Domino extraction

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MattRoberts

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Love the domino. Hate extracting them after a dry fit! Anyone have any good tips how to do this other than clamping the workpiece and article the domino out with pliars?
 
I keep a bag of the sizes that I mainly use, which have each had a couple of plane strokes all round to slim them down. They're all marked with a big red "X" on each face so they never get mixed up, these are the ones that get used for dry test fits.

Other workshops I've been in sometimes kiss the domino on a sander if a job will require multiple test assemblies. I know craftsmen way above my level who follow this practise, but personally I'm not convinced. I trust in Festool to have optimised the fit for the strongest possible joint, so I prefer to do the final glue up with untouched, full size Dominos.

On the subject of tight Dominos, if you glue up a big, complex frame with Dominos and PVA you can get caught out by the PVA "grabbing". On a hot day, especially if the Dominos have swollen slightly because they've not been stored properly in the dry, you can get the joints 90% home, but if you'd messed around too long when you get the cramps on for the final tighten the glue has "grabbed" (PVA is pressure sensitive) and either won't shift at all or needs a big sash cramp with a pipe on the tommy bar. To avoid those kind of heart attack moments I take real care storing Dominos to make sure they're bone dry, and on really complicated assemblies I'll us a slow setting UF glue (such as Cascamite) which isn't pressure sensitive.

One final point, on the really big XL Dominos the fit seems to be a fraction looser. Just the impression I get, maybe sample variation, be interesting to hear from other users.
 
As per Custard I keep some of the commonly used sizes of dominos that I have relieved so that they fit easily. They do not need much. There is a little lip on the edge of each which I removed with a stanley knife and then chamfered the ends. I keep thinking I should drill a hole in the face of them so I can use a philips screwdriver to pull them out. The problem with planing or sanding the face is you lose a little of the accuracy.
 
A quick rub on all sides on a sheet of 40 grit is all it takes to knock off the ridges for easier dry fitting.
 
It's interesting reading this, I just pull them out by hand but it can be challenging. I like the idea of having an assembly set of slimmed down Domino's, I must do that at some point.
Interestingly I also found the xl700 gives a very slightly looser fit than the df500 so it's not just you custard.
I very rarely use the tight setting on the domino so that undoubtedly makes them easier to wiggle out by hand, I can see why you guys use pliers.
 
Having a set of slimmer ones for dry fits is a great idea, thank you.

Surprised Festool don't have a domino extractor machine for £5000 for sale :D
 
I use pliers and it is a bit of a pain. But am I missing something.....if you plane or sand the faces then the dry fit isn't accurate any more is it? In other words, if your dry fit is to test whether for example 2 faces will come up exactly flush then by taking a smidge off each domino you're going to throw off the dimensions n'est-ce-que pas?
 
I don't think there's enough in it for that to be the case. Sanding the ridges off only means it fits as easily as a normal domino does in a bit of super dry end grain, it's not wobbling about in the hole or anything. Can't speak for planing though.
 
I also keep an assortment of slightly under width sizes separate for dry fitting. I have'nt had any issues with misalignment when coming to final assembly & glue up.

As Custard stated, keeping the Domino's dry is important. I keep a couple of packets of Silica Gel in my Domino Systainer case and it works a treat. In fact, I have a pack in most of my power tool cases as well, it prevents rust spots forming on the steel components such as chucks and pillars on a Router.
 
How about drilling a small hole, big enough for a screwdriver to pass through close to the ends of each Domino. Easy to pull out and keeps the accuracy of the test fit.
 
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