metal taper hole reamer (for 3mm-12mm dia. holes), high carbon steel. Made in Japan. ENGINEER tr-01

Great product super quick delivery

Great tool for making the tuning machine holes bigger on a guitar, I put some masking tape in the approximate position on the reamer and did a few test fittings. Cuts very quickly, very easy to use and much safer than drilling

I purchased this item as I had a 1590 style aluminium guitar pedal enclosure with a hole that needed enlarging by 3mm. The tool arrives in a cardboard-backed plastic wrapper and is pretty foolproof to use: you simply pass the detachable rod through the hole in the tool and rotate it.I'm not familiar with these kinds of tools and was expecting to have to spend a good part of 15mins twiddling the tool round and round but it literally took under a minute to get the job done and the resultant enlarged hole was very cleanly finished. I can't comment on how it compares to other similar tools or how it would fare with a harder material, but for my singular purpose I couldn't be happier with the result and would thoroughly recommend the item based on my experience.

It works well, although as other commenters mention you have to be careful not to scrape your knuckles.The vertical bar is not held in by friction or spring like some other tools so it slides out really easily, this makes it slightly harder to use but also means it can get separated easily when storing it away, I ended up making a foam insert to store it.

Used It on a instrument and now the tuner is brilliant and tunes up with great accuracy

I bought this to widen some 8mm holes in my guitar headstock to 10mm and this was perfect for the job. It took a little while but worth the effort.

This tool arrived on time and was as described. I had to widen thirty-two 3mm holes in metal struts and I did it fairly easily with this tool. However, I am not a DIY guy and I can only imagine how it could be used to give precise results. Tough protective gloves are necessary to prevent damage to fingers when working with this tool.

Accurate and well made with sufficient hardness leaving a smooth clean finish. I would recommend using a cutting paste for best fit.