What can cause reamers to cut oversize?

When reamers cut oversize, built-up edges due to excessive stock allowance can contribute significantly to this issue. A reamer is designed to refine the hole size created by an earlier operation, typically drilling. If the initial drilling operation leaves too much material, excessive stock can lead to the formation of built-up edges on the reamer's cutting edges. These edges consist of material that has adhered to the tool due to heat and mechanical force during the cutting process, which can alter the effective diameter of the reamer. As a result, instead of achieving the desired hole size, the reamer may end up cutting an oversized hole.

While the other factors can impact the performance and accuracy of machining operations, they do not specifically relate to the direct cutting action and consequences seen with reamers in this context as effectively as built-up edges due to excessive stock allowance does. Incorrect drill sizes may affect hole precision before reaming, poor machine calibration may lead to overall inaccuracies, and insufficient cooling may cause tool wear and thermal distortion, but they resonate less directly with the issue of oversize cutting by reamers compared to the effects of built-up edges.