Friday, December 4, 2009

A Dedicated Sharpening Bench - part 5

Shaping the Feet and Finishing the Frame

In my last post I finished the leg to bench surface joinery and can now get into the rest of the mortise and tenon joinery to complete the frame work. As mentioned, the stock is 1 1/2" square so I'm making 1/2" tenons and mortises. It's a work out chopping through the Ipe but my mortise chisel is up for the task. Remember I usually bore out the waste with my brace and bit but this wood wreaked havoc on my vintage augers and they only went in about 1/8". So lots of hammering and sawing and fitting the tenons. One nice thing about the 1 1/2" stock is the tenons are relatively small so after a few hours of banging around the basement I'll have the frame complete.

Chopping a Mortise

First thing is to establish the perimeter and I do this with some crisp knife lines. In this first shot you can see where I've marked the overall size of the stretcher and then in the middle you can see my scribe lines...notice I marked off the center? This would have given me somewhere to register my auger bit but as mentioned, it didn't quite work out that way.

To begin, I place my mortise chisel at the far end of the mortise area, about 3/16 " away from the scribe line. I hammer down, taking small 'bites' as I go. I'm holding the chisel so the bevel side is facing my body and work my way down the mortise section. I'm careful to stay inside the lines and not to hammer the chisel in too deep...yet!

Once I get to the end of the mortise section I stop just shy of the scribe line, again somewhere in the 1/8" range. I then go back and carefully pry out the small chips and get ready for a second, deeper pass. This time I'm a little harder on the hammer and begin working my way down through the hardwood.

I continue on with this routine until I get close to my finished depth, checking after each pass. Once the mortise is at it's finished depth I'll square up the ends. Place your body in front of the work so you can eye the chisel straight down, square into the opening. If you have trouble chopping square then place a square on your bench top, behind the work for reference. Another mortising trick you can try is marking the finished mortise depth on the back side of your chisel with a felt marker before you begin; that way you can make sure you're not chopping down too deep.

This process is repeated fifteen more times and when complete I'll begin to saw out the tenons. Refer back to my last post to see my set up for that.

When everything is looking good I go back and re-visit the foot components and shape them.
This being a workbench I could have easily left them square- not like anyone will be looking at them ~ ;) but I've always liked the look of rounded feet on workbenches. I find it gives the bench a traditional look and there will be much less chance of me tripping on them while I stumble around the shop. My own workbench has square feet but I think that taking the extra 30 minutes or so to round them over adds a nice touch.

Shaping the Feet

To begin shaping the feet I draw out the arch and scribe the lines to determine the recess in the top of each foot. On my bench hook I'll make the first cross cut to establish the small fillet down and then I'll put the stock upright and rip down to remove the shoulder.

Next, I make an angled cut to remove most of the waste and with some rasps and files I fair out the curve.

As you know, my work shop is in my basement and the floor down there is far from flat! With that in mind I decide to remove the middle, underside of the feet to create four contact points where they meet the floor instead of the bench sitting on the entire length of the foot stock. This will make for a more stable bench.
To remove the material I make a series of cross cuts down to my desired depth which in this case is 1/4".

Then I grab my biggest, meanest Japanese chisel and start chopping the waste out between the saw kerfs. I take my time doing this part so I don't blow out any of the wood grain. Working from the inside of the foot I chop down a little over half way and then flip the board over and now working from the outside, show-side of each foot to complete the cut.

A quick going over with a sharp card scraper and it's done. When I have the first foot shaped I'll use it as a pattern and trace the rest of the feet off of it. This will insure they're all the same without having to measure every time. A bit of sanding and they're good to go!

With the feet shaped and the joinery cut I'll do another dry fit and we'll call it a day. I begin by laying out the left front and back legs and insert the cross stretcher and foot. I'll mirror this assembly on my bench top with the right hand side as well.

Leaving the frames flat on the bench top I'll insert the cross stretchers.

Finally, I'll peg the right hand frame onto the end of the stretchers and stand the whole unit upright. I'm happy with the results and my joints are looking pretty descent. In this final shot you can see how the work surface will slide down into the front slip joints and sit on the rear stub tenons. When I glue up the frame I'll drill and peg all of these joints for a bench that'll probably be around a lot longer than I will...My mortising is done for today but I'll add another cross stretcher at the top, rear of the frame that will serve dual pupose- it'll have a dado running along it's length to peg the drawer holders into as well as another pick-up point for the surface to sit on. This final cross stretcher will be made of oak because I want it to be at least 2" wide and as you know, the Ipe came pre-dimensioned at 1 1/2".

In the next post I'll cut the giant hole in the work surface top for the granite insert (the horror-the horror!) as well as make the final stretcher and some last minute details before I glue up the frame assembly and build the under carriage that will hold the granite in place...stay tuned.

