domino mortises seem too tight

[brightonmaker]

Using my new domino jointer, I have to really hammer in the 5x30 dominoes quite hard - they are wider than the opening; is this deliberate to allow for a little compression?  In the videos I've seen, they seem to be snug but just about possible to push in by hand.  This is impossible for me I really have to apply a lot of force, and sometimes the wood has split around the joint when I've closed the joint with clamps etc.  A bit disappointed because of this.  Anyone else with this experience?

 

[Alan m]

welcome to the forum

thats not normal. i would check the cutter to see is it the right exact size. a vernier calipers would work for this perfectly.
are the other sized dominos normal.

 

[jonny round boy]

Are you sure you're not plunging too quickly?

Plunging too fast can cause extra force on the cutter, which in turn makes the machine wobble a little. This makes the mortice slightly too narrow.

Depending on the material, it should take 5-6 seconds (IIRC) to plunge to full depth.

 

[mouppe]

Assuming the machine and cutter are ok, this is not normal if your technique is correct. It sounds to me as if you are plunging too fast as mentioned before. Also, try using a little less glue perhaps. I usually use a rubber mallet to seat the dominoes, especially if the glue has set up a little. The videos on youtube of the moustachioed fellow dropping the dominoes in the mortises with ease do not fit my general experience.

Welcome to FOGland!

 

[slb]

Using my new domino jointer, I have to really hammer in the 5x30 dominoes quite hard - they are wider than the opening; is this deliberate to allow for a little compression?  In the videos I've seen, they seem to be snug but just about possible to push in by hand.  This is impossible for me I really have to apply a lot of force, and sometimes the wood has split around the joint when I've closed the joint with clamps etc.  A bit disappointed because of this.  Anyone else with this experience?

Just to make sure we're on the same page, the posts so far assume you mean the size across the wide direction of the slot, not the thickness across the narrow direction.  I'd agree with the advice already posted that technique is the most likely culprit.

I've had no trouble with the wide direction, but find that there is a lot of variation in the thickness, with some domino dowels measuring as much as 0.15 mm oversize.  At that extreme they are very hard to put into the slots and must either be shaved down or baked to get them smaller.

 

[Neill]

Great advice so far.  I would also be sure that you are storing your dominoes in a cool, DRY place.  Moisture would make them swell, maybe just enough to cause the problem you are having.  This might have happened even before you purchased them if the dealer did not store them properly.

A temporary solution might be to put them in a warm oven (not a microwave) to extract the moisture from them or just use the next larger setting on the machine.

If they fill too much of the mortise you will not be able to apply enough glue to secure them in place properly.  The glue will squeeze out thereby "starving" the joint.

Neill

 

[JJ Wavra]

All of my dominoes have a very poor fit. Thi machine is great but the sizing of the tenons is terrible.  I think when my tenons are gone I will just make my own.  As it is now I make adjustments to all of them with a block plane.

Jef

 

[brightonmaker]

WOW! Thanks guys for your rapid responses to my first post on here, and for the welcomes!,  I think I might come here often!
-  Also sorry for not having noticed there's already a thread on this issue.
-  Anyway, in response to the questions;
1. I have tried varying feed speed and find no real difference;
2.  the cutter is as supplied,  brand new with the tool (as yet I only have the 5mm cutter and dominoes) :
3.  the dominoes themselves have been kept in their bag which is always closed (I learnt the lesson re. moisture and swelling the hard way, with biscuits many years ago, living as I do in humid Britain, and next to the sea as well!;
4.  I can see that holding the tool dead still is essential, cos of the oscillating head,  pressing down with the fence handle seems to do the trick;
5.  the main direction of tightness is in the width, the edges overlapping the mortise ends by about 1 to 1.5 mm at each end.  If I use the middle setting for mortise width, it works easier (and here a light tap with a rubber mallet would do it) but I then lose the benefit of the precision setting.  I feel I need a means of adjusting the arc of travel of the cutter holder!  (don't think it's a goer though....!)

 

[Jesse Cloud]

Yup, its the humidity.  Here in the desert (3 per cent relative humidity today), they slide in like butter.

Sometimes you may get a bag of dominoes with a ridge on the edges that prevents a good fit, easy to sand or plane off.

Also, if you do lots of dry fits to test your joinery, make a set of dominoes thinned down a little to prevent enlarging the mortise.  As with any mortise and tenon, to remove a dry tenon, exert force only directly parallel to the mortise, for the same reason.  If I can't pull a dry tenon out easily, I put the domino in a vice, with the workpiece still on it, and gently tap the piece with a non-marring hammer until the tenon is free.

 

[Rick Christopherson]

A bit disappointed because of this. 

The tightness of the tenon is what makes Domino so precise and the joint so strong. I would be disappointed if I didn't have to drive the tenons in with a mallet.

 

[Neill]

A bit disappointed because of this. 

The tightness of the tenon is what makes Domino so precise and the joint so strong. I would be disappointed if I didn't have to drive the tenons in with a mallet.

Rick,

With all due respect, and I may be wrong, but I don 't think he was having a problem with a "snug fit" but rather having a problem with the fit being so tight as to split his workpiece.

Due to various factors, I am sure some mechanical and some human, I can sometimes insert the dominoes by hand but other times I need one or two blows with my mallet.  But in all cases, they fit reasonably well.

Neill

 

[Rick Christopherson]

The original poster commented about the workpiece splitting when he closed the clamps. That is not due to having too tight of a fit, but due to hydraulic pressure...a completely different issue and relative to the application of the glue.

 

[Les]

Brian at Festool taught us in a class to take a razor knife to the edges of the dominos when using the tight setting. It does help.

 

[awdriven]

Les, to trim down the edge ribs of the dominoes?

 

[brightonmaker]

Well thanks guys and gals for all your ideas etc.  The problem has now been resolved.  I bought the domino assortment today with cutter set and compared the 5mm cutter in there with the one I've been using.  Guess what ?  The new one is 4mm longer than the other (which is only about 10 days old),;  i took the other back to my deealer  (Brighton Tools and Fixings) who reckon the tip is missing!!!!!  and that it was a faulty cutter.  They've sent it back to Germany for inspection and reckon I'll get a replacement soon......I'm sure it didn't come off when I was using it -think I might notice that sort of thing!  So now I have mortices with a nice frictional sliding fit aaaaaahhh!  That's what I'd been expecting;  part ofthe problem was that I'd never actually had a good look at a Dom cutter before so had  no idea what they are supposed to look like!  well onward and inward as they say.  Happy Fessing!

 

[Ken Nagrod]

There are threads/posts on here of members having issues with the bits either breaking or shearing off and it's usually due to plunging too fast.

 

[Alan m]

and i think it has only got to do with the 5mm mostly. i think.

 

[Neill]

I have had no problem with the cutters but my wrench broke.  Not a big deal, just PIA to go get one one at my local Ace.

Neill

 

[Jesse Cloud]

....  I bought the domino assortment today with cutter set and compared the 5mm cutter in there with the one I've been using.  Guess what ?  The new one is 4mm longer than the other (which is only about 10 days old),;  i took the other back to my deealer  (Brighton Tools and Fixings) who reckon the tip is missing!!!!!  and that it was a faulty cutter.  They've sent it back to Germany for inspection and reckon I'll get a replacement soon......

[eek] [eek]Son of a gun!  Never heard of that!  [eek] [eek]

 

[mastercabman]

There are threads/posts on here of members having issues with the bits either breaking or shearing off and it's usually due to plunging too fast.

This happened to me before,and i think it was my error to plunge too fast.It was the 5mm.
Another time i plunge the bit into a screw or stapple and broke the tip.