Home Depot 1/4" Lag Screw

[Tom Watson]

Where does that come from?

Regards,

Tom Watson

[Lew Hodgett]

SFWIW, I use 75% of fastener size for the pilot hole size rounded to nearest standard size drill which can be either fractional, letter, or number size.

YMMV

Lew

[dpb]

...

Long lore, at least...

I don't have a direct URL; I'd expect you'd find the information in some of the US Forest Products Laboratory technical publications. It was something I was taught way back in one of first HS ag-ed classes is first I recall it personally, anyway...don't recall if it was taught as a specific ratio, only "tubafores get smaller, rr-ties get bigger" was the gist of it. :)

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[Tom Watson]

I don't see the point. The pilot hole sizes quoted work for nails where compression determines strength but I don't see any benefit in having a pilot hole of less than the root diameter of a threaded fastener.

Regards,

Tom Watson

[dpb]

If they're a subsidiary of Grainger now, that's a newer realignment--they initially were bought by some (relatively) small Michigan(?) outfit that promised they were going to leave them essentially alone. I recall the letter from McNeely explaining how nothing was going to change. That was when the mail catalog was still only about 10-12 pages or so; almost all the square head and other wood fasteners w/ only a few other things thrown in...

OK, I went anna' looked -- Safety Supply, Inc is the holder which is in turn held by Grainger. But, they didn't buy McFeely until 2007 their site says. I surely thought that announcement was quite some time earlier than that. Came back to farm about this time in '00 and it seemed to me it wasn't much after that....ah, well, it's amazing how time all runs together as one gets geezery....

The original Mr McFeely was at another industrial supply outfit in Lynchburg that was a full-line Delta distributor amongst a zillion other things while we were there and left to start McFeely's about the time I left VA for TN. They started out as primarily a custom sawyer and millworks until after Bill was killed in mid-80s(?) in a mill accident...

[notbob]

Not necessarily. I had a similar problem, likewise, an alternator on a van engine. In my case, the entire top of the alternator hung off the extended bolt shaft. I changed to a grade 8 bolt and it snapped right off from vibration within a couple days, the grade 8 being too brittle. Went back to a grade 5.

nb

[Leon]

Yeah I remember that now, going way back. IIRC McFeeley himself sold the business to JIM? IIRC Jim? worked there already. The Grainger thing is pretty recent, last 2 or 3 years. The other one you are talking about was probably 20+ years ago.

[Leon]

I did not look and don't doubt your findings but if fully embedded threads are not going to hold, a tight hole is not going to be any better. IMHO making the pilot hole smaller will crush the wood fibers when the screw goes in and in turn would weaken the part that the threads cut into. Then add to that the unnessary extra torque to properly seat the screw which IMHO would increase the chance of breakage.

[Jon Danniken]

Cool, thanks Chris, that'll save me having to look up charts and deciding which one is the correct value next time!

Jon

[Jon Danniken]

Bah, it was I who needed more coffee. What I meant to say was that 1/8" is actually too *large* for a 1/4" (size 14) screw.

Of course, that is for a wood screw, which I do realize now uses a slightly smaller hole than does a lag screw.

Jon

[Jon Danniken]

'Ya know, I sheared off a 1/4" machine bolt I bought from HD a half a dozen years ago. Same deal, was tightening it up, just past snug, when it turned to butter.

I figured it was a fluke, but maybe this last go round will be enough to convince me to steer clear of the bright shiny objects in the grabit bins.

Jon

[Existential Angst]

Well, it seems to me that compression would strengthen the material surrounding the lag threads. Think roll tapping (or thread forming) vs cut tapping, and/or think of a simple nail that compresses wood fibers. Roll tapping sposedly forms a stronger thread than cut tapping -- not perfectly analogous here, but it does sort of illustrate the benefit and strength of displaced material.

The Q is: what is the best overall compromise? In soft wood, I would go .010 smaller than root diameter, just to guarantee full thread engagement, esp. with iffy drilling. Which would only be .005 worth of compression. But, appaently in hard wood, you don't even want full engagement! Go figger....

The japanese dispensed with threads altogether, and just used dowels/pins/pegs. In the case, say, of a corner fence post, if you put snug-ish dowels in X, Y, and Z (per joint), the joint would be fully constrained. If all dowel holes were made through holes, the dowels could be easily removed. Actually, I think you could just as well dispense with the Z dowel, as each dowel effectively constrains 2 dimensions.

Don't know how practical this is, but it does have its own elegance. I heard recently about japanese/tibetan structures fastened like this, still standing after centuries -- nary a thread in sight. Of course, gravity helps in these cases, as well.

[Steve]

And Ace and TruValue don't count.

[JoeSpareBedroom]

Why not?

[Andrew Erickson]

Undoubtedly; I think that's the only place in VT where WallyWorld and HD share a parking lot. (I think the only other city with both stores is Rutland.) And yes, it's a horrid parking lot layout.

For those who are morbidly curious, the two stores are at opposite ends of this lot, which has unbroken lanes running from store to store with perpendicular parking. The two entrances/exits to the lot are at the corners where the stores and the parking lot meet, so that the only way to enter or exit the lot (by vehicle) is to drive along the fire lanes where other shoppers are trying to navigate to or from their cars. Why on earth they didn't have a single car entrance/exit lane across the middle away from the pedestrians is a great mystery to me.

Or, if you're a visual sort of person, see the madness from above:

[JIMMIE]

I had that happen to me helping my friend build a deck using bolts from the big box store. We snapped two of them off. Thats when I turned my friend on to Howes Hardware. Best place I know of for industrial quality fastenerd..

Jimmie

[krw]

Is there another HD in VT? Didn't the Rutland HD close?

[krw]

A few of them might count, but the only resemblance of an Ace or TV to a real hardware store is purely unintentional.

[The Daring Dufas]

They needed all the metal to make swords for lopping the heads off of their enemies.

TDD

[Doug Miller]

I see you're in Indianapolis too... What do *you* consider to be "actual hardware stores" here, then, if Ace and TV don't count?