SIMDUNL 28-4 — boring bar, 1.75" bar diameter, 2.500" minimum bore, 14.0" overall length. Made in the USA by RMC Tooling.
-3° End Cutting Edge Angle for Negative 55° Diamond DNM_ Inserts.
Steel-shank indexable boring bar from RMC Tooling, machined in the United States. Ground shank, standard indexable geometry, and a rigid clamping system sized to the bar diameter — the combination that keeps chatter down at the depths where boring bars usually give up.
Sized by minimum bore, so start there: pick the largest bar diameter your bore will clear. Every clamp, lock pin, seat and screw in this bar is a stocked RMC service part, listed below.
These are the service parts RMC lists for this exact model — not a generic cross-reference. Every one is stocked.
| Insert | DNM_-432 (e.g. DNMG 432) — 1/2" I.C. · 3/16" thick · 1/32" nose radius |
| Seat / shim | IDSN-433 |
| Lock pin | NL-46 |
| Clamp | CL-12 |
| Clamp screw | XNS-59 |
| Seat screw | S-46 |
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 48.
