Dial calipers are a must have in the shop. You can use them to confirm dimensions and if you truly want a flush wood to metal fit, using calipers is a must since each part and bushing has a +/- 0.002 tolerance. The graduations are 0.001 each. Giving you a resolution of 0.0005 or better. These calipers can measure up to 6" in length. They can measure ID, OD, and depth. The cost is around $22.00.