TS 55 REBQ and MFT/3 not square on 45 degrees but square on 0 degrees

[mystudio]

Again need your help guys. Sorry for that. But I've a problem which I can't solve, it seems and it's driving me crazy. 
My MFT/3 is perfectly square, aligned with dog benches and when I'm doing the 5 cut test, it's all good. No issues at all. So, me happy. However, when I'm trying to do cuts on 45 degrees with the TS 55, the line is not square anymore. How is this possible? I've tried everything, moved the fence to the middle of the table, to the end of the table (because in the first place I was thinking it could probably be that the guide rail was bending a little), however, whatever I try, nothing helps, the cut is not square. When, with exact the same setup, I move the TS 55 to the 90 degrees (or 0, depending on how you see this) position, the cut again is perfectly square. What is happening, what could be the problem?
See here the square cut:https://1drv.ms/v/s!AgBl459hbinflOQIZGzuqMIkZ_0hkw
And the 45 degrees cut:https://1drv.ms/v/s!AgBl459hbinflOQJQbyYCwrhhR-Hkg

 

[Dick Mahany]

I have had boards "creep" ever so slightly when cross cutting with 45 degree bevel angles.  (It has happened on a table saw saw also).  Try clamping the board down with clamps and repeat the test to see if it helps.  I believe that the due to the direction of blade rotation, it has a tendency to feed the board from left to right when cutting at steep bevel angles, pulling the board into the saw.  This would result in a cut which is less than 90 degrees, measured at the end of the cut, which is what your video shows.

Since you have done a thorough job of establishing square and verifying it with the 5 cut test, and have ruled out guide rail flex, it is very mysterious.  Good luck.

 

[peter halle]

I will second trying to clamp the board to see if for some reason the workpiece is moving a tiny distance as the saw meets the workpiece initially.

I have had this exact thing happen when using my Kapex with a pretty worn blade and thought I was losing my mind.  When you put the blade on the bevel and there is resistance it wants to push the work away.  Your cut in the wood is also longer (diagonal) which obviously could have an effect.  In my case replacing the blade solved my issue.

It might be interesting also to see if going slower at the beginning helps.  I realize that no one wants to go slower but it might help to work towards finding out what is going on.

Peter

 

[Bohdan]

Check that the rail support (the hinged end) is set for the correct height. If it is a little high it will make your saw climb and the cut will not be square at 45° but perfect at 90°.

 

[Roseland]

I've seen this as well.  There are two factors I've identified as contributing to the problem, but I think there are more.

The first problem is stopping the saw as soon as the cut is completed, rather than continuing on until the back of the blade is past the last bit of wood.  I reckon this is down to a toe-in/toe-out issue.

The second one is that my MFT top had sagged, and flipping it over made a big difference.

Let me know if you find a fix, I still hate 45° cuts.

Andrew

 

[mystudio]

thx for all responses. Allright, tried everything I could, again. It's getting better, but, not perfect. One of the problems is the guiderails, as it always bends a little when you cut plywood of 9mm thickness and the cut in the plywood is only 8 cm. I clamped it at three positions and thereby it is getting better, however the start of the cut still is slightly different from the rest of the cut. A little a 'round' start of the cut still. Mayby I also should try another blade (the default blade in the TS55 is the 48 tooth). By the way, everything is brand new, so, the blade is sharp. Maybe the special 52 tooth blade for laminates?

 

[antss]

Are you cutting the boards to length first (square cut) and then cutting the 45 bevel?

- or - Are you doing both at the same time.  Meaning , do you have waste board on the outside of the blade?  Those boards aren't very big, so it prob. isn't really affecting it much.  But the ts55 sure doesn't like long bevel cuts with material on the outside of the blade.  Just a thought.

 

[Holmz]

Is 8 or 9 mm ply too thick for it?

If there is a shop you got it from maybe you should go back and get a test or tune up?

How hard do you have to push when doing the cut? That is somewhat a gauge of sharpness if you really need to be shoving it along.

Is the blade bent? Or does it spin perfect on the arbor shaft?

 

[mystudio]

No, no extra board on the right side of the saw, almost. It's the right length when I do the 45 degrees cut.

I don't think 9mm plywood is too thick. The TS55 can easily do that. The 55 is brand new, so is the blade. So, I don't have to push really hard to do the cuts. Today I tried to do the same with 18mm MDF. The results are more or less the same. It's really perfect if you do a cut on the 0 degrees position and with the same setup and the saw in the 45 degrees setup, it's not that perfect anymore. You'll get slight differences.
The saw has full speed before it hits the board and is down allready before starting the cut. At the end of the board the blade is completely free from the bord before I lift it up and turn the power off.

