Sutton 32mm Bridge Reamer #4 Morse Taper Shank - HSS

The Sutton R104 is a bridge reamer with a Morse taper shank, for machine use. It is for opening out existing holes and is ideal for alignment in fabrication and construction work. It is HSS with a bright finish (uncoated and polished) and 15° left-hand flutes.

There are 15 sizes from 13 mm to 32 mm, all with 5 flutes, and the shank taper steps up with the size: MT2 for 13 to 16 mm, MT3 for 17 to 30 mm and MT4 for 32 to 32 mm. Each reamer has a tapered lead at the tip: the catalogue gives a tip diameter (d2) and a lead length (l3) for every size, and the numbers work out to a 1 in 10 taper from the tip up to full diameter. The tapered lead lets the reamer start in a hole that is slightly out of line.

Where this product is used

• Opening out and aligning holes that have been drilled in separate pieces of fabricated or structural steelwork before they are bolted or pinned.
• Construction and fabrication jobs where holes in mating parts do not quite line up.
• Machine reaming existing holes to a clean, round finish on a machine fitted with a matching Morse taper socket.

Getting the best results

• Leave enough stock to cut. The starting guide for machine reaming is 0.20 mm for a 6 mm hole, 0.30 mm for a 12 mm hole and 0.50 mm for a 50 mm hole. Too little stock makes the reamer burnish rather than cut.
• Run slowly. The most efficient reaming speed is often about two-thirds of the speed you would drill the same material at, and the rule is that speed must not be high enough to permit chatter. Drop the speed again when you need close tolerance and a fine finish.
• Keep the feed up. Reaming feeds are usually much higher than drilling feeds: 0.038 to 0.10 mm per flute per revolution is a suggested starting point. Too low a feed can cause glazing, wear and chatter; too high costs accuracy and finish.
• Use straight cutting oil. In reaming the lubricant is chosen for finish rather than cooling, and that usually means a straight cutting oil.

General starting surface speeds for reaming:

If it chatters, wears quickly or breaks: Misalignment is a cause of breakage and wear, and the fix is to align the holes or use a bridge reamer, which is what this tool is for. Also check speed and feed, dirt or burrs in the spindle or socket, rigidity, and slow the approach feed as the reamer enters the work.

Key specifications

Related reaming tools

For precision finishing to H7 after alignment, the R101 machine reamer is a Morse taper machine reamer with a finer tolerance, and the R100 hand reamer covers sizes by hand. The Morse Taper Guide explains how to match the shank to your machine.

See also the Bridge Reamers collection. Having reaming problems? Our Cutting Tool Troubleshooting Guide covers reamers alongside drills and taps.