# Coplanarity Profile Callout Confusion

Engineering Asked on January 1, 2022

From Krulikowski (1997), the callout for several coplanar surfaces using the Profile symbol is done by using two surfaces to establish datum plane A-B and then tolerancing the remaining coplanar surfaces in reference to A-B.

Can other non-coplanar features reference this datum plane A-B as I would a normal datum? See below for example.

In the O-ring groove above (2.5 x 1.6), the callout on the left is for coplanarity. The callout on the right is for location and form, NOT coplanarity. I guess it would be obvious that it is not coplanar, but something about it looks off.

Is referencing datum A-B for non-coplanar features legal, illegal, or just plain bad notation? Or is it just a matter of preference?

I think you need something inline with this:

Note that the datum A is identified by using an indicator under the callout. A-B could equally be used with the same meaning if you identify the two surfaces.

You can have more explanation in ASME 14.5:2018 figure 6-6.

Answered by Jean-François MAUREL on January 1, 2022

This is fine, but not typical for cylindrical faces.

The Profile GD&T symbol describes a 3D tolerance zone around the face, and as such is typically used for complex surfaces where other symbols cannot be used. See https://www.gdandtbasics.com/profile-of-a-surface

Answered by Jonathan R Swift on January 1, 2022

## Related Questions

### Types of articulation

1  Asked on October 28, 2020 by mcccccc

### How can I get final value of $V_{out}$ at $t=∞$ in RC circuit?

1  Asked on October 27, 2020 by hihello

### Rack and Pinion: Increasing Linear Movement of Rack

1  Asked on October 25, 2020 by joe-bloggs

### Effects of constructed tubular/annular beam upon moment of inertia

2  Asked on October 25, 2020 by user16

### How to calculate Average temperature from area under the curve?

4  Asked on October 22, 2020 by scico111

### Fluid Mechanics – Fluid flow

1  Asked on October 22, 2020 by zaki

### Shear modulus in terms of 2 Young’s moduli and Poisson ratio

0  Asked on October 14, 2020 by mikeb

### Which kind/model of sensor is appropriate for detecting vibration at one end of 1000 m steel block?

1  Asked on October 9, 2020 by masfiqur-rahaman

### In what cases we use both LRFD and ASD approaches in structural analysis?

0  Asked on October 9, 2020 by user3600630

### Can You Identify This Deep Groove Ball Baring Bearing and/or Give an SKF Equivalent?

0  Asked on October 7, 2020 by nicholasm

### Regarding automotive engine mounts

1  Asked on October 3, 2020 by ss4

### Mechanical vibration of objects

1  Asked on October 3, 2020

### Meaning of flow rate in water pump

1  Asked on September 27, 2020 by jtl

### Some questions about the specific speed (Ns) of hydro turbines

1  Asked on September 27, 2020 by sithvincent

### How to add friction to a rope without using abrasion

2  Asked on September 25, 2020 by john-henckel

### Window mounted split air conditioner

2  Asked on September 24, 2020 by jean

### Material selection of heating element

3  Asked on September 23, 2020 by eddiep

### How were the tones for DTMF chosen?

1  Asked on September 22, 2020 by natebot13

### Why Do Airborne Wind Energy Systems Use Kites And Not Balloons?

1  Asked on September 21, 2020 by georgewtrump

### Anti-Squat Force Transmission

1  Asked on September 17, 2020 by redhelmet