Process question for mounting with threaded inserts

[Prometheus]

Hi all. Well, here I am again, asking for help. I'm posting this in "Tips and Tricks", and while I'm just asking questions, I'm hoping others' answers will fit the bill for "tips".

It looks as though my body and neck will ship in the foreseeable future, and I'd like to get myself straightened out for the process of mounting the neck. I plan to use threaded inserts. Yes, I've read the relevant threads here, and they've been a big help. (special thanks to Cagey for all his pointers, esp. http://unofficialwarmoth.com/index.php?topic=22486.msg333429#msg333429).

I have a full-sized drill press, and know how to use it. And various doo-dads for positioning and fixing, including an XY vise. And I have the threaded inserts on hand - both the EZlok ones as well as the larger-threaded sharp ones. And I have the ferrules and machine screws, drill bits (regular, brad point, and forstner), and taps for the EZloks. And soap and wax. And some hard maple stock to practice on. I might be shy on the courage though - but hey, one of our family mottos is "God hates a coward", so I'll be heading in.

So what's my question? Well, I want confirmation and advice on the order of business. Neither the neck nor body will have any holes in them. My biggest concern is getting everything where it should be. So here's my current plan:

1) Pray.

2) Measure, measure, measure, and find the right position for the mounting holes. Narrow enough so that the inserts will have enough clearance from the edge of the neck, and wide enough so that I maximize the strength and stability of the join, without the furrules. Mark locations on body.

3) Dry fit the neck and find some way to keep it there. Creative and careful application of clamps is in order. Neck fit must be 100% correct, and must not move a whisker during the drilling process. Try to find an orientation as close as possible to perpendicular to the neck joint face.

4) Pray.

5) Drill holes large enough for the machine scews, through the body and neck. Quadruple-check the drilling depth first! Nobody likes holes in their fretboard, right? Careful jigging should allow me to get all the holes parallel. And I'll have reference/pilot holes for the subsequent neck drilling (see step 5). Actually, before leaving each location, I may as well forstner the wells for the ferrules. Swap bits for that. Swap back when done. Repeat the whole thing x3.

6) Remove the neck from the body. Pick a neck hole. Mounting the drill bit that was previously engaged to drill through both units, jimmy and wiggle the neck into the correct orientation and clamp it there. Try not to snap off the drill bit along the way. Switch bits and drill for the insert. Countersink that hole a tad. Repeat x3.

7) Tap the holes for the inserts. Wax/soap an insert. Using a jig to keep the tap square, tap 'er in. Slowly. Gently. Carefully. Repeat x3. Any recommendations on whether I should do it by hand, or if I'd be better off using the drill press as an arbor?

8) Measure for machine screw lengths. Cut 'em to suit. Label them somehow, so I don't get mixed up.

9) Dry fit neck. Bolt it on with machine screws and ferrules.

10) Drink (in either case, success or failure)

Sooo... laughter, corrections, adjustments, feedback, ideas - all are welcome, come one, come all.

 

[swarfrat]

I had trouble getting the inserts in without eating their way in and destroying the hole in the process. I stopped right away, and I'm embarassed to admit my beautiful short scale BK strat has sat for about a year because I barely have time to play, let alone do projects.

My idea is to make a block with ANOTHER threaded insert, one sized for the tap I'm using for the inserts going in the neck. Then I can clamp it in place and use the 2nd insert to hold the tap rigidly. That should prevent the rosemary's baby thread tap problem. I think thays the best way.

 

[Prometheus]

Oh, so a threaded threaded-insert inserter ?     

Yes, driving the tap with a "feeder" that matches the thread is "almost foolproof". Just not always easy to set up.

 

[Cagey]

Sooo... laughter, corrections, adjustments, feedback, ideas - all are welcome, come one, come all.

Sounds like you got a pretty good handle on it, except I don't think I'd try drilling the body/neck together. It sounds good up front, but you're quite likely to have alignment/handling problems that could easily result in an accident or something off-angle. Nothing will want to sit flat, clamps will get in the way, on and on. Running in machine screws, it's important that everything be at 90s or they're liable to cross thread.

