Why am I suddenly having difficulty squaring up sheet goods?

[Spike]

Hey Guy's,

Let me run this by you step by step clearly and see if anything jumps out at you.

1. Set a sheet of 1/2" cherry ply on my assembly/cut table and cleaned up one factory edge (long edge) trimming a 1/2" off.

2. Measured over 34" for second rip and verified placement of guide rail with story stick too, ripped piece to 34".

3. Cleaned up second factory edge (short 34" edge) trimming a 1/2" off.

4. Accurately (or so I thought) measured 85" down from cleaned up 34" edge.

5. 34" x 85" is 1/16" out of square diagonally.

So...How do you accurately break down sheet goods making them square with guide rails?

I appreciate it,
Thanks all.

 

[WarnerConstCo.]

Just a 1/16"?

Seems pretty good for using a tape measure, a pencil, eye balls and a rail guided saw.

I cut up 45 panels the other night in about 45 minutes, all were within a 1/16" of square.

 

[ccmviking]

There are a lot of variables but we can assume you've been able to cut square before because you said "suddenly" in your title.

1)  Check guide rail rubber strip to ensure your blade is cutting at it, and thus you are aligning the rail properly to your mark.
2)  Please make sure you are clamping the rail.  It's not too hard to push the rail off your mark while cutting if not extremely careful.
3)  Make sure you are holding your tape measure parallel to your stock when measuring (you stated use of a story stick so this may not be an issue).
4)  Make sure your saw to guide rail gibs are set correctly to remove any slop on the rail.
5)  Check to see if you made a parallelogram (maybe the end you measured off of wasn't square to begin with (you may have assumed the sheet you bought was square which usually isn't the case).

There are numerous other things as well...  What have you tried/checked so far?

Hey Guy's,

Let me run this by you step by step clearly and see if anything jumps out at you.

1. Set a sheet of 1/2" cherry ply on my assembly/cut table and cleaned up one factory edge (long edge) trimming a 1/2" off.

2. Measured over 34" for second rip and verified placement of guide rail with story stick too, ripped piece to 34".

3. Cleaned up second factory edge (short 34" edge) trimming a 1/2" off.

4. Accurately (or so I thought) measured 85" down from cleaned up 34" edge.

5. 34" x 85" is 1/16" out of square diagonally.

So...How do you accurately break down sheet goods making them square with guide rails?

I appreciate it,
Thanks all.

 

[Spike]

Hi Viking,
I think the parallelogram is the issue. My saw is adjusted to rail perfectly. Blade sharp. Rail clamped. I'll verify the rubber strip tomorrow but I think it's fine. The rail is dead straight according to my 6' long 40lb Starrett straight edge.

So what is your sequence to breaking down sheets with guide rails? What do you use to square the shorter guide rails for the cross cuts?

Thank you

There are a lot of variables but we can assume you've been able to cut square before because you said "suddenly" in your title.

1)  Check guide rail rubber strip to ensure your blade is cutting at it, and thus you are aligning the rail properly to your mark.
2)  Please make sure you are clamping the rail.  It's not too hard to push the rail off your mark while cutting if not extremely careful.
3)  Make sure you are holding your tape measure parallel to your stock when measuring (you stated use of a story stick so this may not be an issue).
4)  Make sure your saw to guide rail gibs are set correctly to remove any slop on the rail.
5)  Check to see if you made a parallelogram (maybe the end you measured off of wasn't square to begin with (you may have assumed the sheet you bought was square which usually isn't the case).

There are numerous other things as well...   What have you tried/checked so far?

Hey Guy's,

Let me run this by you step by step clearly and see if anything jumps out at you.

1. Set a sheet of 1/2" cherry ply on my assembly/cut table and cleaned up one factory edge (long edge) trimming a 1/2" off.

2. Measured over 34" for second rip and verified placement of guide rail with story stick too, ripped piece to 34".

3. Cleaned up second factory edge (short 34" edge) trimming a 1/2" off.

4. Accurately (or so I thought) measured 85" down from cleaned up 34" edge.

5. 34" x 85" is 1/16" out of square diagonally.

So...How do you accurately break down sheet goods making them square with guide rails?

I appreciate it,
Thanks all.

 

[tbellemare]

Taos:

It looks like your error occured in step 3 of your sequence as Chris pointed out.

How did you determine that cut was square to the first two cuts?

