Woodmounting singlecoil with threaded insert: Reinventing the wheel
- Thread starter fdesalvo
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The McMasters 95807A100 looks like what skuttlefunk has and what you're using, right? There's a guy on Ebay who's selling some steel hex-drive ones with a very similar size, the question becomes - do you drill a 1/4" hole like McMasters says, a 5/16" drill like skuttlefunk uses, or an in-between 17/64", 9/32", even a 7mm is like, 35/128" (or so)... the choice between cracking the neck by using too small a hole, or your neck falling off from too large a hole. To get a 1/2" long insert from McMasters you have to go to a 3/8" exterior hole, which is right on the edge of the neck.
Cagey
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Those are the ones I use.
I've debated using the hex drive parts with otherwise similar dimensions, but haven't yet due to a concern that the drive socket will fail, rounding off internally and preventing the insert from being driven in any further, and requiring a bolt/stud extractor to get the little bugger out. Might not happen, but knowing the amount of force it takes to get inserts into hardwood with the added torque you're able to apply with the larger diameter flat driver, I'm just skeptical.
As for hole size, the supplier calls for 1/4", which is probably fine for pine or softer/more compressible hardwoods. But, I don't know of any necks made of such materials. The flimsiest stuff used is probably Mahogany, and that's not exactly flimsy. But, it does have a more open grain and is therefore more forgiving of threaded fasteners pushing it around. Get into something nice and dense like Bloodwood, though, and it's gonna fight. So, I usually drill out the 1/4" hole first using a Forstner bit to make a clean hole, then hit it again with a 9/32" twist drill to bore it out just a tad and give the wood someplace to go when the insert is doing its thread cutting thing. Even with that, you're still liable to get a bit of blister on the back of the neck, but it doesn't seem to hurt anything. The neck still bolts up square and tight.
I don't think there would be anything to gain by going to a 1/2" depth insert. You'd only pick up a couple threads, and with the 3/8" part you're already far ahead of using #8 wood screws. Look at it like this: if you were bolting together two pieces of wood with a clearance-bored thru-hole on both parts, what would the difference be if you used a nut that was 1/4", 3/8" or 1/2" tall? None. More likely the head would break off the bolt, the bolt itself would break, or the wood would break before any of those three nuts let go.
I've debated using the hex drive parts with otherwise similar dimensions, but haven't yet due to a concern that the drive socket will fail, rounding off internally and preventing the insert from being driven in any further, and requiring a bolt/stud extractor to get the little bugger out. Might not happen, but knowing the amount of force it takes to get inserts into hardwood with the added torque you're able to apply with the larger diameter flat driver, I'm just skeptical.
As for hole size, the supplier calls for 1/4", which is probably fine for pine or softer/more compressible hardwoods. But, I don't know of any necks made of such materials. The flimsiest stuff used is probably Mahogany, and that's not exactly flimsy. But, it does have a more open grain and is therefore more forgiving of threaded fasteners pushing it around. Get into something nice and dense like Bloodwood, though, and it's gonna fight. So, I usually drill out the 1/4" hole first using a Forstner bit to make a clean hole, then hit it again with a 9/32" twist drill to bore it out just a tad and give the wood someplace to go when the insert is doing its thread cutting thing. Even with that, you're still liable to get a bit of blister on the back of the neck, but it doesn't seem to hurt anything. The neck still bolts up square and tight.
I don't think there would be anything to gain by going to a 1/2" depth insert. You'd only pick up a couple threads, and with the 3/8" part you're already far ahead of using #8 wood screws. Look at it like this: if you were bolting together two pieces of wood with a clearance-bored thru-hole on both parts, what would the difference be if you used a nut that was 1/4", 3/8" or 1/2" tall? None. More likely the head would break off the bolt, the bolt itself would break, or the wood would break before any of those three nuts let go.
Just for the record, McFeely's has the hex drive inserts in 8-32:
http://www.mcfeelys.com/product/3603-STS/8-32-Steel-Threaded-Inserts
and 10-24, which they claim needs only a 9/32" hole:
http://www.mcfeelys.com/product/3604-STS/10-24-Steel-Threaded-Inserts
and even stainless, but they say themselves there's not much tooth there:
http://www.mcfeelys.com/stainless-inserts
http://www.mcfeelys.com/product/3603-STS/8-32-Steel-Threaded-Inserts
and 10-24, which they claim needs only a 9/32" hole:
http://www.mcfeelys.com/product/3604-STS/10-24-Steel-Threaded-Inserts
and even stainless, but they say themselves there's not much tooth there:
http://www.mcfeelys.com/stainless-inserts
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