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Outrigger for Circular Saw

Much more portable than a table saw
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(For those who prefer the metric system, remember that one foot of length in the old-fashioned English measuring system is 30.48cm.)

Several months ago I watched two big burly guys trying to cut an 8x4 sheet of plywood (8feet by 4feet) on a table saw that was rather undersized for the job. The results were not pretty. Today I found myself having to cut up a full sheet into some pretty big pieces, with some long straight cuts required. What to do?

A while back I had rigged up a plank of wood, about two feet long, as a low-budget (and dangerous!) variety of table saw. Basically, you mount an ordinary circular saw near one edge of the plank, but in the middle of the plank, kind of like this ASCII sketch:
-------------------- edge of plank --------------------

(surface of plank)
. . . . . . . . . . . . . . . . ______
-------------------- edge of plank --------------------
Ignore the dots; the dark line in the lower middle represents the edge-on circular-saw blade going through the plank. Use some short screws to mount the saw on the plank (you don't want the points of the screws coming out the other side; use a thicker plank if necessary).

Now get an appropriate sized trash can, and set the saw and plank upside down on the trash can (the circular saw is inside the top area of the can). What you now see on top is a flat plank with a saw blade partly through it. Your low-budget (and dangerous!) table saw now needs just two more things.

One is a suitable clamp, that you can use to activate the trigger of the circular saw, and keep it running. It is best to do this with the power cord unplugged. When you want to turn the saw on, just plug it into an outlet.

The last thing needed is a nice thin but straight piece of wood that's also a couple of feet long (plain baseboard molding can work). You will screw this into the top of the plank, parallel with the saw blade, as a guide for the wood you want to cut. Obviously you must measure its location accurately before screwing it down, and, equally obviously, you must unscrew it and remeasure any other width-of-cut that you are interested in making. (This guide is the "outrigger" of the Idea title.)

Like I said earlier, I've had this nice little tool for a while (several years). The maximum width I could cut was about 4 inches (about 11cm). Note that because the plank-and-saw was only a little heavier than the saw alone, I could also use this thing in a pretty ordinary way on a big sheet of plywood. That is, I can hold the saw in my hands on top of the plywood sheet (but with the attached plank in-between saw and sheet), and I can use the plank's edge guide to cut a long and very straight strip of wood from the sheet.

However, the limit of about 4 inches was much too small for what I needed to do today! I therefore decided to get a longer plank of wood:
-------------------- edge of plank --------------------
. |
. |
-------------------- edge of plank --------------------
Ignore the dots as before; the saw blade goes through this plank near one end of the plank. The thin straight edge-guide piece of wood can be mounted anywhere along the length of the plank, again parallel to the saw blade. The total length of THIS plank is a little more than 4 feet, allowing me to cut an 8x4 sheet into any smaller size (4feet is half its size; if I want a piece bigger than 4 feet; I just cut a smaller piece off; and the desired bigger piece is what's left over).

As before, the saw is mounted onto one side of this long plank, and the edge-guide is mounted onto the side where the blade comes through. As before, I can hold the saw on top of the sheet of wood, and use the guide to make long straight cuts. The only difference is that this new bigger plank is a little heavier and more cumbersome than the old plank. But not enough to keep it from having worked great, today!

Vernon, Nov 15 2010

The high tech solution http://www.tritontools.com/
Available in the USA [infidel, Nov 16 2010]

Low tech http://www.milescra...pictures/1400a2.jpg
[2 fries shy of a happy meal, Nov 16 2010]

Triton Table, as promised http://www.flickr.c...086@N07/5183975632/
You can see the tool slots on the right, for your saw to mount upside down under the table. You can also see the gate to the left. The tabletop may be adjusted farther to the left, to accommodate wide cuts, as may the gate. The workpiece may be slid over the smooth table top easily. [infidel, Nov 17 2010]

[link]






       What you're describing is called a "gate" in the building trade and woodworking fraternity.   

       It can be affixed to the workpiece with screws or clamps.
infidel, Nov 16 2010
  

       [infidel], the link you posted shows a saw with a gude that doesn't look to have the range of the big one that I made. I won't say that such doesn't exist, but I did do some looking around for something like what I descrbed here, and didn't find it.   

