Fit of the dominoes

[Fruit bomb]

Hello all,

I am new to this forum,  but have been following this for a year since my first Festool purchace. Since then several green labelled tools have found their way to my shop,  latest was the Domino XL. My wife thanks all of you for praising the well made tools and therefore encouraging me to purchace more and more of them  [tongue] [big grin]

My first impression of this new machine was as with all the other Festools:  high quality,  made for accuracy and joy to hold in your hands.  First plunges proved my thoughts about the machine itself. 

BUT. 
I also purchased the three systainers of dominoes.  First time I slid the domino in the slot,  I was a bit surprised to find out that domino is not fitting tightly in the slot sideways.  Or actually it was touching the slot from both sides,  but only with a very tiny contact surface.  The rounding of the domino was something else than the bit radius. This leaves a cavity between the domino and the slot. Cavity is approximately 1mm. See pictures below.  Ok,  I tried all the other bits and dominoes to see that if it was my bad,  but all ended up with the same result.

I have seen several projects in this forum and in youtube where people are using through dominoes.  E.g. The woodwhisperer built a stool few years ago as an example of through domino usage.  Now I have a project in my mind where I would like to use similar technique,  but all my domino tenons will end up ugly. 

Does anyone know when the dominoes have changed from accurate slot filling ones to not so accurate ones,  or do I just have a monday products from a company who does not have mondays in their production calendar at all?

 

[grbmds]

I don't have the 700, but do have the 500. Here are some suggestions of things to watch when cutting the slots and others will probably respond also. However, I'd say in advance, my problem is usually that the Dominos fit too tightly; both from side to side and across the Domino thickness.

1. Do you have the Domino set so that it is cutting the narrowest slot? There are 3 settings. The narrowest setting should cut a slot that just fits the Domino tenon. The other 2 are used to permit movement from side to side when assembling if needed.

2. When plunging, make sure the machine doesn't move even slightly from side to side. If it does, the result could be a slot wider than the tenon and possibly a more ragged cut. When plunging horizontally I put downward pressure on the depth plate to both keep it on the face of the wood and to help prevent side to side motion. When plunging there should just be naturally enough pressure in the horizontal direction.

3. Plunge evenly and slowly so that the bit isn't forced into the wood. Forcing it could also shift the tool because of the side to side motion of the bit.

4. Make sure you use dust collection. A lot of chips are produced and they must be removed from the slot while plunging.

5. If there is play vertically, I suppose it's possible that the you are inadvertently tilting the tool while plunging. It must be kept perfectly horizontal. I would think the result of this would more likely be difficulty in assembling because the slots are not in perfect alignment with each other, but it might cause a larger slot.

Can't think of anything else right now and you may be aware of all these things already. However, whenever I get a slot which isn't exactly right, it's because I've done one of the above incorrectly, usually not putting enough pressure on the plate or trying to plunge too quickly because I'm in a hurry.

Hope this helps. It's also possible that yours is defective in some way, but the percentages are low that it is.

 

[greg mann]

What you are seeing is a condition that has always existed. It is easier to see with the XL because the dominoes are bigger and the gaps are bigger. The gap allows glue to escape to prevent hydro-lock. If you are doing through mortises you may want to make your own dominoes with a full profile or you may want to hammer whatever part is sticking through to mushroom fiber into the gaps before trimming them flush.

Edit: I don't think there is anything wrong with the OP's technique, he is just seeing the intentional lack of full profile.

 

[toadjeep]

You need room for the glue to push out if not it will act like a piston!!

 

[Fruit bomb]

Thank you for the prompt replies! Even though I am new to domino,  I think that my technique at least moderately right since the width and the height in the slots are ok and the position is also as intended.  The scale of the squeeze out cavity fully surprised  me. I thought that the tiny slots and ripples on the surface of the tenon would have been adequate for the glue to squeeze. 

Since my sets of dominoes are ok, I just need to revise my plans and perhaps use self made tenons in visible through joints.

