Thursday, June 19, 2014

DIY Folding Buck Saw Details & New Never Before Seen Buck Saw design!

DIY Folding Buck Saw Details & New Never Before Seen Buck Saw design!

Read on my friends and stay tuned because out one of a kind bushcrafters lightweight and packable buck saw IS NOW available for sale in the bushcraft products section of http://www.paracordist.com ! With just the information and dimensions on photos herein, you will learn how to make your own folding bucksaw. 

Within the last couple months, I pretty quietly undertook a project to make my first buck saw. I posted pictures of it with a promise that I’d offer more detail when time allowed. Here we go!

I started the process with the intent of making a “folding bucksaw”, one that would allow the blade connections to remain at all times (therefore no chance of losing hardware during breakdown/assembly). Searching online revealed relatively few details! There are a few articles with dimensions and written descriptions, but I felt none provided the detail I needed. I basically learned generally how this sort of saw worked and was constructed, then laid mine out around the blade (21” from end to end) I had in the garage on an aluminum bow saw. Here are the general dimensions:

I had a table saw at my disposal, so I learned from a youtube video that a tenon can be cut quickly by setting my blade to the depth of the desired tenon shoulder, then just cutting several kerf widths right next to each other, thereby shaving down and revealing the tenon as I repeated this process on all 4 sides. The mortise was more difficult. I don’t have a drill press. I read a method that included drilling out the mortise with slightly overlapping drill holes the diameter of the desired mortise width. Then just use a wood chisel to square it. My problem was that the bit didn’t want to drill that precise by hand! If I was to do it again I’d have drilled pilot holes with a small diameter bit first! I did finally get working joints.
I’ve seen two modes of breakdown of this sort of saw as follows:

1.       Breakdown occurs by pulling the mortise/tenon cross member then turning the vertical arms inward 90 degrees until they just about meet in the middle of the saw blade and cover the teeth in the saw kerf cut down the entire inside edge. This requires that the drill hole for the blade-holding bolt be closer to the inside of the vertical arm. I thought that the closer the hole was to the inside, the more likely the bolt would be to shear when under full tension.
2.       Breakdown would occur by pulling out the cross member, than folding the vertical arms outward and around 270 degrees so that the blade’s teeth would rest protected within a kerf cut along the entire outside faces of each vertical arm. This method requires that the drill hole for blade be as close as possible to the outside edge of the vertical arm (see 1” horizontal dimension on photo below). This allows the most wood to resist shear of the hole once the saw is tensioned, so it made the most sense to me.

These photos show varied angles and some important dimensions around the blade attachment point. As you can see, the kerf cut for hiding the blade is a major way through the wood. This leaves only ½” of oak undisturbed in the vertical member. I could have made this a bit thicker if I shifted the bold hole closer to the outer edge.


I used a jig saw to cut out some curves and sandpaper and linseed oil to finish. The saw cuts very well, and the space between the blade and cross member allows for a 6” diameter cut. The saw looks great and weighs not much more than a pound. I don’t have an elegant way to bind all the pieces together once broken down, I’ve been experimenting with various straps, bandanna, paracord, bungees etc. All functional but not quite what I’m looking for. I also don’t have the skills at the moment to make a nice little carry sack for it.

There are pros and cons to this design that got me thinking outside the box for better ways. This saw protects the blade and protects against hardware loss by avoiding the need to remove any for setup/breakdown. The tradeoff, which is no small one, is strength. I don’t know exactly how much my saw is weakened by the long cuts, but I’d imagine quite a bit. It has taken some pretty serious tensioning without fail, but it’s still young and it is mighty oak! Not sure how an inferior wood would do. I want a design that will afford protection to the saw’s most critical element – the blade, while maintaining maximum strength in the members. Breakdown is important, because I want a packable saw. The nature of the breakdown in my first saw limits the length of the vertical arms as they must meet in the middle of the saw blade); which in turn limits the diameter of the possible cut. I wanted to develop a design that would maximize the cut-able diameter for the given blade length. I wanted to find a way to protect the blade upon breakdown that does not limit the length of the vertical arms! I don’t want it to be too heavy, I don’t want to copy someone else’s design, I wanted it to be unique and innovative, I wanted it to look good and be a true craftsman’s project. I want, I want, I want!! I wasn’t sure I could have it all; I mean there are usually tradeoffs with everything. I’m limited in my woodworking skills, so I turned to my friend Todd Thompson (who is quite a pro) to do some brainstorming.

Together we’ve been going back and forth, and I think he’s come up with some things that have never been done before!

The coolest idea by far that Todd's actually brought to reality is bulletproof protection for the blade – its encased completely INSIDE the cross member, from tenon to tenon, during breakdown.
 
Todd did some woodworking magic to accomplish this. The cross member was made in two pieces, then carefully glued together with Titebond III wood glue. Upon breakdown, the blade is slipped into the member and secured there using the same hardware that’s used to connect the blade when assembled.
The pieces are bound in the middle by some 550 paracord from the windlass, or bandana, leather thong etc..The vertical arms are no longer limited in length, so we’ve extended them to allow a full 8” diameter cut for the same blade length.
Also, they are solid pieces of oak – no strength concern here. To address the concern for losing hardware on setup/breakdown, he’s come up with a way to imbed a removable bolt, two nuts and two washers in one of the members!

Adding a touch of style and identity, is this special Paracordist windlass

Here are some highlights of the prototype in progress. Will it be the best collapsible bucksaw on the market? We think so!

Wood = oak

Assembled dimensions: 21.75” W x 16” H x ¾” thick

Broken down dimensions: 21” x 2.5” x 1.75”

Total weight: 1lb 10oz.

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