fixing into 12mm MDF

[skeetstar]

Gentles all, sorry if this is a bone question that has been answered before, but..

I've made a box for someone who intends to give it away as a present, It is made from 12mm MR MDF. I need to fix hinges to the top edge to facilitate the lid. I assume that fixing suitable screws into the face of the board will be OK.. I could add a dab of epoxy if that were a good plan to combat the board turning back to resin dust or whatever,

I'm less sanguine about fixing to the 'end grain'. Would it be worth, or indeed good practice. to drill the edge of the board, insert 6mm dowels and then drill my pilot holes for the hinge screws into the wooden dowels? Or is this an unnecessary complication.

Would value some guidance.

 

[J-G]

Would it be worth, or indeed good practice. to drill the edge of the board, insert 6mm dowels and then drill my pilot holes for the hinge screws into the wooden dowels? Or is this an unnecessary complication.

If you are contemplating drilling into the edge to insert the dowel then you are as bad burned as scolded!

If you mean drilling a hole for the dowel into the 'face' then it would be worthwhile.

Using the first method you would still be screwing into 'end-grain' -- ie. along the centre of the dowel -- which is always a no-no, with the second method you would screw into the face-grain of the dowel.

 

[custard]

I assume that fixing suitable screws into the face of the board will be OK.

If the box just sits there looking pretty then it'll be okay. But if the box gets used, ie the lid is repeatedly opened and closed, then the screws will probably pull out. Hinge screws are subject to quite a lot of force, if the hinge is rebated a whisker too deep the screws can be tugged out just by shutting the lid. If the lid is left open to access the contents then the full weight of the lid is pulling on the screws.

Solid wood plugs let into MDF to receive fastenings are a good idea, otherwise an oversized pilot hole filled with epoxy is another option.

It's always a trade off with sheet goods, MDF for flatness, precise dimensions, and a great veneer substrate; or ply for taking fastenings.

 

[skeetstar]

Ah, ok, I'll make the lid out of ply, I had planned on oak edge trims anyway.

Still think I'll go for some oak dowels in the 'edge grain', they're going to be much stronger than softwood or the mdf, surely.

 

[xy mosian]

I had a similar problem with a small cupboard door once over. My solution was to form a groove, depth to equal length of screw,along the MDF edge. Insert a slip of suitable timber, glued of course, then screw the hinge fixings into that. It has not failed in about ten years and as it covers the letter box it is frequently opened.
HTH, xy

 

[skeetstar]

Thanks xy, I could do that, I have a groove cutter for my router, one that is normally used for cutting grooves for biscuits.,that could be a better approach than dowels, thanks.

 

[Ollie78]

For screwing into MDF in kitchen manufacture, they often use "Euro" screws which are fat and have a course type of thread, this helps prevent the fixing pulling out, I guess it increases surface area a fair bit.

Ollie

 

[xy mosian]

Thanks xy, I could do that, I have a groove cutter for my router, one that is normally used for cutting grooves for biscuits.,that could be a better approach than dowels, thanks.

I hope it works out for you. By the way a wider groove can be made by taking two different passes.
When glueing the strip in, clamp the MDF in such away that it cannot be forced into being thicker. Often when trying to get a 'snug' fit in a situation like that the material can be split. A slip of timber, goes for tenons too, can be just too thick. Stop any widening of the stock by clamping.
Have fun.
xy

 

[TheUnicorn]

I would glue a baton of wood on the inside of the box and lid, then screw through the mdf into the baton. Not sure if that fits with your design?

 

[Phil Pascoe]

I think if I'd wanted to end up where you hope to end up, I'd have started off from somewhere different. Good luck with it.