Domino Fit Too Tight

[SJDIYguy70]

I used my 6mm bit on 3/4" panel. When I went to insert the 6x40 domino the fit was very tight. I had to use a small finishing hammer to tap them in. Is this normal. Could it be moisture causing them to swell.

 

[copcarcollector]

In my limited Domino experience, tight fit is indeed normal. You can always adjust the width setting to give yourself more side to side play if needed.

 

[SJDIYguy70]

Thanks for the reply. I opened or widened the mouth but it was the height that was very tight. My concern was that it could cause bulging. 

 

[SittingElf]

Thanks for the reply. I opened or widened the mouth but it was the height that was very tight. My concern was that it could cause bulging.

Don't worry, it won't.  The reference mortice is often very tight, but it should not be a concern, unless you are in a particularly high humidity area.  I'd just continue to bang them in! [big grin]

Cheers,
Frank

 

[gsdvorak]

Yes- tight fit is normal, although I have noticed that humidity does have an effect on them.  I did see a neat trick on the FOG last year where a member sanded some dominoes and marked them for use during the dry-fit process.  When the humidity returns here, I will definitely be using that method.

Regards,
Gerald

 

[John Broomall]

I have run into this occasionally especially with some of the smaller sizes and it is not unusual for them to need a bit of sanding.

 

[SJDIYguy70]

Thank you all.

 

[Gary in Texas]

I've also read if you think the dominos have swelled due to moister, stick a handful in the microwave....

 

[Stone Message]

I do not live in a high humidity area (others in the UK might disagree as the weather is often very wet !)...

Dominos will be tight and should never be a loose fit. Do not sand them unless you are making up a set to use "dry" (ie without glue) for the trial assembly stage of a project.

The microwave idea is a good one and is used by wood turners all over the world.

Peter

 

[sancho57]

I just bang them in with a plastic hammer. I'll be doing that tomorrow again...

 

[Locks14]

What confuses me about the domino system is once it's boiled down, it's just loose tenon joinery. Now, if you look up best practice for loose tenon's we are told they should be "snug" not tight. I watched a New Yankee Workshop episode where Norm made a front door with loose tenons and he was able to relatively easily sink them into the mortice by hand, no hammers, etc.

I don't understand why Festool insist on them being quite as tight as they are.

 

[Phil Beckley]

What confuses me about the domino system is once it's boiled down, it's just loose tenon joinery. Now, if you look up best practice for loose tenon's we are told they should be "snug" not tight. I watched a New Yankee Workshop episode where Norm made a front door with loose tenons and he was able to relatively easily sink them into the mortice by hand, no hammers, etc.

I don't understand why Festool insist on them being quite as tight as they are.

....it also makes loose tenon joinery simple and adaptable. As the dominoes are from solid then some slight movement is going to happen but is dependent on how they are stored. Personally i like the fact that the joint will hold together so sizing can be checked easily and accurately.
rg
Phil

 

[Doug S]

I made some doors using my domino XL a couple of weeks ago, took the dominos out of packet and they slipped in perfectly, came to assemble them next day and the dominos needed a lot of hammering to get them in. Could not believe how much they had swelled up in my workshop overnight once they had come out of the packet. Had to sand them as there was no room for glue.

Doug

 

[JCLP]

Yes dominos are tight and high humidity will cause frustration. I found the by storing them in air tight cans that are used for storing coffee works well. We buy are coffee in large cans and when they are empty I use them to store dominos, mdf plugs and maple plugs. They work great and keep the humidity out.
Cheers,
JC

 

[jacko9]

I just reviewed a book "Understanding Wood" by R. Bruce Hoadley and in a chapter on joining wood he describes the adhesion characteristics one of them being the ideal glue line being no more than 0.002" or 0.05mm.  This is a long chapter but I think the take away is that a tight domino fir is not a bad thing and the cross hatching on the surface grabs and spreads the glue as the joint is assembled.

The point is that the glue by itself is not the bond but the resulting cohesive bond between the glue and the wood.  I think a lose fitting mortise and tenon is looking for trouble.  I might lightly sand a domino from time to time but the insertion is still very tight from hard hand pressing to my mallet.

Jack

 

[bkharman]

I keep a lot of the silica gel packets in my domino cases. I also noticed that the 5 and 6 mm domino swell the worst. The bigger the domino the better the fit for me.

Cheers. Bryan.

 

[Stone Message]

On a couple of occasions I have thought that I had a loose domino so I put it to one side and tried another and another...only to find that I had made a slight oversized domino slot by rushing and allowing the Domino to move slightly.

I believe that dominos should be tight and I am sure that is how Mr Festool designed them to be - otherwise I would have come across loads of loose ones by now !

I am making a chair out of cherry in order to demonstrate that it can be done with the DF 500. As always, I clamp my Domino joints in order to bring it up tight and once the hydraulic pressure from the glue has been given a chance to go I take the clamps off, check for square and wipe off excess glue. I might then return one or two strategic clamps but the tightness of the dominos will be keeping it together.

No matter what jointing method I am using I always remove my clamps after about 1 - 2 hours to ensure that there are no pre-stressing effects built into the finished construction due to the clamps.

Peter

 

[marty schlosser]

My Domino's (I've the 500) slip tenon joints are consistently tight and I like them that way.  The only time I've run into difficulty due to the tight fit was the first time when I applied glue to both the mortise and the tenon, and the piston fit and excess glue caused the wood to split.  I then did a series of tests, with different thicknesses of tenons, different species of wood, glue on the mortise only, then in the tenon, only, and on both the tenon and in the mortise.  The one consistent thing I came away with was that if the mortise was too close to the surface of the wood (or approximately closer than 3/16") then splitting would occur when glue was applied to both the tenon and inside the mortise.

 

[jacko9]

My Domino's (I've the 500) slip tenon joints are consistently tight and I like them that way.  The only time I've run into difficulty due to the tight fit was the first time when I applied glue to both the mortise and the tenon, and the piston fit and excess glue caused the wood to split.  I then did a series of tests, with different thicknesses of tenons, different species of wood, glue on the mortise only, then in the tenon, only, and on both the tenon and in the mortise.  The one consistent thing I came away with was that if the mortise was too close to the surface of the wood (or approximately closer than 3/16") then splitting would occur when glue was applied to both the tenon and inside the mortise.

Marty,

I have experienced the wood splitting by having too much glue in the mortise and having hydraulic tension at the bottom of the mortise causing the splitting.  I have used clamps to cross clamp the joint and the glue cured into the cracks and sealed itself.  The tenon length in the domino system allows for space at the bottom of each mortise.

Jack

 

[mprzybylski]

I live in suburban Chicago and store my dominos in their systainer in my garage. They swell because of the humidity here and I routinely microwave the ones I'm about to use for roughly 20-30 seconds, let them cool on a paper towel and use them up. Works great for me.