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.

[Jay Boutwell]

Mike what I do is use a large framing square and pick a corner and square it up.  This would be a long side and one end of the plywood sheet. Then use a straight edge to guide the saw cutting the long side and the end you squared up.  This gives you a long side and one end that is square.  Using the end or the long side that you just cut as a reference you can then square up the opposite side and end .  

To check a sheet of plywood for seeing if it is square pull a tape diagonally across the sheet corner to corner and obtain the measurment.  Then swith corners and check the measurment.  If square the measurment will be the same.

To check if your framing square is accurate pick a straight surface and place the squares tongue (short side) against the edge and draw a line down the long side of the square.  Flip the square over and place the tongue against the straight surface and check if the long side will aline with the mark. 

Glad to see you here and beginning to enjoy a remarkabe and rewarding hobby.   

 

[james wilhelm]

Mike ,If the ends of your ply wood are straight , you could take a 24 " sq. and make a line  in from each end , then take your straight edge guide from the two marks to take off enough to get a straight edge .  Then you should be able to cut the size boards you need from that edge , hope this helps , JIM

[mike]

Problem I have is cutting straight when edges are not. Essentially the cut I want to do will make edge straight. I am having problems with this.

Thanks

[John Schaben]

HI Mike - that is what Jay was refering to by using a straight edge to guide the saw. Here are some commercially availabe ones: edge guides

There are a lot of alternatives to buying those though, several shop built designs are on the net and even something as simple as a piece of 1by lumber long enough and clamped down will guide the sole plate of the saw adequately.

BTW - IMHO, there is no jobsite saw that should be used for cutting sheet goods unless it has been setup and mounted for that purpose.

mike said:

Problem I have is cutting straight when edges are not. Essentially the cut I want to do will make edge straight. I am having problems with this.

Thanks

[mike]

Jay,

Thanks so much. I did just this on my current project. If I don't have any square corners, Is there a way to square? I think this is the question I initially wanted to get across. Your explanation about checking with Framing square was just was I was looking for. Can you recommend an edge guide I should purchase? Is there a specific brand of Framing Square. I appreciate you taking the time answering my questions.

Thanks,

Mike

Jay Boutwell said:

Mike what I do is use a large framing square and pick a corner and square it up.  This would be a long side and one end of the plywood sheet. Then use a straight edge to guide the saw cutting the long side and the end you squared up.  This gives you a long side and one end that is square.  Using the end or the long side that you just cut as a reference you can then square up the opposite side and end .  

To check a sheet of plywood for seeing if it is square pull a tape diagonally across the sheet corner to corner and obtain the measurment.  Then swith corners and check the measurment.  If square the measurment will be the same.

To check if your framing square is accurate pick a straight surface and place the squares tongue (short side) against the edge and draw a line down the long side of the square.  Flip the square over and place the tongue against the straight surface and check if the long side will aline with the mark. 

Glad to see you here and beginning to enjoy a remarkabe and rewarding hobby.   

 

[John Schaben]

Hi Mike, The guides I linked to in my previous post work pretty well. Similar are also available at Big Box stores, many of the online woodworking sites and some of the better lumber yards. However, here is a link to a shop made guide that will work as well as any plus has the added benefit of not having to calculate shoe offset for each cut.

http://www.popularmechanics.com/home/reviews/4283497

 

As for framing squares, they are vitually everywhere, including WalMart. Stanley is one of the bigger brands but not sure it makes a lot of difference as they all need to be checked for square, and tweaked as needed, occasionally.

[Ken Kortch]

I use the saw guide from http://www.eurekazone.com. They use a base that is attached to your own circular saw. This does three things that a simple straight edge guide won't.

First the base & guide prevent the saw from going left or right - it simply can't go off straight. This was the issue that sent me to the use of the guide. I hated using a table saw to cut plywood (scared the heck out of me, required two people to manage the cut, and always seemed to be burning blades), and I couldn't cut a straight line with a circular saw to save my life. I built a guide like the one in the link above. It provides a nice cut line reference, but for some reason the saw kept moving away from the straight edge. Not sure why. It drove me NUTS.

Second, the base edge and the base press down on the cut edge preventing tear out and providing a VERY clean cut.

Third, the white plastic guide edge is trimmed with its first use, so the edge marks the exact location of future cuts. Dead nuts on.

