how to check symmetry

[Programinator]

I have a shaft with a flat on one side and a flat on the other. The flat features have to be symmetrical to shaft OD within .0008 What is the propor way to check this. We dont have a cmm. Our customer says to put it on a v block and zero indicator over one flat. Then spin part to the other flat and the differance is your symmetry. I thought that was central but im not an inspector. Anyone know the propor way to check this?

[strabe]

quote:

---

Our customer says to put it on a v block and zero indicator over one flat. Then spin part to the other flat and the differance is your symmetry.

---

This could work assuming the shaft is perfectly straight.

 

I would indicate the apex of the shaft and then indicate the flat and record the difference. Then without spinning the shaft in the vee block, repeat the procedure for the bottom side of the shaft. The difference between the two measurements is your symmetry.

 

HTH

 

Ken

 

[ 07-30-2009, 12:52 PM: Message edited by: strabe ]

[Guest]

set the 2 flats on some parallels and then check the shaft all the way down it on both sides is another way

[Jim at Gentex]

Rotate the part or the v-block?

 

If you have precision v-blocks, I would clamp the shaft into the v-block with the flats perpendicular to the surface plate, aligning the flat vertically using a precision square to get it as close to vertical as possible.

 

Then I would flip the v-block on its side and check the first flat with a height gage and indicator to see if it is parallel to the surface plate. Adjust as needed by rotating the shaft slightly until you get a zero reading across the flat. Once you get a zero reading with the clamps tight, flip the whole v-block and part assembly onto its opposite side without unclamping it. Run the indicator over the second flat, and the difference will be the symmetry.

[Bruce Caulley]

I would just put the shaft on a surface table and check the gap on each side with slips.

 

Bruce

[MotorCityMinion]

What DEL said.

[3R!< W3NG3R]

get an electronic height gage. Perfect for things like that.

[Programinator]

thanks for all the comments. i tried a few of them and it worked out ok. Parts are good