I plan to add a steel plate on the back side of the walnut base member with a 1/4 inch and 9/64 inch diameter hole as a drill guide for drilling and creating the key hole cut out.

I am debating (thinking) about a guide bushing mortise in the jig plate to mortise the bolt clearance cavity beneath the strike plate on the lid and it would seal the deal so to speak.  No use stopping at 3rd base when a home run is in sight!

COMPLETED MORTISE JIG

I added another guide bushing mortise to the jig plate to route for the bolt recess beneath the strike plate and a drill guide to the rear for drilling the two holes for the key hole slot.  I used a total of four (4) E-Z LOC threaded bushings for 1/4 x 20 x 1.25 socket head screws.  This jig is SN 73.

Center line of mortise slots for the guide bushing at both ends of the full mortise lock jig plate.  The smaller outboard mortise slot for the bolt recess under the striker plate (lower right) requires a separate adjustment of the fence and/or appropriate spacer, of which the spacer will probably be the way to go. 

Tested out the full mortise lock jig and pleased so far!

Very pleased with the final results!

Purple heart drill guide bushing below.

GETTING STARTED

I had some scrap aka unallocated phenolic laminated 1/2 inch thick plywood used for making jigs and table saw inserts which would be good for making such a full mortise lock jig.  I also had unallocated 12 mm Plexiglas which would work, but elected to use the phenolic coated plywood instead.

The size of the jig platform is 13 1/8 x 4 1/8 x 1/2 inches and basically somewhat controlled by my mortise jig since the cut-out opening in the Plexiglas top is 3 x 6 7/8 inches and have plenty of flexibility in the longitudinal plane, but limited to the 3 inch width in relationship to the left guide rail and clamping system, of which I can increase the width of the mortise slot if ever needed.  A plunge router using just edge guides would be a nightmare to create the mortises for this full mortise lock jig in my humble opinion, but the experienced can make it happen for sure!  The mortise jig is the way to make it easier and more accurate, again in my humble opinion!

My main equipment for making this jig will be my custom made Pat Warner design Mortise Jig and a 1/2 inch diameter two flute up-spiral solid carbide router bit that is four (4) inches in length.  This full mortise jig will use a 3/8 inch diameter router guide bushing and a 3/16 inch diameter solid carbide up-spiral router bit.  I do not have a long enough router bit to complete the cut-out for the lock body, but have the appropriate length 3/16 inch diameter carbide tipped flat bottom bit on order from Rocker SKU 56249.

The simple formula for calculating the offset is: (Outside diameter of guide bush – diameter of cutter) divided by 2.  You will notice in some of the thumbnail pixs, I have the length of the jig plate mortise slot in the test samples annotated if you plan to build this type of jig.

I used a 1/4 inch diameter solid carbide two flute router bit in the Mortise jig 3HP router to create the mortise in the jig plate for the bolt striker mortise and moved the router lateral on the mortise jig to get the appropriate width of the mortise slot since the 1/2 inch diameter router bit was to large for the jig plate bolt mortise.

The above Pat Warner design mortise jig that I made has really gotten plenty of usage and a valuable tool when you want precision mortises.  I used a Brown and Sharp dial caliper to verify measurements of the Rocker full mortise lock SKU 130261 part and here is a down loadable .pdf file for this lock.

I used scrap white pine to test the width and length of the mortises before routing the 1/2 inch thickness phenolic laminated plywood jig material.

THUMBNAIL PIXS

Click on the below thumbnail pixs taken for a larger screen view:

I definitely need to add a fine tune adjustment to my Pat Warner design mortise jig for the lateral (East to West) router movement on the stainless steel guide rods.  I am currently using a thin strip of wood on the left hand side of the mortise jig held in position by two small C clamps.  I drilled the left router guide rail and installed an E-Z LOC threaded bushing for a 1/4 x 20 tpi threaded rod with knob for such an adjustment, but as the old saying, "When I get around to it".........grin if you must!

A COUPLE ROOKIE MISTAKES

I had a couple "rookie" mistakes making this jig by not clamping the jig plate securely enough to the base of the mortise jig Plexiglas member which allowed the jig plate to shift.  I corrected one of the rookie mistakes by gluing in a 1/2 inch diameter dowel rod to the end of one of the mortises on the jig plate which was too long because the longitudinal temporary stop on the mortise jig was not properly engaged to the router sub-base.  Allowed the glue to set and then re-routed the mortise slot in the jig plate with the temporary longitudinal stop firmly in place.  The other rookie mistake did not affect the accuracy of the jig plate, cosmetic only.  

TWEAKING THE JIG

I am still waiting on a long shank 3/16 inch diameter, flat bottom, two carbide blades and 1/4 inch diameter shaft in order to route the cavity for the body of the lock which requires a 1.625 inch deep cavity.

I had a piece of 3/4 inch unallocated cedar that was left over from a toy chest that I build for my Grandson Xander McKnight Gonzales and decided to use it as a test sample before committing the secretary/letter box and glad that I did.

It was quickly evident the the mortise for the bolt to travel behind the striker plate on the lid of the box was too short and had to set the mortise jig back up to complete the mortise in the jig plate. 

Also, the cavity for the body of the lock was a little too close in tolerance and lengthened the mortise slot in the jig plate and gave both mortises on the jig plate a test run.

Above is the test pieces for the box and the lid.  I didn't take any serious time setting the depth of the router cavity for both mortises.  The lock bolt travels upward and then to the left to engage the striker plate cut-out.

