www.KitGuitarsForum.com

Learn to Kit Build a Guitar. Learn to Scratch Build a Guitar. Learn EVERYTHING Guitars Here!
It is currently Thu May 23, 2019 7:58 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 11 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Thu Mar 07, 2019 9:36 pm 
Offline

Joined: Sat Mar 24, 2018 5:41 pm
Posts: 23
Location: Durham, NC
I have two bolt-on necks that I am preparing to do a neck set on. Both necks have a single hole pre-drilled to accept the 1/4-20 threaded insert that will eventually mate with the neck bolt.

I purchased brass inserts at a big box store but I paused when trying to install/insert them because it looked and felt like a disaster waiting to happen. On the first attempt a "tang" (one side of the screwdriver slot in the insert) of the insert broke off, but I was able to extract that insert without incident. On the second attempt I proceeded very slowly and paid close attention to the resistance I was feeling while turning. I ultimately stopped because it felt like I was having to apply way too much pressure and I was afraid I was either going to split the tenon or break off another "tang".

So my question is, what is the process for inserting these brass inserts? (by the way this is a mahogany neck).

The OD of the insert is .394 and the OD of the pre-drilled hole is .309 or so. That doesn't seem like an unreasonable variance to allow for the threads to bite??

I tried to search the web for some guidance on the subject but didn't find much. I would guess that most of John's forum followers are dovetail folks, but I am hopeful that someone might have some helpful words to get me over the hump on this one.

Thanks for any help.

Rex Zimmerman

_________________
------------

Rex


Top
 Profile  
 
PostPosted: Thu Mar 07, 2019 10:56 pm 
Offline

Joined: Thu May 24, 2012 8:03 am
Posts: 1065
Location: Chestertown Maryland
The slots that look like they are for a screwdriver go down into the hole first. They help cut and clear the threads. You need a tool of some sort to install the insert. The one you can buy is expensive, but a bolt and 2 nuts are pretty cheap, In the following pictures I am installing the insert before I cut the sides of the tenon to give enough meat to the piece so the insert won't split it. If you have already cut the tenon, clamp on a c-clamp while you are drilling and inserting

1) drill the pilot - use a square to help your aim, or even a drill press, and masking tape as a depth guide.

2) cut the head off a long bolt as an installation tool - 3 or 4 inches to help you see if it is square. Put on 2 nuts and back them against each other with 2 wrenches, screw the bolt into the insert, then use the top nut to screw the insert into the tenon. If you use a drill press, chucking the bolt helps to push down hard enough to get it easily started.

3) use the lower nut to back out the tool - voila.

I always put a very small amount of epoxy on the wall of the hole before I screw it in to firm up the end grain - wax the bolt threads to get wax on the internal insert threads. Some run a 3/8" wooden dowel down the height of the neck from the fretboard side to heel cap side before drilling, then the insert is screwed into long grain instead of end grain, and I will start doing that next time.

Ed


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
 
PostPosted: Thu Mar 07, 2019 11:04 pm 
Offline

Joined: Thu May 24, 2012 8:03 am
Posts: 1065
Location: Chestertown Maryland
Found another picture of using a drill press to start the insert. Here I am screwing it in with a wrench while I push down with the quill. This is an Osage Orange ukulele neck


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
 
PostPosted: Fri Mar 08, 2019 8:35 am 
Offline

Joined: Mon Jul 28, 2014 7:50 am
Posts: 657
Location: Chadds Ford, PA
Rex,
I really like Ed's solutions. Two other considerations; a t-wrench and John had a brass insert supplier with less 'tight' threads that are easier to insert. A t-wrench (less controllable than Ed's press idea) costs $5.


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
 
PostPosted: Fri Mar 08, 2019 9:43 am 
Offline

Joined: Sat Mar 24, 2018 5:41 pm
Posts: 23
Location: Durham, NC
Many thanks to both of you for your excellent solutions. I will proceed with the drill press based solution after supporting the sides of the tenon, which are already cut.

I don't know if I will be using bolt-on necks again as I prefer to learn and use the art of the dovetail joint, but if I do I will try to remember that John has a source with inserts that are a bit easier to install.

What is also great information is the fact that the inserts go in with the slotted side first! My intuition that the slot was to accept a screwdriver was totally off-base!! The lack of detailed information on the web about how these inserts are supposed to be used is surprising. I went to the supplier's website (in this case Hillman) and found zilch about use or installation.

I am a little (well, maybe more than a little) confused about the use of a dowel. Are you saying that one would drill down from the fret board side of the neck to insert a dowel? Is the thought that the grain would make it less likely for the insert to back out?

