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View Full Version : Forstner Bit Kind of Test: (*PICS*)



John Weber
02-16-2004, 11:40 AM
I needed a forstner bit size I didn’t have so I bought a Magna made in the USA bit off the bay, not knowing if it would arrive in time I also borrowed my Dad’s forstner bit set, he bought at the wood show last year. You see them everywhere, made in China, full set, wood case… Well they arrived the same day, so I though I would compare the two. The US made Magna bit is much nicer looking, more machining, non machined surfaces are black and smooth, traditional forstner design, stamped made in the USA. The Chinese bit just looked cheap, saw tooth design, very little machine (only at the very edge of the cutting surface), rough non machined surfaces, the inside on the saw teeth looked terrible. So on sight alone the US bit seemed well worth the $20+ price versus the $20 for a complete set of Chinese bits. However, I though I better do a little hole boring, before giving final judgment. After all, that is the main purpose of the bit.

I cranked the drill press down to the lowest speed (450 rpm) and chucked the US bit, it cut very well, nice fluffy curls spun out, easy pressure, centered well, seemed to do a very good job. The only negative was a slight burning on the sidewalls of the hole.

Now time for the Chinese bit, I began to drill, it didn’t seem like it found center quite as easily, but took easy pressure and also delivered curls, also not quite as wide as the US bit (I assume do to the saw teeth), but curls non the less. The Chinese bit also produced a fair bit more dust then the US bit. But the Chinese bit had no burning that I could tell. Maybe the saw tooth design – who knows.

The verdict: The US bit is a much nicer bit from a construction prospective, it left a cleaner hole, including a smoother bottom, and the outside cutter leaves a very clean line, however there was some light burning in the holes I drilled. The Chinese bit drill a nice hole, the bottom was rougher and the saw tooth edge left a more pronounced and jagged outside edge on the bottom (noticeable when the hole is left unfilled). Both bits drilled with easy pressure, and had clean entry cuts.

Finally assessment: for the money, the Chinese bits is hard to beat, hole was not quite as nice as the US bit, but it did not have any burning as the US bit did. The US made bit looks like it will be easier to maintain, as it has a clear bevel on the outer diameter and a full angle bevel on the cutting surface. The Chinese bit doesn’t really have any grinding on the outer diameter and only a partial grind on the cutting surface. Both bits were brand new and I do not know how either will hold up over time.

The test were done in hard maple, and are totally unscientific, and anecdotal, so take it as that. Neither bit was coated, and may or may not be representative of similar bits.

John

The Magna US made bit and results are on the left:

<img src=http://www.weberwoodworking.com/picsw04/fb1.jpg><p><img src=http://www.weberwoodworking.com/picsw04/fb2.jpg><p>
<img src=http://www.weberwoodworking.com/picsw04/fbholes.jpg><p>

Jim Becker
02-16-2004, 11:52 AM
John, I've used the Chinese bits for some time (I bought a set years ago at WWW) and they do work fine for occasional use. What I've found, however, is that over use, they don't hold a sharpening that great, although they can be touched up a bit with a diamond hone. The sizes I use a lot have been "replaced" with the good ones; others, I still use the Chinese versions.

John Weber
02-16-2004, 11:59 AM
Jim,

I bought a set of Irwin forstners years ago, and they have done super. I was really surprized by the burning with the Magna bit, but agree I think for common sizes better bits are the way to go, the chinese bits are bascially throw aways.

John

Dennis Peacock
02-16-2004, 2:44 PM
Jim,

I bought a set of Irwin forstners years ago, and they have done super. I was really surprized by the burning with the Magna bit, but agree I think for common sizes better bits are the way to go, the chinese bits are bascially throw aways.

John

John,

I read an article somewhere about the Magna bits vs. other brands. During their tests they didn't have any burning with the Magna bits.

You can bet that one of these days, I will have a nice set of Magna bits.