Completed mortises in the test pieces and everything worked as it should.  The mortise for the bolt to engage the striker plate looks a little ragged, but didn't clean off the routed edges from the spiral up-cut router bit.

When the long shank router bit arrives, then the acid test for the full mortise lock jig will get its first work out. 

Web page updated by Bill aka Mickey Porter on 05-31-19.

ROUTING THE BOX PROCEDURES

In usage, the jig will be resting on top of the front of the box and clamped to the box.  A center line and center mark on the box front side will be the locator for the jig.  Once the back walnut fence that is below the jig is set to have the jig guide bushing mortise centered over the center of the box front where the selvedge will rest, the fence is locked tight with the set screws and the jig clamped securely to the box.

The router depth is set for the thickness of the selvedge which is about .093 inches.  Using a small plunge router, DeWalt DWP611PK with 3/8 inch diameter guide bushing and a 3/16 inch diameter router bit, route the mortise for the selvedge.  Remove your clamps.

Slide the jig where the cut-out mortise in the jig for the full mortise of the lock is centered over the selvedge and set your router depth for the required depth of the lock being about 1.625 inches.  Clamp the jig in place to prevent any movement which will spoil your routed cavity for the body of the lock and route the cavity aka mortise using multiple passes until you reach the required depth.  Usually 3/16 to 1/4 inch depth passes will not load the little 1.25 HP router down or spoil the router bit.

Using a 1/4 inch and 9/64 inch diameter drill bit, drill each hole using the purple heart drill guide plate which is correctly positioned already for the lock key way.  You later can free hand chisel or route the distance between the 1/4 inch diameter hole and the 9/64 inch diameter hole to complete the key access to the lock.  Do not drill through the entire thickness of the box stock.

NOTE:  I plan to add a steel plate (drill guide bushing) and replace the purple heart drill guide bushing plate, but in all probably the purple heart will last for a very long time....will wait and see on this idea!

ROUTING THE LID PROCEDURES

Remove the jig from the box and position the jig onto the lid.  The black walnut fence should already be correct.  Position the center of the mortise cut-out in the jig plate over the center of where the strike plate will go and secure the jig with clamps to prevent any jig movement.  Set your router depth for the thickness of the strike plate which is .050 inches.  Complete your routed mortise.  Remove the clamps.

Loosen the two set screws and reposition the rear walnut fence, or add an appropriate thickness filler strip where the smallest mortise in the jig plate is centered over the strike plate and clamp the jig in place.  Set the router depth to 3/8 inch and route the mortise for the lock bolt.  Remove the jig from the box lid.

Using a chisel or small router such as a Dremel tool, etc., remove material between the 1/4 inch diameter hole and the 9/64 inch diameter hole for the key access.  This will be the only free hand operation for the lock install.  The holes are close enough to blend them together using the 9/64 drill bit.

I used a Dremel and 1/8 inch solid carbide spiral cutter to fine tune the key hole access.

Routed the mortises for the full mortise lock and the lid striker plate and lock bolt mortise.  I had to rework the drill jig plate for the key slot and the jig plate was not properly centered to the jig plate.  My first drill holes were to the right of center line, but when corrected, the escutcheon adequately covered the ragged looking hole which looked like a giant Warf rat had gnawed the opening.....grin if you must!

I will install the lock and striker plate, but will leave off the escutcheon; cover and tape the opening when I spray lacquer and drill holes for the escutcheon pins.  I will also mask over the lock selvedge plate and strike plate also prior to spraying several coats of lacquer. 

Striker plate below getting pilot holes drilled for the lock bolt to engage.

I used a Speedy 5/64 self-centering drill and then drilled the pilot holes to 3/32 inch which gives about .010 inch grip and more than enough.  It is very easy to strip the soft brass screws even with the 5/64 inch pilot hole in very hard wood.

In summary, the jig works well, but with the length of the jig plate for all the mortises presents a few clamping challenges, but clamping is doable!

The mortise for the lock body cavity needs to be reduced in width a few thousands where the lock body mortise will not be flush with the selvedge plate of the lock.  At the moment, both the selvedge mortise and the lock body mortise is .375 +- inches.  I will simply add a piece of tape to the mortise in the jig plate to reduce the lock body cavity mortise width.  The router guide bushing rides against the inside wall of the mortise on the jig plate and doubt I would ever wear the tape out.

I am seriously thinking about making a Plexiglas 1/4 inch thick template for the Rockler Jig It jig mortise system since I already have my mortises figured out for a 3/8 inch diameter bushing with a 3/16 inch diameter router bit.  This will be another challenge due to my equipment limitations, but I believe I can make it happen by thinking outside the box so to speak as far as positioning the Plexiglas underneath my mortise jig.  

Web page published by Bill aka Mickey Porter on 05-27-19 and updated on 06-03-19.

REWORKED THE JIG PLATE

I glued a thin strip of maple approximately .030 to the straight side of the jig plate mortise for the lock body and had to fine tune it by filing and sanding it down and got an excellent fit using some scrap cedar wood to do test mortises, etc.  I also fine tuned the drill plate for the key hole too.

Web page updated by Bill aka Mickey Porter on 06-04-19.

COMPLETED SECRETARY/LETTER BOX

Above pix taken under a light box; doesn't' high light the wood color and grain pattern.

My bride is enjoying the secretary/letter box!

Web page updated by Bill aka Mickey Porter on 06-11-19.