What Is a Straight Reamer?
A straight reamer is a type of blade used in reaming, a process for high-precision hole finishing. It is similar to a spiral reamer, which serves the same purpose.
Reaming creates holes with predetermined dimensions and minimal diameter discrepancies. This is achieved through high-precision finishing after drilling the initial hole.
These reamers are suitable for manual (hand) reaming or machine-assisted reaming.
Reamers vary in material, shank size, tooth length, and cost, ranging from a few dollars to 150 dollars. Recently, reamers are often available at relatively low prices on auction sites.
Uses of Straight Reamers
For instance, when using a hand reamer, one first drills a pre-hole, ensuring the dimensions match the intended finished hole. It is advisable to consider the reamer diameter and workpiece material when selecting the finishing allowance.
The reamer is then passed through this pre-hole for high-precision finishing. To ensure straight passage, it is sometimes necessary to use tools like a square to keep the reamer perpendicular to the workpiece.
Hand reaming requires experience, as consistent rotation speed and feed rate are crucial for quality finishing.
Principles of Straight Reamers
Straight reamers resemble drills with straight, lengthwise teeth. High-precision finishing is achieved by initially drilling a hole slightly smaller than the desired finished size and then passing the reamer through to remove the excess material, resulting in an accurately finished hole.
Compared to drilling, the allowance and blade shape of a reamer allow for a more accurate finish. However, there are factors to consider, such as the potential for slight surface cracking due to the straight blade. This can be influenced by clamping force, pre-drilled hole quality, cutting oil, and the rotation and feed rate. Manual machining requires significant experience.
The tooth shape of spiral reamers, used in similar applications differs. Spiral reamers have twisted teeth, producing facets directed from the tip of the machining section toward the hole’s entrance in the workpiece.
When selecting a new straight reamer, consider a variety of products from different manufacturers, ensuring compatibility with the workpiece to be machined.