After the pilot bore is complete, the reamer is pulled back through the hole to enlarge it to the diameter needed for the product pipe. Choosing the right reamer type and size is critical for a clean, stable bore. The wrong reamer can collapse the bore wall, cause excessive torque, or leave the hole too rough for product installation. This guide covers the main reamer types available for Vermeer and Ditch Witch rigs.

How to Size a Reamer

The general rule of thumb is to ream the hole to 1.5× the OD of the product pipe being installed. For example, if you are installing 4″ HDPE pipe, you would typically ream to 6″. In unstable or collapsing soils, you may need to ream to 2× the product pipe OD to maintain a stable annulus for the drilling fluid.

Reamer Types by Ground Condition

1. Tornado® Reamer — Sand, Clay, and Mixed Soil

The Tornado is Melfred Borzall’s best-selling reamer for soft to medium ground conditions. Its spiral blade design creates a smooth, circular bore and efficiently moves cuttings back to the entry pit. Available in compact versions for the Tri-Con™ system (6″, 8″, 10″ cut diameters) and standard versions for larger rigs. The Fastream® cutter blocks for the FastBack® system are modeled after the Tornado design.

2. Juggernaut® Reamer — Cobble, Gravel, and Hard Clay

The Juggernaut is designed for harder, more abrasive ground conditions. It features carbide-tipped cutting blades that can handle cobble, gravel, and hard clay without excessive wear. Available in compact versions for the Tri-Con™ system (6″ and 8″ cut diameters).

3. Barrel Reamer — Soft Soil and Packer Applications

The Barrel reamer (also called a packer reamer) is used in soft, uniform soil conditions and for swabbing the hole clean before product installation. It has a smooth, cylindrical design that packs the bore wall rather than cutting it. Available in compact versions for the Tri-Con™ system (4″ and 6″ cut diameters).

4. Vermeer Mix Master™ HD Reamer

Vermeer’s Mix Master™ HD reamer is designed for soft to medium soil conditions and is optimized for mixing drilling fluid with cuttings to create a stable slurry. It is available in multiple sizes and is compatible with the QuickFire® connection system for fast field assembly.

Quick Reference: Reamer Selection Guide

Ground Condition	Recommended Reamer	Notes
Soft clay / sandy loam	Tornado® or Barrel	Barrel for swabbing/packing; Tornado for cutting
Medium clay / mixed soil	Tornado®	Best all-around reamer for most conditions
Sand / loose gravel	Tornado® or Juggernaut®	Juggernaut for abrasive sand
Cobble / hard clay	Juggernaut®	Carbide tips for hard ground
Direct pullback (up to 12″)	Fastream® Cutter Blocks	Used with FastBack® system — no need to remove drill head

FastBack® System: Ream and Pullback Without Removing the Drill Head

For shots up to 12″ product pipe, the Melfred Borzall FastBack® System allows you to backream and pull back the product pipe without ever removing the drill head. Bolt-on Fastream® cutter blocks attach directly to the SD Housing and are available in 2.5″, 2.75″, and 3.25″ shaft diameters with cutting diameters from 4.5″ to 12″. This dramatically reduces production time on residential service line shots and short commercial bores.