Domino Mortise size issue

[EJFRT]

Hi, I’m new to the world of the domino joiner. I’m UK based & have the DF 500 Q. Whenever I cut mortises on the tight setting the dominoes are always loose. At first I thought it was user error & I’ve made a couple of jigs up to stop lateral movements & I’ve made sure it’s flat so you can apply the correct pressure & there is no tipping. I’ve  tried it on scrap as well as hard wood and the result is always the same. Please follow link to see the attached video. Apologies it’s not great.
Thanks for your help.

(I’ve only got the cutter it was supplied with, purchased last September.)

 

[squall_line]

If the only cutter that you have is the one that came with the DF500, it comes stock with a 5mm cutter.

I can't tell from the video, but the domino you have looks very much like the 4mm tenon/domino, which has a small, squat, squarish profile rather than the rounded one of the 5, 6, 8, 10, 12, and 14mm tenons/dominoes.

The tenon/domino itself should have a marking on it that says what size it is.  You may need to rub a pencil on it to read it, but if it says "4mmx20mm", it's the wrong size for the 5mm mortise that you cut.

 

[ChuckM]

What size was the cutter you installed in the machine?
What size was the domino tested in the mortise in the video?

 

[afish]

Yea.  looks like the wrong domino/cutter combo for sure.  There is no way you should have slop 360° around the domino like that unless you only have 3 fingers and using one hand to operate it.

 

[Crazyraceguy]

yeah, that's wrong. Most of the time you have to tap them in, nothing crazy, but with some swelling from the glue, a little hammer tap is usually a thing.