Were you using an MFT, or any other mechanism to get square?

Tom

 

[Wood_Junkie]

Following your first two cuts, which gives two parallel edges, you need a square of some sort to mark your first cross cut.  If you measure only from the edge to be crosscut you are certainly making a parallelogram.

 

[Rick Christopherson]

Your procedure assumes that the original sheet was square, but did you confirm this? They typically are, but I never trust this, and it wouldn't surprise me to have them be 1/16" out of square.

 

[cahudson42]

It also seems to me the problem occurs in step 3 - not assuring the first short cut is 90-degrees to the first long trim cut.

When I breakdown a 4 X 8, after I make my first long trim cut, I pencil mark that trimmed edge with a few small 'R's (for Reference) to remind myself to reference everything that follows off that. Then I use a large slightly bent carpenters square against the R edge to set up the rail for the second short cut. ( see below FinishCut_30x30.jpg - from my cfnet.net/yc ply chair project).

Then the second long cut, using a tape or story-stick to again measure off the R edge. For the final short cut, I again use the carpenter's square flipped and against the first R edge.

These days for smaller square pieces I use my MFT 1080, with its fence perpendicular to the rail, which replaces the carpenter's square. After trimming the longer side, it becomes the R edge - which then snugs up against the MFT guide rail fence - for the first shorter cut 90-degrees to R.  Then I cartwheel the piece, and do the second short cut - again with R snugged against the MFT fence. Finally, I do the final long cut, marking using a story-stick/tape measure from the first long R cut edge.

Good Luck!
Chris

 

[Sparktrician]

One method I frequently use to assure a square panel is to use the panel dimensions to figure a diagonal measurement, then set my story stick to that resulting dimension.  I'll lightly pencil in the width and length using a known-good square and 6' straightedge, then verify it in both directions with the story stick.  Only when I have that confirmed do the rails ever hit the wood, and I do clamp rails to the sheet goods to prevent rail creep.  As spendy as cherry veneered plywood is, I can't afford goofs.  My Construction Master Pro calculator takes care of the gozintas quite well.  Example: Let's say I'm cutting a cabinet side panel at 24" x 34 1/2".  The calculator says that the diagonal is 42", and that's how I set the story stick.  Once the cut is made, I again use the story stick to validate that the cuts were good ones. 

 

[Wood_Junkie]

My Construction Master Pro calculator takes care of the gozintas quite well. 

[blink]

I had to Google that.  Math game, Gazintas?

 

[John2532]

I think gozintas come from the Beverly Hillbillies show.  Jethro used to show off his math skills and was especially proud of the higher level he called gozintos. 2 gozinto 8 four times, 3 gozinto 6 two times, etc.

 

[Sparktrician]

I think gozintas come from the Beverly Hillbillies show.  Jethro used to show off his math skills and was especially proud of the higher level he called gozintos. 2 gozinto 8 four times, 3 gozinto 6 two times, etc.

Bingo!!! 

[big grin]

 

[Ken Nagrod]

I've used this and found it very helpful.  I made a storage tube out of pvc pipe with a screw-in plug on one end to protect and transport it.

http://www.amazon.com/CH--Square-Folding-Triangle-Package/dp/B00004TKDP/ref=sr_1_1?s=hi&ie=UTF8&qid=1285102760&sr=1-1

 

[Jonhilgen]

Ever since I purchased Qwas' GUIDE RAIL  SQUARE, I have had no issues squaring off goods.  And itsa fraction of the cost of an mft if money is an issue.  Best purchase in a long time.

http://festoolownersgroup.com/festool-wish-list/guide-rail-speed-square-dedicated-90-for-crosscutting-and-shelf-dadoes/

 

[mikeneron]

I've used this and found it very helpful.  I made a storage tube out of pvc pipe with a screw-in plug on one end to protect and transport it.

http://www.amazon.com/CH--Square-Folding-Triangle-Package/dp/B00004TKDP/ref=sr_1_1?s=hi&ie=UTF8&qid=1285102760&sr=1-1

You could try building your own triangle and see how that goes with some scrap wood from around the shop.  Won't cost you anything at least to try.

http://festoolownersgroup.com/festool-jigs-tool-enhancements/homemade-triangle/

 

[ccarrolladams]

There are many kinds of plywood and other sheet material that are "square enough" for certain purposes.

