“Thanks for continuing to strive for excellence in the many services you provide. The website looks great. The more streamlined look is less distracting and I think will make navigating the sight even better!

I have been using LMII as my main wood/parts supplier for almost 5 years now. LMII not only provides excellent products, but has been a link for me to gain access to a tremendous amount of expert knowledge and instruction on acoustic guitar building. Thanks for striving so hard to connect the dots for newer luthiers like myself to be able to benefit from the hard earned experience of the pros. I am now starting on my tenth guitar and have sold 6 of them. With each build, I strive to venture to new personal ground and it comforts me to know that LMII is always there and I can depend upon you guys for whatever I need, every step of the way."

- m.o. (Praus Guitars)

O‘Brien Neck Joint Jig & Templates

Robbie O'Brien on his LMI Neck Joint Jig

Neck joint jig, front & back drawings
SPMTS straight mortise & tenon template
SPMTD, dovetail mortise & tenon template
Template guide bushing


Robbie O'Brien - influenced by many others - came up with the idea for this clever neck alignment and routing jig. The jig is simple but elegant in the way it helps you determine your correct neck angle and then gives you an easy way to transfer the angle to your neck. It also enables you to rout both the mortise and tenon accurately. Only a small amount of fitting is necessary after the routing is done. 

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.


The LMI mortise and tenon templates (SPMTSSPMTD) are designed to be used with the O'Brien Neck Joint Jig, but they can also be used separately. They are manufactured from 1/4 inch mdf to keep the price reasonable. If you expect to use these templates more than a few times in your shop, we recommend flooding the adjustment slots with cyano-acrylate glue to harden them a bit and prolong the life of the jig.

You need to use a 5/8 inch OD router guide bushing when using these templates. Sets of guide bushings can typically be purchased wherever routers are sold.  Our 3/8 inch bit (SPRB38) works well for hogging out the material on a dovetail–then you can follow with the 7 degree dovetail bit (SP7DTL). Use the 1/2 inch straight bit (SPRB12) for use with the straight mortise and tenon template.

The dimensions of the mortise and tenon
prior to fitting them are: 
    • Mortise - 7/8" (.875")
    • Tenon - 15/16" (.938") The tenon is slightly oversized
        so you can remove just a bit of material and 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.

• Router bits & template guide bushing, sold below, 
   are not included with the Jig/Templates.

VIDEO VIDEO Documentation
HomepageVIDEOtipsRed75ASSEMBLY HomepageVIDEOtipsRed75HOW TO USE

Assembly Instructions

How to use the 
LMI Mortise & Tenon Templates

SKU Product Name In Stock Each  
NJRJD O'Brien Dovetail Neck Joint Routing Jig, includes dovetail template set
Yes $181.40
NJRJS O'Brien Straight Neck Joint Routing Jig, includes straight template set
Yes $181.40
SPMTS Template, LMI mortise & tenon, straight
Yes $31.45
SPMTD Template, LMI mortise & tenon, dovetail
Yes $31.45
SPRB38 3/8" carbide router bit, straight cut, 1 1/4" LOC, 1/2" shank, 3" OAL Yes $16.85
SP7DT 1/2" carbide router bit, 7 degree dovetail, 3/4" LOC, 1/2" shank, 2-1/2" OAL Yes $22.84
SP7DTL 1/2" carbide router bit, 7 degree dovetail, 3/4" LOC, 1/2" shank, 3-1/8" OAL Yes $29.75
SPRB12 1/2" carbide router bit, straight cut, 1 1/4" LOC, 1/2" shank, 3" OAL Yes $18.85
SPGB58 5/8" template guide bushing with centering pin Yes $14.95