I am starting a project (set of kitchen cabinets) that will involve a lot more plywood work than I am accustomed to. In the past I have generally done a rough cut with a circ saw and used my table saw / crosscut table to get it to the size I want. However many dimensions for this project will be outside the range of what I can handle in this way.
So I bought one of those long aluminum guides to get a straight cut with the circ saw and a good blade. I am planning on using this to get a finish cut, unless someone can lead me to a better way. I have one problem and one question: 1) the arbor on my circ saw has a small amoung of play in the same axis as the motor, i.e. it moves in and out about 1/16″. I looked at a tool store and all the other brands – even high end p-c, etc. seem to have some play in the blade arbor. This seems like it will lead to NOT a finished cut.
2) stupid question, but I’ve never tried – can you joint plywood to get a finished edge?
thanks in advance,
remodeler
Replies
If you find your saw is giving a poor cut, you could cut close to your line with your circular saw-- within 2- 3 mm, with a fine, and sharp plywood blade. Then get a good edge using your new straight edge and run the edge of the base of a router along it. Fit a fairly large straight bit in your router, something like 25mm (1") diameter. A bit tedious being a two stage operation, but do-able. Or you could buy a new circular saw that doesn't have a wobble, ha, ha. Slainte.
Website The poster formerly known as Sgian Dubh.
i ve built many cabinets using melamine/mdf and plywoods, a good quality circular saw and that straight edge should give a nearly perfect edge with a top grade blade
i use a pc saw with a freud laminate blade, a newly sharpened blade even cuts cheap melamine panels perfectly on both sides
another trick if that isnt good enough, is to prescore the first layer of ply by setting the blade depth just deep enough to cut the top layer and then recutting through all the way
also when cutting the full lenght of the sheet i always brace the middle of the straight edge with a scrap and a clamp
Remodeler,
Question #1: Most circular saws use helical gears to drive the blade. These gears have angled teeth, under a load they will pull the arbor shaft solidly to one side and hold it there, stabilizing the blade. In any case I've done a lot of cutting as you plan to do and have never had a problem I could trace to the saw blade wandering.
Set up a 4' by 8' grid of 2x4's, set on edge, on a pair of knee high saw horses to do the cutting on, this will make it easy to kneel on the plywood as you make the cuts. Set your depth of cut a bit deeper than the plywood and figure the 2x4's will get chewed up a bit.
Placing the straightedge the proper distance from your cut line, to compensate for the width of the sole plate of the saw, can be a problem. The offset is usually an odd dimension and easy to get wrong as the day goes on. The simplest solution is to make a small block the length of the offset dimension and then use it to mark the offset from the cut line mark. Pay attention to which side you are setting the cutting guide, it's easy to set up on the wrong side of your cutting line and come out with your panel too narrow by the thickness of the saw kerf.
For cabinetmaking, never ever trust the factory edges of the plywood to be perfectly straight and definitely don't trust the corners to be square, which brings up question number #2: Can you joint the edges of a plywood?
Yes, you can joint the edges of the plywood on a jointer but the glue lines between the plys will instantly create little notches in any steel jointer blade. You can continue to use the blade for edging plywood, but it will leave raised lines on any solid stock that you try to joint afterward. The best solution is to do all your plywood jointing with the jointer fence all the way to the back of the tables and then move it forward an inch for other work. Carbide blades will solve the wear problem but they're expensive and not commonly available for small jointers.
An alternative to a stationary jointer is to use a hand held power plane to clean up the edges. The planes have fences to hold them square to the face of the panel and many now have carbide disposable blades. Often times they're easier to use than trying to balance a large sheet of plywood on a stationary jointer. Hope this helps.
John W.
Edited 4/18/2003 11:13:18 AM ET by JohnW
Edited 4/18/2003 11:29:13 AM ET by JohnW
Be careful of those "long aluminum guides." My experience has been that they are rarely straight, and usually bow in the middle. A homemade jig using two pieces of plywood (one as the straight edge and one as the "rail" that the saw rides on) is probably the way to go. If you want to make the jig more durable tack a piece of angle iron to the guiding strip of plywood. I would definitely use the 2 by 4 cutting grid described above. It makes things a lot more pleasant.
Remodeler -
Although you may not be in any tool-buying mood, the tasks you mention is something I will be facing soon with no table saw in my arsenal yet.
You may want to take a look at Festo's ATF-55 plunge cut saw and guiderail system.
No, I am not affiliated with Festo in any way.
Been looking at their Spring special package that combines the saw, vac, router, guiderail and the two RO sanders.
The saw/guiderail system geared mainly for plywood and melamine, etc.
If nothing else, their tools are worth a look.
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