On 2010-07-19 Michael Winters, wrote: These days with everything being fixed price jobs we look for every possible way to get the job done faster. We had been using the Milwaukee selfeed drill bits for many years and used them with stud drills for making access holes for electrical and plumbing. We tried these DeWalt bits to see if they were better than the Milwaukee and to a limited degree they are.
Overall though they suffer from the same limitations with the self-feeding screw tip only being of use with soft woods and dangerous in hard wood and they still take too much drill power to be used effectively on cordless drills. Cutting the entire section of wood out of a stud to make a 2´ hole is obviously less efficient than cutting the hole without removing all the wood - like using a bi-metal hole saw.
I can cut 4 times as large a hole with the same hand drill by using a modern big gullet hole cutter like the Milwaukee Big Hawg or the Blue Boar TCT compared to any self feed (or selfeed) drill bit. I can cut the hole in 5 seconds instead of 30 and use 1/6 the battery charge per hole.
BLUE BOAR 6-1/4´ (159mm) Self-Feed TCT 2-1/4´ deep multipurpose Tungsten Carbide hole cutter outperforms self-feed bits & bi-metal hole saws. Cut wood, MDF, OSB, laminates, Hardie & chipboard, plaster, drywall, brick, Formica
By way of example the Milwaukee corded Hawg stud drill is rated for a maximum hole saw size of 4-5/8 inches in wood. But I can take a Milwaukee 18 volt 2611 18 volt cordless drill, that is rated for a maximum 1-7/8´ hole with a self feed drill bit, and cut a 6-1/4 inch diameter hole in the same piece of wood. Once we realized we could cut bigger holes even using cordless drills we stopped using self-feed drill bits unless we needed to cut through 4x4 or thicker dimensional lumber.
One of the problems with hole saws is the amount of time it takes to knock out the cut piece of wood so you can make another hole. With self feed drill bits this is not a problem, but then it is not a problem with modern big gullet hole cutters either. Cutting depth is a limitation with bi-metal holes saws that generally have a cutting depth of 1-5/8 or less but not with the Blue Boar TCT that have a cutting depth of 2-1/4´ or more.
With self feed bits like these you not only need a bigger drill but you also need a vacuum to clean up the mess. We like using the Hole Pro hole saw shields that catch all the shavings and eliminate the time spent in cleanup by our guys. We can also control the cutting depth so when cutting into a wall or floor or ceiling we cut only the flooring or wall material and don´t accidentally cut a wire or pipe or PEX line. The Hole Pro hole saw shield work great with any hole saw, whether it be a old-fashioned bi-metal type, a carbide grit for ceramic tile, or one of the TCT Blue Boar big gullet hole cutters.
Hole Pro XL Shield Kit
. And summed up by saying OK bits for DIY but for pro there are much better alternatives. Currently DEWALT DW1649 8 Piece Selfeed Bit Kit, 7/16-Inch Shank has an overall rating of 8 over 10.
DEWALT DW1649 8 Piece Selfeed Bit Kit, 7/16-Inch Shank can also be found in the following searches:
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