Mt55cc is this a joke?

So I shimmed really quick, didn't make any live cuts so my observations don't account if splinter guard when first cut gets sucked towards blade and springs back about 5 thousandths because blade is now that much farther away from s/g.  (later when I have time I will check distance without washers.)

Washers I used, coincidentally, are apparently 5 thousandths too thick because bevel adjustment moves blade to within molecules of corner edge of s/g.  Measurements made without spring installed but I doubt that tension moves anything. 

One thing that I did learn was using the rail on the saw (everything upside down on a big sponge) is perhaps the best easiest way to check parallel between slot and blade. 
I never moved factory set screw but shimming gave the impression of more slop on front end of saw base to plastic block registration side so I wanted to check parallel.  I thought it would be simple using a caliper.  So many ways to create false readings (won't get into it).  But I came to appreciate that the only place your saw tracks the rail is where the settings wheels push it against the slot.  In fact I remembered those sections of slot were painted when new and is the only real wear along the slot on mine so far (I don't do a third the daily woodwork most of you do).  The slot at the front edge of the base especially, and the back to a degree, seem to be wider on purpose.  
Anyways none of that matters - just take your rail, plop it on, snug setting wheels and you have a factory calibration tool installed. You can either use your eye to mate carbide teeth to edge or now measure much more accurately and easily with whatever. 

edit: whoops - forgot to tighten setting wheels when I was measuring right side up (saw weighted on track) and that took care of about 3~4 thousandths of distance for some reason and moved bevel away about 3~4 thousandths.  Guess upside down the track was tilted slightly. 

My conclusion / opinion -

So it seems to boil down to rail flex as to why they offset the bevel. If you’re using your system on a flat table in a shop you could take the training wheels off and shim it. But it you’re cutting on anything that could flex the rail during a bevel and you’ve adjusted the bevel to within a hair of splinter guard edge you’re going to eventually trim a bevel into the guard.

I don’t know if the festool rail is a stiffer than the Bosch/Mafell so that they chose to set less bevel offset but it would make sense. (Also if someone owns the Bosch version of the MT it would be interesting to know how far out the bevel offset is).

Taking off the base and replacing is not a high calibration task. The front is keyed in to two registration posts and the back just gets pushed against the set screw as you snug down coarse thread base screws - done.

If shimming gives a little bit of slop (maybe 5thou) at the front it still doesn’t matter just stick on a tiny piece of aluminum tape to one of the standoffs if it bothers you and push both ends towards blade and snug screws. The one set screw is really your only adjustment, you can't change the front. After I took out the thicker test washers and put in thin I didn’t bother with shimming the side of post. I’m only mentioning this if you are highly critical - the saw doesn’t require that much attention to cut like magic. Besides the design is such that at shallow plunge it cuts closer and then moves away a bit for the rest of the remaining depth. (probably something to do with designing a plunge saw so they made the most of this phenomenon by calling it a feature, after all it’s a base attached to a bevel attached to a plunge).

If your material requires the full depth of a 162 and you’re concerned about losing a mm start buying 165 Bosch blades and grind the bottom inside edge of the door a touch (if you even have to). It’s a tool, so own it.

The fact is this thing was designed to be adjusted and it’s rather simple. I’ve heard a few stories of people dropping their saws then checking it out and it still cuts fine. Nothing’s going to loosen on you, if it did it can only move the back of the blade away from the splinter guard. There’s no difference between the base sitting on plastic pushed up against a set screw and the same only sitting on washers - the screws they chose will stay put and keep base accurate, otherwise we would all know about it by now. (depending if you rough up washers you could even make it ‘stickier’ ).

Everyone will decide for themselves but one of the main reasons I got the saw was to simplify and speed up work. Laying that edge on the mark is key for me, even if it’s the occasional 45º. I’m happier with the tool being set how I want it and being conscious of this than the other way around. And either way you set it up you are going to be buying new guards eventually anyways.


(Sure there are a few parts left over that I couldn't remember where they went but the saw seems to cut fine without them.)

I know some of you know this, but, for those who don't, there has been a similar thread running for quite some time now:

mafell-users-forum.freeforums.net/thread/920/mt55cc-mitre-cutting-offset?page=1


My heart sank, a couple of weeks ago, when I realised that my saw, too, is experiencing exactly the same geometry errors.

As discussed in this present thread, it is apparent that the height of the saw, in relation to the rail, can influence the resultant closeness of the top surface of the cut in the material in relation to the visible edge/line of the splinter guard.

kraftt has offered some nice suggestions about shimming the saw in relation to its own base (and I may try that myself). To my mind, it should be easy to calculate exactly what thickness of shim one should try, by simply tilting the saw to 45 degrees, observing what the horizontal discrepancy is, and applying precisely that same thickness vertically in the form of shims.


That aside, in terms of why on earth Mafell are manufacturing saws with such a huge margin of error, I personally feel none of us should be making excuses for them, regarding them supposedly accommodating potential loss of substrate material if the rail flexes during a cutting-pass. I understand that logic, but I don't feel it legitimises the bevel discrepancy in the MT55CC. This saw is sold on the express basis of it being the cream of the crop of high-precision fine-woodworking track saws. Frankly, I'm pi$$ed off that my saw has an error of approximately 2mm when cutting a 45 degree bevel. 2mm is ENORMOUS, and unacceptable for such a premium product.

One thing which does not seem to have been mentioned in this thread, but which was mentioned in the thread I linked, is that another area of potential manufacturing (or wear&tear) discrepancy is the rubber 'anti-slip' strips on the underside of the rails. If these are worn thinner, OR IF THEY ARE SUBJECT TO MANUFACTURING VARIATIONS, then they could induce a net error as per what many of us are experiencing. The closer the saw gets to the rail, the greater the potential variation between 90 degree and 45 degree alignment with the sg, but so, too, the closer the rail itself gets to the workpiece/substrate the greater the same potential variation between 90 degree and 45 degree alignment with the sg.


In any case, I am not happy, and I'm currently considering my options, as my saw is only approximately 3 months old. I must say, I don't relish the prospect of having to send my saw to Germany, in terms of both shipping expense and not being able to use the saw for several weeks.

That is the trouble, even with this flaw the saw is still better.

I still love my Festool stuff though

was about to edit and add that there is almost an advantage to have a saw that overcuts on bevels in that if you know rough work is scheduled for your MT you could remove the shims to protect your nice s/g edge. Then I had a light bulb moment ... ok actually a Doh! you idiot moment.  I thought about the hassle of removing the washers, not that bad, and realized I should never have used conventional washers. Instead if you make custom horse-shoe washers with a tab to pull them out (forceps / needle nose), insertion and removal becomes much faster.  The tabs for the two closest the blade (tabs could just be tape) will clear the tilt base by design and the two furthest from the blade have room for a tab jutting out towards the opposite edge of base.  Now you only loosen base screws, slip in/out shims (phenolic, aluminum, very hard plastic) and re-snug base screws.  If it's too much trouble to make them just slice open regular washers with a dremel and use tape as your tabs.