Thanks!

 

[Birdhunter]

Being curious, I did a test cut with my 700 using a 12mm bit. I used the tight fit position and my best technique.

My mortise/tenon looked exactly like the OP's pictures.

 

[Fruit bomb]

Thanks for confirming.  No need to return the systainers.

 

[Shane Holland]

I think the general thought is that the tenons are round on the ends. They are actually tapered a bit, angular, by design. So, yes, this is normal.

 

[grbmds]

Interesting! I've never noticed it on the Dominos with the 500 although I really haven't used the larger sizes of those. I guess it's a good reason to choose another method instead of doing through Dominos. Still, at a recent Festool class, I did see an example of through Dominos in a drawer and really couldn't see any gaps. These are #4's or #5's so I suppose the gap would be tiny, but still you'd think you would see it.

I didn't mean to imply [member=60095]Fruit bomb[/member] didn't have good technique. I just know that, when my Domino slots aren't right it's because I've haven't been careful on technique or have done something dumb like not hanging the board over the edge of my work surface. So, sorry . . .

 

[chrisrosenb]

As Shane said, that is normal. There has to be a space for air to escape when the domino is inserted in the mortice.

 

[Birdhunter]

One technique I've seen is to put the mortise through the wood and out the "show side". Use a sharp chisel to square out the hole deep enough to hold rectangular plug of a contrasting color. You need to leave enough room on the jointing side to hold the tenon.

 

[Locks14]

I have observed that expansion from storing dominos in a humid condition can expand them to the point where they are devilishly hard to insert and fill the entire notice as they are forced through vs. Dominos with a lower moisture content.

 

[rst]

I keep my dominos the same way  I used to store my biscuits...in zip lock freezer bags that I vac the air out of when I store them.

 

[Birdhunter]

Ziplock bag with a package of desiccant works well.

 

[travisj]

In theory, since the dominos are compressed, wouldn't the absorption of glue swell the domino to fill the gaps as it dried?  I know biscuits react this way.  I have never glued a through domino joint or cut a domino joint apart, but now I am curious as to what it would look like.

 

[Fruit bomb]

I didn't mean to imply [member=60095]Fruit bomb[/member] didn't have good technique. I just know that, when my Domino slots aren't right it's because I've haven't been careful on technique or have done something dumb like not hanging the board over the edge of my work surface. So, sorry . . .

Don't be sorry,  I did not take your comments offensive,  more like a good advise! Those are the things which need to be considered first if dominoing somehow fails.

I'll do a test with smaller bits also to see if the gap is smaller and report back.  I will use the seneca bit extender for that. 

As an example of the usage in through dominoes is in this video at the end where Mark is making a stool as some Festool domino demo. (Interesting stuff starts from 8mins and the result is seen approx 27mins.)
the wood whisperer using throug dominoes

 

[sancho57]

IMO there has to be a gap, How else are the dominos to fit and the glue to escape? The glue does take up a certain amount of room and the excess has to escape,  the domino does need to have room to fit in the mortise.

So I feel this is by design

 

[Fruit bomb]

Yep,  understand that now after doing some glueups with the domis.

I made the tests with the smaller dominoes and the result was the same - > definitely a designed feature.

I wouldn't use these as a through tenons though....

 

[jacko9]

Yes, there can be some gaps (or not depending on the wood expansion with moisture) and you can still use them for through tenons.  I a few projects I have been lucky enough to have almost to gaps showing in others I have used a Japanese Dovetail saw with a 0.020" kerf and cut slots for tapered wedges.  Also I use the Sipo stick stock to cut my domino pieces to get contrast with light color woods.  I do through tenons either flush or bevel the ends and leave them proud.

 

[Fruit bomb]

[member=8318]jacko9[/member] might I ask you some close up photos of the joints you have made? Just to get some encouragement.    [embarassed]

I have one paint grade project going on where I probably try the through tenons,  flush sawn.  How ever the joint will end up,  I will over paint them...