How do I fix this Pro-Ject turntable dustcover hinge attachment?
February 3, 2022 10:04 AM   Subscribe

I have this Pro-Ject turntable that I am basically quite happy with. Unfortunately, the dust cover hinge came out and I cannot reattach it--more details inside.

The turntable has a "heavy, solid MDF plinth," and this attaches to the dustcover by way of these hinges.

One of the hinges came out of the MDF, screws and all. I tried to put it back in with some Titebond Original, and that worked for about a week. Opening and closing the dust cover puts quite a bit of torque on those hinges--the metal part sits very snugly in the plastic part--and so it came right back out and now the screws are just covered in glue and MDF particles.

What should I do to fix this thing? (As of now, I just put on and remove the dustcover, but I use the turntable basically all day, so it's a little annoying and I'd like to restore this bit of functionality to the thing.)
posted by kensington314 to Home & Garden (8 answers total) 1 user marked this as a favorite
 
Best answer: I'd probably try drilling out the holes using a drill bit size that is wider than the screws and then filling the wider holes with a wood repair epoxy putty. Let the epoxy putty thoroughly set — I'd probably wait 24 hours. After the epoxy is set I would drill small diameter pilot holes in the epoxy and then reattach the hinge.
posted by RichardP at 10:36 AM on February 3, 2022 [3 favorites]


Best answer: Another possibility, if the torn out holes are far enough from each other, would be to get a hardwood dowel from the hardware store with a diameter under half the thickness of the MDF plinth (maybe 5/16" ?). Drill holes the diameter of the dowel (or very slightly larger) where each screw pulled out, deeper than the length of the screws. Cut the dowel into a few pieces, each slightly shorter than the depth of your holes. Put a little Titebond in one of the holes and on the surface of one piece of the dowel, and insert the piece into the hole. Repeat for the other hole. Wait for the glue to dry. If necessary, cut or sand the dowels flush with the surface of the plinth and then drill small diameter pilot holes in the dowels. Reattach the hinge.
posted by RichardP at 10:54 AM on February 3, 2022 [4 favorites]


Other options, if the above doesn't work, are to (1) drill out the hole, tap it, and insert a heli-coil (steel insert that makes a big threaded hole into a smaller very strong threaded hole, sold by a few names), or (2) if there's nothing preventing it, drill all the way through and put a washer and nut on the other side to capture the body, with a longer screw. Both need $70 in tools or a friend who already has them.
posted by eotvos at 12:55 PM on February 3, 2022 [1 favorite]


Another option would be to fit metal inserts. I can't find how this specific variant would be called your side of the Atlantic, but they would look something like this: a metal cylinder, coarsely threaded on the outside, some standard bolt thread on the inside, and slotted or (like in that image) having a hex recess to screw them in. You'll obviously have to drill out the holes in the plinth to fit the inserts.
posted by Stoneshop at 1:00 PM on February 3, 2022


Um, heliccoils as suggested by Eotvos, are meant to sit in a metal object; I strongly doubt they'll work in MDF.

What would definitely work is a steel plate the size of the rear of the plinth, with threaded holes where the hinges attach, and six or so holes around the plate to fix it to the plinth. Whether that's aesthetically acceptable is another matter; for me it would be.
posted by Stoneshop at 1:12 PM on February 3, 2022 [1 favorite]


Best answer: Looking at photo #22 in this document, I can see there is a problem in the way these hinges attach. Assuming the plinth is a solid piece of MDF, the screws are both going into the side of the MDF (equivalent to screwing into end grain on solid timber) and very close to the bottom edge. These combine to make a fundamentally weak design. Using longer screws may help, but won't resolve the inherent weakness.

If you are handy enough, one way to strengthen this would be to attach the hinges to one side of a piece of aluminium angle using small bolts and screw the other side of the aluminium angle to the bottom of the plinth using four screws (screwing into the bottom face of the MDF will be stronger than into the edge, but you could also glue to the bottom of the plinth for extra strength). You would need to recess the back edge of the plinth where the bolts are to allow the angle to sit flush against the plinth. Ideally, recess the angle itself into the back of the plinth so the outside edge is flush, to avoid any geometry changes. Done carefully, this would be largely invisible and far stronger than the original poor design.
posted by dg at 2:22 PM on February 3, 2022 [1 favorite]


The point of using MDF is that it’s heavy and acoustically dead compared to lumber or plywood and has no preferred direction of sound propagation, so it seems a little odd to me to be attaching a large, stiff, and lightweight piece of plastic that’s almost like an acoustic resonator to it with connectors that have no provision for vibration isolation. It seems almost inevitable to me that you'd get some positive feedback effects from having that dust cover attached to the MDF plinth that way.

Which means this might be the prefect occasion to make the dust cover free standing. Something like dg's suggestion of a piece of aluminum angle to attach the hinges to, but having the angle attach not to the MDF but to some other relatively massive object such as a block of wood or plastic or a metal plate that would allow you to slide the dust cover up close to the MDF plinth in almost the position it was before, but not touching it, with some provision for standoffs at the front of the turntable that would prevent it from touching there either.

This could seem like a lot more work, but maybe not as much as you might think, because if one side of that hinge has worked free, the other is probably not in great shape either, and you could well need to repair both of them right now, anyway
posted by jamjam at 8:22 PM on February 3, 2022 [1 favorite]


Looking at this picture it's clear to me why these hinges have their screws pull out. Opening the cover you torque the hinges which will then try to rotate around the lower edge of the black plastic part. The two screws have to provide the force to counteract that torque, but the distance between the screws and the lower edge of the plastic part is quite small, resulting in a fairly large pulling force even under moderate torque.

Had they designed the hinges so that the screws were above the hinge axis, the distance between the lower edge of the hinge and the screws would easily be three times as large, resulting in a three times lower force pulling the screws out. Second-best: the black part extending downwards a bit more with the screws still in the same place.

To fix yours you could look if it's possible to swap the hinges, then mounting them with the plastic part pointing upward. Bonus: not only is the force pulling on the screws quite a bit lower, you're putting them into unblemished MDF. The possible snags will be the slot in the hinge where that pin comes out of the hinge axis, and the height of the plinth requiring you to mount the hinges with their axis a bit lower than they are now. You can probably compensate that by not sliding the dust cover down on the hinge pins all the way, for instance by putting a filler disc in the top of the holes in the dust cover.

Another way would be to add a support more or less the way dg suggests, but outboard of those hinges so that you don't have to modify the plinth except for making room for the bolt heads. And that would be right where the screws pulled out, so you'd just have to appropriately enlarge those holes.
posted by Stoneshop at 12:11 AM on February 5, 2022


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