LMT Onsrud 56-310 5/16" Solid Carbide 2-Flute Straight V-Flute Router Bit for Wood – 1-1/8" Cut Length, 1/2" Shank, 3" OAL

The LMT Onsrud 56-310 is a 5/16" solid carbide, two-flute straight V-flute router bit from Onsrud's 56-300 wood series, ground for a superior finish and long cutter life in hardwood, softwood, and wood composites. A straight flute cuts with no upward or downward pull on the material, which makes it the right choice for dadoes, grooves, mortises, and inlay pockets where you want a flat, clean floor and crisp walls without lifting veneer or fuzzing the top edge. The heavy 1/2" shank behind a 5/16" cutting diameter gives this bit far more rigidity than a 5/16"-shank tool, so it holds size on deep passes and resists deflection on long cuts.

LMT Onsrud 56-310 specifications

What the 56-310 is designed to cut

• Hardwoods such as oak, maple, walnut, and cherry
• Softwoods and plywood
• MDF, particleboard, and laminated wood composites
• Veneered and melamine-faced panels where edge chipping must be minimized

Straight flute vs. spiral: when to pick this bit

A spiral upcut pulls chips out of the cut but can tear the top edge; a downcut leaves a clean top but packs chips into a deep slot. A straight V-flute does neither. It shears the material cleanly on both edges, which is why straight-flute carbide bits remain the standard for grooving, dadoes, and inlay work in cabinet shops. Keep passes shallower than you would with a spiral and let dust collection do the chip clearing.

Fitment

The 1/2" shank requires a 1/2" collet: ER20, ER25, ER32, or a 1/2" collet on a full-size router. It will not fit 1/4"-collet trim routers or ER11/ER16 spindles. The 5/16" cutting diameter is a direct match for 5/16" hardware slots, 8 mm-class dadoes, and standard shelf-pin and T-track grooves.

Frequently asked questions

Why is the shank bigger than the cutting diameter?
Rigidity. A 1/2" shank with a short 5/16" cutter deflects far less than a 5/16" shank, so you get better accuracy and longer tool life on deep grooves.

Can I plunge straight down with a straight-flute bit?
Yes, at a reduced plunge rate. For repeated deep plunges, ramp or helix into the cut to reduce load on the tip.

Is this bit suitable for plastics?
It will cut plastics, but LMT Onsrud's 56-000P series is ground specifically for hard plastics and solid surface. The 56-310 is optimized for wood.

Genuine LMT Onsrud tooling, manufactured in Waukegan, Illinois, USA.