Thursday, March 25, 2010

Roubo Bench Build Part 4

    With the base done it was time to get the top ready and fit.  Looking back at the last picture you will notice that there are tenons at the top of each leg.  I put the top on my workstation upside down and clamped it with the appropriate spacers in between each segment. Remembering that I wanted the front face of the top to be flush with the front face of the legs, was the determining restraint for the space between the slabs.  Next I positioned the base on top of the top and marked out the location for the leg tenons.

The drill press hogged out most of the waste, and the mortises were cleaned up using a router with a tall straight bit and some chiseling to square the corners.


It took a bit of fettling, but I finally got the top fitted using a file to slim the the leg tenons.  The light at the end of tunnel was finally beginning to show.  I grabbed the quick action vise I had been previously using as a face vise, and started marking out the mortise for the rear jaw. A router and straight edge are your friend here. Take your time and make multiple passes.  

You will notice a spacer block to lower the vise and keep more meat near the top edge of the benchtop slab.  This is an Anant copy of the original Record 52 1/2 ED, and is a passable iron vise.

I also left some space for a cork lining of the rear jaw to counter act some marring that would occur on a metal surface.  Heavy weight tooling leather is a better option but this was on hand.

I finished up by drilling 2 rows of dog holes in the front slab:

These are 6" on center (2 3/8" from the edge) on the left and go down to 3" near the end vise.  Do you need this many dog holes? Thinking back on it prolly not, but getting them dead square with no tear-out in the bottom is a many step process I did not care to do again, so we will see if I swiss cheesed the top or its was just right.

You will notice some aluminum angle on the left in the photo.  Schwarz has mentioned using these as winding sticks, so I thought for 6 bucks for a pair I would keep some around for the upcoming flattening.

It is starting to look like a bench.

Thursday, March 18, 2010

Roubo Bench Build Part 3

     It was time to get this base assembled, and I was able to get the rest of the joinery for the base finished. I laid out all the parts and  got ready for a dry-fit:

This bench's base is assembled using 2 side assemblies connected together using front/rear stretchers with barrel  bolts.  I thought drawboring the side assemblies was appropriate.  I used 3/8" oak dowel stock with a 3/32" offset. Once the the holes were bored, I used the same brad point bit to mark the center point of the the holes in the mortise cheeks.

With the side assemblies glued and drawbored, I had to figure out an accurate way to drill the bolt holes for the stretchers.  I decide to do this in 2 steps: drill a whole in the center of the mortise from the inside out, and then dry assemble the base and use that hole to drill into the tenon.

For some things nothing beats a bit and brace, if you don't believe me try it. You will be surprised at how accurately and cleanly this wheaties powered device will bore holes. Keep a square handy, to make sure your sense of square is true.

With that I bored the holes for the barrel nuts, got the ratchet out and cranked these bolts home.  

This base is stout, heavy and I can't wait to mount the split top to it.

Thursday, March 11, 2010

Roubo Bench Build Part 2

  Scale affects technique and the logistics of completing a project.  When the thickness of your parts hover around 4-5", normal rip and cut dimensioning is not so easily accomplished.

    Take for instance the tops, at 9 1/2" x 60" x 4",  there was no safe way to run these across the table saw.  Taking cues from Chris Schwarz I got the circular saw out and with the aid of a straight guide I was able to crosscut the tops square.

   When it came to the legs, I used their shorter length as an excuse to abuse my crosscut sled. Although the work still had to be flipped over, referencing the cut line was much easier than using a circular saw

     With the legs accurately cut to final length, I turned to the joinery of the leg assemblies.  Assembly meaning a pair of legs with one end stretcher and one end apron.  Here is where the bench begins to stray from Roubo's design.  This bench is meant to fully knockdown, and following in Jameel's footsteps, the bench's design would have to change to accommodate bolts.  It only made sense to break down the base into a pair of leg assemblies connected together using the front and rear stretchers ( more on this later).

When dealing with any kind of Mortise & Tenon project, I find ganging the parts together and laying out the joinery for all the pieces at once essential to accurate assembly.

Line them up, clamp tight and using your favorite rule and square layout all your mortises.

I fired up the drill press and started boring:

And here were the results:

Its time to sharpen a chisel and square up the corners.  I look forward to getting the stretcher tenons cut shortly and moving on to some actual assembly.

Tuesday, March 9, 2010

Roubo Bench Build Part 1

     I think it is somewhat fitting that the first post on this log is the creation of a workbench.  The bench is a variant of a workbench attributed to a Andre Roubo, dating to the 18th century.  The design is thoroughly reviewed in what I consider a must read book "Workbenches: from Design & Theory to Construction & Use", Schwarz; and I highly recommend it to anyone remotely interested in workbench design.

    I am endeavoring to fit an old-school work bench, in a 8' x 15' workshop, along with a few other machines; thus, there are a few restrictions on size and assembly. I decided to model the bench after a travel bench that Jameel at built. 

So to the meat, or the SYP in this case:

14 boards at 4 1/4" x 61", thickness planed down to 1 1/4" will comprise the split top.  The boards were quite a chore to rip, due to the warp even in 16' 2 x12's.   You will notice some cup, that I had to take care of using the clamps and glue.

Digging deep into the clamp selection and keeping the gallon of glue nearby, I started gluing up pairs.

Here we are coming out of the clamps, got the grain direction marked on all the boards, as I did not want the grain reversing on me when I did the finally flattening and benchtop maintenance. 

Here is where I will leave it. top planed and ready to be crosscut square.