How would you measure this hole location?

[BANDY]

I have this hole that is dimensioned from the flanges around it. It shows that the flanges are 0.400 from the tangent of the hole.(see bp) I was thinking of creating some points on the flange offsetting them 0.400, then create a plane from these points, then measure the hole with a cylinder then try to construct a point at the intersection of the plane and the cylinder. I wonder if this is going to work, anyone done this before?

[John Riggins]

For flange 1: I would measure a plane (construct from points) on the flange and then do a 3D distance from the circle to the plane (subtract radius).
For flange 2: the same, except that flange looks curved. If your tolerance is great enough then the above method will probably be ok. (maybe it isn't curved, looks close enough to flat that it is probably ok)

[BANDY]

Yes, I think that will work, as usual I was over complicating the method. Thanks for the reply.

[Andrew Gardner]

That's how I used to measure holes from flanges before.

[Paul Sarrach]

That's how I used to measure holes from flanges before.

Okay, then how do you measure them now?

[JamesMannes]

For flange 1: I would measure a plane (construct from points) on the flange and then do a 3D distance from the circle to the plane (subtract radius).
For flange 2: the same, except that flange looks curved. If your tolerance is great enough then the above method will probably be ok. (maybe it isn't curved, looks close enough to flat that it is probably ok)

Using 3D will give you a value that includes all three axis'.

What you want to do is be sure that you are in the correct view plane (if looking down from above it would be +Z), open dimension tab "distance" choose the circle and then choose the plane, choose subtract radius, choose "feature to feature". This will give you a distance that is parallel and/or perpendicular to your features.

[Matthew D. Hoedeman]

How I would measure them, since I see NO datums called out, I ouwld measure all of the features back to the ABC datums, using the CAD data. I would call those 'build dimensions', dimension put on the print so that a cad model can be created.

[Paul Sarrach]

Using 3D will give you a value that includes all three axis'.

Okay, I am lost. 3 axis's? I believe a Plane to a point ( Centroid ) would give you a perpendicular distance ( one axis ). Am I missing something here?

I would use pre-hits when taking that circle.

[JamesMannes]

Okay, I am lost. 3 axis's? I believe a Plane to a point ( Centroid ) would give you a perpendicular distance ( one axis ). Am I missing something here?

I would use pre-hits when taking that circle.

As far as I understand the 3D distance feature, it is workplane independant, and will report a value that is "as the crow flies". That is using a 3D line from centroid to centroid.

Yes, No, maybe so?

[Paul Sarrach]

As far as I understand the 3D distance feature, it is workplane independant, and will report a value that is "as the crow flies". That is using a 3D line from centroid to centroid.

Yes, No, maybe so?

A crow does not fly in a strait line, but the shortest distance to any two things is. Which is only one axis. Yes/No? Then I have a whole lot of reports that are bogus.

[george frick]

something to think about: are the flanges defining the location of the hole
or is the hole defining location of the flanges? .40=2 pl decimal- plenty of
tolerance either way. what do you think?

[JamesMannes]

A crow does not fly in a strait line, but the shortest distance to any two things is. Which is only one axis. Yes/No? Then I have a whole lot of reports that are bogus.

I need some thinking time on this one. I would like to think I'm right, but on the rare occasion it hasn't gone my way. I'll be back in 2 and 2.

[Paul Sarrach]

something to think about: are the flanges defining the location of the hole
or is the hole defining location of the flanges? .40=2 pl decimal- plenty of
tolerance either way. what do you think?

I believe its location of flanges. They just want to make sure there is enough material there for what ever reason. I would bet this weeks check its a Profile callout.

[Wingman]

As far as I understand the 3D distance feature, it is workplane independant, and will report a value that is "as the crow flies". That is using a 3D line from centroid to centroid.

Yes, No, maybe so?

3D distance from a PLANE is NORMAL to the Plane.

[Matthew D. Hoedeman]

As far as I understand the 3D distance feature, it is workplane independant, and will report a value that is "as the crow flies". That is using a 3D line from centroid to centroid.

Yes, No, maybe so?

3D distance from a PLANE is NORMAL to the Plane.

3-D distance in a 'free' dimension. It is not dependant on workplane, alignment, or anything else. ALL features have a centroid, and XYZ value that will show in a DIMENSION LOCATION, that XYZ to the centdoid of any other feature (XYZ) is the 3-D distance. It is the old formula, RADIUS OF A SPHERE:

sqrt(Xdiff^2 + Ydiff^2 + Zdiff^2)