TSO rail square not square

[ferntree@gmail.com]

My square was off. It's "user serviceable" so I corrected the square, checked the rail square: dead on.

How do you correct the rail square?

 

[festal]

My square was off. It's "user serviceable" so I corrected the square, checked the rail square: dead on.

How do you correct the rail square?

I think Paul is talking about his square was out of square not the tso square

 

[PaulMarcel]

I think Paul is talking about his square was out of square not the tso square

Yes, that's correct. I could have written that more clearly. TSO square was dead on, my large square had fallen out of calibration. I used that cut piece actually to do the adjustment.

 

[NiteWalkerGR]

Yes, that's correct. I could have written that more clearly. TSO square was dead on, my large square had fallen out of calibration. I used that cut piece actually to do the adjustment.

Paul, I just wanted to say your videos on festool products are some of the best available, especially the domino. I do miss you making videos, but you gotta keep yourself happy too. Thanks.

On topic, my FS/WA 90 (festool branded version of the GRS16PE) is dead on.

 

[ferntree@gmail.com]

I think Paul is talking about his square was out of square not the tso square

Yes, that's correct. I could have written that more clearly. TSO square was dead on, my large square had fallen out of calibration. I used that cut piece actually to do the adjustment.

Ah. I took it to mean you adjusted your rail square. I was using my thinnest feeler gauge and was getting a consistent gap throughout different spots on the lengths of all 3 of my rails. I wound up using a piece aluminum foil folded twice to get it spot on. I’m gonna email TSO to see what tolerance it should be at. I’m not opposed to keeping that foil there. Or maybe grind the anodizing off the opposite side to get it perfect. I’ve almost given up trying to keep my MFT square for more than one cut.

 

[mino]

Got the pictures here.

[member=74394]LumberSmith[/member]

I do not want to spam too much but I have to make two points:

1) The "engineer's square" you used to check is NOT an "engineers square" and 100% the gap you see is because the "engineer's" square is not square while the GRS is /within tollerance/.

How I know - No precise (engineer's) square has distance marks on itself like the square you used has - making these marks would create tension in the metal and affect the accuracy ..
For your reference, here is how a precise engineer's square looks. This is a DIN class 1 /which is about the precision the GRS is made to/:
https://shop.kinexmeasuring.com/en/precision-flat-square-kinex-300x200-mm-din-875-1-p8471c22c34/

Notice the square has no distance marks and the material thickness is 8mm for a 200x300 pieces. That is required as a thinner one could not maintain its shape sufficiently for the precision.

/I am not familiar with US metrology classes, so those from US please feel free to give an equivalent US class./

2) the back of the rail may not be /absolutely/ parallel with the rail ALONG ITS ENTIRE LENGTH, remember, the reference surface is the one where the saw rides /not the back edge/ AND the rail is guaranteeed to be straight along its entire length within a certain tollerance. NOT at its beginning. To check if this is not your problem, try using the square on the other side of the rail.

I have this issue with one of my rails as it starts a bit "off" - by about 0.05 mm (0.002") on the 150mm square interface distance which puts the cuts off by about 0.5 mm (0.02") over the 1.4 meters of the rail which can be too much at times when combined with other errors.
I found out the hard way and that is why I now recommend the Festool FS-WA above the GRS as someones first or only rail square. It has to be calibrated - so you need a proper engineer's square to go along, but it CAN be calibrated. Unlike a fixed square. So even non-absolutely-straght rail starts or bad technique causing systemic errors can be weeded out /at the cost of fiddling/.

Hope helps.

The first thing I would do - in your shoes - is to get a proper engineer's square so you have some known reference. You will want to have it either way. No matter the outcome with the GRS. You need to shoot for DIN class 1 or better (equivalent) for it to be useful here. - for a 200x300 sqaure that makes 0.025mm max error over the 300 mm /notice that is only 1/4 of the error I have which  already causes me problems/. Yeah, the reference square really needs to be that precise, ideally even better. The GRS 16 generally is at DIN class 1 /from my checks of the Festool version, that is/.

Second, I would try making cuts when the square is attached, e.g. to the middle of the rail. And see where it gets you. So the GRS is attached at a different position on the rail than on the usual "start" one. Using a different section for the reference.

 

[ferntree@gmail.com]

. . .2) the back of the rail may not be /absolutely/ parallel with the rail ALONG ITS ENTIRE LENGTH, remember, the reference surface is the one where the saw rides /not the back edge/ AND the rail is guaranteeed to be straight along its entire length within a certain tollerance. NOT at its beginning. To check if this is not your problem, try using the square on the other side of the rail.

I have this issue with one of my rails as it starts a bit "off" - by about 0.05 mm (0.002") on the 150mm square interface distance which puts the cuts off by about 0.5 mm (0.02") over the 1.4 meters of the rail which can be too much at times when combined with other errors. . .

Funny you mention this. I spoke with TSO and they told me their product is good. Probably my rail. I slide the GRS up and down the rail finding the sweet spot that allows my track saw to make the longest cut that is also “square enough” for me. I still shim it with foil and made reference marks if I need to move the GRS to a longer rail.

Does Festool guarantee the back of the rail to be straight? Or will picking a straight rail be like picking straight boards. Going to Rockler or woodcraft with my square and GRS and testing to find a “straight” guide rail. 

 

[MikeGE]

Going to Rockler or woodcraft with my square and GRS and testing to find a “straight” guide rail.

This reminds me of the Mr. Bean episode where he is shopping for a potato peeler and frying pan.

 

[kitfit1]

Going to Rockler or woodcraft with my square and GRS and testing to find a “straight” guide rail.

This reminds me of the Mr. Bean episode where he is shopping for a potato peeler and frying pan.

[big grin] [big grin] A classic  [thumbs up]