Wednesday, December 2, 2009

A Dedicated Sharpening Bench -part 4

Dimensioning Frame Stock

I mentioned in the first post that I'm using some 'off the shelf' hardwood for the bench frame; this was great for my budget but not ideal for my hand tools. Because it was 'dimensioned' at the mill (and I use that term very loosely) I have to re-dimension it all again before I can start laying out my joinery. They're definition of square must be a little different than mine!
The Ipe is an extremely dense South American hardwood and is very unforgiving to hand tools- perfect irony isn't it? Here I am making a new sharpening bench and the wood species I'm using is ripping the edges off of my plane irons so fast that I'm going back and forth to my old sharpening area being reminded with each pass how much I'm looking forward to having this new one! Some strange motivation I suppose?
With that I begin planing and dimensioning, sharpening and planing some more. The reverse grain is very unusual in this species, its tones and weight are similar to teak but the dust coming off of it is 'Kermit the frog green'...If you're ever using Ipe with power tools make sure you wear a mask! I'm finding the small amount of dust coming off while hand planing a little irritating to my nose and throat. When I have all of the frame components cross cut to length (including joinery) and all surfaced, I can begin my layout.

Whenever possible I like to lay out my joinery in groupings ie: the legs get clamped together and the mortises for the cross stretchers are laid out together. This will help keep things consistent and insure continuity between the pieces. I use a pencil to mark off the thickness of each component and then a deep scribe line with my knife for the joinery.

Mortise and Tenons

All of the joinery for the bench frame is mortise and tenon except the front legs into the top apron by way of the slip joint.(refer back to part 3) The Ipe is close to 1 1/2" square so I'll follow the rule of thirds and lay out 1/2" mortises. I begin at the top of the back legs where they meet the bench top. I saw a tenon into the rear leg tops and chop out the mating mortises. Over in my shoulder vise I get out my favourite back saw and make some dust. You may notice in the pictures my set up for sawing the tenons- I hold them in the tail vise and have my bench hook next to it on my bench top. This is an efficient set up when you have a lot of tenons to cut. I start by ripping down the two cheeks and then turn the workpiece and rip the other two shoulder cuts. Then it's a simple matter of unclamping and sawing at the bench hook without ever having to take a step. I'll get both tenons cut and then back into the tail vise to pare down to the scribe lines.

I've heard some woodworkers say you should saw 'right to your scribe lines' and I suppose in a perfect world this is true. I unfortunately live a few blocks East of a perfect world so I try to leave a bit of material to pare away to. This is especially true on the cross cuts where I want a crisp shoulder line.

With the tenons cut I'll forget that measuring tapes were ever invented and use the actual work piece to lay out my mortises. Again, I begin with a pencil and mark out my perimeter and follow with a knife line to determine the actual mortise size.

I begin with a brace and bit and bore out the bulk of the material. These are relatively shallow, stub tenons so I trust my eye and bore down into the oak. For deeper tenons I'll wrap a piece of tape around the bit to show me the finished depth and for really special work pieces I'll actually make up a wooden 'collar' that slips over the bit creating a built in depth stop. But as mentioned, today I'm using my eyes.

From there I'll use my mortising chisel to chop off the little 'wings' left between auger bit holes and square up the ends. I'll clean out the bottom and get ready for a dry fit. The brace and bit method of cutting mortises is a fast and accurate method but I should also mention when you first lay out the mortise it's a good idea to scribe in a center line. This will give a point of reference for the bit to find center when drilling. The first dry fit shows me that I need to remove a little meat off of the tenon. This is another one of those wood working myths- tenons don't have to look pretty! I know we see them in our favourite woodworking magazines, all crispy and shining like a new dime but really-?
They do need to be straight and they really should be square but besides that they can be as rough as you make 'em. Keeping that in mind I use a rasp to trim the tenons.

It's fast and easy and all of those 'scratch marks' left behind will actually make for a better glue joint. Another dry fit and it's on to the next one.

The bench now has four legs standing proudly, although still inverted on my bench top- I decide to address the bottoms of the legs and the feet. It's a natural progression, but I don't give the sequence too much thought. I suppose you could cut all of the legs first and then move onto all of the stretchers... I enjoy watching a work piece come together and at the end of my work day I like to see what I've accomplished. So I started with the legs and then onto the feet; at least I'll be able to stand the bench upright and get a sense of where things are going for tomorrow!

The process of cutting the mortise and tenons throughout the frame is pretty much the same system as described above. Pencil to scribe lines and then bore out the waste and.....what's that? The wood? Too hard?
Oh yeah, I almost forgot- the crazy-dense exotic wood from South America proved to be a little too hard for my auger bit so I wasn't able to remove the waste like I did in the Oak. Imagine, the quarter sawn white oak in the bench top is actually the 'friendlier' softer wood! That's saying a lot.
So instead of removing the waste with my brace and bit I resort to the crashing and bashing of the mortise chisel. It actually went pretty quickly. As hard as this wood is, it works pretty well and while chopping across the grain for the mortises, I exploited the brittle under tones of the Ipe. The tenons were done as described and before I knew it the legs and the feet are least for tonight. Next time I'll shape the feet and finish the frame. Stay tuned.

