Threaded wood insert help needed

[ezas]

Two more pics.

 

[Cagey]

Whatever works. Can't argue with success. As the great navel-gazer Plato once said: "Necessity is the mother of invention" <grin>

 

[Johnny]

Regarding bottoming taps, Wikipedia says....

Bottoming tap or plug tap

The tap illustrated in the top of the image has a continuous cutting edge with almost no taper — between 1 and 1.5 threads of taper is typical.[3] This feature enables a bottoming tap to cut threads to the bottom of a blind hole. A bottoming tap is usually used to cut threads in a hole that has already been partially threaded using one of the more tapered types of tap; the tapered end ("tap chamfer") of a bottoming tap is too short to successfully start into an unthreaded hole. In the US, they are commonly known as bottoming taps, but in Australia and Britain they are also known as plug taps.

http://en.wikipedia.org/wiki/Tap_and_die

My question is, do you use a "tapered type of tap" to initially to start the threads?

 

[Cagey]

I don't, and I haven't heard of anyone else doing it.

I imagine if it were metal, things would be different. But, even though we're dealing with pretty hard wood, it's no match for the cutting flutes on the tap, so even a bottoming tap will start and cut thread. Just have to be careful to keep it square to the hole while maintaining some feed pressure on it.

 

[Patrick from Davis]

For metal they suggest three tapers if you want it to be well behaved.  We had to tap some stainless with 6-32 threads, that was a pain, and the three tap method becomes understandable.  Our former car mechanic employee broke three taps before learning that by following directions things tend to go faster.  For the 5/16-18 threads, I have both taps, so I'll try the tapered one first to see if it does anything special.  Otherwise I agree with Cagey, the tap is much much harder than the wood so two taps is not really necessary.  That being said, the wood will form around the tap so it will grip the insert quite snugly.  Thus the wax to keep the insert from binding.
Patrick

 

[SalsaNChips]

This is a very interesting topic. I am thinking about going with threaded inserts on the neck I have on order which is mahogany (with Pau Ferro finger board). Also possibly the maple/rosewood Fender neck on my existing Warmoth/Fender "FrankenStrat". I happen to have a drill press, clamps, levels and some expertise in metal working.

After reading through this thread a few times I am still a little confused over self-tapping inserts verses inserts that require a pre-tapped thread via a bottoming tap. I do understand that it depends on the type of wood.  Can someone recommend an insert type applicable to a mahogany neck (self-tapping or otherwise)?

My drill press has limited speed adjustment and I can’t use it for driving the actual insert in. So I will counter-sink the hole and use one of the power driver attachments Cagey recommends on a power screwdriver, hopefully that will give me enough torque. And a LOT of wax.

When I first started reading this thread and thinking about it, I had horrible flashes of splitting the wood when torqueing in the inserts (shudder)

 

[Patrick from Davis]

If you drill the proper size hole for the insert there should not be a problem with splitting.  The drill press holding the power driver attachment is so that the thing goes in to the hole vertically.  The inserts that are designed for metal require that you tap threads.  The wax you put on is to reduce friction, at some point it is overkill to add more.  I don't know if I can help too much, but the threads on any of these things should hold up, they seem about the same as the wood screws.  And those seem to do the trick.
Patrick

 

[Cagey]

After reading through this thread a few times I am still a little confused over self-tapping inserts verses inserts that require a pre-tapped thread via a bottoming tap. I do understand that it depends on the type of wood.  Can someone recommend an insert type applicable to a mahogany neck (self-tapping or otherwise)?

The inserts/tool/screws I specified back at message #5 in this thread will work perfectly in Mahogany. Those work well with the 5/16-18 tap.

My drill press has limited speed adjustment and I can’t use it for driving the actual insert in. So I will counter-sink the hole and use one of the power driver attachments Cagey recommends on a power screwdriver, hopefully that will give me enough torque. And a LOT of wax.

You wouldn't want to use your drill press to put in the inserts anyway. No way you can get one going slow enough, and you have to be able to stop RFN, not coast down. Portable drill motor/powered screwdriver is the way to go.

When I first started reading this thread and thinking about it, I had horrible flashes of splitting the wood when torqueing in the inserts (shudder)

I have that nightmare scenario run through my head every time I do a neck, and it's never happened even on some super-dense woods like Satine. Thing is, it's not like a screw - you can't really force one of these inserts into a hole that's too small. Worst case would be a hole that's too big, so the thing doesn't get a good grip or goes in out of square.

 

[Danuda]

You can use the drill press.  Just turn it by hand.

 

[Cagey]

Sounds like a lotta work. At least it would be on my press. And who owns a drill press but not a portable drill motor?

 

[Johnny]

Cagey, your earlier post showing everything one needs to do this and the part numbers is really great info.  Regarding the screws needed, you stated:

For screws, you want some philips oval head SS machine screws. Depending on whether you've got a standard or contoured body, and whether you've had the "720 mod" done to it, the screws need to be 8-32 x 1 1/4", 1 1/2", or 1 3/4".

Correct me if I'm wrong (because I'm kind of guessing at this), but ignoring the "720 mod", are the following the right screw lengths?

Non-Contoured Heel

4 x 1 3/4"

Contoured Heel

2 x 1 3/4"
2 x 1 1/2"

As for the "720 mod", I'm not going to guess.

 

[Cagey]

Right.

 

[mayfly]

You can use the drill press.  Just turn it by hand.

Yep - this is what I do. It's easy and guarantees the thing goes in straight.

 

[Cagey]

I used to use the self-tappers listed above exclusively as well. Still do, for that matter. But, I tap the holes now. It's just so much easier and less risky, and the tap isn't terribly expensive. Why fight with the installation, or tempt fate with a possible tool slip or heel split? It's never happened to me, but that doesn't mean it can't.

 

[Cagey]

I understand. And before anybody tries it, don't even think about using a zinc insert. Never work in a million years.

 

[Johnny]

So tonight I went out to order the stuff I needed to install theaded inserts for my neck. Since all the hardware on my guitar, including the neck plate, is black, I'd really like to have black screws. The problem is that I can't find black, stainless steel screws in the length I need. I have a contoured heel so I need a couple that are 1 1/2 and a couple that are 1 3/4. Does anyone happen to know where I can find them?

 

[Cagey]

I've looked high and low for them as well, and no joy. And I mean high and low. Extensive search. Really wanted them.

But, the stainless screws I use have a sort of brushed finish to them that is unobtrusive. I've used them with gold, black, and chrome plates and none of them offended my sensibilities as far as aesthetics are concerned. In fact, I thought they were complementary. So, you may want to try that and see if you can keep from gagging. You might end up pleased.

 

[Johnny]

Ha!  I just spent a more than a couple of hours trying to locate some at no avail. Since the neck plate will be etched by DR6, a brushed finish will probably look fine. Besides for these I've been trying to find some other similar items and have come to the conclusion that I'm going to have to do something different or figure out a way to fabricate them myself. It's a long story for a whole other thread

 

[Cagey]

Yeah, I have more than a few hours into it myself. I don't know if it's a problem with finishing stainless or if there's no call for it, but there aren't any out there.

 

[bagman67]

http://www.aaronsmachinescrews.com/cfusion/DisplayProduct.cfm?ITEM=1731SN2076