This is just a prototype made with some leftover Southern Yellow Pine that I had in the shop.

I may, or may not, remake the frame out of hardwood at a later date.

So, here is the blade, it's 27 1/2" long and 1 1/2" wide 5ppi filed rip cut. $18.95

 I use two 4" long by 1/2" carriage bolts, a wing nut and washer, and some 1/4 - 20 nuts and bolts. All for less than $10 at ACE Hardware. I've cut the head off one of the carriage bolts in this pic. The other one needs the head left in tact.

I had some Southern Yellow Pine kicking around the shop so I put it to use.

I needed a way to hold the bolts. I cut a 1/2" hole in a scrap of pine and then cut it in half. This made a nice fixture for my vise.

The 1/2" carriage bolts both need a 1/4" hole for attaching the saw blade. I filed 1" long flats on either side with a standard mill file to make drilling easier and to give the 1/4-20 bolts a place to seat when tightened.

Both carriage bolts also need a slit cut down the middle for the saw blade. A hacksaw makes short work of this.

Here is why you cut the head off one of the carriage bolts. This is how you will tension the saw blade.

The pine that had was 2x12 and 2x10 stock. I made sure to cut from the edges of the wider boards so that I was left with rift sawn pieces and nice straight grain.

I trimmed one side square and then clamped the pieces together to mark the length on both pieces at the same time.

All the pieces are 1 1/2" x 1 1/2". The long stretchers are 31 1/2" long, and the short stretchers are 19 5/8" long. The length of the long pices takes into acount the through tenons (3" total in this case). From shoulder to shoulder these pieces need to be one inch longer than your saw blade. The short stretchers will simply determine the overall width of your frame and can vary to your liking. Wider is better.

As I mentioned earlier I was shopping for a new tenon saw. Here it is.

Thomas Flinn PAX Tenon Saw. http://www.thebestthings.com/newtools/flinn.htm . I'm really happy with this saw and would recommend it. Good quality, good price, and quite a bit heavier than the Veritas saws that I'm used to.

Once the pieces are planed and trimmed to size I mark out the joinery. For this basic prototype I'm just doing simple through tenons. If I re-make the frame in hardwood later I may decide to get a little fancier with the joinery.

So here it is all put together. 

No glue needed, the tension on the saw blade holds everything together nicely and it can be broken down for storage or travel.

The last thing I need to do is hit it with a spoke shave and a rasp and file to soften all the edges and corners and get the handle area smooth and rounded.

It's woorking way better than I imagined and takes a lot less effort than trying this cut with a standard rip saw.

The Sepele board is 6" wide and 13" long

The cut took me about 7 minutes, but I'll get that time down a lot with some practice.

I hope you liked it, and thanks for following along.