Description
Product Overview
This NT30 Boring Head is a solid, no-frills single-point boring tool designed for use in milling machines equipped with an NT30 (also known as NMTB30) spindle taper. Built from steel with a precision-ground body, it accepts a standard boring bar through its cylindrical bore and allows fine radial adjustment of the cutting tool via a graduated micrometer dial — giving the operator repeatable, measurable control over bore diameter without having to pull the head from the spindle. Whether you’re opening up a rough-drilled hole to a tight tolerance or finishing a bore for a press or slip fit, a boring head like this is the right tool for the job.
- Fine micrometer adjustment at 0.0005″ (half-thou) graduation — The dial ring is graduated in 0.0005″ increments, meaning each click of adjustment translates to a known, repeatable change in the cutting radius. This level of resolution is what separates a boring head from a slop-in, hope-for-the-best setup. For fitting bearings, bushings, or precision housings, half-thou graduation lets you sneak up on a target diameter with confidence.
- NT30 (NMTB30) taper shank — The NT30 taper is a direct-mount standard found on a wide range of knee mills, vertical mills, and older CNC machining centres. It seats directly into a matching spindle without an intermediate holder, which minimises stack-up runout and keeps the setup rigid — critical when single-point boring, where any flex translates directly into taper or chatter in the finished bore.
- Steel body with ground reference surfaces — The boring head body is machined and ground for concentricity. Despite the surface patina visible on the exterior, the functional surfaces remain smooth to the touch and the adjustment mechanism moves freely — the important thing is that the internal geometry is intact, not that the outside looks showroom-fresh.
- Compatibility — Fits any milling machine with an NT30 (NMTB30) spindle taper. Accepts standard boring bars in the cylindrical clamp bore on the head body. A boring bar and insert will be required to use this tool — neither is included. Check your spindle’s drawbar thread before mounting; NT30 spindles typically use a 1/2″–13 UNC drawbar.
- Ideal for — Finishing bored holes to close tolerance on a knee mill or vertical machining centre; opening drilled or rough-bored holes to bearing fit or slip fit dimensions; boring housings for press-fit bushings; single-point boring on manual mills in a toolroom, maintenance shop, or home machine shop.
Condition
Used (Fair Condition / Surface Patina and Discolouration, Mechanically Sound)
This boring head has seen workshop use and it shows on the outside, there is visible surface discolouration and light rust (patina) across the body, consistent with a tool that has lived on a bench or in a drawer rather than a climate-controlled cabinet. The seller confirms it has been kept lubricated and wrapped in plastic, which has preserved the functional surfaces: the adjustment mechanism is smooth to the touch with no rough spots or binding, and the micrometer dial turns freely with no evidence of damage to the graduation ring. The NT30 taper shank should be inspected on arrival for any high spots or dings that could affect seating, a light stone or fine file will deal with any isolated burrs before mounting. The bore clamping area and body faces should similarly be wiped down and inspected. Surface rust of this nature is cosmetic; it does not indicate structural compromise or loss of dimensional integrity in a solid steel tool of this type. Verify the head’s runout against a test bar or dial indicator after mounting, and confirm zero calibration of the dial before committing to a finishing pass. Recommended for a buyer comfortable with cleaning and verifying used tooling, the mechanicals are there, and a light clean-up will have this performing as intended.
Included
- 1 x NT30 Boring Head with micrometer adjustment dial (0.0005″ graduation)
Not Included
Boring bars, cutting inserts, drawbar, storage case. A compatible NT30 drawbar (typically 1/2″–13 UNC) will be required to mount this head in your spindle if not already on hand.
Brand Information
The brand markings on this boring head are not prominently visible in the available imagery, and no specific brand has been confirmed by the seller — this appears to be either an unbranded or OEM-manufactured boring head, likely of Taiwanese or Chinese origin based on the design conventions and construction style. Taiwanese-manufactured boring heads in this configuration have a reasonable reputation in the hobby and light industrial market as functional, fit-for-purpose tooling — they won’t match the concentricity guarantees of a Criterion or Wohlhaupter, but for manual milling work in a job shop or home machine shop, they get the job done. Buyers requiring certified accuracy or production-grade repeatability should factor in verification against a test bar before use.
Specifications
| Feature | Specification |
|---|---|
| Brand | Unbranded / OEM (not confirmed) |
| Type | Single-Point Boring Head |
| Shank / Mount | NT30 (NMTB30) Taper |
| Adjustment Graduation | 0.0005″ (half-thou) per division |
| Adjustment Dial | Micrometer-style dial ring, graduated 0–100 (visible in image) |
| Body Material | Steel (ground body) |
| Country of Origin | Not confirmed (likely China) |
| Condition | Used — Fair. Surface patina, light rust, discolouration. Adjustment mechanism smooth and functional. |
| Included Items | 1 x NT30 Boring Head |
| Not Included | Boring bars, inserts, drawbar, case |
Keywords
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