Domino joining help

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kuato2084

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Jul 23, 2013
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Hey Everyone,

I have the Domino DF 500 and I am very new at using it. I am trying to make a butt joint with 3/4 birch plywood. What domino should i be using 5 or 6mm and what is, if there is, the rule of thumb for determining what domino size to use for the stock thickness you'll be using ? I am thinking of using the 6mm because i would plunge 12 mm in to the face of the 3/4 plywood and then the long board I would plunge 28mm to get a total of 40 mm the length of 6 mm domino. I was originally going to use 5 mm but noticed i would have a considerable space on the side of the board since you can only plunge with a handful of depths. Is there a rule on how much of the domino should be inserted on the wood for a secure joint ? Sorry if this at all confusing, but I will clarify if needed. Oh and I am making an arcade cabinet so i do want a considerable amount of strength. Also how many dominos should i be using or how should one determine this ? Thanks for all the help guys.

Kind Regards,

Ted 
 
Ted,

The general rule of thumb is that the domino should be 1/3 the thickness of the material being joined.  For 3/4" you would use a 6mm domino.

For butt joints, I would recommend putting about half the domino into each side.

For domino spacing, it is a lot of personal preference.  For building a really strong cabinet as ytou want, I would space them every 6-8 inches.

Best,

Ken
 
Hey Ken,

Thanks for the info. When you say the domino should go in about half am i correct in the using the 12 mm in the face of the board that way i am not going all the way through the 3/4 plywood and and plunging 28mm in the connecting piece for the remaining amount ?
 
Ken's right about the standards - domino should typically be 1/3 the dimension, and try to center it (equal parts in both sides).  Of course you can't always do that when dealing with thinner stock like the 3/4" ply.

I made my kitchen cabinets with 3/4" ply and used 6mm dominos for all the main box joinery.  I would plunge 15mm into the face of the plywood, and 25mm into the "edge grain".  That seemed better balanced than 12/28.  Even though I've seen some variation in the 3/4" ply I've used in various projects, I've never seen anything close to 15mm.  I've never blown through.  I think the domino goes a tiny bit deeper than the setting to allow room for glue.

I spaced my dominos about 100mm apart (roughly 4 inches) and that felt like overkill, especially by the 4th or 5th box I made.  I went through a lot of 6mm dominos.  The cabinets are *very* sturdy.

 
Sheeschen is correct for face frames, 12 or 15mm will work. 

I thought I read butt joints (end to end, not end to face), my mistake  [doh]

Ken
 
Hi, Ted

  What they said.  12/28 works well for the 6mm for a 90 degree 3/4" plywood joint.    I like the 12 / 28 because it leaves a bit more plywood backing the face mortise. 

    I have done the 15/15 with 5mm Dominos too. Just be careful when putting the Domino into the face  mortise. If you need to drive it in that you don't break through the back side.

    For cabinet boxes I usually space then about 6 -8" apart.

Seth
 
Thank you everyone for the helpful tips I appreciate all the quick responses :) Seth is there a reason use the 12/28 is better for the 90 degree joints ? Thanks

-Ted
 
sheeschen said:
 I think the domino goes a tiny bit deeper than the setting to allow room for glue.
Click to expand...

Actually, the plunge depth shown on the DF 500 is accurate.  The length of the dominoes are less than than the nominal size by 2mm for exactly that purpose.  A 40mm domino actually measures 38mm in length, for example.  And I'd go with 12/28 spacing rather than 15/25 to keep better surface strength on the 12mm side.  When you use a deadblow hammer to set the dominoes, the resulting pressure can rupture plies.  It doesn't happen often, but it can happen, and I'd prefer to keep the additional thickness. 

 
The 12/28 is the plunge depth I use for face frames attached to plywood cases.  Also ALWAYS glue the domino in the deep hole first!  It will have a little less than 12mm protruding to catch the face frame hole.  If you glue it in the short hole and try to drive it in the case, you will probably blow through the face frame.  (Don't ask me how I know this!
smiley-gen152.gif
)
 
kuato2084 said:
Thank you everyone for the helpful tips I appreciate all the quick responses :) Seth is there a reason use the 12/28 is better for the 90 degree joints ? Thanks

-Ted
Click to expand...

Mostly just to leave more than 3mm of plywood in the face mortise. 3/4" plywood (18mm)  if you use the 15mm plunge  only leaves 3mm.

Also if you are using the 12/28  combo.  Cut all the 12mm first as a way of preventing  the accidental use of the 28 setting on the face of the plywood.  Yup I've mortised straight through  ::)  Check the settings. Check the settings. Check the settings.  [doh]  [mad]

Seth

 
When it comes to blow out it is not the domino, but your glue and inserting technique.

