Fits and tolerances

Question 1

What is MMC?

Answer 1

The maximum material condition, the most amount of material on a part that will keep it in tolerance. On a shaft it will be the widest diameter and the bore/ whole would have the smallest diameter

Question 2

What is LMC?

Answer 2

The minimum allowable material that will keep the part in tolerance

Question 3

What is an interference fit?

Answer 3

It is when the diameter of the shaft is always larger than the mating hole even if the shaft is in LMC

Question 4

What is a clearance fit?

Answer 4

The diameter of the shaft is always smaller than the mating hole, even if both parts are at MMC

Question 5

Where should you shot for when machining parts and how do you get there?

Answer 5

You want to shoot for the average of the allowance or the middle of tolerance. You get the average by adding the tolerance’s together and diving by two. You then add that to the LMC or Subtract it from the MMC

Question 6

What are the three types of fits?

Answer 6

clearance, interference and transition