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Thread: Threaded inserts for mdf

  1. #1
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    Threaded inserts for mdf

    Looking for fastener system for project built with either mdf or plywood, 3/4" thick.
    Looking at the threaded inserts like these from Lowes.

    https://www.lowes.com/pd/The-Hillman...t-Nuts/4316644

    Do these need a special tool to install?

  2. #2
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    i'm not sure how well they will hold in MDF.

    usually just use a hex key to insert them.

  3. #3
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    A 3-Prong Tee Nut would be much stronger but is not always a design option.
    Please help support the Creek.

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  4. #4
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    With regard to an MDF project, it will hold as well as you should need (as long it is inserted in the face and not the edge, of course). In a plywood face, it should hold as well as solid wood.

  5. #5
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    I find the ones you show to be too soft for my applications. Several malformed on insertion with a hex key and had to be replaced. I stick to these (or something similar) for the most part now. I have used them in ash and pecan so MDF should be no problem.
    “Falsehood flies, and the Truth comes limping after it,”
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  6. #6
    I have had good success with them. I prefer the tapered, hex driven kind to the brass ones because they tend to go in straighter if you're driving them by hand. Also, if your design will allow for it, you might be well served by the flanged version of the one you posted, installed where the flange is opposing the pull (like a tee nut would do). Here is a link for what I'm talking about - https://www.amazon.com/E-Z-Threaded-...MQ452WS2SW7EDF

    Regardless, the knife threads hold with a lot of strength. I've never had one pull out.

    I'm not sure if what you are building is something that needs to knock down and disassemble. If not, another alternative for fasteners in mdf is Confirmat screws. They excel with mdf and particle board core. You need a special step drill bit to use them, but they are fast, efficient and strong and might be an option if you need to drive a lot of fasteners into your mdf.

  7. #7
    Quote Originally Posted by glenn bradley View Post
    I find the ones you show to be too soft for my applications. Several malformed on insertion with a hex key and had to be replaced. I stick to these (or something similar) for the most part now. I have used them in ash and pecan so MDF should be no problem.
    I've used the same brass inserts recommended above with great success. They are also available in steel. The key to insert them is to have the correct size pilot hole. I use a hex head bolt with a stop nut instead of the screw driver slot to drive the insert flush. It you want the insert slightly recessed you can then turn it using the screw driver slot.
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  8. #8
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    With MDF I try to use tee nuts. If the insert is going to be sandwiched between pieces I'll use a Forstner bit to cut the recess (sized to the flange of the nut and then drill for the body of the tee nut. I install them either with a bolt/washer combo or with a small arbor press.

  9. #9
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    Not a fan of MDF so no experience there but I've used them in ply. Don't drill the hole too undersized or the wood will raise/distort and I bet MDF would be worse. I've heard of people putting a little epoxy in the outside threads of the insert for better hold.

  10. #10
    I've used the HD brass items sold by Lee Valley. They were used on a reloading bench to hold a press and top was 3/4" MDO.
    Using the correct sized hole is the trick. Very happy with the result.
    Mac

  11. #11
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    The project in mind will probably be assembled and disassembled many times during the build, so strength is a factor. Final assembly might be permanent. I like the idea of adding epoxy to increase strength.
    Thanks for all input.

    Chuck

  12. #12
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    BTW, there will be edge connections in this project. Any advice there? I don't want to split the mdf. MDF thickness will be 3/4 in. I do want to be able to disassemble during build in case of design changes. The project, BTW, is a low budget CNC router.

    Chuck

  13. #13
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    I've used the Lee Valley brass ones in MDF successfully. As others have said, the pilot hole size is key. In MDF, I go a bit bigger than the recommended size and use epoxy to make up for the shallowness of the threads. When putting them into edges (rather than faces), I was getting split out. I started using a C clamp on the face "squeezing" the hole a bit while I screwed in the insert and the problem was solved.
    Grant
    Ottawa ON

  14. #14
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    I will never use threaded inserts in MDF anymore. Right now I'm constructing a basement pantry style cupboard with MDF doors and I'm using Hillman posts, with through hole in the doors, to secure hinges.

    On the edge connections, I would plan the project to have plywood blocks bolted to the Face of MDF, and screw or bolt through the plywood - or angle brackets.

  15. #15
    For the edge connections, barrel nuts work well.

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