If you put glue in the slot and it settles to the bottom, when you insert the domino and tap it in it will act like a piston in a hydraulic pump, the applied pressure will either drive the face off the piece or the domino will stop before it seats. When the domino does not seat, the reaction by most is to "tap" it harder until it does seat. Big mistake doing so.

Apply very little glue to the side of the domino and you should not have a problem. The air below the domino will escape through the ribs in the radius edges.

Tom
 
Ha!  I knew I shouldn't reply so late at night, I'd forget some stuff, like checking to see if the dominos were shorter, or the plunge was deeper.

By the time I made my kitchen cabinets I had already made many mistakes.  The main one was using a mallet to get the dominos into the face without some sort of backing.  Yes, they blow through sometimes.  Fortunately that was on my shop cart, so it didn't matter too much.  For the cabinets, I always had the face on my MFT (and NOT directly over one of the holes!).  I usually did the long part first, though, so no chance of blowing through.

I used the 4mm dominos for the face frames, since I just used them for alignment, with pocket screws to do the holding part.  Much easier fitting, and symmetric - 10mm on each side. 

Seth is *very* correct about doing the 12mm/15mm plunge first.  I can't count the number of times I was about to do a plunge on the face and noticed I hadn't reset to the smaller plunge depth.  I started making it a practice to reset the depth to 15mm after every batch of 25mm plunges.

    Scott
 
Is it worth fussing with depth issues for the thicker tenon?  I've used the 6mm at the 15/25 setting a number of times.  I haven't had a problem with blow out so long as the tenon goes in the end grain first and seats all the way down.  Usually though I go with 5mm and set it and forget it.  

When I attended Festool cabinet training in Vegas we used 5mm for the cases.  We used narrow/narrow for the first mortise then narrow/middle for the rest.  And that's the way I've done it ever since.  For face frame and frameless.

6mm for face frames joints.  Narrow/middle with the narrow in the end grain.  I know that pocket holes are the standard for face frames.  In fact I have a Kreg Foreman.  But I just enjoy using my Domino for face frame joinery so I still do it that way about half the time.  The only serious difference is that you have to address both sides of the joint with loose M&T.  In both cases you have to clamp the joint.  It's just that with pocket holes you can remove the clamp immediately.

5mm for attaching face frame to case narrow/wide, with the narrow in the case.  Or narrow/middle if you're frisky.  

Of all the uses for the domino machine, to me, the trickiest is joining the face frame to the case.  If you want a scribe on the sides then you have to set the fence differently for each.  And so on.  What I generally do is build the cases before I even cut the parts for the face frame.  Then I get exact as-built measurements of the case.  There is no good way that I have found for plunging a mortise into the back face of a 1 1/2" wide rail or stile.  I assemble the frame set it down on the box and mark my locations where I want a tenon on the box and the frame.  Then I turn the frame upside down and punch them right there while it sits on the box.  Then I punch the mortises in the box.  Then assemble and clamp.  

Here's where I have a debate.  Should I punch the face frame attachment mortises in the case parts before assembling the case?  Jury is still out.

Another point of debate.  Where to glue.  

For face frames I put glue in the mortise and on the end grain, two coats on the end grain actually.  I don't glue the edge because I'm guessing where the end grain stops.  Especially true for mid rails and mid stiles.  Why make cleanup harder?  If you put glue in the mortise and use an acid brush to squish it around there's usually some slope around the edge of the mortise anyway.

For the cases?  Say we're not using mechanical fasteners at all.  Glue all around or just in the mortise?  Most of the boxes assembled in the factories only have glue in the dowel holes.  In fact, the latest tech in the factories uses ultrasonic case clamps.  The dowels are plastic and when the box is in the case clamp it is vibrated somehow and the dowel partially melts.  I know, what's next for crying out loud.  Also the back may be glued or stapled while the case is in the clamp.  They even have robotic nail guns mounted to case clamps to staple or nail while the case sits in the clamp, that's what's next for crying out loud.   If you only clue in the mortise then you only need to clamp at the mortise.  How truly valuable is the glue between a melamine face and a bunch of glued saw dust?  How valuable is the glue joint between end grain ply and the face of factory prefinished plywood?  I can scratch fully cured Titebond III of the face of the prefinished ply I use with my finger nail.

Face frame to case?  I glue in the mortises and a light bead all around the edges of the box.  Then I clamp at the mortises and key points like corners.  I use cauls or applied weight for mid stiles and mid rails where there is a partition.

That's how I domino a cabinet and use no mechanical fasteners at all.   It's called getting your thousand bucks worth out of a Domino.

 
Thank you everyone for all the helpful tips. You guys made this learning process so much easier :) Thanks John for providing that pdf very helpful.

Kind Regards,

Ted
 
Once you put a Domino into the joint, it's no longer a 'butt-joint'; is it?

Just being pedantic...  [smile]

Rearguards
Hookie  ;D

 
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