I just picked up a hole saw kit, including a 4.5-inch hole saw. I was excited when it cut through the metal of a conex box with ease, but then I tried to make another cut and all the teeth smoked off the saw. Is this a common issue, or did I just get a bad one?
3 Answers
Honestly, hole saws can be tricky to use effectively and tend to wear out quickly, especially the larger ones on flat metal. If you're welding, a torch is often better, but for tight spots, a hole saw works well—just be ready for a longer cutting time and always use lubrication!
Using cutting fluid and running the drill slowly is crucial. I work with metal frequently and learned the hard way. I eventually switched to a carbide set because they last longer. Just keep the speed in check!
I thought the same about my blades until I checked; turns out, mine were bi-metal too. Always assumed carbide was the way to go!
It sounds like you might be spinning it too fast! A lot of people run hole saws way quicker than they should. For a 4.5-inch size in mild steel, you really want to be around 75 RPM. That speed helps keep the teeth sharp and reduces burning.
Exactly! I've done 2" holes in 1" thick plates with a regular bi-metal hole saw by using a magnetic drill on low speed and plenty of oil. Super important to control the speed.
Totally agree! And be careful about which brands you buy. Some new Milwaukee models don't hold up well at all. I switched to Bosch after a couple of duds.