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  • Screws keep breaking off

    I've had a bit of trouble with the loft bed for the kids' room. I'm using the Lee Valley bed bolt covers to cover up the bolts, but when I'm turning in the screws, they are breaking off before I can even get them snug.

    The pilot holes are appropriate for a #6 screw - 3/32". And they're plenty deep enough. I've had 3 of the screws break off that came with the covers, and 3 more of my own brass screws that I've tried. The rest were fine, and when I used these before, they were fine.

    Any recommendations on what to do? I could go with a slightly larger hole, but then will the screw have enough bite? I guess I could also use a #8 screw.

    If all goes well today (bolt covers not withstanding), I could post pictures of the final product this weekend...

    Thanks,

    Trevor.
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  • #2

    Re: Screws keep breaking off

    Re: Screws keep breaking off

    I drill a pilot hole and then use a similar # size and a size longer steel screw first. But still be careful, if it gets tight when trying the brass screw, stop and look at making the hole a wee bit bigger.
    sigpic
    hobby woodworking since 1972

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    • #3

      Re: Screws keep breaking off

      Re: Screws keep breaking off

      Good idea, using the steel screw first.

      I was also having problems with steel screws in another part of the bed, the solution there was to go to a #10 screw.

      Thanks,

      Trevor.

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      • #4

        Re: Screws keep breaking off

        Re: Screws keep breaking off

        Brass screws are notorious for breaking off, if you insist on using them find a steel screw of the same size and run this in first. Try to leave about an 1/8 of a turn back it out then drive your brass screw. Leave the last turn or so and then use a hand screw drive to finish the snug up. I known using a hand screw drive is considered to be a sacrilege.

        Greg

        I know I'm a slow typist but two posting while I was typing!

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        • #5

          Re: Screws keep breaking off

          Re: Screws keep breaking off

          I've also applied paste wax to the screws but usually Bryan's trick works best with the steel screw first.

          Brian
          If your dreams don't scare you, you are not dreaming big enough

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          • #6

            Re: Screws keep breaking off

            Re: Screws keep breaking off

            Do all of the above Trevor---it takes longer to take out a broken screw
            "Born 50 years too late"

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            • #7

              Re: Screws keep breaking off

              Re: Screws keep breaking off

              You have several "cardinal sins" here so to speak...
              * If the screws are breaking off it is caused by a) need for a bigger/longer pilot hole, as first determined in scrap material, and/or too much torque. One size hole for the screw will vary by material so don't rely on a chart.
              * I am not certain of your use but I gather you are using small brass for a decorative cover only. Brass, let alone small should be tightened only by hand, if you happen to be using a cordless drill, set it aside.
              * assuming you have satisfactorily tested one in scrap per above, determining proper pilot, a little help is to be gained by keeping a candle on hand and rub the threads against the paraffin but don't expect that to overcome shortages described
              * finally, if you are looking for real strength, brass is only for decrative or corrosion purposes. If you want proper construction screws for cabinetry/fixtures/furniture us the appropriate construction screws, see The Grabber Company as examples http://www.grabberman.com/
              Start slow and wind down gracefully

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              • #8

                Re: Screws keep breaking off

                Re: Screws keep breaking off

                This is a little OT but still relevant since you usually have to get the broken screw out, preferably without a lot of damage.
                There's a quite useful rear cover article in the 'Woodworking' magazine- Autumn 2008.
                It describes proper sizes for pilot holes, Tips to avoid breaking screws, removing broken screws with pliers, use of a rotary tool to cut a slot in the broken screw and something called a TUBE EXTRACTOR. It works like a plug cutter around the broken screw.
                I've never heard of a Tube Extractor before (but I lead a sheltered life!), and it's their recommended first choice to remove broken screws. This is a short metal hollow tube with saw-tooth edges that you use with your drill and it cuts a neat, clean hole around the broken screw. When you reach a depth slightly greater than the bottom of the broken screw, you remove the extractor and pop the cut center portion (containing the broken screw) out, and you can plug it and drill a new pilot hole etc. In the diagram they show 3 different sizes.. 1/4" tube for #4-8, 5/16" tube for 10, and 3/8" tube for 10-12.
                Does anyone have experience with them, and are they good ?

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                • #9

                  Re: Screws keep breaking off

                  Re: Screws keep breaking off

                  What I always tell fellows and practice myself, is.... Correct pilot and start with a steel screw the same size, it is strong enough to cut the threads, back it out and put in the brass. Brass screws should alweays be assembled by hand not via powertool. Another problem (I experienced just last weekend) (unless you have a really good set of woodscrew pilot drills) most pilots are set for the threads and not the shaft, Wood screws have a shank above the threads and under the head. This shank is of larger diameter than the pilot, There is a tremendous amount of friction as you force the shank through a smaller hole and as a result it snaps. You need to follow up with a larger drill the size of the shank, drill only as deep as the shank (no threads on the shank and no holding power) all the holding power is in the threads.


                  My procedure is to Drill the pilot, then if in hard wood, counter bore with a larger bit, insert a steel screw to cut the threads, back it out, Use bee's wax or soap on the threads of the screw and hand feed the brass screw.

