Brush Research GBD31218 FLEX-HONE®, 3-1/2" (89mm) Diameter, 180 Grit, Silicon Carbide, For Mild Steel, Stainless Steel Cast Iron and Softer Ferrous Materials

I recently used the Brush Research GBD40024 FLEX-HONE® (4”) while freshening up the cylinders on a small block Chevy 350, and I’ve got to say—this tool impressed me.Right out of the box, it felt solid and well-made. I chucked it into a cordless drill, added some honing oil, and gave each bore about 5–10 seconds of low-speed rotation. The crosshatch pattern it left was textbook perfect—clean, consistent, and exactly what you want before dropping in new rings.What I really appreciated was how forgiving it is, even if you’re not a pro machinist. It centers itself well and doesn’t gouge or chatter. It’s one of those tools that gives you great results without needing a bunch of setup or precision tooling.One heads-up: it’s not cheap, but the quality and time it saves make it absolutely worth the price. If you’re rebuilding an engine or refreshing an old bore, this hone is a no-brainer.

Works good. Used on a 07 chevy 5.3L flawless & good quality

Really good tool, used on a 6.0 LS block and a 6.2 LT worked perfectly

I use these regularly to hone cylinders and they definitely have a great finish and an excellent price point. I buy these in this brand anytime I need a good hone brush.

Working through my first engine rebuild and wanted to do it right.I would highly suggest reading through several sets of instructions and watching several videos on how to do this. Once you figure it out, it is super simple. Worked well and gave a good cross hatch finish on my cylinders. My only complaint would be one of the balls fell off during use. Other than that still worked fine.

Used this to hone four cylinders in a two-stroke outboard motor. Didn’t take long for the honing balls to start breaking off as they passed by the cylinder wall ports. Luckily the ball stems are plastic and didn’t damage the cylinder walls. Eventually got the job done, though, producing a nice crosshatch surface finish.

Very good

Used on a 327 that had previously been bored .30 over and just needed a little freshening up.The flex hone and oil did a great job.10/10 recommend