My Table Saw Creates a Parallelogram
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Hello all,
I just got done setting up my new table saw and I seem to have a problem. When I create a panel using only the fence for instance, the sides are parallel and the front and back are parallel but they are not 90 degrees to each other. In other words, it’s creating a parallelogram with two obtuse and two acute angles.
I’m not sure how this is happening. The fence is within 0.001″ of parallel with the blade. Is it possible that the production cuts I started with were not parallel?
Any suggestions would be appreciated!
Cliff
Replies
If you are talking about cutting plywood, you shouldn't assume the corners are square or that the edges are perfectly straight.
John White, Shop Manager, Fine Woodworking Magazine
Thanks for the reply John.
So if I do find my ply is not square, how do I go about squaring it? Any articles you can point me to or tips you'd be willing to share?
Thanks again!
Cliff
Cliff,You opened the door plenty wide, so I am first going to drive this truck through it - - You have the capability to buy a Saw Stop cabinet saw, and you don't know how to square up your stock (plywood in this case)?To square stock, you secure it against some "device," riding in the miter slot(s) that takes the stock past the blade. The "device" can be a miter gauge, or, better yet, a crosscut sled. The blade must be set parallel to the miter slots, and the rear fence of the crosscut device must be set perfectly square to the direction of travel.A better solution is a sliding table. But that would be a kludge 3rd party add-on to the saw Stop machine.Rich
Rich,
Please forgive my ignorance regarding plywood. And yes, I'm sure that I'm undeserving of a SawStop cabinet saw given my deplorable lack of plywood savvy.
Compared to many on this board, I'm sure I'm a woodworking neophyte. I've only been doing serious woodworking for 8 years. Up until a year ago, all my work was done in the corner of a small basement with a 7 foot ceiling. Every tool I owned was on wheels since I could only use one at a time.
Armed with nothing but a Craftsman table saw, radial arm saw, table top drill press and lots of hand tools, I set out to make what I could. It's amazing what you can do when the mind is willing, but the space is limited. I would never have guessed when I started that I could build so much furniture in such a limited space. While I'm sure nothing I've built is museum quality, I've enjoyed learning the craft and have built many pieces I'm proud of.
Due to my limitations, I was forced to work strictly with solid wood, building panels from scratch. As such, I have a whole stable of sleds, a fair idea of their use, and some limited understand of how to square a panel.
Fast forward to the present...new home, and a real, honest-to-goodness shop! 16 foot ceilings...24'x36'...room to breath! Also, the opportunity to upgrade some of my tools...including a SawStop cabinet saw.
However, with a new tool and a new environment come new challenges...PLYWOOD! Having never been able to handle a sheet in my old shop, the concepts involved with handling, cutting and shaping them are all new. I know how to square a panel...how do I square a 4'x8' panel!? I'm sure it's a process of reducing the larger panel to smaller manageable panels before squaring...but...I'm new..what do I know? Maybe there is a better way?? I was told it never hurts to ask.
I should have been more succinct in my original post...how do you square a piece of plywood?
Anyway, thank again for your kind reply and the good information!
Cheers!
Cliff
Best of luck with your new shop, Cliff. Rich
Dear Cliff,
You go right ahead and ask. You are correct that this is the forum where the open exchange of ideas is welcome.... by most. That being said, congrats on the new house, shop & saw. 16' ceilings! WOW!Best,John
Cliff,
I once took 8 plywood panels to a friend who has a radial arm saw to square the ends and cut to length.
You can also use a shop-made T-square (be sure that it is square) as a guide for a router to square the edge as you trim it.
Monte
Wow, Cliff, it sounds like if anyone deserves a new shop, you do! Congrats. Have you considered (for the long run) building a panel saw? There are a few good designs out there, and a discussion going on right now, here.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Nice on the new home and shop....hope you enjoy it. Feel free to post any of your projects; I'm sure there great!
Kevin
I recommend using a crosscut sled on your table saw to square up one end of a plywood panel before using that end against the fence for the final sizing cut. (Or, just use the sled to cut each end of the panel.) If you are working with larger panels than can easily be cut on a crosscut sled, then using a carefully aligned straight-edge with a portable saw to cut the panel a little oversize, with final cutting to dimension on the table saw, should work well.My normal workflow is to cut plywood panels a little oversize with a portable saw and straight-edge. (It is just too hard to wrestle with full sheets of plywood on my table saw.) Then cut the two longest edges to size (and parallel) on the table saw with the rip fence. This is followed by cutting one shorter edge with the crosscut sled. If the panel's short edge is long enough I may cut the final short edge using the rip fence. If the final edge is too short to use the rip fence safely, then I use the crosscut sled to make the final cut.Good luck,
Richard Baker
That's my guess...make sure you are starting with parallel corners. What kind of saw did you get?
I purchased a SawStop...so far...money well spent! I had been concerned that I was buying a safety feature with a saw attached. On the contrary...this is a well designed and built saw with a great safety feature. So far, I'm in love...we'll see how the long the honeymoon lasts!
Thanks for the reply.
I've got a buddy in Chicago that ordered a contractor SawStop three years ago, and he is still waiting for it. However, they sent him a beta that he absolutely loves. I like the look of the cabinet version, and in reading some of the recent posts on the router accident, I'm sure you will have no regrets. Several years ago and just starting out, I nicked my thumb in the saw and did more damage than they could stitch. I learned the hard way and sometimes wonder what it would have been like to have a SawStop. I've yet to hear anything derogatory. Congrats...I hope you love it.
To second Rich, you can make a cross cut sled very easily, and it's much safer to cross cut large stock than just using the stock miter gauge as the guide. I think that you will rarely ever get a square piece, i.e. plywood, rough lumber or milled stock, so make a good one upfront.
Kevin
Hi,
Congrats on your new shop. I would have built mine that large if the city I live in would have allowed. My 600 sq ft is OK though. Being quit familiar with the cabinet making industry I can tell you that 4 by 8 sheet stock is almost never perfectly square. The first thing cabinet makers do before cutting any panels for cabinets is square up their sheet stock.They usually do this on their expensive European sliding table saws. As you may already know, these saws are designed and built to process large panels very accurately and to stand up to a lot of usage. I was making a delivery once to a cabinet shop where a vendor was setting up a new $40,000 Altendorf panel saw. He showed me how you can put a carpenters square on all four corners of a stock 4 by 8 sheet and it will read square, but if you were to cut it before squaring it, none of the pieces would be truly square. You can try to square up a 4 by 8 panel with a straight edge guide for your router or power hand saw as others have posted , or use one of the nicer straight edge guide systems on the market and sold by Eurekazone and the Festool Co. ,but from experience I can tell you it's not as easy do do as it sounds. Lately what I have been doing though is purchasing my sheet stock directly from a cabinet shop and having them square it up and make a few cuts to the basic sizes I need for the project I'm doing at the time. This way I have perfectly square panels and can easily manage them to my shop for exact processing. This usually only takes them a few minutes, so for just a few dollars more than the cost of a sheet of plywood at your local lumber store you can have perfectly square stock. And if you develop a relationship with them like I have you can get it done for free. Hope this helps!
Edited 1/4/2007 3:47 am ET by brownman
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