Monday, November 30, 2009

A Dedicated Sharpening Bench- part 3

Cutting some Joinery

With the bench top work surface squared on six sides I'll measure and lay out the rabbets for the bread board ends.

Deep scribe lines will help eliminate cross grain tearing and when I clamp the piece into my shoulder vise I'll again add my thicknessed backer board to help with the spelching. I begin the rabbet with a special purpose rabbet plane but once established I change over to my medium shoulder plane. I find I get a better inside edge with the shoulder plane. I think this may have something to do with the nicker on the rabbet; it's necessary when getting the rabbet established but I find the small nicker helps the plane to slowly work its way out from the edge. With the shoulder plane this is eliminated and I can create a much cleaner rabbet.

I should mention that the rabbet plane I was using has a small set screw so I could have stopped and retracted the nicker after the first few passes, but having the shoulder plane ready was a little faster.

With the rabbet cut I'll check for square and flip the board over to cut the bottom edge. This same process is repeated on the opposite end of the surface establishing the thickness of the bread boards. From here I get my apron stock prepared and cut to length making sure I've included all of my joinery. I measure and plough out the dado in the end pieces. Once the grooves are complete I change gears to lay out and cut my dovetails for the apron. These dovetails are laid out as you would for any through dovetail except we're dealing with a larger scale. I scribe the thickness of the aprons to their mating pieces, lay out my dovetails and start sawing. The oak, at 1 1/4" thick is just about the maximum my small dovetail saw can handle but I get them done and can now lay out the mortises for the bread boards.

I've only cut my dovetails into one end of the apron- I'll wait until I finish and fit the main work surface into the side aprons before I commit to the placement of the opposite front apron.

Bread Board Ends

At this point I can dry fit my dovetails and check my dado is lining up between the pieces. I measure and divide the long tenon I still have rabbeted into the ends into three tenons. The entire length of the side will have a small shoulder plus these three tenons. I mark out the cuts and the mortise position inside the dado. For 90% of the mortises I cut I follow this procedure. Once properly laid out I begin with a brace and bit and remove the bulk of the waste.

I then follow with a mortise chisel and clean up the ends as well as determining the final depth. With the mortises chopped, the tenons cut I'll try a dry fit. Now I can establish the opposite end of the front apron and I lay out and cut the through dovetails.

The back apron is laid out and the dovetails are also cut at this point.

I follow with my plough plane and plane out another dado into the top of the rear apron. This groove will become a channel for a work holding tray later in the build.
From here I cross cut, plane and glue up some pieces to create the back splash which also serves dual duty as the front panel on the tool tray.

This also gets a matching groove opposite the rear apron we just finished. I'll bevel the inside of these grooves to make the sliding tool holder a little easier to move.

I have my work surface and apron joinery complete; in the reading and research on work benches I've done I decide to incorporate a through bridal joint for the front legs where they meet the apron. This will create a very strong frame as well as making the front legs of the workbench flush with the front apron- a real benefit when I add some other work holding features to the piece. This being a small work space I try to make the most of my workshop projects and have them serve dual duty.
I lay out and rip down the deep leg joinery; this is sawn down and then the bulk of the waste is removed with a fret saw and cleaned up with a chisel. The corresponding tongue of the slip joint is cut into the front apron.

With a good dry fit I'll measure and mark the small shoulder that needs to be cut into the back of each leg. Since the leg stock is 1 1/2" thick and my apron stock is only 1 1/4" thick, I have 1/4" of material that needs to be removed so the work surface can sit up tight to the apron. I could cut out a small section of the work surface, leaving the full depth of the legs but I decide to remove the material off of the legs creating a small shoulder the surface will rest on. I can do another dry fit with the front legs attached and really get a sense of the bench dimensions. I begin with the two apron ends and then dry fit the front into the dovetails. I insert the rear apron and flip the piece over on my bench top. Now I can slide in the front legs and see how I'm far so good! Here are some shots of the dry fit assembly thus far~

Top surface with side and front apron attached.

Rear apron dovetails

Tool tray framed with rabbets

That completes the top joinery and front legs for now; I'll get my stock ready for the rest of the frame and start the mortise and tenons next time...

Additional content-
Had a comment on how I cut the half lap in the legs- here are a few additional shots. The half lap or bridal joint is laid out and the legs are ripped down in my shoulder vise. I then remove most of the waste with a fret saw and clean up the bottom with a chisel. The small rear shoulder that will sit under the table top is cut on my bench hook- hope that explains it more clearly...thanks for the comments.