JIECHENG Bi-Metal 4 inch Hole Saw with Arbor Mandrel for Cutting Wood,Cornhole Boards,Drywall,Plasterboard,Plywood,Steel,Aluminium,Brass,Copper,Zinc,Tin,102mm

I was gonna return this and vent a different direction where I could cut the hole through a single piece of wood. I thought I could use my jigsaw. Changed my mind again and opened the box and found nothing to secure the drill piece to the saw piece . Just the bit saw and hex wrench. totally unsafe and wouldnt work. Thank you Amazon for free returns!

I bought this to install 6inch Lithonia LED recessed downlighting. Chewed right through drywall and wood and came out to be a perfect fit.

No problems easy set up and use

Lasted about 5 minutes

This will not fit either of my black and decker 3/8 drills. I contacted the company and this is their response: Hello ，thank you for your feedback, we dont find your video or picture , but i send you some pictures in attachment of the 3/8 arbor, you can see we measure the distance between two sides, please note it is two sides not two corners. this is the customary standard in the hardware tool industry. another question is to see if your chuck of electric hand drills is marked 3/8, sometimes the chuck is not standard too. so there are many reasons for this. in fact we are company in China, no branch in USA, so we cant send you another pcs for test. but if youd like to buy this stronger arbor, maybe can be better, but not sure if it fit your chuck, the link is : https://www.amazon.com/dp/B081VQQQT4?ref=myi_title_dp . and another way is that if can not use it, please return this item to amazon. sorry for it. and hope you have a nice day! regards Jack The three pictures showing the measurements are the pictures mentioned in the response. The key point is the measurement of the arbor is not point to point, its side to side. It might fit most 3/8 chucks but not all. Good luck.

Dull drill bit,stripped set screw,soft metal not round, Save your money

Looked like it would work good but havent used it yet got it to move my dryer vent

I had to drill 10 holes in a ceiling for some recessed lights. By the time I was done with the last hole, it was so dull I wasnt sure it was going to be able to get through. If its supposed to handle the metal they say it can it should still be good for many projects to come. Anyone see any teeth there?

bought to install dryer vent, going through plaster and lath, ALL teeth were smooth and rounded just in the plaster (old horse hair plaster, very soft) would not cut through to outside, had to run to hardware store and buy another brand to finish cut, obviously not hardened teeth, or bi-metal, waste of money

No problems easy set up and use