Usually projects built using Festools require that "square be square" and not sort-of square. Assuming a sheet is square is a sucker bet.

Generally you will find the long edges parallel to each other. On many brands of cabinet grade sheet goods there will be a lot number stenciled near an end of the long side. Many of us deliberately make the first trim cut on the other long side, so seeing the lot number tells us that is a rough factory edge. My experience is it is rarely necessary to make a 12mm or 0.5" trim cut, especially with a 2.2mm kerf on a Festool TS.

Once a long side is trimmed, then you can safely measure from it to make accurate rips that will be parallel to the trimmed side.

My experience is that it is not safe to assume the short side is square exactly to the long side. Long before I bought my first Festool TS55 and guide rails I had invested in a steel square 36" on the short leg and 48" on the other leg. When I went to the store to buy that big framing square, I had a sheet of MDO on my truck. I has trimmed one long side of that using an accurate 14" table saw and I had checked the edge with an 8" level. At the store I asked a sales assistant to meet me in the parking lot with a stack of those squares. Near an end I place the first one on the trimmed edge with the open end pointed away from the middle of the MDO. I drew a fine pencil line with the square, then flipped it over and compared the fit to the line. For each square I auditioned I used a different color pencil. On my third square both lines coincided, a sure proof of square. Since 1962 I have used this same steel framing square to check the set up of all my equipment and to set the cross cuts when using guide rails. Every time I take that square with me out of my shop, after I make the long side trim, on the back of the sheet I re-test the square with a pencil test. In 48 years it has not gone out of square.

 

[Wonderwino]

Always true up one long edge with your long rail first.  Then square the second rail to the first like this:

I line up the spine of the long rail with the edge I just trued, leaving enough room for the second rail at one end, then place the second rail rail perpendicular to the first with a framing square to ensure a right angle. 

This picture shows the method on dimension stock, but it works equally well on sheet goods.  [cool]

 

[Spike]

Hi all,
I just found this thread in a search as I am having the same issue. I recently posted a topic "Suddenly having a problem squaring up sheet goods". The problem it turns out is that my guide rail rubber strip is all notched up where my blade plunges into and exits out of the material. WHen setting my rail "on the mark" it's impossible to now know exactly where to accurately place the rail.
Yesterday I bought the new clear rubber guide rail strips and trimmed them to my TS55 perfectly. My TS has #491952 48 tooth installed. Gibs are snug to guide rail with zero side play but not to snug. Rails are dead straight. I used one of the new rails last night and it is trashed, see pictures.

What I'm noticing in the TS is a small amount of flex when you grip the handle and just lightly twist (kind of unavoidable in the normal use of the saw) especially during the plunge and exit of a cut.

Not sure how to address this but take a look at you rubber strips on your guide rails, I'll guarantee most if not all display this.

 

[mouppe]

Since this problem is only occurring with plunge cuts, I wonder if it is because the guide rail is not sitting completely flat on the material? As you plunge down, any flex in the guide rail is removed and the saw becomes perpendicular to the material. When you are doing regular cuts the saw is already perpendicular when it enters the wood so you do not see any "notching" on the guide rail strip.

Also, is the blade completely up to speed before you plunge?

I have not experienced the problem you are having, but I am just brainstorming any possible reasons for it.

 

[Sparktrician]

Hi all,
I just found this thread in a search as I am having the same issue. I recently posted a topic "Suddenly having a problem squaring up sheet goods". The problem it turns out is that my guide rail rubber strip is all notched up where my blade plunges into and exits out of the material. WHen setting my rail "on the mark" it's impossible to now know exactly where to accurately place the rail.
Yesterday I bought the new clear rubber guide rail strips and trimmed them to my TS55 perfectly. My TS has #491952 48 tooth installed. Gibs are snug to guide rail with zero side play but not to snug. Rails are dead straight. I used one of the new rails last night and it is trashed, see pictures.

What I'm noticing in the TS is a small amount of flex when you grip the handle and just lightly twist (kind of unavoidable in the normal use of the saw) especially during the plunge and exit of a cut.

Not sure how to address this but take a look at you rubber strips on your guide rails, I'll guarantee most if not all display this.

There are two green thumbwheels on the left side of the soleplate of the saw that help keep it snugly aligned with the track.  From your description of the problem, I'd suggest that one or both could be snugged up a bit to prevent the TS from yawing on the track as you slip it forward. 

[smile]