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Squaring up sheet goods

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Forum topic by deadherring posted 01-23-2014 03:54 PM 1321 views 0 times favorited 8 replies Add to Favorites Watch
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deadherring

35 posts in 1108 days


01-23-2014 03:54 PM

In working on some recent projects I have been wondering about the right way to break down sheet goods to end up with square components.

I made one of those circular saw guides and have been breaking down the sheet both length and width before getting it on my crosscut sled on the table saw to square up. I must not be very careful when laying out and clamping the guide because even after squaring up on the table saw when I measure the width (or length) from the two ends of the sheet I sometimes get different measurements, sometimes a difference of as much as 1/8”. So my question is, if I want to end up with a square piece am I going to have to make sure that I am dead on when setting up the guide for the initial break down of the sheet?

And, a follow on to that, I’ve got a bunch of previously cut pieces laying around the shop. If I go to use one, is the proper way to verify if it’s ok to measure two sides and if the measurements match it’s ok? How do I return the sheet to square if neither the length or the width is square?

Thanks in advance.

Nathan


8 replies so far

View waho6o9's profile

waho6o9

7174 posts in 2041 days


#1 posted 01-23-2014 03:57 PM

Check the diagonal measurements and if they’re the same it’s square.

View Loren's profile

Loren

8308 posts in 3112 days


#2 posted 01-23-2014 04:52 PM

Generally if the piece is small enough to feed on the table saw,
identify a straight long edge and feed that edge against the
table saw fence to rip a parallel edge. Then get your your
crosscut box and square the ends.

View TomWS's profile

TomWS

7 posts in 1118 days


#3 posted 01-23-2014 11:47 PM

If you’re making cabinets that are 24” or less deep then I would recommend what I do. I break down large sheets on my sheet goods cutoff table, making the pieces slightly oversize (to deal with slightly out of square). These pieces are then ripped to depth on the TS – now you have two edges parallel to each other. I then use a 24” deep crosscut sled, which has been aligned to be perfectly 90 degrees to the TS blade/miter slot. I crosscut the third edge, just to square it up, and then cut the fourth and final edge to final length using the parallel edges as reference.

Assuming you make your crosscut sled so the blade just fits in the sliding surface, then you’ve got a zero clearance slot to reduce tearout on your crosscuts (you won’t get this with just a circular saw and single sided guide).

The reason I mention 24” limit is that a deeper crosscut sled gets pretty unwieldy and you might want to look into a sliding top for your TS or full blown panel cutter instead.

If you want to look at my sheet goods cutting setup, I’ve recently posted it in the comments section of my Workshop…

Tom

-- TomWS, North Carolina

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deadherring

35 posts in 1108 days


#4 posted 01-24-2014 09:29 PM

Thanks for the replies. I’ve been doing what is described above—breaking the sheet goods down with a guide and cicular swa, cutting oversized and then squaring up on the circle saw, but I’m still ending up with cuts that are not square (wider by as much as 1/8” on one side).

I know that my crosscut sled is square so I think the problem might be that the side that goes against the crosscut fence is not square. And I think thats happening because when I made that cut with the circular saw and guide the two ends of the guide were not lined up perfectly. I find it hard to get it lined up and clamped exactly right.

Does that make sense? Do you have to make sure that the measurements for the guide are lined up just so if you expect to get a square sheet later?

Do I need to invest in a track saw to make sure that my initial breakdown the sheet cuts are dead on?

Thanks for the help, hopefully I am being clear.

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waho6o9

7174 posts in 2041 days


#5 posted 01-24-2014 09:42 PM

http://wnwoodworkingschool.com/5-cuts-to-a-perfect-cross-cut-sled/

Sounds to me like your sled is messed up.

Maybe the above link will help you figure it out, good luck.

View TomWS's profile

TomWS

7 posts in 1118 days


#6 posted 01-24-2014 09:43 PM

I guess I wasn’t clear in my previous posting. I crosscut on a tablesaw (TS), not with a circular saw. On the tablesaw, if you first rip along the long edge of your workpiece, then the two long sides of the workpiece will be parallel (assuming the edge you placed against the fence was straight – cutting a straight line is a starting point to getting square stock…)

Once you have the workpiece with the two long edges parallel, then use a crosscut sled on the tablesaw. You can use the two parallel edges against the sled’s fence and the tablesaw will cut the remaining two cuts square to the first two edges.

Make sense?

What kind of guide are you using for your circular saw? The best one I have is simply two pieces of 1/4 inch MDF layered with the top piece about 5” wide and 60” long and the bottom piece started about 11” wide but the first cut establishes the cut line for that saw. From that point forward, you simply line up that edge with your cut line, clamp it down, and run the circular saw in the track supported by the bottom layer and referenced to the top layer… Straight, accurate, and very fast to set up! Cheap too :-)

Tom

-- TomWS, North Carolina

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TomWS

7 posts in 1118 days


#7 posted 01-24-2014 10:29 PM

+1 for waho6o9! Good link! Thanks!

What do they say? A 36 minute video is worth…

-- TomWS, North Carolina

View Volund's profile

Volund

36 posts in 1419 days


#8 posted 01-24-2014 10:36 PM

DH,

From the sound of it, you are using the circ-saw cuts for more than 1 edge of the final piece. That’s no good. Everything should measure from a single corner.

The way to get these sides parallel is exactly the same as truing a block square with a plane. Get 1 edge straight. Use that as the reference for all 3 other sides. So, even if your clamped straight edge is not square to the factory edge or parallel to the opposite edge, it doesn’t matter. It doesn’t even need to be square to the material or factory edge. What matters is that you original reference edge is straight.

1) Break down the sheet.
2) Mark the side that you want to be the reference edge. Take care to keep this cut smooth and straight & be sure to use a straight edge.
3) Cut the piece free of the sheet, leaving an extra 1” or so on each remaining edge.
4) Place the reference edge on your rip fence. Cut the opposite side to final size.
5) Place the reference edge on the square edge (fence) of your x-cut sled. trim the first side, staying close to the edge of the material.
6) Flip the sheet, keeping the reference edge against the fence of the sled. Cut to final width.

Assuming your sled is square, this will give you a perfectly square piece every time. If the sled is out of square, the reference edge will be shorter or longer by 2x. Flipping the piece magnifies the error and will make it easier to spot the error if there is one, so you can fix the sled.

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