Ideas

Dimensioning Frame Stock

I mentioned in the first post that Im 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. Theyre 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 isnt it? Here I am making a new sharpening bench and the wood species Im using is ripping the edges off of my plane irons so fast that Im going back and forth to my old sharpening area being reminded with each pass how much Im 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 youre ever using Ipe with power tools make sure you wear a mask! Im 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 Ill 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 its a simple matter of unclamping and sawing at the bench hook without ever having to take a step. Ill get both tenons cut and then back into the tail vise to pare down to the scribe lines.






















Ive 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 Ill 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 Ill wrap a piece of tape around the bit to show me the finished depth and for really special work pieces Ill actually make up a wooden collar that slips over the bit creating a built in depth stop. But as mentioned, today Im using my eyes.

From there Ill use my mortising chisel to chop off the little wings left between auger bit holes and square up the ends. Ill 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 its 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 dont 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.






















Its fast and easy and all of those scratch marks left behind will actually make for a better glue joint. Another dry fit and its 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. Its a natural progression, but I dont 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 Ive accomplished. So I started with the legs and then onto the feet; at least Ill 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.....whats 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 wasnt 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! Thats 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 complete...at least for tonight. Next time Ill shape the feet and finish the frame. Stay tuned.

Here are some new pictures of the mantle and corbles being stained. At this point, they have 3 coats of stain on them, and I am getting ready to apply the polyurethane. Obviously, this is not an overnight process! Each coat has to dry completely to get the best results. Additionally, if I want an extreme shine with the poly, steel wool is used between each application, which lengthens the finishing phase.

However, once this is complete, I will be ready to hang the mantle, then apply the surrounding trim, and the project will be complete! Its almost done!!!

There wasnt much left to do on the saw, but it still took me awhile. I snuck in one short work session during the week and one longer one today and the saw is done! Wahoo!

To mount the knobs and rods I had to bore holes through both arms near the bottom. First I had to rework the bottom section of the "handle" arm. I had left it wider than the other arm, and while I am sure I had a reason, I couldnt remember why I had done that, and it didnt allow for enough of the rod to clear the arm. While using the spokeshave, I went ahead and reworked the curve in the bottom of the stretcher to more closely match the curves of the arms. After that, I used a brace and bit to bore both holes.

Heres a shot of the saw, at that point:


That was all I accomplished during the week. Today I moved on to mounting the blade in the rods. After filing a flat to stop the bit from sliding off the bolt, I used my small hand drill to make the holes for the pins that would hold the blade. I experimented a little here, and heated the first bolt to red hot and let it cool. I wanted to see if it made a noticeable difference. It didnt. Hmm. Thats the opposite of what I experienced with the bolt heads. Maybe Im mental. I dont suppose bolts have that much carbon in the steel - so no dramatic change makes sense.

Heres a shot of the first bolt in the vise:


Then, using a hacksaw, I cut the slots for the blade. I returned the drill bit to the hole to help me align the slot at right angles to the hole. Heres the result:


Now it was blade time. I assembled the saw and measured the distance between the pins (3p finish nails) in the rods. Then I subtracted 1/16 of an inch and I had my distance for the pin holes in the blade. This would bring the bottoms of the arms together slightly, allowing for the blade to be stretched taught when the tension mechanism pulled the tops of the arms back together, and the bottoms apart. The 1/16th was just a guess. Turned out I should have made it more like 1/8th, but Im getting ahead of myself.

I cut the blade with an extra 1/4 inch beyond each hole location. Heres my high tech band saw blade cutting apparatus:


It worked great and had no trouble cutting the 1/4 inch blade. The vise allows for more control and the use of body weight to assist with the cut.

To drill the pin holes in the blade, I just clamped the blade to a piece of scrap and had at it. It took some pressure to get started, but once it did, the bit had no problem. I did use my fist under my chin to help apply steady pressure on the handle of the hand drill.

I have heard of others punching holes in the blade with a hammer, a punch and a block of hardwood (end grain up). I tried this before and didnt have good results. For whatever reason, Ive had much better luck with just drilling. Maybe my blades are cheap or something...


Once the blade was mounted in the rods I could make the simple tensioning system. I cut about 12 feet or so of twine and soaked it liberally with mineral oil. Its my pet theory that the oil allows the fibers and strands to slide over one another and "self adjust" so that they all share the load equally. I have no proof that this works, but I dramatically reduced my breakage rate once I started using this approach.

To apply the twine, I wrapped it around one arm several times and then started looping it around both arms. When I ran out of twine, I wrapped the running end around the loops several times and then passed it through between them. I inserted the toggle stick between the loops and started winding. As the twine twisted tight, the extra oil got squeezed out. I just rubbed it into the saw.

To test the blade tension, I plucked it with a fingernail. Heres where I realized that I should have shorted the blade holes by 1/8 rather than 1/16 of an inch. The tenons were fully seated and the blade was not fully tensioned. The real fix would have been to make a new blade, and I probably will - at some point. The temporary fix was to put a washer between each knob an the frame. I kept on applying tension until it started to sound musical; changing from a "thunk" to a "twang!"

Time for some test cuts. Not very pretty, but that was my fault not the saw. I wasnt really watching what I was doing: I kept looking at the saw to see if it was flexing or moving. Nope - ship shape! It worked great.


Heres a final shot of the new turning saw posing in front of its predecessors:


Oh yeah - when I took that last picture, I had forgotten to snip off the nails that are functioning as the pins to final size. Quick work with nippers - should have done it before the picture. Doh!

My "prototype" turning saw finally died. It was a quick and dirty project that was never intended to last. The original idea was to work out the bugs in the design, and then move on and make/use a nicer saw. It didnt end up that way. In fact the prototype was superior, and was my turning saw of choice over the years while the "nicer" saw hung on the wall.

Heres a shot of the DOA saw:


The epoxy that held the brass pin in the handle finally let go. I could just fix it, but as good as this little saw was (way better than you might guess from looking at it) Ive been wanting to build that nicer saw that really works too. I though this was probably the time.

The new saw will be made of oak. I still have some left from the broken library chair episode. After making some cardboard templates, I traced the design onto the stock. I decided to make the handle convex where my hand will hold it, much like a panel saw handle, rather than the more standard concave bowsaw handle. Im not sure if this will end up being a good idea or a bad idea. Ill know soon enough.


I prefer to do the mortising while the stock is still square. The setup is easy with the holdfasts. The big (giant!) mortise chisel and mallet do the grunt work and the smaller chisel is for cleaning out the chips and flattening the bottom:


The mortising sequence - start in the middle and work to one end (not quite to the layout line):


Back to the middle and work the other way:


Continue until the mortise is deep enough, then clean up the ends:


After laying out the tenons with the same gauge setting used for the mortises, I cut just outside the lines with a backsaw and trimmed with a shoulder plane to a snug fit.


Heres the saw so far - looking very chunky in its unshaped form:


In Part II I will shape the frame parts, make the blade assembly and create the tensioning system. After that, Ill try it out.

If history repeats itself, Ill be regluing the prototype in Part III.

After a stalled few weeks of Tree House building due to Woodworking in America and Hurricane Sandy, I managed to get back out to work last week.

After cutting all the T1-11 sheathing/siding to length, I managed to get 2-1/2 walls hung. Hopefully next weekend Ill get to finish closing in the envelope.