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Cutting wood screw threads

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  • Cutting wood screw threads

    A bathroom fixture that I want to use has a pair of machine screws (10-32) as fasteners. I need wood screws/sheet metal screws so it can be fastened into plastic wall anchors. There is little stress and the piece is essentially decorative, not weight bearing.

    I have looked in hardware stores, big box etc to find the size/length/style I want with no luck.

    Is there a way to convert the existing screws to ones that would cut their own threads? Gashing the end like a self-tapping screw? Is the taper at the point-end of a wood screw essential to the process? Are the 32 tpi threads too fine in any event to cut threads and grip?

    How would I "thread cut" a wood screw style thread?

    Other fasteners or ideas?

  • #2
    Not trying to be crass but....

    BFH?
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    Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

    It is true, there is nothing free about freedom, don't be so quick to give it away.

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    • #3
      I'd expect that making wood screw threads would be a PITA, even more to put them on an existing screw over other threads. How about making a plate that you can lag into the wall with whatever that has 10-32 threads in it for the mounting? Failing that you can hold things with the 10-32 run into wood if the fixture isn't too heavy or gets yanked on in use.

      Heck, if all else fails get some lags with shanks large enough to drill and tap for 10-32 and run the screws into the wood screw shanks, retain with Loctite.

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      • #4
        I am not understanding why you can't find something suitable. 10-32 is a very common size and there are many thread and head options that are close to that size in all styles of screws.
        Free software for calculating bolt circles and similar: Click Here

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        • #5
          find the size/length/style I want with no luck
          what is it you are looking for? The only thing you may have difficulty with is "style" and then perhaps only the finish (assuming to match whatever the fixture is)

          those plastic wall anchors will take just about any sort of thread except really fine...there sort of needs to be some "bite" but even then, fine thread may hold for awhile depending on use...

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          • #6
            Another thought: if the 10-32 screws are long enough there are toggle bolts and hollow wall expanders that are 10-32.

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            • #7
              Plastic wall anchors will work fine with sheet metal screws.

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              • #8
                This does not answer you question exactly but this is a setup I came up with to grind a tapered thread.





                It actually worked quite well.
                Outback
                So much to learn, so little time

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                • #9
                  Originally posted by outback
                  This does not answer you question exactly but this is a setup I came up with to grind a tapered thread.





                  It actually worked quite well.
                  Outback
                  Now that's clever!
                  Don Young

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                  • #10
                    No need for wood screw theads. If you can't thread them in with pressure, just gash the end with a small v-file, or grind a section of the tip side away.

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                    • #11
                      Take a grade 8 socket head bolt that's 10-32 and grind a flat on both sides at the tip. That's your tap. Works well. One of my favorite taps made like this is a drywall screw. I ground a fairly long flat on both sides of it, and I've probably tapped 200 holes with it now, mostly in pvc. I've also made a countersink cutter specifically to match the shape of the screw head.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                      • #12
                        A similar situation, license plates are typically held to the vehicle with something like sheet metal screws with a hex head, screwed into a nylon insert in the bumper or body. The hex head is convenient for thieves, and the plating on the screw eventually disappears allowing the screw to rust.

                        Having just a healthy level of paranoia, I replaced the stock screws with stainless steel button head machine screws that required an Allen wrench for removal. I also went a step further and used longer than necessary screws with fine threads. This way, if it were the rare thief with brains enough to have Allen wrenches at hand, he might get discouraged with the extra time and effort needed to turn the screws out.

                        No special preparation was needed to install the screws, as the stock screws had already made a starting point for the threads, but some effort was required even after the new screws had been installed once. The nylon gripped the screws pretty tightly.
                        Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                        ~Practitioner of the Electromechanical Arts~

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                        • #13
                          If I get the problem, (you want to use a 10-32 bolt in a plastic wall anchour), I would try to run a 10-32 tap through the anchour first, That way there would be some appropriate threads (even if they are only partial) in the plastic that might be strong enough for your purpose.

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                          • #14
                            You can buy it ready made, It's called a hanger bolt. Any DECENT hardware store should have it. Bob.

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                            • #15
                              To the question how to make wood screw style threads you could perhaps try this method which I used for an internal thread but may work for external.

                              I cut a 2 start thread with quite a quick helix and then machined the second crest off and reduced the flank of the remaining crest to make it very sharp, I hope this picture shows up what I mean:



                              This screwed onto a wooden cane and worked very well.

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