Also, I'd drill the body first from the face side so the back laying on the stage keeps the pocket perpendicular to the quill, use those holes to mark the neck once you're sure it's placed properly, then use the X/Y clamp to drill the neck. Again, it'll be easier to keep everything square that way.

As for tapping by hand vs. using the press, I always do it by hand. My press is usually geared down to the lowest speed, so it wants to fight my turning the spindle by hand, which you'd have to do unless you wanted to run the tap all the way through the neck. So, eliminate a step and just use a tap handle, kinda like I did here.

Finally, you shouldn't need to cut your mounting screws. 1 3/4" for the long ones, 1 1/2" for the short (for contoured necks) generally work.

Good luck! I'm sure you'll be fine. Take pictures, so we can watch.

 

[Cagey]

I had trouble getting the inserts in without eating their way in and destroying the hole in the process. I stopped right away, and I'm embarassed to admit my beautiful short scale BK strat has sat for about a year because I barely have time to play, let alone do projects.

Did you tap the holes? If not, the type of insert and the hardness of the wood can cause that sort of thing. Or if you did tap, perhaps the tap thread isn't the same as the insert thread. Or, you're not using enough force.

My idea is to make a block with ANOTHER threaded insert, one sized for the tap I'm using for the inserts going in the neck. Then I can clamp it in place and use the 2nd insert to hold the tap rigidly. That should prevent the rosemary's baby thread tap problem. I think thays the best way.

I would advise against that. For one thing, assuming it worked at all, the tap will quickly eat up the guiding insert and you'll have to make a new jig. For another, you need room for shavings to escape.

If you want to use a jig to tap, and I'd recommend it, see the link in the post above. Super-simple jig, works well, lasts forever.

 

[Prometheus]

Hey Cagey, thanks for chipping in.

I like your plan for drilling the holes. Yup, same effect, just a little less prone to blundering. Which I like !

And yeah, I saw that tapping rig you did up, and it's exactly what I planned to use. In fact, that thread is the one I linked to. It's great, thanks again for that.

About the inserts - which make/type do you prefer now? I have the EZlok type (8-32 inside) and the taps for them (both regular and bottoming). But I'd wondered about that type, because they don't look like they have a lot of thread real estate, and wondered if they'd have enough "bite". I also have the other type (SS, much coarser thread gauge, but bigger lands, and sharp edges). The thing with those is, I have no tap to match, and wouldn't know where I'd get one. Or whether I should even bother.

I have some little brass inserts (4-40) too, for other locations. But both of the above are steel.

Thoughts?

 

[swarfrat]

What I had in mind looks exactly like your jig, but the guide insert is to keep the tap from advancing slower than the pitch rate and pretending its a drill instead of a tap. I was trying to thread the wood for the insert when i ran into this problem.

An idea I just had, which appears to have some suport in woodworking circles, is to just drill a hole big enough to drop the insert in place, and epoxy the insert in place. This has the advantage of making sure the alignment is perfect, as the screw is run into he insert and the epoxy allowed to dure while the screw is holding alignment.  If i mess up again, i will probably try that. For this method he hole can be rough, it helps mechanically lock the epoxy in.

 

[Cagey]

About the inserts - which make/type do you prefer now? I have the EZlok type (8-32 inside) and the taps for them (both regular and bottoming). But I'd wondered about that type, because they don't look like they have a lot of thread real estate, and wondered if they'd have enough "bite". I also have the other type (SS, much coarser thread gauge, but bigger lands, and sharp edges). The thing with those is, I have no tap to match, and wouldn't know where I'd get one. Or whether I should even bother.

I'm using the brass E-Z Lok part number 400-008. I get 'em from McMaster-Carr, but they're all over the place.

Don't worry about the depth; they're much larger in diameter than the #8 wood screw that normally holds a neck on, and the threads are deeper. Lotta surface, so they grip like dammit.

The SS parts are relatively expensive and ended up causing me too much grief, so I stopped using them.

