Microjig clamps on MFT

[Bob D.]

I saw a photo of a MFT/3 with a grid of dovetail slots in the top surface.

Anyone tried this and if so how well does it work?

 

[Svar]

I have not tried it, but imagine it would weaken the top substantially. It would sag easily.

 

[Bob D.]

My thought too. I guess you could add some reinforcement underneath but that would interfere with using clamps in some locations.

 

[Cheese]

Well, if a guy fabbed a MFT from aluminum instead... [popcorn]

 

[StevoWevo]

What about 3/4 ply? I’m working on my first table now and this sounds interesting.

 

[Bob D.]

I'll see if I can locate the photo I saw the other day.

 

[cubevandude]

The MicroJig website has a bench design close to what you describe

=emb_logo

The video shows good quality 3/4" plywood and 2 layers of 3/4" MDF.  Even if you had a couple of rows for clamping material for cutting it would be good.  I find when I build cabinets with melamine they are very slippery.  I use the dogs and UJK rail clips.  A couple of dovetail slots would allow me to clamp the sheets from moving.

 

[Bob D.]

Yes, I saw that video, but the other image I saw was an actual MFT/# with a dovetail grid spaced between the dog holes over the whole table top.

Here it is was on Menard's website.

 

[grbmds]

I would think that the dovetailed grooves take up at least half the thickness of the MFT top so that there is something to hold the bar in place when under stress. That would certainly weaken the MFT top.

In some ways, a Microjig grid on the MFT is redundant. It basically serves the same purpose as the holes when it comes to clamping, maybe a little more flexible for moving the clamps around, but essentially just adding a capability that already exists on the MFT.

Plus, although the bar on the Festool clamps and the Microjig clamps are different angles (and maybe size also), they both are dovetailed; just with a different angle.

 

[jeffinsgf]

That is for guys who wear belts and suspenders at the same time.  [blink]

 

[Cheese]

Maybe this is a viable alternative if you use 1" thick Baltic birch? 

Certainly I'd not recommend it using 3/4"MDF. Or maybe you just have to use a very very light touch on the screw clamps. [tongue]

 

[Michael Kellough]

In reply #8 there are $450 worth of clamps. What does a vacuum bag set up cost?

 

[jeffinsgf]

I'm not really into the idea of both...but I am thinking about building an assembly table with machined slots instead of holes. I love being able to clamp things down, but every screw, washer and nut I drop finds one of the holes in the top of my MFT. I bought the bit that Axminster sells to cut a slot for Festool clamps. I'm going to give that a test...if it works, great, if it doesn't work, I'll have plenty of room to enlarge the slot and install regular T-track.

 

[Bob D.]

Microjig says you can use a standard 14° 1/2 inch shank dovetail bit to cut the dovetail tracks for their clamps. They make their own bit but the only difference is it rounds over the top corner of the dovetail to take the sharp edge off.

Will a Festool or Bessy clamp fit a 14° dovetail slot 3/8" deep? I believe that's the depth they tell you to cut the slot for their clamps.

I agree it would weaken the MFT top, especially since it's MDF. I wouldn't do it to my MFT top. But maybe a 3/4" plywood top used in place of the MDF and only a few 20mm holes placed to allow for fence alignment and squaring or 45 cuts using saw track.