Ideas

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.