Crosscutting on MFT3 leaves bad saw mark at end of piece

[Gabeloooooo]

When crosscutting, I get this saw blade mark right at the top end of the piece, any idea what could cause this?

See picture.

Thanks!

 

[woodie]

Are you pushing the saw all the way through the cut before lifting?

 

[Administrator_JSVN]

To add to woodie's suggestion... let the blade come to a stop before releasing the plunge.

 

[sgryd]

I have the same problem with some types of wood. Try to tape some blue tape around the end of the board or use a backing board for tough cases. I don't know where I got the blue tape idea from, but I'd guess it's from our own Mr blue-tape, aka Paul-Marcel.

A point about the under side of the board:
I see on the picture that your kerf in the MFT is quite broad. The MFT works as a backing board for the cut. It works better if you keep the kerf at 2.2 mm, i.e. the blade width. It then works as a true zero clearance board.

//Michael

 

[Gabeloooooo]

The blade actually clears the piece completely, so the stopping/lifting shouldn't be the issue.

Blue tape helps with the tear off at the end, but not the inner top mark (as shown on picture)

As for the MDF kerf, I'm currently having a hard time recalibrating 90 degrees. Which is why the cuts are now all over the place. But that should only be a problem for the tearout underneath, right? My plan is to flip the MDF top when I finally get the calibration right.

I'm starting to think maybe it is the blade alignment that is slightly off on the saw itself?

 

[PeterK]

Yep - need to mount or position a separate small board at the end of the cut to back up the wood fibers. Also, use Bondo or something like wood filler to fill in the groove and start a new slot. You will get a much nicer edge on the bottom of your cut with it fully supported. I need to redo mine!

 

[sgryd]

I routed my top to fit a strip of MDF. When I damage the kerf I'll just slid in a new strip of 6 mm MDF. I say "when", because even if I'm very careful to preserve my 2.2 mm kerf, I will damage it when I do beveled cuts. I wouldn't do this to a regular MFT without taking measures for stability, i.e. maybe glue some extra MDF under the MFT to give support. I have an aluminum extrusion right under the kerf to prevent sagging.

[attachthumb=#]

 

[sgryd]

Looking at your picture again I see that I misunderstood. It not a tear out problem.. I haven't seen such a blade mark on my boards. What if you stop the saw progress when the center of the blade is above the end of the board. Let the blade stop spinning before lifting it up.

 

[Gabeloooooo]

Here is a better look at it.

I'm thinking back of blade out of adjustment. These are strictly back of blades marks.

 

[galwaydude18@gmail.com]

Did your saw ever fall? It looks like there it toe out rather than toe in

 

[panelchat]

if you are running the entire blade past the end of the cut before lifting, then i definitely vote for toe-out also.
im no expert, but after chasing down a weird toe-in problem on my ts55, my impression is that the toe setting arrangement on the saw is very sensitive, and could go out of adjustment if the saw is banged or dropped. not too hard to correct, though.

 

[Gabeloooooo]

Nope, never fell. Not my baby!

I'm trying very small adjustments as per http://www.waterfront-woods.com/festool/TS_55_EQ_US.pdf

My thinking is the back of the blade is either too close to the rail (Hinge Block adjustment), or skewed at a -1 angle (Rear Stop Screw). Thoughts?

Can you explain what you mean by toe out rather than toe in?

 

[galwaydude18@gmail.com]

Toe in means that the front of the blade is slightly in towards the rail and the back of the blade sticks out away from the rail. In other words the blade is not truly square with the rail. Toe out would be the opposite of toe in.

 

[Gabeloooooo]

I was not getting any results with small adjustments. Went crazy, moved the back of the blade FAR away from the rail, and the problem is indeed gone.

I tried the paper shim trick but with poor results (I'm probably the problem though). What I will do is move the back of the blade back, little by little, until the problem reappears, that should be the limit at which it is parallel, right?

UPDATE: It works! Now cutting realllllly clean. No more marks. Something tells me I'm perhaps a tiny bit toe-in, but it doesn't seem to affect cut (I'm guessing worst case, it makes the kerf of the blade ever so slightly wider)

My fear is that I've turned the Front and Rear Stop screws to slightly different levels. The cutting something in half and flipping the offcut test shows pretty perfect results though. I'll try and test on thick MDF to be sure. Is there a test to make sure both screws are at same adjustment?

 

[galwaydude18@gmail.com]

I'm not sure to be honest but I'm sure someone with more knowledge than me will chime in and let you know.

 

[jonny round boy]

My plan is to flip the MDF top when I finally get the calibration right.

I don't own an MFT, so please bear that in mind, but I don't think that will work. The MDF top is what holds the whole table square, therefore stops the front and back rails from moving relative to each other.

If you square everything up, then flip the MDF, isn't there a high probability that the back rail will be in a slightly different position relative to the front, throwing the rail assembly out of square again?

 

[peter halle]

Flipping the top will not have an effect on squareness of the table or your rail stop settings.  The frame (extrusions) are connected together and the top is installed with bolts into the corner pieces which hold the sides and fronts together.

Your saw should have a slight amount of toe in - the front of the blade (away from the power cord end of the saw) should be slightly closer to the rail than the rear of the blade.

When you mention front and rear stop screws are you talking about the bevel screws on the saw?

Peter

 

[Gabeloooooo]

On flipping the MDF:
Since I use qwas dogs as my fence, I expect I may have to recalibrate slighty when flipping. But at that point, I should be able to quickly calibrate since all the kinks will have been ironed out (toe-out, bevel, etc.)

On stop screws:
See picture attached. I mean the stop screws. Basically, they set your 0 degree angle. I think the back one was not perfectly set with the front one. Here's my procedure:

1. Take 2x6 and joint face
2. Plane other face (both faces now parallel)
3. Cut on MFT, check square of cut
4. Adjust back screw until square
5. When I find a zone where I'm either slightly off inwards, or outwards, tweak SLIGHTLY front screw.
6. Repeat until I get a square cut.

Using this procedure, I've gotten a pretty good result.

As for toe-out, that was it. I've no longer those awful marks and squaring my table has become FAR easier:

1. Place dogs parallel to guide rail on the left column of holes closest to the rail
2. Place the fence rail that comes with the MF3 between dogs and guide rail
3. Press firmly guide rail against fence rail, clamp guide rail holders in place
4. do a test cut, check for square
5. if not square, move the bottom guide rail holder until square (repeat 4-5 for 15 hours)
6. Adjust factory stops to match adjustment.