HSS Drill Reamer .240" Aircraft Tooling 900120-240, Spiral Flute x 6" Long

A high-speed steel (HSS) drill reamer marked .240 inch (6.10 mm) nominal, about 6 inches long with a spiral flute. It carries the part number 900120-240 and is aircraft tooling.

The spiral flute clears chips along the length of the cut and helps the tool finish deep holes to a precise diameter and a smooth bore. A 6 inch length gives the reach to size holes that sit well below the surface, the kind found in aircraft and aerospace structural assembly as well as general machine-shop and MRO hole finishing.

This is a single used tool. Sold as-is, surplus from King Surplus inventory in Del Rio, Texas. Same-day shipping on orders before 3:00 PM CT.

• Manufacturer: none. No manufacturer name is legible on the tool, and no serial number appears in any photograph.
• Type: Drill reamer, spiral flute, as shown in the photographs
• Markings, as photographed: DET .8 and S. Engraved text above the "DET .8" marking is obscured and this pass does not resolve it.
• Part number: the item title reads 900120-240 and this record's Model field (FID 57) reads 900120-240924. Neither is legible in the photographs, so neither is confirmed here and the two forms are reported as they stand.
• Diameter conflict, reported not resolved: the title and the previous entry state .240 in (6.10 mm) nominal, while this record's own Model field records a caliper reading of .2117 in. Those differ by more than 0.028 in, which is far outside any reamer tolerance, so they cannot both describe the cutting diameter. Both are stated here and neither has been picked over the other. A tool of this kind must be measured before it is sold on a diameter claim.
• Overall Length: approximately 6 in - OUR measurement. This is not a factory marking.
• Material: not established. The title and the previous entry state HSS, but no material marking appears on the tool and the tool is unbranded, so no maker's catalogue applies. HSS is not asserted here.
• Flute count, helix angle, shank type and tolerance class are not marked on the tool and are not stated here.

Spec Basis: Verified 2026-09-16 against this tool's own photographs (KSC record 8473), cross-checked against Manufacturer (FID 56, "Generic") and Model (FID 57). The prior entry gave "Diameter: .240 inch (6.10 mm) nominal", "Material: HSS" and "Part Number: 900120-240" as plain specifications. None of the three is supported by the photographs, and the diameter is contradicted by our own caliper reading held in FID 57; all three are now stated with their source and their conflict.