Domino 'mortise width dial' setting for a 45degree bevel-jointed box?

[gearhound]

Over the weekend I "attempted" to make a floating night-stand cutting my 1st bevels with the TS-55/MFT3 setup and joining with the domino....I had the domino on the tightest mortise setting and it was a pain in the assss getting the last board in flush. I followed the Half-Inch Shy guy's video for setup and put a domino in each corner referencing off the 'edge stop dogs'.

The joints looked sloppy with gaps so I quickly broke it apart before the glue set. After getting pretty frustrated, I'm now ready to give it another shot. I just re-cut all the parts a tad bit smaller after re-checking my MFT for square-ness with my woodpecker square.

I'm thinking I should probably have the domino set on the middle mortise width setting so I've got a bit of wiggle room? Or should I go all the way to the loosest setting? Anyone have experience making something like this with the tracksaw/mft/domino combo? I'm new to all 3 of these things and any tips would be greatly appreciated.

Thanks

 

[JonSchuck]

I think the guys that know more than me are going to want pictures to see what gaps you are talking about.  I could never imagine using the widest setting for anything.  The most I would ever do is narrow on one piece and medium on the other.  However with a little tweaking and practice I think you should be able to use both on narrow.  You can always sand a smidgen if not perfect. 
If your last joint had a gap, you weren't getting perfect 45 degree cuts.  You also should probably dry fit before gluing. 

 

[gearhound]

Unfortunately didn't have time to take pics as I wanted to get it taken back apart before the glue cured. The bottom and 2 sides went together just fine, but with the tight mortise setting I had to literally pound on the final top piece to get the dominos in and that created gaps on the other bevels.

Thinking about it now, using the tightest domino setting for all of them doesn't seem to make much sense....with no play in the joints I'm not sure how it's possible to even get the final piece in without a huge struggle?

 

[ear3]

Dominoes in a mitered box joint should work fine, but you want to double check all your settings on the TS and MFT to make sure you're cutting a true 45, otherwise the 45 fence setting on the domino will work at cross purposes with the joint.  Especially on bevelk cuts, you'll want to make sure that your rail is supported all the way through the cut, and that when making the cut you keep one hand to steady the base on the rail and prevent the saw from rocking/tipping.

For alignment purposes, you really only need 1 narrow mortise -- anything more is just going to give you problems fitting, as you experienced.  You don't technically even have to use the narrow setting, and can do the alignment as you're doing the glue up, which may actually help ease the fit of the joints.

The only time I've ever found using the widest mortise setting useful was when I was edge gluing really long pieces (6 ft. and up), as the increased play helps during the fitting.  The middle setting is where it's at most of the time.

 

[JonSchuck]

You might have missed it but I just edited my first post to say that if you have gaps in all the bevels you are not getting perfect 45 degree cuts.

 

[gearhound]

What's the best way to check if my tracksaw is cutting at exactly 45degrees? I've got one of the digital angle readers for my table saw, but being a brand new saw I figured it would be pretty true out of the box.....guess I should flip it upside down and test with my reader?

In terms of a dry fit, I guess I need to sand my dominos down a bit? The fit is so tight that I sometimes can't even get them out with a pliers.

EDIT: I've been using my left hand on the bevel cuts to secure the saw to the track, but not really certain on the best way to support the rail? I'm feeding the stock from the left so the rail seems to be supported?

EDIT 2: Attempted to use my magnetic angle gauge to test the 45degree setting and it doesn't appear that there's an easy way to do it with the saw upside down and rocking around?

 

[Shane Holland]

If you're assembling a box with 45s using the Domino, put two sets made of two pieces together. Then connect those two sets to one another. In other words, put board 1 & 2 together, then put board 3 & 4 together, then connect the two sets to one another.

Trying to assemble side-by-side, the last side is going to be hard to put together.

I hope that makes sense the way I described it.

That's not going to fix any issues you have with your angles being off, but it will keep you from having to bang things together.

 

[ear3]

If you have a square you trust, you could simply cut a board at 45, flip the offcut so that it forms a 90 degree angle, and check if the joint is tight when abutting the square.  If you have a combo square you can also check the cut piece with that.

As far as track support goes, the crucial part is usually entering the cut.  Depending on the width of the material being cut, sometimes there will be a large enough gap between the front rail backet and the start of the work piece that the weight of the saw will cause the rail to sag slightly.  This doesn't matter on a 90 degree cut, but can sometimes throw off the bevel by a degree or two  at the front of the joint.  Easiest way to prevent this is to have a scrap board same size as workpiece supporting the rail in the gap -- if there indeed is a gap.

What's the best way to check if my tracksaw is cutting at exactly 45degrees? I've got one of the digital angle readers for my table saw, but being a brand new saw I figured it would be pretty true out of the box.....guess I should flip it upside down and test with my reader?

In terms of a dry fit, I guess I need to sand my dominos down a bit? The fit is so tight that I sometimes can't even get them out with a pliers.

EDIT: I've been using my left hand on the bevel cuts to secure the saw to the track, but not really certain on the best way to support the rail? I'm feeding the stock from the left so the rail seems to be supported?

EDIT 2: Attempted to use my magnetic angle gauge to test the 45degree setting and it doesn't appear that there's an easy way to do it with the saw upside down and rocking around?

 

[Gregor]

If you're assembling a box with 45s using the Domino, put two sets made of two pieces together. Then connect those two sets to one another. In other words, put board 1 & 2 together, then put board 3 & 4 together, then connect the two sets to one another.

Trying to assemble side-by-side, the last side is going to be hard to put together.

I would go one step further and do a dry-fit test, then break it apart along only one diagonal and glue these two ones, keeping the dry-fit on the other two to hold it together and align the box, after the glue bound do the other diagonal.