LumberJocks

Plunge Router Mortising Jig

  • Advertise with us
Project by Calmudgeon posted 03-11-2021 03:16 PM 1794 views 6 times favorited 10 comments Add to Favorites Watch

I recently completed this jig, a mashup of a version from The Woodsmith TV program, Season 12 and an earlier Shopnotes No. 64 design from which the Woodsmith version obviously evolved. The overall dimensions are those from the Woodsmith design, but I wanted to incorporate the better capability to clamp and register stock (both vertically and horizontally) from the Shopnotes version. The Shopnotes version includes the slots which assure that the clamping block is always parallel or perpendicular to the routed face.

The jig is constructed entirely of Baltic birch. I created two clamp blocks so that I didn’t have to fuss with adjusting the clamp as I moved back and forth from 3/4” to 1 1/2” stock.

The performance is good. I used it to do loose tenon joinery on a series of nesting tables and end tables I recently did. I want to add a few features (measuring tapes and cursors) which will speed up dialing in precise placement of the mortise, but I’m happy with the results overall.

-- "As are the things we make, so are we ourselves." - Lin Yutang





10 comments so far

View rbrjr1's profile

rbrjr1

217 posts in 1538 days


#1 posted 03-11-2021 03:36 PM

cool! love it!

can you add some more photos of the unit from the other angles, I might be interested in one myself..

-- only an idiot dismisses an intelligent statement because they dont know anything about the person delivering it.

View Bill_Steele's profile

Bill_Steele

779 posts in 3064 days


#2 posted 03-11-2021 03:47 PM

Nice job on this jig. I find that using a jig like this really speeds up your ability to reproduce the same mortise in multiple same-sized pieces.

I made something similar, but I took inspiration from the Morely mortiser and the mortiser developed by Bill Hylton.

I use a router edge guide and trap it in a channel on the back of the jig. I can move the router side-to-side along the channel and fine-tune the centering of the bit with the edge guide. I made little stops that slide in the dovetails so that I can duplicate the position for repeat cuts on same-sized stock. I was concerned about how deep I could cut the mortise and so I opted for a design where stock is positioned flush with the router base.

One update you might consider (I also want to do this)—is to develop a way or jig to quickly set the width of the mortise so that the mortise will match your existing tenon stock. If you make “standard” widths of tenon stock (e.g. 1/4” x 1”, 1/4” x 1.5”, 3/8” x 2”, etc.) and then have some way to set up your jig so that the mortise matches the tenon stock then you won’t have to make custom tenon stock.

View Calmudgeon's profile

Calmudgeon

586 posts in 2760 days


#3 posted 03-11-2021 05:13 PM

One update you might consider (I also want to do this)—is to develop a way or jig to quickly set the width of the mortise so that the mortise will match your existing tenon stock. If you make “standard” widths of tenon stock (e.g. 1/4” x 1”, 1/4” x 1.5”, 3/8” x 2”, etc.) and then have some way to set up your jig so that the mortise matches the tenon stock then you won t have to make custom tenon stock.

- Bill_Steele

I mill my own tenon stock to precise 1/4”, 3/8” and 1/2” thicknesses and the mortise width is determined by the corresponding spiral bit I employ, so there’s no dialing in required. My process for milling tenon stock goes like this: mill 4/4 stock (usually maple) to the precise length of the desired tenon stock. At the table saw, take slices that are just slightly oversized for the final tenon thickness, then dial in the precise thickness at the drum sander. Next step: roundovers at the router table. Then I route longitudinal grooves for glue egress. I’m not sure how important this is, but this method does get away from flat-sawn tenon stock, which could, potentially, be more prone to seasonal expansion/contraction.

-- "As are the things we make, so are we ourselves." - Lin Yutang

View Redoak49's profile

Redoak49

5464 posts in 3321 days


#4 posted 03-11-2021 05:38 PM

An excellent jig.

View Calmudgeon's profile

Calmudgeon

586 posts in 2760 days


#5 posted 03-11-2021 05:49 PM



cool! love it!

can you add some more photos of the unit from the other angles, I might be interested in one myself..

- rbrjr1


OK, here goes.

One of the features that might not be readily evident is that every moving element rides on some sort of rail or guide. For example the clamping block can be slid along the positioning rail.

And the positioning rail slides on a guide, either vertically or horizontally, that mates with a grooves in the face of the base.

The top of the jig slides on two 1/4” hardboard rails embedded in the top of the base. This is how the mortise is positioned across the piece to be routed.

And the 1/4” thick stop blocks slide in a wide groove routed (or in my case hogged out with a dado blade) into the top of the jig. The width of this groove is determined by the size of your router base. Try to ensure that the groove is shallow enough (or your router base thick enough) that the handles on your router clear the sides and the stop blocks. Positioning these stop blocks determines both the longitudinal position and length of the mortise.

Here’s a look at the clamp assembly in position.

I hope that helps.

-- "As are the things we make, so are we ourselves." - Lin Yutang

View Calmudgeon's profile

Calmudgeon

586 posts in 2760 days


#6 posted 03-11-2021 05:55 PM

Oh, one thing I failed to mention: the reason for the 45 deg angles on the back of the alignment block is to accommodate doing mortises in mitered stock. I didn’t include a clamp for this, because I didn’t know that I would ever use it, but it didn’t cost anything to incorporate the feature, so I thought if I ever need it, I’ll devise a clamping system then.

-- "As are the things we make, so are we ourselves." - Lin Yutang

View WillliamMSP's profile

WillliamMSP

1162 posts in 2937 days


#7 posted 03-11-2021 07:23 PM

That’s awesome, and you’re half-way to a wooden MFT!

-- Practice makes less sucky. (Bill, Minneapolis, MN)

View Calmudgeon's profile

Calmudgeon

586 posts in 2760 days


#8 posted 03-11-2021 07:35 PM

Oh, one thing I failed to mention: the reason for the 45 deg angles on the back of the alignment block is to accommodate doing mortises in mitered stock. I didn’t include a clamp for this, because I didn’t know that I would ever use it, but it didn’t cost anything to incorporate the feature, so I thought if I ever need it, I’ll devise a clamping system then.

-- "As are the things we make, so are we ourselves." - Lin Yutang

View Craftsman on the lake's profile

Craftsman on the lake

3892 posts in 4770 days


#9 posted 03-12-2021 03:07 PM

Nice jig (and others posting theirs too). I made one of those years ago. Loose tenons also. It went by the wayside when I got my Kreg pocket hole jig. Sacrilegious I know but I only make tenons occasionally now and when I do I make them by hand as they are far and in between.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View Woodmaster1's profile

Woodmaster1

1880 posts in 3919 days


#10 posted 03-13-2021 03:57 PM

Nice work on the jig. It’s been on my bucket list since seeing it on Woodsmith Shop. Now I am going to have to make it. I think I will add your modifications.

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com