I also have their older model 90 degree cross cutting guide. Its current version can provide that 90 degree cut after you make the straight edge, though using a framing square with the guide would work well too - just not as fast.

A side note: It was with using that cross cut guide that I realized that the thing that makes those tracks unique is that they have a dovetail-like groove  which ensures that attachments align the same way every time they are connected. Not sure if they'd planned this from the start, but it works very well. 

BTW, I don't have anything to do with that company. Just a happy user of their tracks. 

[Jay Boutwell]

Mike, for a framing square, there are several brands out there that are accurate and one of the most popular ones are made by "Stanley" however this is not the only accurate square out there.  Even if you get the best out there I would still check the square for its accuracy using the method I described in my prior post.  Should you find one that is not accurate you can fix it by laying the square on a hard surface and do the following.  If the tongue is too much in towards the long blade pein the inside of the square with a hammer and punch right at the corner where the tongues make the 90 degree bend.  This will move the tongue outward.  If the tongue is to far out from the 90 degree pein the square at the outer corner at the point and it will move the  tongue closed.  It is not often that you will find the square to be out of accuracy but it does happen from being dropped and mis handled.   I'm sure some will doubt this fix however I have fixed many squares using this method.  Another method to check the square is by using another square to check the accuracy by laying it inside of the two tongues.  Like John says above they often need to be "checked and "tweaked.  

As for a saw guide there are many out there however I have my own that I made that is a strip of 3/4"plywood about 12 inches wide  that I have added a strip of 1" wide and 1/2 inch high aluminum channel  down the middle and attached it with screws.  Using a skil saw, that you will need to dedicate it use each time you need to rip a piece of plywood,  place the saw against the side you wish to use for the shoe of the saw to slide on and rip the excess off the edge.  This now becomes your straight edge and each time you need to rip a a piece of plywood or other material you can use the edge of the plywood as the easy method of setting the rip width.

The saw will track along the side of the aluminum and the blade will cut at the same kerf each time as long as you do not change a saw blade to a different kerf width.   You use some clamps to attack it to the material you are going to rip.  You will note that this method will decrease the cut debth of your saw so you will have to adjust it accordingly.  At one time I had three make of different lengths for ease of use on different length and widths.  One advantage of this method is that it makes it quick to do. You have to remember that the saw will cut its kerf with the inside of the saw so to cut say a 12 inch wide piece you will have to add the width of the saw blade kerf to you initial measurement.  if the blade is cutting a 1/8 wide kerf measure over to 12 and one 1/8 inch.  Hope this helps you with your questions.  If not feel free to contact me.

 

mike said:

Jay,

Thanks so much. I did just this on my current project. If I don't have any square corners, Is there a way to square? I think this is the question I initially wanted to get across. Your explanation about checking with Framing square was just was I was looking for. Can you recommend an edge guide I should purchase? Is there a specific brand of Framing Square. I appreciate you taking the time answering my questions.

Thanks,

Mike

Jay Boutwell said:

Mike what I do is use a large framing square and pick a corner and square it up.  This would be a long side and one end of the plywood sheet. Then use a straight edge to guide the saw cutting the long side and the end you squared up.  This gives you a long side and one end that is square.  Using the end or the long side that you just cut as a reference you can then square up the opposite side and end .  

To check a sheet of plywood for seeing if it is square pull a tape diagonally across the sheet corner to corner and obtain the measurment.  Then swith corners and check the measurment.  If square the measurment will be the same.

To check if your framing square is accurate pick a straight surface and place the squares tongue (short side) against the edge and draw a line down the long side of the square.  Flip the square over and place the tongue against the straight surface and check if the long side will aline with the mark. 

Glad to see you here and beginning to enjoy a remarkabe and rewarding hobby.   

 

[mike]

John,

Thanks for the info. I looked at the rockler guide and it looks nice.

[mike]

Ken,

I believe I saw that this morning. Can you link to the product you purchased? Is it called the UEG? They have so many products I get confused. I saw video on setup and it looked so complicated. Did you find it difficult to set up?

Thanks,

Mike





Ken Kortch said:

I use the saw guide from http://www.eurekazone.com. They use a base that is attached to your own circular saw. This does three things that a simple straight edge guide won't.

