Adjusting a TS75

MDP

Member
Joined
Jan 12, 2013
Messages
2
I have a TS75 with a MFT3.  Using the "5 cut method" I am consistently off by 1/64" inch (wider at the top part of the cut or the end of the cut pushing away).  I am using tool improvements bench dogs as my fence so I know I am square to the guide rail.  After calling Festool and being told that the factory stops on the guide rail  attachments are not always set parallel to each other I set them myself using the bench dogs and the fence that comes with the MFT as a spacer.  Problem is I am consistently off by 1/64.  I assume it is the ts75 but i don't know what adjustments to make.  The owners manual does not address the subject.  Any thoughts?
 
First - Welcome  [welcome] to the FOG!

Next, a few questions:  What is the length of your cut (1/64" difference over 12" is worse than 1/64" over 24")?  What is the cut quality on the edge of the piece that results under the guide rail - is the cut straight and smooth, or does it have saw marks?  Have you adjusted the two green knobs on your saw to make sure that the base slides with any slop on the guide rail?  Is there any play if you grab the end of the rail closest to you and wiggle side to side while rail is lowered and the prong is fully in the slot?

If I was having this issue I would grab a new piece to try, put the dogs into a different set of holes and then see what happens.  If the same result I would skip the spacer and reset the guide rail tight to the dogs and see if that is better.

Peter
 
Bear in mind that the five cut method multiplies your error by a factor of 4. 1/64 divided by 4 equals .004" on each cut. Like Peter said, if it is .004 over 24" that's not too shabby. Heck, for most things that's not too bad over a foot. The saw is just moving along the rail so unless there is an issue with cut quality it should not be the saw. The only other observation I can make is that, if you can, have the saw fully plunged before you start the cut and run it fully past the workpiece before you stop. That way the cut edge 'sees' the entire blade, front to back, just in case there is any saw mis-alignment influencing your measurements. If that improves your results then you may have a saw adjustment necessary, but the easiest way to rule out the saw is to evaluate the quality of cut. If the cut is smooth and there is no chipout, in other words exactly what you want, then I would be loathe to do anything to the saw. Square cuts are usually a result of the guiderail set-up.

It sounds like you are doing the right things. Just keep in mind how small a deviation you already have.
 
The Kapex supplemental manual by Rick Christopherson has a handy calculator for determining error using the 5 cut method. The process is explained on page 24 with the calculator on page 25. You have to download and open the PDF via Adobe for the calculator to work properly (at least I did). I used this to help dial-in my MFT/3.

http://www.waterfront-woods.com/festool/Kapex_KS120.pdf

 
MDP said:
......I set them myself using the bench dogs and the fence that comes with the MFT as a spacer.  Problem is I am consistently off by 1/64. 

From this statement, it kind of sounds like you are using the holes in the MFT top to set your fence and guide rail, and that is why you keep getting the same results. If that is the case, then obviously your holes are off by a small fraction of a degree. I've never checked the calibration of the holes. They are expected to be close, but even CNC operations that produce the holes have tolerances.

Set your fence the way you normally do using the bench dogs. Then perform the 4-cut calibration described in the Kapex manual linked in the posting above mine. Then you adjust the stops on your MFT table based on this error. However, remember that you are only moving your stops by a vary small amount. (You don't really need to use the calculator in the Kapex manual to make adjustments. It just gives you the angular error as an easy reference.)

  • Take your 4-cut error (the 1/64") and divide by 4
  • Take this number and divide by the length of the 4-cut offcut (12 inches or what ever size scrap you used).
  • Take that number and multiply by the width of your MFT table (I'm not sure, but this is probably around 30 inches).
  • The result is how far you need to move the far stop to the left (when standing in front of the stop). This will be a very small number, so a feeler gauge and an extra stop would come in handy.
  • Place a second stop this far away from the first stop using a feeler gauge.
  • Remove the feeler gauge, and then move the main stop until it touches the temporary stop.
  • Remove the temporary stop.

P.S. if the far end of your offcut is wider than the near end, then move the far-stop to the left. If this is reversed, then move the far-stop to the right (as viewed facing the stop). I think I have that correct, but if not, then simply reverse them.
 
First of all, to all that responded a hearty Thank You!!  I apologize if I am not responding individually but I couldn't figure out how to do it.  This is the first time I have ever posted anything on a discussion board.  Please excuse my lack of etiquette.

Peter:  Thank you for the welcome.  I did check the play that you referenced and there really is no movement.  The length of the board is 18"x18".  I checked out your video and that is how I got the idea to use the dogs originally.  Thanks for your help and the video.  The cut quality is good and (per your suggestion) I adjusted the green knobs that guide the saw along the track.

Rick and Woodie:  I did the calculations you referred to.  Now I get it!  I will get a feeler gauge and make the adjustment. 

Greg:  Got it 100%.  I think I will leave the saw alone and just adjust the guide rail.  Thanks.  To your point, I don't think my three year old son will notice that his bed is off by .004 over 24". 

Fatroman:  Thanks for the reference.  I will check to see if the cut is 90 degrees to the face.  I am sure it is fine.

Thanks again for all of your help.

Mark

 
Back
Top