 

[Cagey]

What I had in mind looks exactly like your jig, but the guide insert is to keep the tap from advancing slower than the pitch rate and pretending its a drill instead of a tap. I was trying to thread the wood for the insert when i ran into this problem.

I see. Sounds like you just weren't putting enough consistent pressure on the tap to start it. You can't stop pushing until you've got a few threads cut, otherwise it will do just as you describe.

An idea I just had, which appears to have some suport in woodworking circles, is to just drill a hole big enough to drop the insert in place, and epoxy the insert in place. This has the advantage of making sure the alignment is perfect, as the screw is run into he insert and the epoxy allowed to dure while the screw is holding alignment.  If i mess up again, i will probably try that. For this method he hole can be rough, it helps mechanically lock the epoxy in.

I could see that working for some things, but a neck attachment? No. Lotta force there. I suspect you'd pull that thing right outta there, then you'd have a real bitch of repair job in front of you.

 

[stubhead]

This:
http://www.philtone.com/inserts.html

Except I use carbon steel, EZ-Lok 319-3 - 10/24 screws,  5/16-18 external threads. These are basically designed to hold aluminum automobile engines together. I do clean out the pink gunk (wire brush), and tap the full size threads. While it may look like not much thread area, compare it to the thread area on a #8 woodscrew - a much steeper pitch. And once they're all ducky, I back them out and line the holes with epoxy. They're not going anywhere.

And I was one of those who said, as long as you're going in, might as well use steel instead of brass. But somebody here recently figured up the actual stress on them, and the brass ones are strong enough. You can remember, even with just woodscrews, you could give a Fender a mighty whack and it'd hold together. But - if you like to change necks between instruments, or if you might possibly want to ship one de-necked, or fit one into hand luggage, well - why NOT? It's like 20 or 30 minutes work, maximum.

And, there are at LEAST four different sized "#8 wood screws" - the threads are all at the same pitch, but the shaft, and size of the threads, are different. If you bought a neck on Ebay that had been held on with the fatties, and you tried to screw it down with the skinnies - it might just fall off right then!

http://www.catalogds.com/db/service?domain=ezlok&command=locate&category=thin_crbn_unc

 

[swarfrat]

You don't need to be stuffing basses in the overhead bin or have a stygian neck... All it really takes os a rear routed strat with anything but a 21 fret neck.

 

[swarfrat]

Hey - can anyone else with E-Z Lok inserts confirm the external thread size? 5/16 - 16? I ask because it's a VERY odd size, and I'm having trouble finding taps at any of the usual suppliers. I have found the tap, often at exorbitant prices ($100+). Actually I'm sure it's 16 pitch, because it threads losely by hand into a 3/8-16 threaded hole (which is steel, so I know it's not eating its way through close but not quite threads)

Since it 3/8-16" is a common size, and it does ride in the threads (ie, doesn't pull out), I'm tempted to thread it 3/8-16 and call it "free alignment space" and let the epoxy snug it up.

 

[swarfrat]

Actually.... check this out - it looks like da bomb:

No funky oddball taps. The screw itself provides the locking. I've already drilled a smidge bigger than than suggested hole, because the 400-008 Knife edge inserts suggest drilling 0.250" (and 270-008 suggests a 0.234" Hole), but it's only 1/64th too big (but the fins still require compression to fit, epoxy to the rescue).

 

[Cagey]

I know that's an oddball tap size that's hard to find, but it's what you need and you don't have to pay $100. There's one here for $12.

Also, those inserts you're looking at in the previous post wouldn't be suitable for neck mounts. There's a lotta stress on neck heel. You want something with more/deeper threads like I've pointed out before, or you're liable to just pull the insert out the first time you string up the guitar.

 

[swarfrat]

Well, in the name of science, I ordered a bag of EZ Lok 270-008 Finserts. I'm not sure such a thing as wenge scraps exist (yet, lets hope it stays  that way) but i do have a mahogany block, and plan to do some sort of test.  My suspicion is actually that the finserts may have an edge over tapped threads, simply because the insert actually deforms when the screw is installed the first time.

