Replies to this message

Re: IN GD&T-HOLE POSITION TOLERANCE
: IN GD&T-HOLE POSITION TOLERANCE -- G.Manikandan	Post Reply	Top of thread	Engineering Forum

Posted by: gm2612 ® 01/21/2006, 10:02:37 Author Profile eMail author Edit

Hi, Please send the detailed question about it. I think, I can try to clarify you to little extend. Thanks and Regards, G.Manikandan

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

|   |

Re: IN GD&T-HOLE POSITION TOLERANCE
: IN GD&T-HOLE POSITION TOLERANCE -- G.Manikandan	Post Reply	Top of thread	Engineering Forum

Posted by: traingdt ® 07/04/2005, 10:44:32 Author Profile eMail author Edit

If you are seeking a general explanation of a position tolerance, it can be summarized this way: Position (sometimes called "true position") is a GD&T method of controlling the location for a feature of size (hole, pin, slot, etc.). It has three distinct advantages over the traditional plus/minus method. 1. GD&T's position always includes one or more datums to explicitly relate the hole back to another feature. And the sequence of the datum letters implies the order of precedence in setting up the part. 2. GD&T position is not restricted to a square-shaped tolerance area, which is what we had with traditional x-y coordinate control. So, with GD&T position, we often include the diameter symbol in front of the number to indicate a cylindrical tolerance zone. This makes more sense for a feature like a hole or a pin. 3. GD&T position can also be modified with the MMC or LMC symbols (shown as a circled M or circled L, respectively). This would indicate that the given tolerance applies when that hole (or pin) is at its MMC or LMC size. The position tolerance can then deviate from the given number as the size of the hole varies. This is a very useful concept that saves money by realizing more usable parts, and should be used for any clearance fit! There are some position calculations on Engineers Edge that will give you a picture of how position works: /true_position.htm Hope that helps!

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

| |

: Re: IN GD&T-HOLE POSITION TOLERANCE
: Re: IN GD&T-HOLE POSITION TOLERANCE -- traingdt	Post Reply	Top of thread	Engineering Forum

Posted by: samraj ® 04/09/2009, 10:24:02 Author Profile eMail author Edit

Hi friends, In GD&T positional tolerancing what is the meaning of the second and third datums (eg) if datums are A ,D and C , the datum A means the hole centre from which the coordinates must be calclated but what dose the other datums means, my assumption is that the second and third datums means the perpendicularity , angularity etc.. should also be calculated. please reply me if you know the correct answer.....

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

| |

: : Re: IN GD&T-HOLE POSITION TOLERANCE
: : Re: IN GD&T-HOLE POSITION TOLERANCE -- samraj	Post Reply	Top of thread	Engineering Forum

Posted by: Kelly Bramble ® 04/09/2009, 10:26:31 Author Profile eMail author Edit

No way to know without seeing the drawing and specification. Make a gif or jpg and attach to this forum. BTW, welcome to Engineers Edge!

Post Reply Tell a Friend (must be logged in) Alert Admin About Post

Where am I? Original Top of thread

|   |