Router Bit For Dominos

[mat]

I am looking at making some dominos to fit the max size mortice made by the Domino. That is at the 10mm ++ size.

Has anyone made some 10mm dominos and used either a roundover or bullnose to round the sides. There are not many 5mm radius or 10mm diameter bits on the market.

Which ones do people use?

 

[Mike_Chrest]

Hi Mat,
  I don't have one but it looks like part # 491 012 in the Festool catalog would work for you.
Mike

Kind of pricey $50.50

You could try a 3/16" radius roundover
http://www.woodworkersworld.net/roundover_bits.shtml

$18.80 8)

 

[spikfot]

I Rough up the grain of  the beech ripwise with 36/40 grit to hold the glue better. 
  Highly recommend CMT metric bits/cutters.  Best carbide around. 

 

[Jesse Cloud]

I wouldn't sweat getting the round over exactly right, unless your tenons will show in the finished piece.  The fit of the round over is not critical, many of us leave a little extra room for movement anyhow.  If you are using one of the two looser fit settings, then the shape of the round over is totally irrelevant.

 

[JJ Wavra]

I just used the festool 3mm roundover to make the 6 mm domino.  It worked great.  I found a reducing collet at woodcraft to go from 1/2 to 8 mm so I could put it in my router table.  they were through so they had to be right.

JJ
.
PS the bit cut extremely well with no burning and a very smooth surface

 

[Dave Ronyak]

I, too, wouldn't sweat over getting an exact radius size match.  There are other threads on FOG that discuss this subject.  I think that Jerry Work (maybe John Lucas, too) have written about this.  One issue that others have identified that must be dealt it is hydraulic lock.  If your domino is an exact fit (like an engine piston in its cylinder bore), in the presence of the glue, the domino your driving in is going to be sealed relative to the mortice.  Something will have to give.  Either you won't be able to drive in the domino all the way, or your going to rupture the piece having the mortice due to hydraulic presure which acts equally in all directions.  Festool's dominos avert this problem due to the embossed striations (miniature grooves) on them.  These allow air and glue that would otherwise be trapped to escape.  The lengthwise dimensions of Festool's dominos and recommended depth settings when machining the  mortices also create excess depth of the mortices when the joint is assembled relative to the overall length of a stock domino to prevent hydraulic locking.  So, I recommend that you intentionally create a slight mismatch of the radius of shop made dominos relative to the mortices. 

Where the end of the domino will be visible in the finished workpiece, you might try setting the length of domino dimension to be such that a portion of the end of the domino projects above the surrounding surface of the workpiece, and hammering it after installation to compress the end fibers to fill any small void.  This may sound ridiculous at first, but it is a variation of a technique I once witnessed Tage Frid demonstrate to repair and hide sloppy dovetail joints he intentionally created simply to show how a craftsman can fix the inevitable occasional mistakes that occur. He sawed a narrow kerf along the ill-fitting joint, inserted a piece of veneer wetted with yellow aliphatic glue and pounded it home.  Note that I have not tried this with any domino.  Obviously, it is more likely to be effective with softer woods than something like IPE.

Dave R.

 

[ROb McGilp]

Tezzer, who sometimes posts here, makes his own 32 mm wide dominoes and uses a 45 degree chamfer bit instead of a round over. IMO, these dominoes are actually better for straight cabinet work than the rounded ones. You have no chance of hydraulic locking and you actually get a stronger bond. This may be worth trying. There's also nothing wrong with making dominoes larger than the widest cut.

Regards,

Rob

 

[Warrior]

I Rough up the grain of  the beech ripwise with 36/40 grit to hold the glue better. 
  Highly recommend CMT metric bits/cutters.  Best carbide around. 

Spikfot,
You actually get a much stronger glue joint between smooth wood surfaces than with rough surfaces. there is an actual chemical bond at the wood cell level that you can not achieve with a roughed up surface.

Eiji

 

[Dave Rudy]

Tezzer, who sometimes posts here, makes his own 32 mm wide dominoes and uses a 45 degree chamfer bit instead of a round over.

Rob

DIVERSION FROM TOPIC

Rob,

Where has Tezzer been?  Miss his great posts.  Also Llap Goch.  Anyone heard from Pat?

I don't want to get too nostalgic, it might give away my age.  But we have some truly great contributors here -- people who are not just fun to read but who you would actually want to sit down and visit.  Many of them (but not all) are NAINA, of course.

END DIVERSION

 

[Michael Kellough]

Tezzer, who sometimes posts here, makes his own 32 mm wide dominoes and uses a 45 degree chamfer bit instead of a round over. IMO, these dominoes are actually better for straight cabinet work than the rounded ones. You have no chance of hydraulic locking and you actually get a stronger bond. This may be worth trying. There's also nothing wrong with making dominoes larger than the widest cut.

Regards,

Rob

Well, there is something wrong with it...

 

[spikfot]

I Rough up the grain of  the beech ripwise with 36/40 grit to hold the glue better. 
  Highly recommend CMT metric bits/cutters.  Best carbide around. 

Spikfot,
You actually get a much stronger glue joint between smooth wood surfaces than with rough surfaces. there is an actual chemical bond at the wood cell level that you can not achieve with a roughed up surface.

Eiji

The topic was domios,- aka- floating tenons. Beech expands a lot, and the roughing up i referenced is to allow for more gluing surface. the same reason that the packaged dominos are grooved, and not planed smooth.
I will assume that you were referring to parallel glue-ups with your response, which was not the subject of the thread.

 

[Wood_Junkie]

The topic was domios,- aka- floating tenons. Beech expands a lot, and the roughing up i referenced is to allow for more gluing surface. the same reason that the packaged dominos are grooved, and not planed smooth.
I will assume that you were referring to parallel glue-ups with your response, which was not the subject of the thread.

Actually, *compressed* beech expands a lot (e.g. biscuits).  The Dominos are solid beech, but not compressed.  The embossed channels are to allow glue to escape from the mortise depth, preventing hydraulic lock.  Reputedly, the Dominos don't expand a all (beyond normal wood movement).

Back to OP's question:  I used to make floating tenon stock when I had my Mortise Pal.  A bullnose bit is a LOT faster and more precisely shaped for the edges.  But as someone else mentioned, the edge contact is irrelevant compared to the face glue surface.