First the base & guide prevent the saw from going left or right - it simply can't go off straight. This was the issue that sent me to the use of the guide. I hated using a table saw to cut plywood (scared the heck out of me, required two people to manage the cut, and always seemed to be burning blades), and I couldn't cut a straight line with a circular saw to save my life. I built a guide like the one in the link above. It provides a nice cut line reference, but for some reason the saw kept moving away from the straight edge. Not sure why. It drove me NUTS.

Second, the base edge and the base press down on the cut edge preventing tear out and providing a VERY clean cut.

Third, the white plastic guide edge is trimmed with its first use, so the edge marks the exact location of future cuts. Dead nuts on.

BTW, I don't have anything to do with that company. Just a happy user of their tracks. 

[Ken Kortch]

They have a product called a Powerbench. Someday I'd like to have one, but not yet. Think of it as a track saw with a cutting table under it. It can also be used with routers, jig saws, and other tools - use imagination here.

I had purchased a pre-setup circular saw - with the base already on it, so I didn't attach the base myself. They've modified the base since I bought mine. The newer type is the UEG - also called the "New Smart Base". This new base is intended to make it easier to properly place the circular saw - the plastic tabs make it align to the blade, then you just clamp it, drill holes, and bolt the base down.  The instructions seem pretty straight forward to me. If you want them to do it for you I'm sure they'd oblige - for a fee.

To be clear, once you put the saw on the base it stays there. You can use it on the track or add the "off track insert" to use it on its own. 

I myself just have their tracks - not the powerbench. They do fine with me. Just connect two tracks with the connectors (don't over tighten - it doesn't take much and the aluminum can dimple), lay the tracks on the plywood, clamp down the clamps, and cut away.

If you have ANY questions, just use the Contact Us link at the top to ask a question. Its a small company based out of Florida and they are pretty quick to reply. They sell kits via Amazon.com. That's probably the route I'd go now. Search for Eurekazone in Amazon. 

I'd get the longer 108" double-track to allow you to cut the full length of a sheet of plywood.

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. 

I know there are other track makers out there. This is the one I use and I like it. It allowed me to add other stuff slowly. I recently purchase their "super smart clamps" that allow me to do very narrow rips - such as cutting down 1x's and 2x's - and making tapers. 

If you want to learn more about how their stuff works follow the resources link on the top of the web site. The instructions are useful. Better yet, go to youtube and search on Eurekazone. They explain a lot.

Sorry for being so wordy here. Just trying to help explain.

[mike]

Thanks ken. I will definitely consider your suggestions. I like that you can start small and add to their products as time goes on.

Thanks again



Ken Kortch said:

They have a product called a Powerbench. Someday I'd like to have one, but not yet. Think of it as a track saw with a cutting table under it. It can also be used with routers, jig saws, and other tools - use imagination here.

I had purchased a pre-setup circular saw - with the base already on it, so I didn't attach the base myself. They've modified the base since I bought mine. The newer type is the UEG - also called the "New Smart Base". This new base is intended to make it easier to properly place the circular saw - the plastic tabs make it align to the blade, then you just clamp it, drill holes, and bolt the base down.  The instructions seem pretty straight forward to me. If you want them to do it for you I'm sure they'd oblige - for a fee.

To be clear, once you put the saw on the base it stays there. You can use it on the track or add the "off track insert" to use it on its own. 

I myself just have their tracks - not the powerbench. They do fine with me. Just connect two tracks with the connectors (don't over tighten - it doesn't take much and the aluminum can dimple), lay the tracks on the plywood, clamp down the clamps, and cut away.

If you have ANY questions, just use the Contact Us link at the top to ask a question. Its a small company based out of Florida and they are pretty quick to reply. They sell kits via Amazon.com. That's probably the route I'd go now. Search for Eurekazone in Amazon. 

I'd get the longer 108" double-track to allow you to cut the full length of a sheet of plywood.

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. 

I know there are other track makers out there. This is the one I use and I like it. It allowed me to add other stuff slowly. I recently purchase their "super smart clamps" that allow me to do very narrow rips - such as cutting down 1x's and 2x's - and making tapers. 

If you want to learn more about how their stuff works follow the resources link on the top of the web site. The instructions are useful. Better yet, go to youtube and search on Eurekazone. They explain a lot.

Sorry for being so wordy here. Just trying to help explain.