i'd love to see one too.

as to squareness, the edges of the face plate are made to be parallel to the blade at the factory, and they are not adjustable (at least i have never seen one). if they are not parallel, you probably need a new saw.

so couldn't you just clamp a straight board to the piece you are cutting parallel to the cut you want to make? measure the distance from the edge of the blade to the edge of the faceplate, and then measure that distance on both ends of the piece and clamp the board there.

alternatively, bobj has a track and runner setup that makes sure the saw stays on the line.

 

This is the simplest I have seen - use this one myself.....

MAKING STRAIGHT CUTS WITH A HOMEMADE JIG - YouTube

hardboard base with 1/2" ply fence.....

 

Thanks but that jig I have. What I need is one to make a crosscut at 90 deg. referenced to the straight edge that jig produces, preferably off a single measurement along that edge.

I've seen some on YouTube and elsewhere but they all assume a true 90 off a frameing square or the like. This is used to attach another fence on the underside perpendicular to the cut fence on the top. Once the 90 is established the reference fence is fixed to the jig with screws and glue.

The reference fence is registered to a straight edge of the panel or board and the cut fence sets up the 90 deg. cut.

What I have in mind is one step further. Do the initial setup with the frameing square but just clamp it in place. Drill and insert a dowel at the intersection of the two fences to be used to both anchor the two at that point and to provide a pivot point. Further toward the other end of the reference fence awat from the cut but still under the runner board (didn't know what else to call it) drill a pilot hole to act as a guide for a adjustment screw in the reference fence and a slightly oversized hole in the runner. The runner would be extra wide to have some meat on the side of the cut fence oposite the cut

Calibration:

With the screw holding the jig to the original square from the frameing square, make a cut on a test board. Flip the test board horizontally keeping the reference edge against the reference fence and make a cut on the other side of the test board. Assuming some error in square the length measured at the base of the test board and the top will be different by twice the amount the jig is out of square. Loosen the adjustment screw for a friction contact, move the refernce fence to correct, retighten the screw and repeat the proceedure. When you reach the level of accuracy desired another dowel can be inserted near the screw to lock the jig in place and other screws can be used for reinforcement.

GCG

 

From another Gulf Coast Guy,

Sounds to me like you have it figured out already. I made three 8' saw guides from one sheet of masonite and some 1/2' ply, and cut one into 5' and 3' lengths. On the 3' I added the 90 deg cleat under it for your crosscut jig, only I did have the benefit of a 24" drafting triangle to square it up with.

Plus, you have already described the adjustment setup and calibration to a tee. I say just go make some sawdust! :yes4:

Mike

 

Square-Cut

You might be thinking of something along these lines.

Or attach a batten at right angles to the jig in the previous video. Once it's set, its set....

I mark a line with the framing square and then line my jig up on that line, then clamp in place....

 

That's a neat jig, James. If I were cutting a lot of 2X material, I think $11 would be a great investment. As it is, I just align my saw blade with the cut line and slide the "Speed Square" to the saw plate.
For anything wider than 12", I use my red neck track saw.
Gene

 

just take a 18" piece of 1x4 and a 18" piece 1x2. make sure they are perfectly straight. glue and screw them perpendicular to each other near one end of the 1x4 piece. make sure it is exactly 90*. how you make them exactly 90* is up to you. there are lots of ways.

then run the saw along the 1x4 piece to cut the 1x2 piece at the blade. there is your jig.

now all you have to do is line up the edge of the cut off part of the with your line and clamp it in place. it would look like this:

 

Here is a fairly simple circular crosscut jig if this what you had in mind.

 

Thanks for the input but it still doesn't address the angle concern.

 

@James
I've seen the Square Cut. Bench Dog and Stanley both have similar products and that's what I'd go with if the pieces were narrow ... up to say 12". I'm going to have panels at around 20" - maybe more. I have two framing squares and both are off by more than a thin pencil mark at 24". I guess I could pop one of them with a punch a couple of times and see if that corrects the error. Then I could use that to make the batten modified jig that you and, later, Chris described.

Thanks all for the input.

GCG

 

I'm guessing you considered a good quality drywall T square?
Wal-Board Calibrated T-Square 54 in. - 1/8 in. WTS-54 (WLB-88-016) | WallTools.com

Obviously you wouldn't be able to make the sawcut without damaging the Tee, but they're sure convenient for the layout part.
Unlike a framing sq. the Tee arm is undermounted making for a really solid contact with the reference edge...not prone to slipping off.
I use mine for plywood layout as well as drywall; no complaint.

 

Actually they had one at work that I checked with the 3-4-5 rule and it seemed fairly acurate. I've found some scrap MDF I thought I'd thrown out so I'm going to try my idea if for nothing else to see how close I can get. If that bombs I'll probably give the drywall square another look.

GCG

 

Twenty inches or more would be easier with a guide like this.
This one is 8' long, but I have a 48" one also.
Just a piece of Birch ply and a T track. And an insert to bolt to the saw.
Make the guide wider than needed and the first cut with the saw establishes the subsequent cut lines. I also left enough in the left side for clamping.
With a Tenryu plywood blade, I get no tear out.

 

woodworkingtips com etips

Try woodworkingtips com for "Circular Saw Crosscut Jig".

BTW I don't understand why this forum wouldn't let me post a URL unless I have at least 10 posts!!

 

Try woodworkingtips com for "Circular Saw Crosscut Jig".

BTW I don't understand why this forum wouldn't let me post a URL unless I have at least 10 posts!!

probably trying to guard against spammers

 

Do it all with the item below, quick and easy with a small stick clamped to the square that takes of the angle concern..

Amazon.com: Swanson Tool SO107 12-Inch Speed Square: Home Improvement

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Hey James, neat idea! (Referring to the video on square cut jig.)Think I'll be making this one myself. I've be been using a piece of aluminum that I salvaged off of an old machine at work, and it has worked great, but with that jig in the video, you don't have to measure for the offset of the saw and plate each time you make a cut. Just mark your ply and line up the jig, clamp it, and make your cut. I'll be making that one very soon! Thanks again.

 

Honestly, I'm still a little confused about the issue here ... sorry ...

It sounds to me like the main problem is that your square is not exactly square. If it isn't, then maybe a new square is in order. :shrug:

 

I'd agree except I'm on my second bad one and I'm pretty sure I can get it right. If I want to gamble, the casinos are a short drive to Biloxi.

GCG

 

I drew this up for you as a concept, but I haven't built it yet so you might have to tweak it a bit. You'll notice one of the parts has a slot in it so that you can adjust it for squareness.

 

nice!