Need help: cutting a 315 mm PVC pipe

[Marco Bernardini]

I keep my anvil in the garden, because I don't have space enough in the "goat room" I use as shop.
Since during the summer we rent the lower half of our home, I want to avoid the kids of tourists (the people causing the need for absurd warning signs on tools… define them as you want) will hit the anvil horns with their heads, or the parents will break their back trying to lift it («Hey, look at this!»).
So I bought a 315 mm PVC pipe to make a sort of "lid", surrounding the whole anvil, which I'll screw to the base.
Now the problem is: how to cut straight the PVC without the machine used by plumbers?
None of the plumbers in the surround has a machine large enough, and all of them suggested to use a hacksaw and some sand paper to reduce the "jagginess" of the cut, but I know I'll get a very rough result.
I have to reduce the length of the pipe and to make two cuts along it, so it can slide around the anvil feet.
My idea for the shortening cut is to place the pipe vertical on the table, clamp a hand drill with a slitting saw on the edge and turn the pipe until it's cut.
But for the longitudinal cuts I've no idea how to make a jig: a 315 mm pipe is not actually easy to be placed into a V block…
I'm thinking to a piece of thin iron wire with a couple of lump hammers hanging from it to keep it straight, and a welding torch to make the wire hot enough to cut the PVC. Do you think this could be a solution?
I can't make tests because I bought all the 315 mm pipe available in the valley (1 metre!), so the first attempt must be the good one.

 

[Ulma Doctor]

Marco,
i have a simple solution that requires very little set up and only one moving part.
i have used the method many times.
use a piece of heavy twine as your cutting tool. i make 2 loops on either end to use as handles.
simply mark where you want to cut the pipe, wrap the twine around the back side of the pipe.
make kind of a see saw motion with your hands holding the twine.
the friction from the twine will cut the pipe rapidly and pretty clean
you may want to finish off the cut surface with a rasp or file or sandpaper. a hose clamp is a great guide for small pipe
if you have a helper have the helper step inside the drop end to keep the pipe from rolling.
another tool that works are the backpackers finger saws,
it's the same concept it just uses a steel blade rather than twine for the cutting edge )

p.s. it can be used longitudinally or transverse

 

[Don B]

What about 2 pieces of ply wood ( width = radius of pipe ) make a wooden V-block for laying it out, I would think even a hand saw should cut that just fine.:thinking:

 

[Mike Nash]

 

[francist]

I've made simple v-blocks for porch columns out of short off cuts of 2 x 8. The birds mouth doesn't need to dead accurate, close will be enough to support the pipe stable. A wide piece of paper wrapped around the diameter will give a straight line to follow with a hacksaw, and a little block plane will tune up the PVC faster and cleaner than sandpaper or files.

-frank

 

[Rich]

If I understand it correctly, you were wanting to lay out a longitudinal line the length of the pipe. A quick trick is to just lay a straight piece of angle iron legs down on top of the pipe. The angle iron will only lay on it parallel to the axis of the pipe.

 

[Marco Bernardini]

Thanks everybody for the suggestions!
This photo will give you an idea of the size of the pipe:



Maybe I need also a bigger vise:



The thickness of the PVC must be around 3 mm.
I see a well ballasted iron wire, 1 mm thick, leave a sign when hot.
Tomorrow I'll borrow a butane welder from the neighbor: a Bic lighter is not exactly a plasma torch (even if the wire becomes red for a moment, around 600°C).

 

[Hawkeye]

Do you have access to a table saw? I would set the fence the required distance from the blade, then raise the blade about 3/4" above the table. With some care, it is possible to slide the tube onto the blade with the end firmly against the fence, then rotate the tube opposite to the rotation of the blade until it is cut almost all the way around. Then stop moving and shut off the saw. The last bit can be cut with a hacksaw.

 

[xalky]

I would just use a hand held circular saw, a wood blade will work fine. Mark an even line with a black marker. Put the pipe down on the floor and follow the line as you roll the pipe. Thats how i cut big round things like that. You could refine the edge with a belt sander or sander of your choice if you feel the need.

 

[DaveD]

Do you have access to a table saw? I would set the fence the required distance from the blade, then raise the blade about 3/4" above the table. With some care, it is possible to slide the tube onto the blade with the end firmly against the fence, then rotate the tube opposite to the rotation of the blade until it is cut almost all the way around. Then stop moving and shut off the saw. The last bit can be cut with a hacksaw.

Be sure you have good health insurance and an ambulance stand by. At least have your LOML stand by with a clean pair of underwear.:bitingnails:

Mike Nash has the right tool shown. Everyday saber saw.