Thanks again for the great information and ideas.

Rex

_________________
------------

Rex


Top
 Profile  
 
PostPosted: Fri Mar 08, 2019 10:18 am 
Offline

Joined: Mon Jul 28, 2014 7:50 am
Posts: 657
Location: Chadds Ford, PA
Rag Thumb wrote:
...What is also great information is the fact that the inserts go in with the slotted side first! My intuition that the slot was to accept a screwdriver was totally off-base!! The lack of detailed information on the web about how these inserts are supposed to be used is surprising....

Just as a side note, I didn't want to confess to having experience inserting these backwards, but I did. It was excruciatingly difficult and aggravating. I got properly schooled shortly after that first one and installations went better. I also buckled down and moved on to the traditional dovetail...


Top
 Profile  
 
PostPosted: Fri Mar 08, 2019 2:38 pm 
Offline

Joined: Thu May 24, 2012 8:03 am
Posts: 1065
Location: Chestertown Maryland
I put a couple in backwards too, but didn't seem to have much trouble doing it.

I don't see an advantage in the dovetail other than it is a cool skill to have. I had to set one neck with a dovetail and it went smoothly, but a mortice and tenon is so simple to make and to use that I can't imagine using the other. I have started using just one bolt down low, and making the tenon just 3/8" long. After 8 instruments, I still have not glued a fretboard extension down to the top, and see no issues.

As you thought, you drill a hole straight down through the fretboard side (before the fretboard goes on) and out at the cap side centered perhaps 3/8" in from the end of the tenon. This way, about half of the threads on the insert are in the long grain of the dowel while the rest is in the en grain of the tenon.

Ed


Top
 Profile  
 
PostPosted: Fri Mar 08, 2019 6:25 pm 
Offline

Joined: Sat Apr 10, 2010 10:50 pm
Posts: 2353
Location: Seattle
From a previous thread, These are the ones you want many of the big box inserts are not made for ingrain and will fail. Also some of the big box inserts do have a screwdriver slot not a cutting slot. If you do not have the right ones it is worth taking the time to get them.

tippie53 wrote:
http://www.essentracomponents.com/shop/ProductDisplay?urlRequestType=Base&catalogId=10051&productId=77780&urlLangId=-1&langId=-1&top_category=&storeId=10152

these are the inserts I use and CF Martin uses. I have yet to see one fail other than catasrophic damage ( Backed over by a car ).

These bite will and are installed with the slot first. I use a shoulder bolt to set them in.

In your case I would epoxy the lower one plug the upper and redrill and use these.

_________________
http://www.harvestmoonguitars.com


Top
 Profile  
 
PostPosted: Sat Mar 09, 2019 1:07 pm 
Offline

Joined: Sat Mar 24, 2018 5:41 pm
Posts: 23
Location: Durham, NC
Thanks again to everyone for your insightful inputs.

I successfully installed the big box inserts yesterday morning - this time putting the slotted ends in first, using epoxy, putting soap on the threads, using two nuts as my driver on a bolt I cut off to chuck in the drill press, and using the drill press as my guide/feed mechanism. Unbelievable how much easier it was!

In my case I was using a neck that already had the fret board attached so I couldn't employ the dowel trick but will remember that for the future (add that to my checklist ??).

The neck and the neck block only have one hole and it is located down near the bottom of the tenon. I am a bit unclear on of the advice to epoxy a hole and drill another one. What hole location do you prefer and why? I'm not sure I am comfortable redrilling a straight hole in a neck block that is already in the guitar.

PS I should explain that the guitar and neck are ones that a buddy took up to the point of finishing the body and gluing the fretboard on the unfinished neck. I am taking it from there.

Rex

_________________
------------

Rex


Top
 Profile  
 
PostPosted: Sat Mar 09, 2019 1:45 pm 
Offline

Joined: Thu May 24, 2012 8:03 am
Posts: 1065
Location: Chestertown Maryland
Thumb
Sorry If I confused - I was showing drilling a hole in a tenon that did not already have one. I put the epoxy in the hole and spread it around the sides of the hole avoiding a puddle at the bottom, then I let it soak in for a minute so it penetrates a little into the wood, then I wax the threads of the insert tool and screw it into the insert, then I install the insert in the epoxy saturated hole, then I back out the bolt leaving a little wax on the insert threads to keep epoxy off of them and to make it easy run in the neck attachment bolt later on.

Ed


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 posts ]  Go to page 1, 2  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group