It's really complex to make really good and nice 45 degrees cuts. Why? The result is that if you make a box, like on the picture, it's almost perfect, but not quite. Still no idea what I am doing wrong.....

 

[mystudio]

Okay, ordered a new blade for the TS55, the 52 tooth blade specially for laminates. See if that makes a difference. Also mounted a new FS 1400/2 parallel rail on the MFT/3, you never know. Seems to be getting better by only that. Could the original 1080/2 be not quite right?

 

[mystudio]

Okay, still no idea what causes the problem. Could it be the TS55, in your opinion? What I do see that it's not an allignment problem; if you look closely at the picture you see that the problem is that it wideness underneath the rail allready. So, on the top there is more wood between the rail and the cut than there is on the bottem. There the cut is perfectly under the rail/the splinterguard. So, it hasn't something to do with the allignment of the fence or rail, the problem arrises at the saw/rail combination itself.

What you see under the rail is 10mm plywood HPL cut on 45 degrees. Top of the plywood is black HPL. You see that the cut itself doesn't allign with the rail over the length of the rail.

Any ideas? (if I do the same cut again without the 45 degrees, it's perfectly alligned with the rail/spinterguard. So, this just happens with the 45 degreees setting. The wood was really well clamped, no possible movement at all) I really have no idea anymore.

 

[Birdhunter]

In my opinion, either the rail or the wood has to be moving. It looks like the change in the cut happens gradually from top to bottom. The lateral and vertical forces the saw exerts are greatest at 45 degrees and least at 90 degrees due to the thickness of the wood in the cut.

Is it possible to test this theory by using double sided tape between the wood and rail and doing a test cut? The tape would eliminate any movement between the rail and wood. Clamping the wood down would further eliminate movement.

Also, I've noticed that, as I push the saw down the rail on a long cut, my control of the saw lessens. I can't exert as much downward pressure on the saw as it gets further away from my body.

I use my table saw for the angled cuts so I'm not an expert in diagnosing this problem.

 

[Holmz]

In my opinion, either the rail or the wood has to be moving.
...
... I'm not an expert in diagnosing ...

There is actually a science to diagnosing things, so we can avoid opinions.
First one makes a full list of the mechanisms that could cause the issues. This is often referred to as a fishbone diagram.

In any case of the saw is repeatable at 45 then we have some shot at figuring out what is happening.

Other options include a hand plane to clean up the cut.

So throwing out the most likely mechanism is statistically good for a person to fix their saw.
But it does little to help people figure out how to fix their saw.

 

[mystudio]

In my opinion, either the rail or the wood has to be moving. It looks like the change in the cut happens gradually from top to bottom. The lateral and vertical forces the saw exerts are greatest at 45 degrees and least at 90 degrees due to the thickness of the wood in the cut.

Is it possible to test this theory by using double sided tape between the wood and rail and doing a test cut? The tape would eliminate any movement between the rail and wood. Clamping the wood down would further eliminate movement.

Also, I've noticed that, as I push the saw down the rail on a long cut, my control of the saw lessens. I can't exert as much downward pressure on the saw as it gets further away from my body.

I use my table saw for the angled cuts so I'm not an expert in diagnosing this problem.

There is absolutely no movement possible anymore. The wood is really clamped well, by hand and forced it won't move. The rail is mounted as it should be, so, the movement of the rail is also no option.

I really think it has something to do with the TS 55. Maybe the allignment of the blade differs from the 0 degree position, if mounted in the 45 degrees position. But, not sure how this can happen, really.

 

[grbmds]

Based on the rest of your posts and your original pictures, I think that the difference has to do with how you position yourself during the cut and what direction you are putting force on saw during the cut. Cutting a piece at a 45 degree angle is much different than a cut at 90. It is much easier to go off track on a 45 cut just because of where the force on the blade and saw is. I have had slight problems when I haven't paid attention to making sure I'm behind the saw and pushing it forward rather than on the side of the saw and putting some sideways force on the saw during the cut.

One other possibility could be the bevel setting. I don't know if your saw is older or newer, but on mine, setting the bevel is a little bit of a challenge. It really requires that you are careful when setting for a beveled cut. Any slight force on the front while tightening the bevel indicator will deflect the saw; only slightly but your difference isn't much.