Making a bow saw

[woodchips]

Hi folks,

When out this weekend I tried making a temporary bow for my 24inch saw blade I bought. I was inspired by seeing a picture in one of rays books and an episode in Belarus where it briefly shows him making one by taking a small branch, bending it in a fire then hammering the blade into the ends.

The hammering part and getting it to grip I found worked ok, I used a couple of bolts at each end to stop the blade slipping out, however the bit I just couldnt do was bend the bow without cracking it.

I tried Alder, Willow and Ash, my most sucsessull attempt was with the Alder, I got it to hold the blade straight and it kind of worked untill it completely broke. I then tried willow which ended in disaster and then then an Ash sapling (taken in a responsible manner with land owners permission).

The ash was incredibly strong and took being bent into a bow without breaking, but even with four pairs of hands I couldnt bend the bow with enough control to enable hammering the saw into the ends, I ended up with a wierd warped looking thing only useful for sawing round corners.

Could anyone give me any tips on how to go about this as I must say I would prefere to make it in the field rather than take a full saw in with me. Do I have to hold it in the fire for a long time (I was concerned about baking it dry) or shoud I be carving it a bit to get more of an even curve on it rather than the triangle shaped result I was getting?

 

[Draven]

Did you cut wood from a live tree or use dead wood?

Fresh wood would be easier to bend, although instead of making it bend with a fire, I'd just boil it in water methinks or steam it. Dunno which would be better...

Personally I thought that the fire would dry it and stop it bending so I don't understand that, unless he bent it and then fired it to keep it bent...

 

[woodchips]

I used green wood freshly cut. I am not sure exactly what he was doing with the fire because it was filmed so quickly, I think he just took it out of the fire and started hammering the saw into it. I guess I could boil a billy can over the fire and steam it above that, I could also boil the ends in the billy. but I woudnt be able to get much in the can, just 6 inches or so. I cant remember what the full length was but it must have been about 36 to 40 inches to get a decent curve on it..

 

[gregorach]

Nah, green wood heated over fire will bend nicely - it kinda steams internally.

Personally, I'd probably go for a buck saw rather than a bow saw. Getting the tension right on a bow saw without a tensioning bolt must be problematic. Of course, with a buck saw, the problem is jointing the ends onto the spine securely.

 

[outdoorgirl]

Young, green wood taken in the spring is best - older or dead wood is rubbish. Steam it or soak it in water to increase it's flexibility - it's the same technique used to bend wood to make bows for archery, or to bend wood for skis etc.

Willow or Hazel should work well - give it another go with the steaming method...

 

[sargey]

or you could build a mors kochanski inspired bucksaw

this is an old photo, it has a new blade now.

cheers, and.

 

[sharp88]

Your talking about an improvised swede saw handle right?

Iv made those before. I used coppice. Dunno what it was though. Get it when its green and it dries over time to set like iron.

P.S. very nice bucksaw sargey.

 

[Ratbag]

or you could build a mors kochanski inspired bucksaw

cheers, and.

Fantastic! Please would you be able to post close up pictures of the joint (assembled and disassembled, if possible) and of the part where the frame holds the blade? I'd love to make one of these.

It certainly doesn't look like a quick job to knock one up though....

Regards

Rat

 

[Buckshot]

I've made one of those in about 20 mins Ratbag. Slightly different in that I didn't cut slots in my uprights - everything is friction fit.
Works well though.

In terms of bending wood using the fire, as greg says it seems to steam itself. Take it slowly making sure it's heated all the way through. Sounds like you're bending it too quickly causing it to bend more at the weaker points - hence the triangle shape.

Good luck

Mark

 

[woodchips]

I believe you would call it a swede saw sharp88, basically just a simple bow. I will try it in spring as Outdoorgirl suggests using hazel or willow and maybe just a little more patience

I might try making a bucksaw as gregorach linked too, I have some reclaimed oak and mahogany kicking about that I have been looking for a use for.

