MIMF

I wanted to have a better bow saw.

There are things I wanted to improve.

I hate coping saw blades and coping saws. They are very soft steel, break easily, get dull quick and are much too expensive to purchase for what little you obtain.

I wanted to be able to use small blades (1/16, 1/8 and 1/4 inch blades) in the same holder if needed.

I did not want to have to use any wrenches for attaching the blades, and I wanted to use broken/ left over bandsaw blade material.

The basic design and shape and tensioning mechanism are fine otherwise.

My first bowsaw several years ago used a 1/2 bolt, cut down to about 2 inches. The end had a saw kerf from the hacksaw. I drilled a hole through to slip a piece of small nail and this held the blades quite nicely, if not elegantly. The nail was a little uncomfortable if you don't bend the end over.
There are a couple of limitations with this design. I wanted to place smaller blades in the bowsaw, rather than 1/2 inch blades.

To accommodate smaller baldes, I soldered a slip of flattened steel to the end of the blade and pinned it in place. Again, not as elegant as I hoped for, but functional. And somewhat time consuming to solder the blade ends.

I have tried several mechanisms which have been successful.

I will try to explain all of them.

They all use a bolt as the basis for their construction.
I drill a hold through the center of the bolt. I do this with my drill press, as I don't have a metal lathe.
They don't always look perfect, but this is not quite as hard as it seems.

When you are picking your bolt, use the lowest quality bolt, as the higher quality steel bolts will be harder on your drill bits.

To start the drilling, I run the head of the bolt against coarse sand paper to get any dimples or manufacturer's codes off of the head.

I use a dry wall screw that is screwed into a stick to start the center. The screw point is just out of the wood a little ways to minimize wandering. Start the center with little pressure, and cautiously. It is one of the odd things about turning, that it is relatively easy to find center.

The first tightening mechanism is essentially like a 2 part collet.

I took a piece of steel, heated the end a little, pounded it some with a hammer until it swelled, then use the jewelers saw to saw a slit in the end.
Next, smooth down the edges, open the slot wide enough for a band saw blade (.025") and polish it up.

I like to have a nut big enough to adjust by hand so I don't have to reach for wrenches.

I like a way to rotate the blade without wrenches. I drill a place to put a small nail into the head of the bolt.

I had some brass laying around which was about the thickness I wanted, so I used that for the tightening nut.

Make sure all of the edges are smooth enough and that the bolt does not stick out too far as you are doing this. You want this to be comfortable when you grab the area when you are sawing.

This holds well. If it does not, you need to adjust the angles where the collet enters the shaft of the barrel.

It has one problem. As you are tightening the nut, it can rotate in the barrel some.

So, I came up with 2 other mechanisms.

I used the same barrel, and made a wedging action in the blade part of the barrel.

One mechanism tightens as the wedge is drawn back into the barrel, and the other tightens as the wedge is advanced in to the far part of the barrel.

I had trouble really drawing these out, and the mechanism is relatively small to get good pictures.

What I did on the first, is to cut half of the rod that sits inside of the barrel, and solder a small piece just inside of the barrel. The other part of the rod is ground and filed away, but at the very end, you need to allow just enough room to get a blade in place, and enough angle on the rod to wedge as it is tightened.

With the rod drawing back, it is easy to place a nut on the adjusting end.

This is the picture of the blade holder with the screw advancing the wedge.

If someone wants more details of the mechanism, I would be happy to try to explain it better.

The various mechanisms use 1/4 to 3/8 inch bolts.

Some other comments--

Band saw blades (high carbon steel) are very hard at the tips.

If you want to sharpen them, you need to use stones or diamond files. They have a very aggressive cut, and if you don't like the way they perform in your saw, you might want to soften the steel by heating the tips and refiling the angles.

Even though they are hardened tips, the rest of the blade can usually be drilled with out heating the steel. (I can fairly consistently drill 1/4 inch blades.)

I placed a small spring around the holders.

When changing blades or if one of the blades falls out, it is easy to lose your holder.

I would comment that bow saws are nice to have around. I use mine a lot.
I actually have several now. And lots of left over bandsaw blades!

Nice one Steve. Great idea.

Steve,
You are one of the most inventive, resourcful people I've ever met. Looking back at all the tools you have posted over the years, it's a shame you didn't go into a tool and die career instead such a dead end profession as medicine <g>.

You, more than anyone here, are what started me thinking "just make one...why buy it".