Cut straight when edges aren't

[mike]

Any suggestions on cutting plywood (Circular Saw) straight when the edges aren't? If I use a straight edge guide and the edges aren't straight, how do I find another straight line to refer it to? I am a beginner and I am enjoying my new hobby. I just want to learn the tricks of the trade to make my projects worthwhile. The detail work (straight boards) are so important and I am lacking in this ability.

BTW- I only have a small Craftsman Jobsite Table saw, and this isn't fit to cut large pieces of Ply.

I appreciate this site and everyone that is so helpful.

[Ken Darga]

Carpenters/framing square

 

combination square

Rafter square

Cabinet makers square

Adjustable angle square

[Alan Shotts]

Mike,

In addition to all this really good advice, I just want to add one thing.

"If I don't have any square corners, Is there a way to square?" This was your question. Remember your Geometry class and the 3, 4, 5 rule. Use any units of 3, 4, and 5 on the sides of a triangle will create a 90 degree angle. Needless to say the more carefully you measure the more accurate it will be, but sometimes this can be useful when working with a sheet of plywood that has been whacked up and you need to start over to get a square corner.

[Jerrod McCrary]

I would just clamp the straight edge guide on the plywood and make a cut.  Then I would use a combination square and place the long side on the freshly cut side and mark your next cut.  Once you have the cut marked I would flip the combiation sqaure around so the short side is on the fresh cut side and this will allow you to mark a longer cut line.  Then finally I would clamp down the straight edge guide and do the final cut and you should have a 90 degree angle.  Then you could do the rest of the corners and you should have a 4 90 degree corners.

 

 

[Dino Makropoulos]

They also sell the Universal Edge Guide to do repeated rips (using the straight edge on the board), but I'll be honest and say that it makes me nervous since the saw could theoretically veer toward the uncut edge. This was the issue I had with my homemade straight edge. 

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ken, the ueg  comes with a secondary guide device on the sawbase. We call it the FIN.

Even if you try you can't move the saw from the cut line.

the FIN is a safety device and prevents kickbacks the same time.

If you have a true straight edge ( All panels are straight but not square) there is no reason to use long tracks of even lift the panel to the table.

here is me cutting 3/4" ply with the UEG.

Enjoy.

http://www.youtube.com/watch?v=bFziH_ymiOM

ycf dino

eurekazone.

[John Schaben]

I've got several of these clamps, from 24" to 100" that work very well. I can also use some of the shorter ones as temporary fences when the situation arises. Especially on my bandsaw where the stock fence is to tall to get me a narrow cut.

Clamp guides

Good job avoiding cutting full sheets on the table saw. I don't consider that a safe operation on a full size saw (sans serious infeed, outfeed and side support) much less on a table top.

[Gary roofner]

I would say the contrary the UEW it has a rival knife behind the blade to minimize kickback. The Uew looks a lot like John Schaben  homemade jig .

[Gary roofner]

I used the wrong name the UEG .  http://www.youtube.com/watch?v=bFziH_ymiOM  Watch the video there is a rival knife behind the blade.

[Dino Makropoulos]

Gary roofner said:

I used the wrong name the UEG .  http://www.youtube.com/watch?v=bFziH_ymiOM  Watch the video there is a rival knife behind the blade.

Hi Gary,

Looks like a riving knife but is much closer to a TS spliter.

Riving knifes flex and they become useless after few bumps.

The FIN is study and  eliminates kickbacks.

The same time works like a  secondary guide.

holds  the cut piece and don't allow the edge guide to move even if you try...

Believe it or not...if you have a straight edge...the cut is better than any tracksaw system.

Aluminum extrusions are straight but is very well known that many people are using the straight edge of the panels to align the guides.

here is the FIN at work.

and  a new design of patented inserts....with a $5.00 old blade.

The first video shows the FIn and the other shows the antisplintering insert.

enjoy.

http://tracksawforum.com/showthread.php?p=32073#post32073

ycf dino

eurekazone