Thread: Reinforcing MDF box hinges

I would probably run a groove through the edge of the lid and glue in a hardwood spline to take the screws. Or change the design to use a pin hinge - extend the sides up past the ends of the lid and then come in from the top corner of the end and into the lid as far as you like with a bit of brass rod or something.

I was thinking of using the Domino to put in the little 5mm ones down about 6mm. A mini mini domino! (just as reinforcing), but thought the dowel would be easier with a drill. I can mark the hole from the hinge, drill, glue in a short dowel and screw end grain....but I like the idea of SilentC, perhaps use a router to make a groove and inlay a strip of hardwood., which would be very Domino-like....

A really fine single square mortise would work too....if I had a mini mortiser!

Yeah I was trying to think of quick and easy in terms of mass-production, given they are to be painted. You don't want to be fiddling around too much if you are working to a price. If I was doing a lot of them, I'd buy a slot cutter for the router of the correct thickness (probably 3mm). But I'd try one first because a bit of hardwood that thin is likely to split if the screws are close to the edge.

Another option might be Euro screws, which are used to fasten cup hinges and drawer runners in cabinet sides made from composite materials. They are fatter than a normal screw with deep threads. Might be a bit difficult to locate them the right size. They are usually 10mm long.

I would have thought that the inlay strip option would give you the benefit of not having to screw into end grain. A dowel would result in the screw going into the end grain, which would have better holding power than just the MDF but not as strong as the inlay strip.

Euro Screws are at Sachy's

No pecuniary interest, just a happy customer.

I think you want to minimize the time it takes to install each hinge.

5mm coarse thread screws might be an option but would require you drilling and counter sinking each hinge.

screwing into a piece of wood might allow small screws to bite, but inserting the holding strip into the MDF would be time consuming.

is using epoxy to attach the hinges an option

Could you use a plug cutter ?

Have you bought the hinges. If not, maybe use the type that do an outside mount. That seems to be the way cheaper packaging-type boxware is usually done. You will not be constrained about the screw gauge that way.
Arron

Originally Posted by Evanism

Ive a commish to make a zillion MDF boxes of 9mm with hinged lids.

Besides MDF being evil, this is the material the client has asked for as it's later painted.

I've struck a few problems with the lids and hinges. I rebate the hinge a touch in the body so the lid sits flat, but the screws into the lid are tiny due to the 9mm thickness.

It looks like they will tear out very easily. I've carefully predrilled and pre-hardened the area with a few drops of CA, which sort of works.

My thought was to drill a short 6mm hole and glue a dowel in, then insert the screw into that.

I'm wondering what strategies others use to reinforce this fragile area? Drop of epoxy?

so how is teh hinge installation going?

All went very good.

For the first demo box made earlier in the month, I was thinking too hard about it being the same as a hardwood box. I very carefully depth drilled 7mm into the 9mm lid, took the little 12mm screws to the grinder and removed the offending point and inserted them. All 4 barely had any grip in the lid. A few drops of CA to harden the hole up ... It was very bodgy.

I was disappointed and it looked crap. There would be no longevity.

The next 6 I was not relishing grinding back 24 screws and depth stopping such small predrilled holes, then thought, "frag it" and drilled right through after marking it with a fresh 2mm bit... put the entire screw right in! It pointed out the top of the box, so I used a little diamond file and filed it flat, filled with a tiny spot of Polyfilla and a quick sand once dry.

Since they are to be painted anyway, so what!

With the earlier incarnation the MDF split a bit and looked lumpy. By pre drilling right through, the screw bit right into the MDF very solidly indeed.

MDF is such a rotten material. But, the customer wants these made to a budget and in some quantity, plus flat for art....so MDF it is.

There are photos, because it did happen, but I'm my iPad.

(the dust! Jesus spare me!)

Boat builders often have this problem as well when attempting to screw a fitting onto a fibreglass hull or deck. What they often do is to drill out a larger hole, say 50% bigger than the hinge screw with a bradpoint or small forstener bit then fill the hole with epoxy so it creates a plug. When cured pre drill the plug to suit the small hinge screws which should hold it. Set up a fence with stops on your drill press, set the depth and then drill the plug holes for the zillion boxes.

I'd get a larger screw and either nip the tip off with cutters or hold in vice grips and grind the point off. Pre-drill the hole and away you go.