MFT/3 bevel cuts

[wm_crash]

Howdy,

I am having some strange issues with the MFT/3. Hope someone can shed some light here.

I calibrated the heck out of it to where the cut is perfectly 90 degrees on straight up crosscuts. Now I want to cut a miter at the end of a board and I should simply tilt the TS 75 to 45 degrees I would think. Well, the cut is no longer straight. Over a 9" span, I have about 3mm out of square. The piece of wood is a 1.5" soft maple. I tried adding supports under the rail to keep it nice and flat, same problem. I thought maybe I have a problem with the rail where the thickness tapers, and that would affect the miter cut only. I pulled out the  Oneway Multi-Gauge and nope, the rail has a perfectly even thickness.

Last attempt to figure out what happened, I think I may have found the culprit. The TS75 is quite heavy. If it cuts straight up, it sits nice and straight. Once tilted to 45 for a bevel, it's hard (for me at least) to keep it at a consistent angle without having it tip over.

So my question is, has anyone tried a 45 degree bevel cut with a TS75 on an MFT and gotten good results?

If the TS75 and it's weight is truly the problem here, would I have the same problem in a (not yet purchased) TS55?

[edit]
Forgot to mention, my cut is only 10 mm deep, not going all the way through 1.5" of maple.

cheers,
Cosmin

 

[wm_crash]

I got some improvements, so I figure I'd mention here:

1. tightened the gibs really well to the point where there was some noticeable resistance in moving the saw in the track (thanks for the suggestion, J)

2. set the MFT fence vertical and retracted it out from under the rail

3. completely padded with matching thickness stock under the rail

4. concentrated my pressure at the front of the saw plate (for balance) which is where the cut is made anyways

All this gave me a cut that is a hair off of perfect. I will work on that hair tomorrow.

cheers,
Cosmin

 

[butzla]

I had the same trouble with my TS75 cutting some mitered corners for a humidor.  I wasted all morning and the better part of an afternoon calibrating and fussing just like you.  Frustrated, I walked over to my table saw and was successful the very first try.  My guess it has a lot to do with the heft of the TS75.  I'm guessing the TS55 would be better suited for this task.  Either way, this is one of the very few disappointments I've had with any Festool products and hope it is addressed in future releases.

 

[atlr]

The  TS75 Parallel Guide 492243 can be used as an outrigger to support an acute angle. (I know - yet another Festool accessory, right)

I cannot remember if I read this tip here or someone at the local Rockler store showed me.

 

[RDMuller]

I found that making 2 cuts when doing 45 bevels does wonders.  Cut the first one with the piece being a little longer than you want ---  say 1/16 of an inch or 1/8.  Watch out for the saw wandering too far off course.  Then come back for the second cut using the saw as "a planer".  Perfect results every time.    The laws of physics make it rough to be perfect when sawing through 2 thick pieces at 45 degree