That bucksaw you made is awesome though sargey. Is it possible to make those holes for the center piece to fit through using just a knife or do you need a chisel. How to you get the blade to attach? I can see what looks like metal strips across the ends? Looks like a realy good thing to make in the field.

 

[sharp88]

Looks like he attached it with keyrings?!

 

[demographic]

Never made a bowsaw but don't you cut the notches in first, fit bolts thouugh the saw ends then attatch it so the bolts cant pull through the notches instead of hammering it through while holding tension.
I don't think I am explaining it very well though.

That way sounds like a recipie for a nasty cut.

 

[sharp88]

I think i know what you mean, demographic. You just cut slots in the bottom with a saw basically.

What I wanna know is how do you make the slots for the stick in the middle? What tool would you use? Did you make a series of holes and then neaten it up?

 

[leon-1]

If it is the same as the one that Sargey had at the Bushmoot (bar the saw blade), yes they are split rings that sargey has fitted to the holes on the saw blade. I think Sargey actually carved the slots in the upright supports using a knife, although I cannot remember for sure.

The slots for the bow saw blade are normally either cut with a saw (as previously mentioned) or they are literally a knife battoned in to blade depth (rather than length). The rings can help to stop the uprights from splitting, as can a little binding above the saw blade.

I hope this is of use

 

[sharp88]

I was perhaps thinking a less orthodox method would be to drill out 3 holes next to each other on either side for the middle slots with a drill and neaten them up with chisel or knife.

 

[sharp88]

I just had a look at Kochanski's Bushcraft and his is different to sargeys. I think sargeys is better though...simpler in a way.

 

[sargey]

here's a close up of the joint. this one was done with a knife and baton, hitting the pommel of the knife and using it like a chisel. you need a knife with a relatively fine point.you don't really need to go all the way through.

i have seen examples that use a blind joint. you could take the easy route, drill a couple of holes with the awl on your swiss army knife and link them together with the swiss army knife saw. mors demonstrated the idea of very carefully using the bowsaw blade unsupported apart from a wrapping of tape. you can use the tape wrapped blade to saw all the components to length. you do risk irreparably damaging your only saw blade though.

yes the blade is secured using keyrings, they're a bit lighter than nuts and bolts, and it's a bit harder to lose a critical component. the slot to hold the blade is a simple split. the idea of the tapered ends on the wood is so that any pressure will cause the wood to clamp the balde tighter and prevent the split migrating up the wood.

the actual mors' design is dependant on pressure to hold it together, it also requires a little more cordage. mine was inspired by mors in that i used all his dimensions &c. this saw has been in use with a couple of scout groups over a couple of years. scouts usually break stuff in a very short time, they have lost the mask that was made from a split hose, but they haven't broken the saw, yet.

cheers, and.

 

[OldJimbo]

The fact that the kids didn't manage to kink the blade is pretty good evidence that this design is solid. Simple one piece bent stick frames combined with the fact that saw blades are often made for green wood wood but used on seasoned wood for fires - can lead to blade kinking problems for people without experience.

 

[gregorach]

Well, I'm just back from a trip where I made a saw like this. I just used wooden pegs instead of split rings - they wouldn't last more that a day or two, but then you just make new ones.

The one problem I had was that my mortice joints (made using knife and batton, as sargey describes) weren't tight enough in the vertical plane, which meant that the saw would go out of shape during use.

One thing to be very careful of is to make sure that the slots that hold the blade are straight and in line. Make the frame up first, then use the blade as a straight edge to mark where they should go, and make sure that you can sight straight through both slots along the line of the saw - other wise you'll bend the blade.

 

[woodchips]

Those close up pictures are great Sargey, I realy like the idea of using the key rings, will have to keep an eye out for some, although gregorach's wooden pegs sound like a good backup plan

I think next time I am sat round a fire with nothing to do I might give the stick bending thing another go, if anything its a good education in the properties of different woods.

I quite like the idea of making a 12inch buck saw using my spare wood at home then giving these field made buck saws a go. Thanks for all the advice guys its given me lots of inspiration!