The tapping arm worked great for tapping plenty of holes into6061 aluminium, 4041 steel, and ar500 steel plates.The only problem initially is figuring out what taps actuallyfit in the included collets though. From looking at the Q/A areasupposedly ISO 529 taps work, but the ones I ordered did not, including the metric ones too.Ended up finding imperial tapping collets from ToolLots.Tap sizes that seem to work with the included collets are the 3/16-18 in the m12others seem to be too large or need a little tape to keep in place.4/5 stars since the collets weren't simple to figure out, but saved a heck of lot of time on tapping ~80 holes in AR500 with 3% larger holes than standard in roughly 1 hour vs the 3 days it took for hand taping in a drill press.

Can't try it out yet as I need different taps. To help others mine came with DIN noted on the collets and I have the following shank/square requirements to use them.Collet Shank SQUARE DIN 371 SIZESM3 3.5 2.7M4 4.5 3.4M5-6 6 4.9M8 8 6.2M10 10 8M12 9 7

Can't try it out yet as I need different taps. To help others mine came with DIN noted on the collets and I have the following shank/square requirements to use them.Collet Shank SQUARE DIN 371 SIZESM3 3.5 2.7M4 4.5 3.4M5-6 6 4.9M8 8 6.2M10 10 8M12 9 7