6 Pcs High Speed Steel HSS 4241 1/4 Inch Hex Shank Screw Thread Metric Tap Drill Bit M3/4/5/6/8/10 Combination Drill and Tap Set

I actually love these little things, but there's a little technique required to use them successfully. I've used them on plastic (great for threading 3D printed parts), aluminum and steel electrical conduit. I see the complaints about them snapping in other reviews and I see how easily this could happen. Here's my $0.02 on using them successfully...First, I'd advise you to use them in a hand-held drill, even though this seems somewhat counterintuitive with regards to tapping threads. The reason for this is once the pilot hole goes in so far, the thread cutters will start to grab and grab HARD. When this happens you get off the trigger in a hurry. Then re-engage slowly and carefully.Second, don't use them on material that is thicker than the length of the pilot drill parts of the bit. If you do, what will happen is that you'll still be drilling a pilot hole and the cutting threads will grab and either the piece will fly out of your hand or, if held down well, will either strip out the threads you're trying to cut or snap the bit off.Finally, if you MUST use these in thicker material, drill the pilot hole with a separate bit. These aren't a replacement for a tap and die set, but they are very convenient if you have the right application. Try practice pieces (in a soft material)until you get the hang of them and I think you'll come to like them as much as I do.

Wow! It did what I expected it to do. Drilled perfectly through aluminum making threads for 4mm screw. I would buy again....

Not suitable for hard tempered steel. The second you pass drill portion and getting in to tap portion - its snaps.Will work on brass or aluminum, but not hardened steel.

Buen producto, no tienen tan buena calidad pero esta bien por el precio pagado.

Product was garbage every bit I used they broke in half not a happycustomer

I am happy with them.

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The smaller sizes are very fragile and i broke a few.