diameter at the end of the cone. Yea, kinda tight.
That is what I get (just about 0.0007" angularity). Using rule of thumb of 10 to 1 the cmm would need to be theoretically capable of discriminating to 70 millionths. Tight.
My company checks a lot of gages that incorporate all types of angles. 0.02° converts to 0°1'12", which in the gage industry is not considered overly critical. I have done a comparison check between checking the angle on the CMM and checking the angle on a surface plate a number of times. On the surface plate I use a sine plate build up and indicator attached to a height stand. The results have been very comparable. I would suggest, if possible, you do the same thing. With the part you have shown, you will need to use a vee block on the sine plate to hold your part. Rotate the part to a few different position to ensure that you are checking the form of the taper as well.
I do the same thing when questioning or validating tight tolerance cone/taper angles. I do prefer to use our Zeiss and scan something like this. We have a part for a customer that has an angle tolerance of +/- 0° 0' 25". Can't really trust a comparator and ti's either a sine plate or the CMM.
I know this has been talked about before, but for measuring a large number of points for multiple levels I have been told by an AE to use prime numbers.
0.02 degrees over the length of that part gives you a different of 0.00036". I would say the CMM is NOT capable of measuring that. Less than 4/10? That is pretty d@mn small.