                  PS I have heard where a screw manufacturer has stated that you should not use soap as it starts the rusting process internally (if using steel screws) been doing it 40+ years w/o a problem. But if I had a chunk of Bbee's wax I would prefer it. (priced that stuff lately?)

                  Again, cut your threads with steel, wax and replace with the brass. That, along with a correct shaft hole as well as a pilot hole will solve your problem.
                  Bill "Hickory" Simpson

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                  • #10

                    Re: Screws keep breaking off

                    Re: Screws keep breaking off

                    Bill (and all)FWIW...The unthreaded shank should never enter the wood that the threads are engaging in. If it does, the screw is too long. If you are fastening hardware like a hinge (or a bed bolt cover as is the case here), the screw should be fully threaded.
                    If the screw has an unthreaded shank portion, it's intended for holding two pieces of wood together. The unthreaded portion allows the screw to pull the two pieces together. In this instance you are correct that the pilot hole has to be opened up to allow for this but only in the top piece. Not the piece the threads are engaging in. This is accounted for in the manufacture of the screws. If you choose the proper sized screw for the job it will have the proper sized shank.

                    Some pilot hole/countersink bits allow for this in one step.
                    J.P. Rap Mount Hope Ont.
                    Carpe Ductum (Seize The Tape)


                    "In this world, you must be oh so smart, or oh so pleasant." Well, for years I was smart. I recommend pleasant. Elwood P. Dowd

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                    • #11

                      Re: Screws keep breaking off

                      Re: Screws keep breaking off

                      JP and Bill bring up a good point about using 2 different sized pilot holes, one for the shank and one for the thread. All screws used to have shanks even the ones for hinges and other hardware. Then along came rolled threads that meant cheaper manufacturing costs and today it's getting pretty hard to find a screw with a cut thread or a slot head for that matter.
                      Of course the correct way to install brass screws is to use a gimlet but most people nowadays think they are for boring holes. Before 1832 there were no points on screws, just a flat blunt end and the gimlet was used to produce a threaded pilot hole with a smooth shank hole so that the screw could actually start to screw. Gimlets were sold in screw sizes to make things simple. The pointed end on a screw was a Canadian invention and the very first Canadian Patent issued to the inventor of the machine if I remember correctly.

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                      • #12

                        Re: Screws keep breaking off

                        Re: Screws keep breaking off

                        This is true Pete but why mention a tool only you and I and some others have or have ever used? The steel screw does the same as the gimlet. I have a #8 & #10 which I seldom use. (however, I have been known to use a gimlet made with Gin & Lime juice) As for shoulders or shanks, you can still get wood screws with shanks although most BORG stores or the like only carry full thread screws.

                        JP, yes the shank should be the length of the thickness of the part being screwed to the material. The part being screwed to should not have the threads enguaged as it will prevent a tight fit, only the part recieving the screw enguages the threads and this will allow it to draw in for tight fit.

                        Again, the problem comes from a soft material like Brass that gets into a bind as it tries to pull the shank deeper into the wood. That is why I said to relieve that bind with a larger shank hole. A pre screw with a steel screw will blaze a trail for the softer brass to follow.

                        On another problem associated with the same shank hole. Often fellows experience a spliting of the wood as the shank is pulled deeper into a "correct" pilot hole. Using steel resists the urge to break but as the steel holds on the wood may fracture Like putting 10 lbs in a 5 pound bag. something has to give, if not the screw then the wood (if you are close to the edge or end.

                        Problem is, Not if or not you enguage the shank into the material but that allowance is made for the larger diameter.

                        We are on the same page here, just offering solutions.
                        Bill "Hickory" Simpson

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                        • #13

                          Re: Screws keep breaking off

                          Re: Screws keep breaking off

                          Good grief Bill stop giving away our ages!!!! I'll bet there have been more broken screws since the invention of the cordless drill----it's leading to the disappearance of the screwdriver---another extinct species
                          "Born 50 years too late"

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                          • #14

                            Re: Screws keep breaking off

                            Re: Screws keep breaking off

                            Originally posted by Bill Simpson View Post
                            We are on the same page here, just offering solutions.


                            I'll never forget stopping at my BILs house one day when he was building his deck. He was using 2X4 PTL for the deck and they were all twisted a bit. He would fasten one end flat then try to pull the twist out by screwing it down tight as he went along. The problem was, the screws kept either stripping or breaking. He was cursing up a storm. I happen to notice the screws he was using were threaded all the way to the top. I tried to explain to him what the problem was but as it turns out, I'm an idiot and they were just cheep crappy screws. The worst part was I had to listen to him whine about it the next few days at work.
                            J.P. Rap Mount Hope Ont.
                            Carpe Ductum (Seize The Tape)


                            "In this world, you must be oh so smart, or oh so pleasant." Well, for years I was smart. I recommend pleasant. Elwood P. Dowd

                            Comment


                            • #15

                              Re: Screws keep breaking off

                              Re: Screws keep breaking off

                              Boat builders dip the threads of brass screws in dish soap.
                              Grillzy

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