       I can understand how fixing a guide to the workpiece would allow the saw to slide along the guide to make the cut, but I don't like the idea of damaging the workpiece with screw-holes or other things (like clamp depressions). In this Idea, only the saw is modified by the add-on gadget.
Vernon, Nov 16 2010
  

       See a Triton work table. Gate is 1220mm ( 4ft ) long. If you use Kwik-Grip clamps you won't get marks on the workpiece. If you dont have them then simply use a piece of cardboard under the gate block to protect the surface.   

       Attaching the gate to the saw means you'll follow the edge of the workpiece. You have to make sure it's straight and you can't cut at an angle to the edge, without a lot of difficulty.
infidel, Nov 16 2010
  

       Yikes! Whoa, don't do that Vernon.
You could lose some parts you might want later.
  

       Cutting unweildy 4x8 sheets is a breeze if you leave them laying down in a stack.
Set your blade depth to barely cut through one sheet, and use one of these guides [link] (I think this is what infidel means) or just stand on a straight 2x4 as a runner.
If you are worried about scoring the underneath sheets just throw some scrap chunks between them.
  

       Do not...I repeat *not* jimmy the trigger and mount a skill saw on anything...unless you have to of course.   

       ...and remember kids, everything is a hammer, except a screwdriver cuz that's a chisel.   

       [infidel], so far I haven't needed to cut any sheets at any angle that wasn't parallel to the edge of the sheet. For a really low-tech version of your "gate" (still haven't seen a picture, but when you say "work table", that brings to mind "table saw" which this Idea is not really about), just take two clamps and a steel yardstick (or meter-stick). Certainly I'll keep that in mind, when the need to cut an angle arises.   

       [2 fries], I did state in the main text (twice!) that this gadget was dangerous. That's what makes it half-baked, of course, even if I do have a working gadget! (And I'm VERY careful, since I know how dangerous it is!) The image you linked is quite obviously limited to cuts that are thinner than one foot. A rather longer extension piece (better, two of them, the second extending sideways from the rear of the saw) would be needed to cut a 4-foot slice off a big sheet of plywood. Also, the main text of this Idea indicates that my wooden guide piece, that slides along the edge of the sheet, is about two feet long, which happens to reduce the chances of twisting the saw relative to the edge --a second outrig strut from the rear of the saw would allow a longer/better guide to attach to both struts.
Vernon, Nov 17 2010
  

       Thanks, [Vernon], nice idea. I try not to get to where I need something like this, but when I do, I'll remember this.
normzone, Nov 17 2010
  

       //Like I said earlier, I've had this nice little tool for a while (several years).//   

       So... baked?
methinksnot, Nov 17 2010
  

       I got all that Vernon...twice
: ]
One of those (+)'s is mine. It's just that I just cut an awful lot of sub-floor doing my job.
I'm not much of a finishing carpenter but I'm half ninja at schwacking up plywood and I stopped running sheets through a table saw about a decade ago. Give me a pair of knee pads and a skill-saw anyday.
  

       [methinksnot], no matter how long such a device as this exists, it will forever be half-baked so long as it is dangerous.   

       [2 fries], an alternate and fairly simple way to not cut a board underneath the one you want to cut is to set the one you want to cut onto two partial sheets. The gap between those partial sheets would be located under the line you want to cut, into the top sheet.
Vernon, Nov 17 2010
  

       Ah, my friend [fries]. Yes, ninja carpentry. Unseen, unheard...Okay, maybe seen or heard, but unappreciated. Okay, maybe appreciated - the community garden and my sweetheart think I'm clever.
normzone, Nov 17 2010
  

       I fail to see the invention here. "Makeshift tablesaw"? No, it's not an invention everytime you try for the darwin award in your workshop.
zeno, Nov 17 2010
  

       [infidel], thanks for the image of the table. Note that while I described a psuedo-table saw in the leadup to the main Idea, it was not really the main Idea (see subtitle for proof).
Vernon, Nov 17 2010
  

       I was cutting rebates yesterday with a circular saw. I simply clamped a piece of wood to the saw's base plate as a guide; the same as you did, but without the plank. At least the safety guard still operated.   

       You could make the slot in the plank large enough to allow the guard to operate. That would reduce the danger, but make it less usable on small objects and near corners, which problem my method has.   

       (Edit: On second thought, my large slot idea is probably not a good one, and may make the rig even more dangerous, as small or thin objects would not be well supported and could easily tip and grab. I had the workpiece firmly clamped, and both hands on the saw, but it would have been horribly dangerous in table saw configuration, guard or no guard.)   

       A proper table saw guard could probably be installed on the plank. I may look into that...
spidermother, Nov 18 2010
  
      
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