Sutton 21/32" Hand Reamer ISO236 - High Speed Steel HSS

The Sutton R100 is a fixed-size hand reamer: each size is ground to its own diameter, so it is not adjustable, and you turn it by hand with a suitable tap wrench to take a drilled or bored hole to its final size and finish. It is made from HSS with a bright finish (uncoated and polished) and 10° left-hand flutes, and conforms to DIN 206 / ISO 236, producing clean, accurate holes to an H7 tolerance.

This is the fractional-inch R100 range: 46 sizes from 1/8 in (3.175 mm) to 1 in (25.4 mm), so you can finish holes to imperial drawings without converting. Flute count rises with size: 6 flutes at 3.175 to 8.731 mm, 8 flutes at 9.128 to 18.256 mm and 10 flutes at 19.05 to 25.4 mm. Working to metric drawings? The matching R100 Hand Reamer DIN206 range runs from 3 mm to 25 mm.

Where this product is used

• Hand-finishing drilled or bored holes to H7 in bearing housings, pin holes and precision assembly locations.
• Bench and toolroom work that calls for an exact, fixed hole diameter rather than an adjustable one.
• Maintenance and field jobs where a drill press or machine reamer is not available or practical.

Getting a clean, accurate hole

• Leave the right amount of stock. A common hand-reaming allowance is 0.08 to 0.13 mm. Too little and the reamer burnishes instead of cutting; too much and it is hard to turn by hand.
• Use straight cutting oil. In reaming, the emphasis is on finish rather than cooling, so a straight cutting oil is the usual choice.
• Start with a good hole. A badly drilled hole can cause all four problems (breakage, wear, chatter and poor finish); the fix is to replace the drill. Check the pre-hole before blaming the reamer.
• Hold the work firmly. Lack of rigidity is among the causes of breakage and chatter, and the fix is to improve rigidity. Turn steadily with a suitable tap wrench and keep the reamer square to the hole.

Fit and tolerance

H7 is the ISO 286 hole tolerance: the finished hole is never smaller than nominal and never larger than nominal plus the IT7 band, which is 10 µm up to 3 mm, 12 µm over 3 to 6 mm, 15 µm over 6 to 10 mm, 18 µm over 10 to 18 mm, 21 µm over 18 to 30 mm and 25 µm over 30 to 50 mm. Sutton holds the cutting diameter of its parallel reamers to M6 limits (BS 122 Part 2), which it says are chosen to produce H7 holes. For example, a Ø6.35 mm reamer has cutting diameter limits of Ø6.356 to Ø6.365 mm, and the finished hole is held within Ø6.350 to Ø6.365 mm (H7); a Ø12.7 mm reamer has cutting diameter limits of Ø12.707 to Ø12.718 mm, and the finished hole is held within Ø12.700 to Ø12.718 mm (H7).

Key specifications

Related reaming tools

Need to ream by machine instead? Look at the R101 machine reamer (Morse taper shank, DIN 208) or the cobalt R102 chucking reamer. For a hole size that sits between standard reamers, the R109 adjustable hand reamer covers a size range with one tool. Our Reamer Guide and the Surface Roughness Guide cover allowances, speeds and fits across the whole reamer family.

Having reaming problems? Our Cutting Tool Troubleshooting Guide covers reamers alongside drills and taps.