MTHOL 12-3B Tool Holder Gang Tool Holder for Shallow Grooving or I.D. Threading for Triangle TNMA_Inserts

MTHOL 12-3B — toolholder, 0.750" square shank, 4.5" overall length. Made in the USA by RMC Tooling.

Gang Toolholder for Shallow Grooving or I.D. Threading for Triangle TNMA Inserts.

Indexable turning toolholder from RMC Tooling, machined in the United States. The shank is ground to a qualified reference surface, so the tool goes back into the turret at the same cutting-point location every time it is swapped — no re-touching off, no lost setup.

Built for production lathes and CNC turning centers. The insert pocket, seat and clamping hardware are all standard RMC service parts, listed below, so the holder stays in service for years instead of being scrapped when a clamp screw strips.

Specifications

• Model: MTHOL 12-3B
• Shank width (A): 0.750"
• Shank height (B): 0.750"
• Overall length (C): 4.5"
• Head length (E): 0.875"
• Maximum bore (M): 2.0"
• Minimum I.D. for grooving: 0.100"
• Blade length (L): 1.50"
• Holding method: clamp and locking pin
• Insert shape: triangle
• Holder style: threading and shallow I.D. grooving
• Holder rake: neutral
• Hand: left hand
• Shank qualification: qualified back and end, 4.5" long
• Brand: RMC Tooling — made in the USA

Exact replacement parts for this tool

These are the service parts RMC lists for this exact model — not a generic cross-reference. Every one is stocked.

See all RMC spare parts & hardware →

Not sure how to read an insert code? Turning insert designation explained.

Dimensions as published in the RMC 2020 catalog, page 16.