Straight Flute Chucking Reamer: .618"  (aka: Sub-5/8 for many of the more popular guts that are too small for a 5/8" bore)

Each gut on our site has the bore size suggested by the manufacturer listed in the item description.

Shank Dia: ≈ 9/16"

Drill your hole 1/64 - 1/32 undersize, and then run the reamer through the bore to open it up to 5/8" - Suggested speed: 100-200 RPM fed into material at a moderate speed.  (The general rule for reamers in wood and metal is to run 1/2 the RPM as the same size drill bit, and feed it into the material 2x as fast as the same size drill bit)

The harder the material - the less undersize the initial hole should be.  For example, wood works fine with 1/64 to 1/32" undersize, but acrylic is better suited to start with a bore only marginally undersize (usually 1/64" or less).  Acrylic requires even slower RPM as well as a reduced feed speed and increased amount of lubrication compared to drilling - 100 RPM or less is suggested in acrylic and LOTS of lubrication.

Guts this reamer works best with:  SR3, SR4  - It is marginal for use with the SR2 and SR11 guts... will work in some cases, and others may be just touch too large due to minor variations from gut to gut.

This is an Import Chucking Reamer