My coping saw, WIP but in working condition

[builderchad]

I made fittings so that I could fit 6" hacksaw blades and 7" coping saw blades. I will probably end up only using it for coping as was initially intended but I also wanted it to be a little more versatile.

At this point it is in working order but needs some refinements:

1) A small ball handle instead of the file handle used, this will bring the hand closer to the frame to give better balance.
2a) Shave off a good 3/8" or so from the frame to lighten it up - turns out to be too heavy even with the hand more forward.
2b) Possibly get the spokshave on the top and bottom of the frame to take the squareness out of this dimension and lighten it up further.
3) Remake the metal parts that hold the blade from silver steel as opposed to the cheap B&Q bar which is too soft. And on these parts make sure the grooves are deeper to take coping blades with longer lengths of metal behind thier pins.
4) Remake the stretcher for a tighter fit to offer more support.

And finally, I need to finish it with something really durable - seeing as its a tool - but I have no idea with what yet.

There are a lot of pictures so here is a link to the gallery:

http://www.zulu.net/ships/thumbnails.php?album=4

Here is a quick snap of the current state:

 

[Alf]

Crikey, Chad, what a behemoth! :shock: I dunno, but I reckon you could probably reduce the thickness by half without compromising the strength - and then you could probably pick it up. :wink: Looking good though.

Cheers, Alf

 

[builderchad]

Yes it is.

The real problem lies in my basing the wholes on penny washers which are an inch in diameter. This means the thickness couldn't go less that 27-28mm, though even taking it down to that will make a big difference. Oddly enough when your hand is near the frame it doesn't feel that bad because most the wieght is lying on the blade which means you dont have to press down on the cut stroke AT ALL :lol:

 

[Alf]

...you dont have to press down on the cut stroke AT ALL :lol:

Getaway, really? :wink: :lol: Funnily enough one of the first tools I made was a coping saw-sized bow saw. Not a thing of beauty, IIRC. Must be in a drawer around here somewhere. :-k

What you could do is drastically reduce the thickness between the limited points - the washers and the mortises. Rather like a wheelwright would put chamfers everywhere to reduce weight - well for the same reason (Duh. Keep up at the back there, Al #-o ) Better still, make another one and take the opportunity to try a different design too - take a look at Brian Buckner's and tell me you don't want to make one like that... Whoops, who put that Slope there? :twisted:

Cheers, Alf

 

[builderchad]

I'll get to work on it today and chamfer all the way around as you say, and round over the ends as well. Will give me a chance practice more with my spokeshave which I am useless at still. I will .

Those bowsaws do look nice and I will definately make another but not until I've had a go at a large frame saw for which I already have the blade and all the metal components.

 

[builderchad]

I have reshaped the wood and it has made a huge difference. It's really quite light. My hand is still a bit too far back for perfect balance but its really coming along now.

 

[mr]

a large frame saw for which I already have the blade and all the metal components.

Also on my evergrowing list of things to do. Where did you get the blade and metal fittings from?
Mike

 

[Paul Kierstead]

And finally, I need to finish it with something really durable - seeing as its a tool - but I have no idea with what yet.

As a different approach, you could use a less durable finish but which is easily repairable, such as many oils. A quick coat once in a blue moon when it is getting bad and in a few years you'll have a really beautiful used tool.

It starting to look good, especially nice shaping.

 

[builderchad]

Also on my evergrowing list of things to do. Where did you get the blade and metal fittings from?
Mike

For my bowsaw I used standard Bacho blades from Axminster which are roughly 6 1/2" with a 5" teeth section. Everything else I made from standard M6 silver steel bar (the best quality ones I got were from Toolbank). I got a cheap tap and die set from Axminster and box sets of mixed washers (which had M6 penny washers) and nuts. Wing nuts and dome nuts I got from B&Q. All the metal parts were blackened with Abbey Blu Gel I got from here: http://www.airpistol.co.uk/guncare12.htm though Liberon do a very large bottle of Haematite which looks like it will do the same thing but its very expensive.
Oh, and I also used an M3 bar I got from B&Q to make the little thumb grip to swivel the blade opposite the handle.

