MFT/3 & Parallel Guides accuracy

[bob_barthelow]

I am new to this whole game of woodworking and learning the Festool way of making cabinets for my house. I have several questions.
I am cutting sides for a cabinet 480 x 736 using the MFT/3 and the parallel guides. I made setup sticks which are notched at 480mm and 736mm and use these for alignment of the parallel guides and MFT/3. My method is to insert the notch around the blade while it is placed on the track and then adjust the stops on the parallel guides and the MFT/3 fence. This is somewhat effective with the parallel guides. For the crosscut I am only able to set the fence side and must depend the alignment of the MFT/3 to ensure a square cut. I have used all the alignment methods I have seen and still cannot get a "nuts on" square cut. I recently received the square from Anderson Plywood and it seems to be the most accurate, as I would expect, given the length of the sides being longer then my W 1281 square.

1. What is an acceptable "nuts on" measurement? I am getting, rather consistently, a 1-2mm difference over 480mm when crosscutting the 736mm parts on the MFT/3.

2. When checking for square by a diagonal measurement on these sides I  find a 1-3mm difference

3. Is it possible to obtain exactness, e.g. < 1/2 mm variation when using these tools?

4. What level of accuracy is good enough?

Thanks.

 

[sancho57]

You need to check your PGs. You should be getting dead on @ 460mm. I get 1.5 mm over 8 ft

 

[ear3]

The method I like, though it depends on the splinter guard being intact, is to have a scrap piece of ply a little smaller than the MFT ttop that has a scribe line drawn on it from a 32" Woodpeckers T-Square.  If the splinterguard follows the line, the setup is square -- if there any adjustments to be made I do it on the rail, as the fence can sometimes move slightly when clamping down the fence stop.

The error you are getting is pretty large, and you should be able to cut it down significantly.

Keep in mind an additional variable -- changing the height of the rail brackets can sometimes affect the alignment, since you may push the bracket up or down such that the rail is slightly out of parallel with the top.

I think the MFT is a bit more finnicky than many of us think it will be when we first get it, but once you get comfortable with the setup, you will be able to get highly accurate and repeatable results. 

I am new to this whole game of woodworking and learning the Festool way of making cabinets for my house. I have several questions.
I am cutting sides for a cabinet 480 x 736 using the MFT/3 and the parallel guides. I made setup sticks which are notched at 480mm and 736mm and use these for alignment of the parallel guides and MFT/3. My method is to insert the notch around the blade while it is placed on the track and then adjust the stops on the parallel guides and the MFT/3 fence. This is somewhat effective with the parallel guides. For the crosscut I am only able to set the fence side and must depend the alignment of the MFT/3 to ensure a square cut. I have used all the alignment methods I have seen and still cannot get a "nuts on" square cut. I recently received the square from Anderson Plywood and it seems to be the most accurate, as I would expect, given the length of the sides being longer then my W 1281 square.

1. What is an acceptable "nuts on" measurement? I am getting, rather consistently, a 1-2mm difference over 480mm when crosscutting the 736mm parts on the MFT/3.

2. When checking for square by a diagonal measurement on these sides I  find a 1-3mm difference

3. Is it possible to obtain exactness, e.g. < 1/2 mm variation when using these tools?

4. What level of accuracy is good enough?

Thanks.

 

[bob_barthelow]

Thanks for the info. I've got a WP square and will test as you outlined. Thanks also for the heads up on raising the track guide. I have wondered if moving the fence such that the track sits on the mft and after alignment moving the fence forward would affect square. I had also thought that leaving the guide elevated for 3/4" stock and shimming when cutting 1/4", 1/2" materiel would avoid resetting depth of cut on the saw and would also eliminate messing with the alignment.