Maybe right, maybe wrong, but it worked lol. Structural Screws for Ledgers By Glenn Mathewson Q: For installing a deck ledger, structural screws such as LedgerLoks (which don’t require pre-drilling) are so much easier to use than the lag screws and through-bolts referenced in the IRC. Lag screws also use a nut to add extra strength and security to help hold things together. Drill through the first piece of wood. Small screws may not be strong enough if you use them only as your structure, like many others, may be subjected to upload stress from wind,storms. In many cases, you will need to use a clamp to keep the items aligned. Need to support up to 1000 lbs total. Weird & Wacky, Copyright © 2021 HowStuffWorks, a division of InfoSpace Holdings, LLC, a System1 Company. Where can I get lag screws? When they're lined up, clamp them together so they stay in place. Lag screws have a hexagonal-shaped head and are tightened by a wrench (as opposed to wood screws, which have a slotted head and are tightened by a screw driver). It also depends on the material you're working with. Insert a 7/32-inch bit for hardwood. For larger or heavy-duty joints use a 3/8-inch-diameter or bigger lag bolt. Drill a hole into the material that is smaller than the diameter of the lag screw. the first step is to make sure that all of the materials involved in the application are aligned. Then use a ratchet to fully tighten the screw down. Because they are quite thick, they require a pilot hole to be pre-drilled. Countersink when needed to hide it or in an area where the head might catch or hook on objects or people. Set the fixture over the anchor and insert the properly sized lag screw through the fixture and into the anchor. This is unlike other wood screws where they thread as they get through wood materials. Hunker may earn compensation through affiliate links in this story. Lag screws cannot be on the ends or sides of a piece of wood. If you’ve ever been asked to use “lag bolts,” then you’ve heard a misleading name relating to a fairly common type of screw. Wear eye protection when working with wood or woodworking tools. The labor difference is so huge that by the time you finish drilling pilot holes and ratcheting in just a few lags, you could have finished the whole job with structural screws and be sipping a cold one. In the past several years, there’s been an increase in the use of screws in applications that have traditionally been reserved for lag screws. If it still resists, drill through the hole with a bit that's 1/32-inch larger than the previous one. Instead, they must be at least one-third of the way toward the middle of a wood piece. To install lag screws, the first step is to make sure that all of the materials involved in the application are aligned. As a rule of thumb, the pilot hole for a lag screw should be approximately 75% of the total diameter of the screw you are using. In most instances 5/16-inch-diameter lag bolts are sufficient. Don't force the lag bolt tighter than needed or you risk stripping it. They are made specifically for the installation of lag screws into masonry materials. Insert the lag bolt into the hole. Even 1/8' lag screws (well down into 'numbered' screw sizes) will have a shear strength of over 3,000 pounds. Remove the clamps. Measure the width of the combined pieces. Because they don’t need pilot holes, they can be used in roughly half the time compared to lag bolts. *You cannot use too long of a lag screw or the screws will be in the same path as each other. Snug it up tight but not too tight. Lag bolts, on the other hand, have a hexagonal head that requires socket wrench for fastening. Then, we will see where to use them. Insert the bit into the hole and drill through the second piece of wood. But, you will need to drill a hole before using them. Shaddy has also worked as a newspaper reporter and writer, and as a contributing writer for Bicycling Magazine. Limitations of Use. Also called lag bolts, lag screws are generally used to connect heavy lumber and other materials that bear an intense load. Today’s post will discuss some of those benefits. To install a lag shield into concrete first drill a hole that is the same diameter as the outside diameter of the lag … I am planning to use 2 metal faceplates . Insert a 1/2-inch Forstner bit into the drill/driver and drill into the hole to a depth of 1/2 inch. A lag screw's head and washer must be screwed flush to the surface but not overtightened; overtightening breaks the wood fibers underneath. As a result, many manufacturing companies — as well as many construction companies — use lag screws to join heavy objects. To use lag screws, you drill a pilot hole that is slightly smaller in diameter than the screw width. Specializing in hardwood furniture, trim carpentry, cabinets, home improvement and architectural millwork, Wade Shaddy has worked in homebuilding since 1972. Lag bolts, which have coarse threading and a hexagonal head, can be used to secure wooden planks and other materials. By creating an account you agree to the Hunker, Fine Homebuilding: Pilot-Hole Sizing for Lag Bolts, Portland Bolts: Pilot Hole Diameter for Lag Bolts, The Family Handyman: Structural Screws vs. Lag Screws. How About Lag Bolts, Machine Screws, and Cap Screws? The thread tapers to a sharp point at its end to help engage the screw by embedding into the surface of the wood. Source(s): General Contractor 30yrs. Hex lag screws are larger than ordinary screws. 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