How square is the MFT/3

[mackaygtrs]

Greetings all,
I recently purchased a TS-55 and decided on the Festool MFT/3. After lots of googling and research I decided to get the TSO MTR-18 and a set of the Bench Dog UK “Quad Dogs”.

I removed the Festool fence (looking into ordering a Bench Dog fence soon) and added the MTR removable foot to the triangle body and aligned the rail to the front edge of the table. After that I added in a few of the Quad Dags (these are the ones that tighten and have no wobble) and when I check the Quag Dogs with the rail using the MTR it’s no longer square. I then realigned the rail with the Quad Dogs “using the MTR” and tested it around the table from hole to hole, flipping the MTR just to be use it’s square and so far all seems pretty darn good but now the edge of the table is no longer square to the rail.

I check the distance from a hole to the edge of the table (the best I could using calipers) and there is definitely a slight difference from one end to the other.

My thought is that if my holes/dogs are all aligned with the rail then I’m good to go. Is it that big a deal the edge of the table is a little off?
Only issue I see would be if I added a 2nd table? I would be mounting it to an edge not parallel to the holes on my existing table.

I did go though the search within FOG and only found a few people that had an issue with the table not being square but never really saw how they resolved it as the post seemed to go off the topic about what the best square to buy was...lol.

Going to go over all this again today after work and see if I’m missing something.

Stuart

 

[Coen]

You can adjust the rail and the original fence. The position of the top vs the aluminium sides is non-adjustable afaik.

If you want the dogholes to be square to the rail, you have to adjust the rail, then adjust the fence to the rail.

Adjusting the guide rail position can be done by adjusting the position of the two stopblocks, which are held in place by an allen screw.

However, I'd recommend against squaring rail vs dogholes, because if you use the fence, you would have to adjust that too and then it might be off if you use it in other places. I'd rather have the fence be true, then adjust the guide rail to it. Dogholes be damned. I don't use those with the guide rail.

 

[ghhsolutions]

I'm not clear why you are concerned about squareness to the edge of the table. The key thing is the squareness of the fence to the rail. Using either the supplied fence or the benchdogs.co.uk fence you can also align to the dog holes if you feel that would be useful (IIRC Festool do not guarantee the holes are square to each other as their primary intention is for them to be used for clamping).

 

[peter halle]

The hole pattern may not be square to the metal extrusions on the edges.  If you want the fold down rail to align with the holes then you will need to adjust and possibly adjust the feather keys inserted in both the front and rear extrusions.  If you are using dogs and rails to make cuts, as mentioned previously along with the other stuff I wrote, the hole patterns are usually extremely accurate but not guaranteed to be in a perfect grid nor diameter hole size.

Peter

 

[dashboardpws]

Note that the top is slightly smaller than the space into which it fits and the frame can be slightly racked as a result. One super simple thing to do is just loosen its four attachment points and yank it tight to one side and one end, then retighten. This will at least improve the squareness situation - if not make it perfect.

 

[Tom the Remodeler]

My understanding is the following:
-- The grid layout is not necessarily perfectly square
-- The grid layout is not necessarily perfectly square to the edges of the table surface
-- The grid layout and/or edges of the table surface are not necessarily perfectly square to the table frame

Yes, the table surface is produced on a CNC, but to my memory, Festool has never released a specification regarding squareness tolerances.

My preference is to use the 20mm holes purely for clamping, and to use other means for setting up a cutting/routing station.

There are a number of great videos put out by Festool on how to set up their MFT/3 hardware square in a repeatable, square fashion.

 

[bertv]

There NEEDS to be a bit of slop in the holes for the dogs to slide in. Most dogs are 0.1 mm smaller than the 20 mm nominal size of the holes. So there is a built in inaccuracy of about 0.1 to 0.05 mm, depending on the way the dogs are used.
If the pressure on two dogs is from the same side there is hardly any difference (and that is why using dogs and a fence pushed against them works).
The most import thing is having the fence and the rail square, where it is advisable to start with the rail being perpendicular to the hole pattern and then setting up the fence.

 

[Birdhunter]

I’ve used dogs on my MFT for years to orient wood for cutting with the TS55 and drop down rail. Every cut has measured perfectly square as measured with either a Starrett square or a Woodpecker square. I never use the MFT protractor. I do use a SlopStop on the rail. My MFT hole pattern must be pretty accurate.

 

[Andrew Wilkerson]

MFT dog hole patterns are pretty accurate.  I agree with Brett though. With tolerances of dogs being different, and the fact that you can wallow out the dog house with use personally I would stick with squaring the track to the guide rail. Sedge mentioned in one of his Festool Friday Lives that he doesn't recommend using the dog holes to square up the MFT.  Instead, he uses a Woodpeckers (or any other highly accurate square) and paper trick.

