Woodworking tips to fix a stripped MDF screw hole WITHOUT glue

Question

Please note: I see some other very similar questions but the recommended answers all suggest using glue in some form. I can't use glue as part of this solution!

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I have a workbench that, on the end cap, has an upside down screw that keeps a piece of wood (on my bench) fastened to an MDF board. The problem is that I've had to move the workbench many times over the years, and each time I do, I need to unscrew and rescrew this upside down screw, and the residual wear-and-tear has started to strip both the wooden and MDF screw holes.

So now, I can pretty much just push the screw into place, and its not really doing its job, and the two pieces of wood come apart easily.

What can I do to make the screw "stick" and properly secure the two pieces of wood together?

I absolutely have to keep the existing MDF board in place; I cannot replace it. I do not want to use any type of glue as that would be permanent. And I am open to using a thicker "gauge" screw but I'm worried this might cause the board and MDF to crack or break apart and, besides, I'm not sure if there are any other woodworking tricks this community could teach me here that would solve the problem without needing new hardware! Thanks in advance!

Answer 1

One non-glue option that comes to mind is a threaded insert, specifically one suited for MDF. I did a quick search for "threaded insert for MDF" which returned many. One promising link is EZ-LOK Soft Wood Inserts as it references MDF among other types of wood.

Two versions are noted in the linked page, providing a metal foundation for the removable screw.

The above image from the web site shows a hex drive insert. One drills the appropriate size hole for the insert and uses a common allen wrench/hex key to insert the insert.

I've used this type with good results, but not on MDF.

The second listed is a press-in style:

This one has text that states it minimizes splintering and splitting. I've had no experience, but it looks promising.

The site has links for drill sizes as well as providing information for various lengths. You may also find other products of a similar nature which perform the same task.

Answer 2

Use a glue/wood mix to fill the hole and let it harden.

Then you can drill it and use the existing screw as it should be used to hold the part in place.

Answer 3

Expanding on fred_dot_u's answer...

Threaded insert is an excellent choice for this application. To make the fix as robust as possible, two details to keep in mind:

• If you have a choice between a threaded insert that takes a machine screw (similar to a Helicoil) vs one that takes a wood screw (similar to Wall Driller drywall anchors), get the one that accepts a machine screw. Those threads will hold up far better to future unscrewing and rescrewing.
• The screw-in insert is far more likely to stay firmly in place over the long term than the press-in one. For best results, I would suggest that you smear a thin layer of glue (I'd probably use slow-setting epoxy) on the outside of the insert; then drive the insert into the MDF; wipe off any excess glue and wait. After the glue is fully cured, put the board in place and screw it down.

This solution will give you a very sturdy threaded metal hole like a regular nut, installed very permanently in the MDF. You can then remove and reinstall the machine screw into the insert as many times as you want without worrying about your insert eventually wiggling its way loose and stripping that hole. It will not result in the board being glued to the desk so you can't remove it.