And the Irwin and harbor freight units are, apparently identical - like from the same factory. They also work great. Even *I* can make mitered joints that line up.
How does this thing work? I would think that it would project a line a ways away from the blade. Do you have to mark your parts with that in mind? Also, is the laser line really sharp enough for a +/- 1/64th inch cut?
I use a radial arm saw a lot. Any reason this wouldn't work on one of those?
HF has a cheapie, I just got one. Supposed to be good for radial arms saws, too. As far as lines are concerned, you can get aftermarket lens arrangements that produce a line from a dot, I've got one for my laser boresighters.
I have a laser (not the spinning kind) on my HF sliding miter saw. While it is very handy for non-precision cuts (and initial alignment), the only way to *really* get a cut dead on is to look at where the cutting tooth connects with the material to be cut.
I've got one on my 10" Hitachi slider compound miter saw. It projects a beam on the part when the blade is up, but the blade gets in the way (shadows the laser) when you lower it to cut.
spaco wrote in news:uKadnZpt1_plu2HXnZ2dnUVZ snipped-for-privacy@bright.net:
The shaft mounted aftermarket type replaces the outboard blade washer and turns itself on only when the blade spins. It projects a dot from the washer outward, right beside the blade. Since it spins with the blade your eye percieves the dot as a 'line'. The right edge of the line is the left edge of the saw blade.
It is accurate, well sort of. The beam can either be between a tooth or lined up with a tooth, so the line can be off actual cut by the difference between the carbide tooth and saw plate thickness. That's your 1/64" right there. It is a repeatable error though so you just compensate by eye if necessary. I haven't bothered to carefully aim it right at the carbide tooth to see if it can be more accurate.
I'm as confident in the accuracy of mine as I am in the accuracy of cutting to a pencil mark... A pencil mark is as wide as your +/-1/64"cut tolerance so use a knife to mark if you need better than 1/32" accuracy and sneak up on the mark with the blade spinning.
The best part of these things is productivity gained, not necessarily accuracy.
Cutting miters for door and window casing is sooo much nicer when you can mark the long or short end of the miter and hit it 'close enough' without having to spin the work end for to get the mark at the start of the cut.
They have been finding any stupid and cheap way of building lasers into things to appeal to joe homeowner. For example drill presses and jigsaws. I wouldn't bother with a fence mounted laser line projector if there are such things. Too much chance of not being accurate when the saw is set to bevel or miter.
I've used a jig/sabre saw with a laser & the laser was useful. It kept the blade pointed in the right direction where otherwise I would have tended to wander.
That is a very good description, closely following my experience. In actual practice, the inboard edge of the resulting laser line is right on the edge of the saw teeth. You really can just mark a corner of a miter, put the line on it and cut. As I said, if *I* can make an accurately fitting miter cut with this setup, I expect pretty much anyone can. Wood is not my best friend.
BTW, I got the Irwin on sale at Lowes. I was told by a guy I met there that the HF unit is EXACTLY identical, down to the patent number stamped on it, but if you buy at the right time, it's cheaper and comes with an extra set of batteries.
I've got a piece of shit Ryobi that just throws a line in one direction. Cost me $10 at a yard sale. One of those would work, but you would have to mount it solid so vibration didn't throw it off, and I'd check it often.
Interesting. The one I saw was NOT blade mounted. It was along the arm beyond the blade & lit downward/forward towards the operator. Obviously, it was in line with blade.
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