For the best reaming results, prepare your holes with just the right amount of stock for the reamer to remove. Too little, and the reamer will rub, leaving a smaller diameter than expected. Too much and the hole may be oversized and have a rough finish. Since reaming is about precision, use stub length tools where possible. The following is an example of how to ream a hole in metal. In this example, we are reaming a 5/16" (.3125") hole in soft, mild steel, step by step:

Reamers are multi-fluted cutting tools used to enlarge existing holes to a precise diameter. They are available in a variety of shank styles that can be mounted into hand tools, chucks, collets, or other tool holders, and are used in a variety of portable or stationary machines such as drill presses, lathes, screw machines, milling machines and more. The cutting end is ground with a 45° chamfer angle for easy entry into the hole. Straight fluted reamers are best for through holes, left-hand spiral flute models are better in blind hole applications. Available in a variety of materials, to suit the application and workpiece material, and some are available in almost any size imaginable. Light cutting oil or coolant is recommended for reaming operations.

Chucking Reamers, or “Machine Chucking Straight Shank Reamers” are used to enlarge existing holes to a very precise diameter. Chucking reamers have round, straight shanks which can be mounted in chucks, collets, or other tool holders, and are used in a variety of portable or stationary machines such as drill presses, lathes, screw machines, milling machines and more. Chucking Reamers are available in almost any size imaginable.

Step 9: Since reaming doesn’t require heavy cutting fluids for optimal performance, use lighter oil or coolant. This will help to produce an accurate size hole and a smooth Finnish.

Step 6: Drill the hole with a size N drill (0.302”). Peck drill to prevent chips from jamming and scoring the walls of the hole.

STC-1 with 10 edges Biggest advantage for any long threads from M24: A shorter process time compared to cutters with inserts and easier assembly.

We believe the Right Tool Is Everything™, and we strive to share our experience and expertise in an effort to ensure you select the right tool for your application, follow best practices, and can push your productivity further.

Smooth cutting and low cutting pressure results in high surface quality and long tool lifes. A conical position of insert pocket guarantees stability of the tool shaft. Further advantages are a radially back ground thread profile, extremely high wedge angle, a more stable cutting edge as well as a positive rake angle. The optimum application area are fine threads and/or very short thread lengths.

Watch this video to learn how to use a reamer to properly and efficiently ream a hole! Tech Team Expert Kurt Repsher walks you through the do's and don't's of reaming a hole with a hand reamer from planning to execution. Subscribe to our YouTube Channel to see more how-to application videos like this one!

A reamer is a cutting tool that is used to open the size of an existing hole by a small amount. A reamer will leave a smoother finish and a more precise size than a drill. Hand reaming, or reaming a hole without coolant or oil will result in an oversized hole and a rougher finish. Avoid reaming to the bottom of a blind hole.

Adjustable Blade Reamers are versatile reamers due to their broad size ranges and are used by hand for resizing of hole diameters to a precise size. The replicable blades slide within tapered slots in the reamer body by loosening the nut at one end and tightening the nut at the other end, allowing the reamer to maintain a specific size. Adjustable Blade Reamers are recommended for through-hole operations.

Step 3:. Subtract 3% (since we’re working in mild steel) from the reamer diameter to determine the best drill size. (For example, .3125 – 3% = .3031"). A good rule of thumb to find the best drill size is to subtract 2% to 4% from the reamer size. 2% for harder metals, and 4% for softer materials.

Step 10: Ream hole with a 5/16” reamer. Don’t stop or peck with the reamer until it exits through the bottom of the hole. With the machine turned off and the spindle completely stopped, pull the reamer straight up, out of the hole.

Step 2: Locate & spot drill hole using a spot drill with a slightly greater taper than the drill being used. (For best results, avoid using a center drill (combination drill & countersink.)

Taper Shank Chucking Reamers are like Machine Chucking Straight Shank Reamers, but these have a Morse Taper shank that will fit a same-size Morse Taper spindle, socket, or toolholder. They’re multi-fluted cutting tools, used to enlarge existing holes to a precise diameter. The shanks on these reamers are used in a Morse Taper spindle, socket, or toolholder.

The affordable system with high performance allows threading and / or circlip grooving in high precision. The polygonal connection of insert and milling body improves the efficiency and precision of the process significantly:

Bottom threads can be cut almost to the bottom without undercuts. By using the same pitches, the storage and acquisition costs decrease also.

For a complete listing of all reamer types and styles, view or download our comprehensive Holemaking Guide, available via the link below.

Shell Reamers are also like Machine Chucking Straight Shank Reamers and Taper Shank Chucking Reamers but without a shank. They are used with a shell reamer arbor, which fits the hole in the reamer. Shell reamers are used to produce larger holes of 3/4" diameter or greater. Shanks/arbors are sold separately and will fit a range of Shell Reamer sizes, which makes these reamers an economical choice for your large-hole reaming needs.