Pilot hole for a lag screw?

[Wade Lippman]

I am building a bed and need to attach the head board. I am planning on attaching each side with 2 3/8" lag screws into the end of a 2x4.

The reference I saw recommended a pilot hole between 15/64" and 11/64". To test that out, I drilled a 3/16" hole in the end of a 2x4 3" deep. I found that i could put the screw in 4" without anything bad happening, which rather surprised me. So I have a few questions...

1) I want the screw to be 3" deep. Do I drill a 3" pilot hole, or something shorter.
2) It was tough all the way; should I wax the screw?

Thanks.

[Doug Garson]

I would drill at least 3" deep and yes wax helps especially in hardwood.

[Charlie Fox]

done tons and tons in slab outdoor furniture - what he said = i always do the length of ther bolt with a bit the same diameter as the shaft. just hold the bit in front of it and if all you see is thread you are good.
screw wax is a huge help - but if you dont have any i have found that a bar of soap works just as well. just drag the screw across it

[Cameron Wood]

Drill the pilot hole the full depth or more.

IME, recommended pilot hole sizes are usually too small. I would drill 5/16". A tight fit is not stronger, as the screw crushes the wood fibers and may cause splitting, especially in end grain.

Yes on the wax.

[Tom M King]

I would use these with the pilot hole drilled the size of the shank.

https://www.amazon.com/SPAX-4581820801275-Corrosion-Resistant-Contractor/dp/B08B5FN7N2/ref=sxin_16_sbv_search_btf?content-id=amzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356%3Aamzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356&crid=1ERXL3HO5YA46&cv_ct_cx=spax%2Bpowerlag%2B5%2F16%2Bx%2B4&keywords=spax%2Bpowerlag%2B5%2F16%2Bx%2B4&pd_rd_i=B08B5FN7N2&pd_rd_r=5f93533d-7321-446c-bcd2-6cb1ebdcb65c&pd_rd_w=XQB7w&pd_rd_wg=AkkuB&pf_rd_p=6cfa532e-9c8f-48d2-87a3-a61547a0d356&pf_rd_r=4MXNN4Q777Q19CX3JSGQ&qid=1693859397&sbo=EO%2BcdOgoisx3waG5xqcZQA%3D%3D&sprefix=SPAX%2Caps%2C110&sr=1-1-5190daf0-67e3-427c-bea6-c72c1df98776&th=1

[Don Stephan]

Keep in mind that screwl threads do not hold as well in end grain as in side grain. Bed bolts have machine thread that passes through the post and engages with a nut mortised into the bed rails.

[Randall J Cox]

I would only use candle wax of some sort, never use soap as I have read many times that it attracts moisture. Been using candle wax for many years, sure helps. Randy

[Bill Dufour]

Big bolt like that run it over candle wax like a file. Then hit with a propane torch to flow the wax for full coverage. Use vice grips if needed.
Pilot hole slightly smaller then the minor diameter.
Bill D

[Ron Selzer]

I would use these with the pilot hole drilled the size of the shank.

https://www.amazon.com/SPAX-4581820801275-Corrosion-Resistant-Contractor/dp/B08B5FN7N2/ref=sxin_16_sbv_search_btf?content-id=amzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356%3Aamzn1.sym.6cfa532e-9c8f-48d2-87a3-a61547a0d356&crid=1ERXL3HO5YA46&cv_ct_cx=spax%2Bpowerlag%2B5%2F16%2Bx%2B4&keywords=spax%2Bpowerlag%2B5%2F16%2Bx%2B4&pd_rd_i=B08B5FN7N2&pd_rd_r=5f93533d-7321-446c-bcd2-6cb1ebdcb65c&pd_rd_w=XQB7w&pd_rd_wg=AkkuB&pf_rd_p=6cfa532e-9c8f-48d2-87a3-a61547a0d356&pf_rd_r=4MXNN4Q777Q19CX3JSGQ&qid=1693859397&sbo=EO%2BcdOgoisx3waG5xqcZQA%3D%3D&sprefix=SPAX%2Caps%2C110&sr=1-1-5190daf0-67e3-427c-bea6-c72c1df98776&th=1


Once again Tom is on top of it, throw those lag screws away.

[Derek Meyer]

The last time I used lag bolts, I was hanging a mounting bracket for a TV and it came with them. I drilled the pilot holes as recomended, but I most have drilled one just a bit too shallow, because when I was tightening the bolt down (3/8") I snapped it in two.

Now I use the construction screws that Tom linked. They are so much easier to deal with. You don't need a pilot at all in softwood. i would drill one if using them in hardwoods.

[Richard Coers]

Threading anything into end grain is not a long term solution, especially if that 2x4 you mentioned is SPF from a box store.. A traditional bolts and barrel nuts are far superior.

[Cameron Wood]

The last time I used lag bolts, I was hanging a mounting bracket for a TV and it came with them. I drilled the pilot holes as recomended, but I most have drilled one just a bit too shallow, because when I was tightening the bolt down (3/8") I snapped it in two.

Now I use the construction screws that Tom linked. They are so much easier to deal with. You don't need a pilot at all in softwood. i would drill one if using them in hardwoods.



It was probably because the recommended pilot hole was too small.

The newer construction screws are good, but lag screws are OK, and occasionally even the better choice.

[George Yetka]

What about sinking a hole in the back of the headboard and drilling through so you can bolt/nut It will make future breakdown easier. Although you can do that later if you strip out the hole with the lags.

[Wade Lippman]

What about sinking a hole in the back of the headboard and drilling through so you can bolt/nut It will make future breakdown easier. Although you can do that later if you strip out the hole with the lags.

It is going into the end of a 2x4. No place for a nut.

[Richard Coers]

It is going into the end of a 2x4. No place for a nut.
You can use a round barrel nut or drill a partial depth hole a few inches back in the 2x4 and put a hex nut there. Bed bolts go way back in history of furniture making. Google bed bolts to see how they are done.

[Malcolm McLeod]

It is going into the end of a 2x4. No place for a nut.

I think this (or similar) will give you a much better, long lasting solution:
https://www.woodcraft.com/products/highpoint-bed-bolt-4-piece?gclid=EAIaIQobChMImoyZzq-WgQMVlTHUAR2LyAiKEAQYAyABEgKQBvD_BwE&gclsrc=aw.ds