*O'Brien neck joint routing jig, choose dovetail or straight mortise and tenon
Robbie O'Brien came up with this clever neck alignment/routing jig. The jig is simple but elegant as it helps you determine your correct neck angle and then gives you an easy way to transfer the angle to your neck. It enables you to rout the mortise and tenon accurately. Only a small amount of fitting is necessary after routing. The jig comes in an unassembled flatpack, but it is relatively easy to assemble with a minimum of tools and glue. The video/article links (below) fully illustrate how to assemble/use the jig and have many helpful hints for making easy work of this often difficult task.
**Router bits/template guides are not included with this tool. One set of templates is included at no additional cost.
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This jig is produced from cabinet-grade medium-density fiberboard (MDF). It is sized for Parlor guitars and larger.
Always test this jig on a mock neck block before using it on your neck!
Straight Mortise and Tenon:
The SPRB12 or SPRB12L straight bit (see below) is recommended for this jig.
The dimensions of the mortise and tenon prior to fitting them are:
• Mortise - .858"
• Tenon - .955" The tenon is slightly oversized so you can remove just a bit of material and get a perfect fit. See the video included here that addresses this.
Dovetail mortise and tenon:
Our 3/8" bit SPRB38 works well for hogging out the material on a dovetail–then follow with the 7-degree dovetail bit SP7DTL. A small amount of fitting will be necessary after routing to get a perfect fit.
PLEASE NOTE: The dovetail mortise and tenon templates are different lengths to accommodate the offset created by the template guide when routing the dovetail mortise.
You need to use a 5/8 inch OD router guide bushing (SPGB58) (not included) when using these templates. If you don't already own this item, see below to purchase one from LMI.
**Router bits/template guides are not included with this tool.
Video: LMI O'Brien Neck Angle Jig Assembly Instructions
Video: LMI Neck Angle Jig In Use
Video: NJRJ - Tenon Doesn't Fit the Mortise
- Shipping Restrictions - Location
- No Restrictions
- Tool Type or Function
I have a question rather than a review, so far. How have buyers finished the jig? I have considered Boiled Linseed oil or a brush-on urethane.
Operator Error Doesn't Curb My Enthusiam
I received the routing jig for Christmas, put it together, and promptly worked on non-guitar projects. I finally used it this week and I must say, it works as advertised. I modified it to add dust collection (see Eric Schaefer's video on YouTube) and created a spot to store the acrylic centerline indicator. The indicator was dead square to the bottom of the table, - very accurate. I used blue tape with a dark centerline mark on the top of my guitar to make it easier to align with the indicator; I didn't want to make a dark pencil line on the top of the guitar. So my error? I should have done what Robert O'Brien recommended in his video - take a very shallow first pass to make sure everything is lined up properly. I didn't do that and my mortise was off-center by 1/16" - totally my fault; I'll compensate when I cut the tenon but that's not ideal. Everything about this build was a test so I'm learning as I go. I highly recommend this jig because when you use it properly, it will produce clean, repeatable cuts. Last thing - if you're not going to purchase the dovetail bit from LMI, make sure you use one that has the same overall length as the LMI bit. Enjoy!
Robbie O’Brien’s neck angle jig
When I purchased this jig there was only one review on it and it was less than inspiring. I’m on my fourth build and cut all my joint by hand previously. I took my time and assembled this apparatus properly. It was intimidating taking a 3 hp router to a 400 dollar guitar body so I took extra time setting up my work. The results I got were absolutely unbelievable. If you take the time to assemble this properly, and you measure everything, properly you will get the best results money can buy. Thanks, great product
Went together easily! Would like to see a little better direction on fasteners (Robbie uses a Brad nailer in the vids, but I don’t own one)
I do have some issue on the body side with the knobs coming off the screws for the clamp. I am guessing I am supposed to epoxy these in place so that loosening the clamp doesn’t loosen the knob, but haven’t gotten there yet.
Also, I wonder if a ukulele sized template could be fabbed up? I’ve used this on guitars, but recently started a ukulele build and am working through how I’m going to get the m&t done.
- 1 out of 1 people found this review useful.
You MUST buy LMI's special bit!
What is not shown anywhere here is that since the top is 1" MDF, and you need to get 7/8" into your body/neck, you need a daggone long bit. The only place you can find a bit long enough is at LMI. I've spent two weeks trying to get other bits to work, but since you need to be able to plunge to 1 7/8" MINIMUM, I cannot get standard bits to work without having only about 5/16" of the bit in the collet, which is dangerous. LMI really needs to add a disclaimer to this that you need an extra long bit for this thing to even work.
- 5 out of 5 people found this review useful.
The jig went together very easy and the instructions were very clear to follow. I watched the videos on using the jig and felt confident enough to try it first time without a test first. The results were flawless. With just a little sanding I was able to make a very clean dovetail joint with amazing results. The package and contents were delivered with no damage and I live in GA which is a long ways from LMI.
- 1 out of 1 people found this review useful.
ot all that
I bought this jig expecting it to be as described on the online video and as shown on the O'Brian online lessons that I purchased. It was not even close to what I expected! It is made out of MDF 3/4 materials that swell, and warp quite easily. I have adjusted, and adjusted, had to take it apart, and back together again, adjusted and had very, very poor results. I cannot get the neck to center on the neck side, the hinge was loose and wobbling, so I had to rework that. Never had it work to where I didn't have to spend time fine tuning either the centering of the cuts and the angle of the neck to get the correct measurement at the bridge. DO NOT BUY THIS UNLESS YOU WANT A LOT OF FRUSTRATION. F - grade
- 1 out of 5 people found this review useful.
Worked perfectly the first time I used it on a guitar! Like the instructions say, test test test! Chucking up a 2x4 and going through the mortise cutting routine helped me tremendously. When I put a real guitar body in the jig, it went absolutely perfectly.
I suggest using a bungee to keep the body tight to the underside and to give it a little more stability.