I did that for a while but found that I still resisted moving the guide rail because of the hassle of ensuring it was square.  I decided to tackle the problem and I designed the MFT Insta-Square. The Insta-Square slots into the top groove on the MFT guide rail and helps you quickly square it to the track.  Takes about 5 seconds (video).

Shamless Plug



Check it an other cool things I have created to solved problems in my shop here.

Thanks,
Andy Wilkerson
Black Raptor Tools

 

[sancho57]

i do it the old fashion way using the OEM angle stop, guide rail , fence and a good square. I dont have these issues

 

[johnyhuh]

I’ve used dogs on my MFT for years to orient wood for cutting with the TS55 and drop down rail. Every cut has measured perfectly square as measured with either a Starrett square or a Woodpecker square. I never use the MFT protractor. I do use a SlopStop on the rail. My MFT hole pattern must be pretty accurate.

What is a SlopStop?

 

[Crazyraceguy]

I’ve used dogs on my MFT for years to orient wood for cutting with the TS55 and drop down rail. Every cut has measured perfectly square as measured with either a Starrett square or a Woodpecker square. I never use the MFT protractor. I do use a SlopStop on the rail. My MFT hole pattern must be pretty accurate.

What is a SlopStop?

It is a slightly tapered "landing point" for the MFT. So when you lower the rail to make a cut, the rail catches into it and makes the position more repeatable.

 

[Ebuwan]

i do it the old fashion way using the OEM angle stop, guide rail , fence and a good square. I dont have these issues

Same.

I did a kitchen cab build this past summer with my buddy, and we "squared" it all up based on the dog holes and that Woodpecker MFT triangle (Black phenolic?). It has holes that you place dogs through into the holes of the MFT.

Big mistake.

it was out of square by the tiniest bit, but put that over 24", it gets worse further out. We had to recut a ton of panels, even the first few that were actually square so lengths matched. I have multiple MFT's, some the dogs would have play, other no play.

So now i have a biggest Woodpecker square, and i square it up with that, never trusting the dog holes again, i'm too scarred.

Bonus is since i don't rely on teh dog holes, i can probably just make my own tops.

 

[peter halle]

Festool has never claimed the accuracy of their MFT hole placement.  Yes, the holes are on a regular grid (more of less based on the accuracy of calipers), but they were placed there for clamping and stops - not as a replacement for the fence and rail for cutting or routing.  Anyone who goes the dog route is rolling the dice that the accuracy obtained will meet their expectations.

Peter

 

[Cheese]

I’ve mentioned this on several occasions, when Woodpeckers was developing their MFT jig, they gathered about 6 MFT’s, several of them brand new, mounted them on their vision system and checked them for pattern to pattern and hole diameter consistency. They wouldn’t reveal the actual numbers but they told me that they were very surprised at the amount of variation.

So if you’re using a “regular “ MFT with dogs for precision work it’s a “you get what you get” situation. As Peter mentioned, it was only intended to be a clamping/assembly aid.

 

[Crazyraceguy]

That is the beauty of the Parf system. You can drill the holes very accurately and actually trust that the rail is square to the other dogs. The holes are generally a tighter fit, but I have heard of people having problems with that? Some say they are too tight, some say too loose?

 

[Bertotti]

A bit late to this thread. Once I got the MTR18 from TSO I took the whole square assembly off of my MFT/3. Am I the only one? I almost universally use the MTR now. I even considered the new smaller 12" version they released but I don't really need it. Just curious if others are using it almost exclusively. I still use my miter saw for some stuff but it is a heavy beast to move around so this has become very handy.

 

[krudawg]

i do it the old fashion way using the OEM angle stop, guide rail , fence and a good square. I dont have these issues

Same.

I did a kitchen cab build this past summer with my buddy, and we "squared" it all up based on the dog holes and that Woodpecker MFT triangle (Black phenolic?). It has holes that you place dogs through into the holes of the MFT.

Big mistake.

it was out of square by the tiniest bit, but put that over 24", it gets worse further out. We had to recut a ton of panels, even the first few that were actually square so lengths matched. I have multiple MFT's, some the dogs would have play, other no play.

So now i have a biggest Woodpecker square, and i square it up with that, never trusting the dog holes again, i'm too scarred.

Bonus is since i don't rely on teh dog holes, i can probably just make my own tops.

Say it ain't so.....  Well all I can say is it is square enough for my work

 

[Michael Kellough]

I only use the holes for clamps.

 

[afish]

I have been saying it for years.  Dogs and dog holes are great for field work where you need to make a cut that is more than reasonably square quick and fast.  However, if you are doing more shop type work or building a project where compounded errors can or could effect you DO NOT RELY on dogs or holes.  Set up a good fence and solid rail square or hinge.  Make sure there is no excessive deflection in either and both are locked down tight with no room for movement or drifting.  Dog holes are great for one off cuts and clamping/fixturing but thats it IMO There is just to much room for error.  Im sure those that make a living selling products designed for dog holes will disagree but will never convince me.