What is the LMC size?

LMC is the condition in which there is the least amount of material, the largest hole or smallest pin, within the stated limits of size. In our example in the animated Figure 2, we can observe that the MMC of the pin is 25 mm, while the LMC is 15 mm.

What does LMC mean in GD?

To apply the least material condition to a dimension, you write after the size tolerance in the feature control frame. In some cases, a datum symbol may be followed. “L” stands for “least material condition” (LMC). This symbol indicates the application of least material requirement.

Does profile tolerance required datum?

Profile can control, form, location, orientation, and size or any subset of these. Profile can be used with or without datum references and with or without basic dimensions.

What does LMC stand for and what does it refer to with respect to the shaft in a hole shaft tolerancing?

Least material
Definition: Least material condition is a feature of size symbol that describes a dimensional or size condition where the least amount of material (volume/size) exists within its dimensional tolerance.

Why is MMC LMC needed?

Maximum material condition (MMC) is used to indicate tolerance for mating parts such as a shaft and its housing. Least material condition (LMC) is used to indicate the strength of holes near edges as well as the thickness of pipes.

Can a form tolerance override Rule 1?

There are two ways Rule #1 can be overridden: If a straightness control is applied to a feature of size, Rule #1 is overridden. If a note such as “Perfect Form at MMC Not Required” is specified next to a FOS dimension, it exempts the FOS dimension from Rule #1.

Is there bonus tolerance at LMC?

As the size of the pin departs from MMC toward LMC, a bonus tolerance is added equal to the amount of change. Bonus tolerance equals the difference between the actual feature size and the MMC of the feature.

How do you find the true position of a hole?

True position can be calculated using the following formula: true position = 2 x (dx^2 + dy^2)^1/2. In this equation, dx is the deviation between the measured x coordinate and the theoretical x coordinate, and dy is the deviation between the measured y coordinate and the theoretical y coordinate.

What is a least material condition?

Least Material Condition (LMC) is that condition of a part or feature which contains the minimum amount of material, e.g. maximum size hole or a minimum size shaft. Circumstances do arise where, for example, a designer would want to limit the minimum wall thickness between a hole and the side of a component.