cylinder stylus with flat bottom

[[Ro...]]

Engineering wants me to order a cylinder stylus with a flat on it to measure lengths with it. I thought I read somewhere that the cylinder stylus was not very accurate for lengths. Does anybody out there use a cylinder stylus for lengths and have good luck with it. Then my next question is how do you calibrate it with the flat on bottom.
Thanks in advance

[[Da...]]

First things first, WHY do they want you to get a flat bottomed cyl. probe ?

[[Mi...]]

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I mean, I guess it'd be useful to measure the height of a curved or pointed surface, sort of like a height gauge.

Whether or not they make them, or how accurate they are, or whether Calypso can calibrate them, I can't answer.

[[Ow...]]

I’ve never used a cylinder probe but, have used a disk probe that have flat bottoms to measure bore shoulders. It’s kind’a cheating and not sub micron accurate by any measure but, if you’re tolerance isn’t too small it works. I think the cylinder probe qualifies like the disk probe taking point on top 1st?

Basically, you take an item with a known step distance and take manual points with the bottom of the disk, which is not going to be accurate, and use that different result from the know distance amount and then use the result element to subtract or add that amount to distances measured with the bottom.

Make sense? I would think you could use the same practice with a cylinder probe.

You would have to make sure the probe retract was big enough to clear everything and also fudge the numbers the probe accesses the points, maybe use a search distance to slow it down?

[[Ro...]]

Thanks for your response .Dave, they think it would be faster on the CMM checking some lengths. I think we can check it better on the floor with a stand up gage.

[[Me...]]

Don't have one but thought it ideal for measuring the lip edge of c'bores. Also for tap I.D.s.

[[Da...]]

They make a ball end cylindrical probe, It calibrates just like a regular probe. Cmm's as a single point height gage, don't do that well in my opinion.

[[Ri...]]

With a cylindrical stylus you would have to ensure the stylus and the feature are as perfect in alignment assembly as you can (assume Z axis for simplicity), otherwise, eventually you will shank out on the cylinder to feature causing errant values.

I have yet to see a CMM stylus system in even near perfect alignment to any axis for a stylus setup. Components are not made to be in perfect alignment, its probably cost inefficient. Even our thermal components are not in perfect alignment (Example a star probe setup). There is always alignment assembly error.
We use Zeiss components almost exclusively.

[[Gr...]]

Rick Stanich is absolutely correct about alignment. If the bore your checking is not straight the Cylindrical stylus will shank out and give false readings.
We purchase both Q-Mark and Zeiss Stylus. Both companies have a sphere on the tip of their cylindrical probes to simplify qualification.