Router Plane

Tuesday, August 6, 2019

FLW Cabinet - #11 Finishing the Leg/Rail Tenons


With the tenons fitting snugly into the mortises I can turn my attention to the final trimming of the tenon shoulder.  Right now, the shoulder is uneven and the tenon is too short.   First thing to do is change the blade from a rip to fine tooth cutoff.  Saw setup then starts by setting the rip fence to the outside tip of the blade at 1 ½”.  Next is to set the depth of cut so the points of the teeth just score the bottom of the tenon.  Last is to add a sacrificial piece between the rail and the crosscut fence.  That’s to minimize any chipout caused by the blade when it exits the cut.  Below you can see the setup and the result.

Here is after the wide faces have been cut.  All that remains is to make the end cuts.  Of course, all four cuts are a different depth so the blade height has to be adjusted for each one.

In the last post I discovered that one of the rails was a little short.  Now is when the problem is corrected.  Since the important distance is between the tenon shoulders and not the overall length I took one good rail clamped it to the short one and transferred that length to the short one.  Here you can see the steel square ready to go.  A marking knife is used so the line is exactly in line with the edge. 

A pass with the knife along the square’s edge cuts a very fine line that for me can be a little hard to see.  My solution is to rub a little chalk into the cut making it pop out as shown below.  Note that I to re-set the rip fence so the blade cuts to the line.  The red marks reminded me when I was cutting the shoulder of all the other pieces not to cut this one.

Since the cutoff blade does not make a flat bottom cut, I am left with a little ridge right where the tenon meets the shoulder.  I could have cut it deeper but did not want to weaken the point where the tenon ends.


To allow the tenon shoulder to butt tight to the mortise that ridge needs to go.  A little work with a sharp chisel makes quick work and leaves a nice clean joint.

A test fit assembling the frame rails and legs is next to see if the pieces go together square.  Once clamped in place comparing diagonal measurements for a squareness check showed the diagonals were almost identical.  Any difference was less than I could see.   While the legs and rails were clamped, I dropped the finished door frame in to check the clearances between them.  The side to side spacing looked great however, the gap between the door and the rails at the top and bottom while being what was planned looked too small.  After some thought I decided to increase it slightly.  At this stage it’s easy to make that change.  Using the table saw and a rip blade I cut 3/64” off both the top and bottom rails.  After reassembling and setting the door in place the gap looked right.  Here is how a typical corner looks.

Unfortunately, when I turned the frame over to check the backside a couple of the joints were not as tight.  Here you can see the small gap in one.   Both instances are between the leg and the bottom rail on the inside of the case.  In post #3 Making & Using the Taper Jig two of the legs had a twist that over time had relaxed to a point where it was almost undetectable.  As it turns out the key point here is almost.  In reality the twist is very slight maybe 1/16” over 78’ but enough to cause the gap.  Now this is going to be under the bottom of the cabinet completely out of sight.  I could have left them as-is but decided to see if I could fix it. 

What worked was to chalk up the joint area and about a foot up the leg like this.  Now when I start to remove the twist, I can easily see my progress.

The actual process is to use a card scraper and start removing material from the high side bringing it down so the edge with the mortise is square with the adjacent face.  Frequent checking with a square helps me track my progress.  Here you can see how the chalked area has been mostly removed.

Reassembling the leg joint I now have a much better fit even if I am the only one who will ever see it.

Next is to do the milling to house the back.  I could have cut an open rabbit then screwed the plywood in place but that would have left me with a bunch of exposed screws and an unfinished back.  When I make furniture, I like to have it look good from all sides.  For this piece I will cut grooves in the back legs and rails to house the plywood back.  That way the back will look like a framed panel.  Here are drawings that show what the groove will look like when the legs and rails are assembled (minus the back panel) plus some detail of each piece.

One of the things I had to decide was how wide to make the groove.  My set of dado blades can cut from ¼” up to 13/16” wide in 1/8” increments.  In addition it has multiple shims from .004” to .02” that can be added between the regular blades.  Using these in various combinations gives me a lot of flexibility in the final cut width.  That said when I measured the plywood it averaged about .23” thick which means using the ¼” blade set gives me two-hundredths of an inch play, just what I need.  Below is the setup for cutting the groove.  For the top rail the blade depth is 3/8” as I don’t want to cut into the bottom of the tenon.  The grooves in the legs and bottom will all be ½” deep.

After running the pieces through the saw I used this little gauge which is a scrap with a pencil line marking the depth to make sure that all the grooves were an even depth.  Occasionally, when making a cut the piece will rise up a little resulting in a shallow cut.  In doing the checking there were a couple of instances where that happened.  While everything is setup the fix is as easy as running the piece through the saw again.  Later on, it’s a lot harder to fix.

Here is what an almost completed leg/rail set looks like.  It’s pretty much done but there are a few more bits of work to do.

Next up – Details on Legs, Profiling Rails & Starting Top

No comments:

Post a Comment