Adjustable Cylinder Hone Tool Set 1 in to 7 in Bore, 4 Piece

A four-tool spring-loaded hone set that covers bores from 1 inch up to 7 inches, so one case handles brake wheel cylinders, caliper bores, master cylinders, small engine jugs and full-size automotive blocks. The kit includes a 1-1/8 in hone (1 in to 2-3/4 in range), a 2 in hone (1-1/4 in to 3-1/2 in range), and two heavy-duty 3 in and 4 in hones that between them cover 2 in to 7 in. Twelve extra 220-grit stones come in the case so you are not shelving the set the first time a set of stones wears down.

Each hone is a three-jaw self-centering design on a flexible shaft. The flex shaft lets the head follow the bore instead of fighting it, which is what keeps you from cutting a taper or a bell mouth at the top of the cylinder. The knurled nut at the base sets stone pressure: back it off for a light deglaze pass, snug it up when you are actually taking material out of a rusted or ridged wall. Bodies are zinc-coated A36 mild steel.

Bench use is straightforward. Chuck the shaft in a 1/2 in drill or air drill, flood the bore with honing oil or ATF, run the drill at low speed and stroke the hone up and down the full length of the bore at a steady rate. The stroke rate is what sets the crosshatch angle; roughly one full up-and-down per second at low drill speed gives the 45-degree pattern rings need to seat. Never start or stop the drill with the hone sitting still inside the bore, and wash the bore out with hot soapy water afterward, not solvent, or the grit stays in the crosshatch and eats the new rings.

The problem this solves is glazed and scored bores. A cylinder wall that has polished smooth will not hold oil, so new rings never seat and the engine burns oil and blows by from the first hour. Same story on the brake side: a wheel cylinder or caliper bore with light rust pitting will tear a fresh cup seal within a few thousand miles. A deglaze pass before reassembly is a ten-minute job that decides whether the rebuild holds.