I got the blade for my frame saw from Dieter Schmid (in Germany I think). They do a huge range of japanese tools and parts:

http://www.fine-tools.com/gestell.htm

I got the rip cut blade (part no. 712951) which measures 600x40mm so its nice and long. I also got the blade holders (no. 301170) which are quite substantial at almost 100mm in length. I may not use them in the end and go for a simpler M10 bar holder approach.

As a different approach, you could use a less durable finish but which is easily repairable, such as many oils. A quick coat once in a blue moon when it is getting bad and in a few years you'll have a really beautiful used tool.

It starting to look good, especially nice shaping.

Paul, I like that idea and was thinking of using Linseed Oil but I don't know what the difference is between raw and boiled and which one I should use. Would Danish Oil or Teak Oil be better?

Cheers.

 

[Alf]

Paul, I like that idea and was thinking of using Linseed Oil but I don't know what the difference is between raw and boiled and which one I should use.

Boiled; raw'll never dry.

Lookin' very shapely now, Chad. Proper job.

Cheers, Alf

 

[builderchad]

Cheers Alf

 

[Paul Kierstead]

Yes, definitely boiled. Danish Oil, Teak Oil, Polymerized Tung Oil (or unpolymerized if you are patient) will all work fine too, plus probably a few others.

 

[mr]

Thanks for the details re the blade etc. I can't see how those blade holders are supposed to work they look much to large to be useful, is it more obvious how they should be used when you see them in the flesh?

Cheers Mike

 

[builderchad]

Thanks for the details re the blade etc. I can't see how those blade holders are supposed to work they look much to large to be useful, is it more obvious how they should be used when you see them in the flesh?

Heres what I planned:

On one end the shank would go through a slot in the saw arm (handle?) and a simple pin would hold it against the wood. On the other end I was going to make one of those tear-drop thingys and attach it to the shank so the blade could be brought under tension. I will get my primitive designs out tommorrow and capture them on the digi cam and show you what I mean.

What I like about them is that they have a wide surface area both where they hold the blade and along the shank meaning that if fixed properly to the wood would prevent the blade twisting and bending laterally etc.

They are roughly 2.8mm thick so not easy making a slot in the wood for that so I was thinking of making the slot much wider and reinforcing the sides with aluminum sleeves folded over on each side of the slot. Over engineering maybe, but the sleeves would have the added bonus of keeping the pin on the one side from digging into the wood and the tear-drop on the other from slowly bruising the wood over time.

 

[builderchad]

Very poor image sorry. I am working on modelling this properly and will post decent pics soon.

 

[mr]

Looking at the description on the Fine tools site for the blade holders, it occurs to me that the reason these blade holders are so long is because they are intended to fit within a turned style handle like the sort you have on your coping saw. They dont appear to be intended to be used midframe as you might on a frame saw. I don't know but I would imagine that you would have problems tensioning the blade sufficiently with a cam type arrangement. The threaded rod idea would seem more effective though not as nice looking. The other problem (problem?) with these is that because the blade doesnt extend into the frame at each end I would wonder whether it had enough support against twisting in the cut. Bear in mind I havent got a clue what Im talking about. I m planning on making a frame saw at some point soon so watching your progress with interest.
Cheers Mike.

 

[builderchad]

I also had concerns about twisting, but then I do have two huge boards of beech to experiment with . The main reason why I wanted to stick with these holders is purely for the looks, but I will probably end up using the steel bar approach as I already have the M10 rod and bits.

My design will also incorporate two fences to ride on each side of the board being resawn which will reduce the twisting and keep the blade on track in unskilled (read: my) hands. I am having the most problems with these, design wise, and still searching for a solution where the fences are locked in position by pushing outward on the frame and so adding to the tension on the blade, rather than pulling it inward which will undo a lot of the effort of the blade tensioning mechanism, whatever that ends up being.

 

[mr]

design will also incorporate two fences to ride on each side of the board being resawn

Did you mean something like this?

Cant remember where I found this picture now but I remember reading at the time that it wasn't a particularly effective means of keeping the blade straight in the cut as the blade would still bend along its length. The fences are certainly an interesting idea, but I'm tending to think that the depth of the blade (teeth to spine) would be more effective in keeping on track. The greater the depth the easier to stay on line?
Mike

 

[Alf]

That'll be Paul Pedersen's I believe.

There's tons and tons of discussion in the Old Tools archive on frame saws; building and using. With any luck this link will work.

Cheers, Alf