[baronpork]

Got my 18mm mdf parts cut, will start drilling for M6 screws.
Did a test hole in the edge, filled it with CA. then had to dump majority of it out of the hole. Now its drying.
My question - how to do CA tap without wasting so much CA ? Any tips ?

Tried wood screws straight in - and as expected they split mdf. Piloting feels a bit dodgy.

Share your butt joining mdf for jgro, please

Thanks.

[ger21]

6mm is a big screw to go into the edge of 18mm MDF.
I've never used the superglue thread trick, but you don't want to fill a hole that big, just apply enough to the surface so that it soaks in and hardens the threads. Make sure you use a thin CA glue, and not a thick or gel version.
I'd try drilling a pilot hole 1mm undersize, and running the screw in without a tap. You might want to clamp blocks on each side before driving the screw to prevent splitting. Then apply CA.
For wood screws, it's important to pre-drill at least the root diameter of the screw.

[baronpork]

It seems all plans i look (JGRO) i see machine bolts for joining pieces together.
I was thinking its a bit of an overkill, but i didn't design the thing, so, not one to question it. Especially being my first cnc build.
But thinking about it screws have larger area of contact than wood screws, grabbing better ? Wood screws have larger thread, but thinner shank/root...

[Little_Chips]

Tightbond wood glue and clamps works good. Spread a coat on each surface and clamp. For added strength use Kreg Jig pocket holes. I like this one. https://www.kregtool.com/store/c13/k...master-system/ works good too but angle the screw away from the edge of any corners such that the screw point does not point to the end on 90 degree corners. There is no problem of which way to angle the screw when making a 90 degree Tee type of joint. If you choose to use Kreg make sure to get the coarse thread screws for use in soft materials. I set my Kreg Jig up on a piece of 2' x 2' x .75" MDF with spacers on each side of the platform to keep edges of workpiece parallel to the Jig bottom. You don't need a lot of pressure on the Jig clamp when drilling, just enough pressure to keep it in place. Also use the highest RPM drill you have. Be sure to oil the drill guide and insert the bit into the guide a little before you start spinning the bit. If you start using it you will understand. It is quite simple and makes strong joints.

It is more time consuming but you may like to use these soft wood inserts Hex Drive Threaded Inserts | Threaded Hex Drive Inserts or Finsert Threaded Insert for Soft Wood | E-Z LOK They will provide free samples. Do not try to use the more common Hard wood inserts, they will not work well in MDF.