What Size Pilot Hole For 3/8 Lag Screw

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• Pilot hole for three/8 in. lag spiral

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Thread: Pilot hole for iii/viii in. lag screw

1. 

   When drilling into a hardwood, such as oak. What size airplane pilot hole should exist drilled for a 3/8 inch lag screw? The length of the lag screw will be nigh 6 inches.

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2. 

   Originally posted by Dale Genther:
   When drilling into a hardwood, such every bit oak. What size pilot pigsty should be drilled for a iii/8 inch lag screw? The length of the lag screw will be well-nigh half-dozen inches.

   The drill flake should be the aforementioned bore equally the root of the spiral. The root is the shaft of the spiral exclusive of the threads. Well-nigh merely eyeball it by holding the drill bit upward to the screw until y'all detect one that matches the root diameter. You'll want to grease the screw with soap, anhydrous lanolin or something similar before driving it of form.

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3. 

   With a lilliputian research I've answered my own question. It shoould be 1/4 in for softwoods and 17/64 for hardwoods

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4. 

   You may wish to drill full diameter (or slightly less) for the length of the shank of your lag bolts. The shank of form is the united nations-threaded portion of the lag. In other words, stride drill for the 2 pregnant diameters that you are dealing with. Past not drilling for the shank bore (total or a pilus less) you are running the risk of splitting your woods when you drive the shank in, peculiarly if you lot are close to the terminate of the piece you are drilling. Endeavour a few examination runs on some bachelor chip if you can. Good luck.

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5. 

   All of the above, plus beeswax is the best lubricant for screws and lags, and a lubricant is obligatory if going into hardwood. Don't neglect to lubricate the shank every bit well as the threads.

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6. 

   I ever use a 5/16 for pilot in both Fir and Oak if the lag is HDG. Bronze lags are a little sharper and will tolerate a niggling tighter hole just 1/4" is much to small. A long lag often will sheer with such a tight airplane pilot. Equally said, y'all must utilize a three/8 top pilot to match the length of the shank. Use full diameter lags and not those with undersize shank and rolled threads.

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7. 

   Regarding screw lubricant: I had always used a cake of beeswax. A year or ii ago, someone hither said he used the soft wax toilet-sealing rings for spiral lube. I tried information technology and it can't be crush.

   Don't employ soap, because the chemicals in the soap can crusade the screws to corrode. And spit is just a petty less corrosive.

   Wayne

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8. 

   Wayne: Right on. I think I was the first on this forum to suggest using toilet rings for lubricating fasteners. And so some wag suggested that we employ used ones at our ain discretion.

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9. 

   How about using Slick Seam? It is mostely Bee's wax, and it is pretty like shooting fish in a barrel to get, etc etc. Would there exist any reasons not to utilise Slickseam?

   Noah

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10. 

    I kept some beeswax aboard for lubricating screws. Then ane day I went to drive some screws and it had disappeared somewhere in the ataxia. In desperation I eyed up the Ivory liquid until I remembered the Slick Seam. I worked fine. So I'll fess up to using information technology ever since.

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11. 

    Thanks, Bayboat. I couldn't recall whom to credit for that handy toilet-ring tip, but I knew I heard it here! I've now got a couple of them in my shop. Who sez nosotros erstwhile dogs tin can't learn new tricks?

    Wayne

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What Size Pilot Hole For 3/8 Lag Screw,

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