 

[swarfrat]

And of yeah, if you're trying to tap any obscenely hard wood, you really should start the hole with a taper tap and chase ot wih a bottoming tap.

 

[Prometheus]

swarfrat, I didn't have any trouble getting a tap. Just walked into my regular nuts-n-bolts place, said "hey, do you have these"?, and walked out with both taper and bottoming, about $15 each. Just keep looking, I guess.

You wanted some confirmation on those threads? Well, if Cagey and Stubhead claim it's right, I'm not sure how much my 2cents deflate to. But yes, I have the E-Zlok 303-008, and they're 8-32 inside and 5/16-18 outside.

I tried it out this weekend on a piece of hard maple. Everything works like a charm. I didn't try the other style yet, and really, may not even bother to. Thanks all for the help.

 

[swarfrat]

You got a 5/16-18 tap. The actualy thread is 5/16-16. But since its wood, you were able to mangle the 18 pitch threads when you ran the 16 pitch insert into place.

 

[stubhead]

This 5/16-16 is the oddball here. I have no doubt that it exists, lordy, if you want to get your head twisted around, just start looking into the history of "thread sizes" - but the 5/16-18 sizes are common as mud, so rather than terrify anyone, I'd be inclined to just say "get normal"* and leave it at that.

Furzample, I had a pressing need for 1" and 1.125" and 1.25" threaded brass and steel balls. I just... did, alright? So I find out that the "lamp parts" business is just wild with threaded balls. Great! Super! Problem solved.... except, lamp parts tend to use a group of really, really weird, unheard-of, totally unique thread sizes. And the reason is (deep breath), to this day, the electric-lamp parts building business is still based around the thread sizes needed to convert old GAS LAMPS from, like, the 1870's and stuff, over into electric lamps. And the reason they need really weird thread sizes (mo' deep breaths, don't hyper here) is because there were, like, three families of Italians {or 2 1/2 or some weird shit} in New York City that installed ALL the gas lamps in ALL the rich people's houses way back when, then they ran off to San Francisco and did the same, Chicago, Cincinnati, whatever - there really weren't very many rich people back then, not rich rich, not when you got to counting. And for whatever reasons, these gas lamp installers used the parts from like "Italian-Family Gas Lamp Parts Inc." or whatever, which had like old-world weirdo cut-by-hand threads or some damn fool thing, so everybody just naturally had to follow-the-leader (naturally), and it's been THAT SCREWY ever since. In 2014. It was like ALL the rich people got gas lamps really fast, because you HAD to to be a cool rich person - "Why the Astors have gas, Dah-ling", you know how it is and then they ALL went electric at the exact same time too and it all happened so fast nobody said like "Hey! Howza 'bout a nice 5/16-18 thread thar, pardner".... Of course not before they burned San Francisco down - the 1906 earthquake - the gas lines - like BOOM BOOM On Went the Lights, if you know what I mean. Reddy Kilowatt not quite reddy enough :laughing3:, still in diapers'd be my guess.

So while I do believe you CAN go up a 5/16-16 thread alley, just, don't, like. It's not like the threaded-balls business, Mamma Mia. But, at least, my balls work great! Really outstanding. Thanks for asking.

P.S. -> BEST LAMP BALLS IN THE WORLD! THIS IS THE ONLY ONE WORTH MESSING WITH.... But they're still kinda miiiiiiiiiiiiiiiiiiiiighty weird ->
http://www.grandbrass.com/

*(Norma... nor... WOHOOHOOO! HAHHAAAH-HA! Wrong hobby, wrong place, wrong, wrong, wrong.... ccasion14

 

[swarfrat]

I think you'll be far better off epoxying the 5/16-16 insert into a 3/8-16 threaded hole than tapping 5/16-18 and then retapping the same hole with 5/16-16. At least the insert will fit captive in a mechanically sound 3/8-16 thread, when you're destroying the wood threads by retapping with a different pitch that is close enough that youre destroying about 90%  of the thread

And Stubs, we love you, and your rants are usually on target but lately they're getting weirder and longer.