Description of RUKO 106200 Speed Steel Bi Metal: Unleashing the Ultimate Cutting Performance
Bi-metal H.S.S. Hole Saw with varied toothing ensures a even cut and requires less effort. High rotational precision. Sturdy body construction. Positive chipping and cutting angles ensure more aggressive and faster cutting. The reduction in vibration and heat development during cutting achieves up to three times the tool life. Hole saws do not come with the Arbors. Arbors sold separately.
The reason I flagged this product in the review is because it NOT really 8 1/4 inches. This hole saw is actually a metric size which is a little under 8 1/4", actually 8 3/16". This information is missing from Revain's product listing page. I bought this hole saw to make a hole for 8" boat view windows (requires an 8 1/4 hole). I'll get by with a hole saw and grinder, but I'd welcome more precision on the list.
I bought these to cut 1/4" sheet steel to make 8" wheels (I used cut outs, no hole). My drill press and used 30 -W motor oil as a lube/coolant I was in no hurry to cut through the plate It wobbles a bit (top/bottom not centered) For that reason expect the hole to be a bit larger It did its job and is still sharp I believe its quality is inferior to the US made crowns but it was less than half the price of a US made crown.
The 4 holes for the mandrel pins were slightly offset and the mandrel would not engage in the holes. I would have returned this hole saw for that reason, but I needed to get the job done so I had to enlarge the pin holes a bit so the pins would snap in order for me to be able to use the hole saw. Another problem is that the internal depth of this hole saw is exactly 1-1/2 inches, so you can barely cut through a nominal 1-1/2 inch thick joist. Other hole saws from Lenox or Milwaukee are slightly