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Benchcrafted Split Top Roubo Workbench #5: Mortises and Tenons, and more

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Blog entry by EarlS posted 07-04-2021 12:33 PM 1178 reads 1 time favorited 6 comments Add to Favorites Watch
« Part 4: Milling Top Boards Part 5 of Benchcrafted Split Top Roubo Workbench series Part 6: This project is going to the dogs »

The base (legs, rails, cabinet supports) are finally finished. Well, finished except for finish. That was kind of the theme of this phase of the build, finished except for finishing. First, a couple pictures of the assembled base.

The walnut has been wiped down with a coat of Watco Black Walnut, and the cherry legs were wiped down with a coat of Watco Cherry Danish Oil. They will get a couple of coats of semi-gloss Arm-R Seal a little later in the process.

Following the plans, the joinery was straight forward mortise and tenons. The plans call for 5/8×2-3/4 tenons for the side top rail and 5/8×3-1/2 for the side bottom rail. Both are 2” deep.

The front rail is 3” thick and 4-1/4” tall, with a 3×1-3/4 tenon that is only 1/2” deep. The back rail is 2×4-1/4 with a 1×3-1/4 tenon that is 2” deep.

Initially, I had aspirations to use the Leigh M&T jig but it isn’t really the right application. Instead, I made a template from some mdf that clamped on the legs for the mortises. Fortunately, I had a couple 1/2 bits that were able to cut the 2” deep mortises.

Tenons were cut using a dado stack on the table saw. After some planing on the tenons things were dry fitted.

That was the easy part. In addition to the mortises, I also used a template to router out the hole for the leg portion of the leg vise criscross.

I spent quite a bit of time reading the instructions, looking at the plans, and watching some Youtube videos. While the plans provided a specific location for the slot, the instructions mention that you can move the location vertically on the leg (and later on the chop, which I haven’t started).

Here’s what I got out of it: there is a recommended minimum distance (1”) between the bottom of the slot and the bottom of the leg to prevent damage to the leg during use. You can also move the slot up higher if you want. What I didn’t realize was that doing so would allow for the chop to be cut shorter. The plans call for a chop that is only 1/2” off the floor.

This brings up the most important detail of the entire build. The plans are full of odd details that are easy to overlook. Those details can be modified to some extent depending on what you want to do. Realizing what can be modified and why takes some time and a bit of contemplation. For example, the longer tenons on the back rail than the front rail helps when it comes time to assemble the base.

When things were dry-fit, I realized that the rails were flush with the outside edges of the legs. Since the legs and rails were different wood species I didn’t like the look. I took 1/4” off the outside face of the side rails and back rail, then added a 22.5 bevel to the outside and bottom edges of the side and back rails. The front rail was left flush with the leg face and only the bottom edges were beveled.

Back to the process:

There are lots of holes that need to be drilled in the legs. In addition to the brad point and forstner bits, I needed long 3/8” and 1/2” bits. The local hardware store had 12” versions that worked well enough for the build. The Porter Cable DP I have has quite a bit of run out which I have been unable to correct. I have been looking at the Nova Viking DP, but haven’t bought it yet. It certainly would have made this part a lot easier.

At any rate, all of the hole locations were marked before drilling them. This is especially important on the front legs due to the crisscross slot which is 1-7/16” deep. The plans call for knockdown bolts which need holes drilled behind the crsicross slot. There is a also a hole for the crisscross pin than is drilled across the top of the slot (not the bottom like I initially did). The location of the leg vise screw hole can also be moved up from the standard location shown in the instructions.

Another side note: While the plans showed the locations for the leg vise hardware, the separate criscross and leg vise instructions had the specific details and required some reading and re-reading to get things correct.

Eventually, I knew what all of the holes were for and any issues to consider before drilling them. The drilling took a couple evenings before they were all finished.

The deadman slide was added to the front rail. It is 1-1/2” wide and 3/4” tall. I glued a couple pieces of walnut together to make a blank. Rather than trying to run the board through the table saw with the blade tipped to 45 deg. I used the router table with a 45 bit. The dado was also made on the router, then the finished piece was ripped off the edge of the board.

After drilling the holes for the knock down bolts, holes were drilled in the front and back rails for the barrel nuts. There was some finessing required since the bolt holes drifted a bit.

The plans call for a shelf but I want to build a cabinet of drawers so I added some support rails and ledger pieces to the front/back rails. The outside supports were a bit tight with the barrel nuts and required some adjustments.

The base build is finished and it will be finished with some Arm-R-Seal after the Watco has had plenty of time to cure.

The drawer cabinet design is coming along in Sketchup and the top work continues intermittently. There are plenty of choices and decisions to make on the top features. I also need to make the chop and deadman. There is plenty of work still to be done. Stay tuned.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"



6 comments so far

View JimYoung's profile

JimYoung

426 posts in 2831 days


#1 posted 07-04-2021 01:22 PM

Fine work, Earl. You are going to love working with this new “tool” in your shop.

-- -Jim, "Nothing says poor craftsmanship more than wrinkles in your duck tape"

View oldrivers's profile

oldrivers

2728 posts in 2811 days


#2 posted 07-04-2021 01:35 PM

Looks as though you have a Dandy started here you will enjoy the great work bench.

-- Soli Deo gloria!

View KelleyCrafts's profile

KelleyCrafts

4610 posts in 1983 days


#3 posted 07-04-2021 01:54 PM

Looking good Earl!

-- Dave - http://kelleycrafts.com/ - pen blanks - knife scales - turning tools

View duckmilk's profile

duckmilk

4843 posts in 2569 days


#4 posted 07-05-2021 06:25 PM

I love following along with a workbench build. Looks great so far.

-- "Duck and Bob would be out doin some farming with funny hats on." chrisstef

View anthm27's profile

anthm27

1851 posts in 2354 days


#5 posted 07-05-2021 11:46 PM

That is Lovely Earl, Great work, I see you taking you time with it and getting everything spot on.
Brilliant Job.
Regards
Anthony

-- There is no hope for any of us if we keep apologizing for telling the truth.

View HokieKen's profile (online now)

HokieKen

19391 posts in 2383 days


#6 posted 07-06-2021 01:35 PM

Looking good Earl and coming along pretty quickly :-) I’m liking the look of the Cherry and Walnut a lot!

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

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