Thread: How to do a longitudinal cut on polypipe?

I would set the fence on the bench saw and slowly push the pipe through. The riving knife would help to stop the pipe rolling so you should be able to end up with the result you are after. A fine toothed blade would be my choice too

thanks for this quick and helpful reply, chambezio. Unfortunately my sawbench doesn't have a riving knife, just a large sheet of metal which serves as a splitter. I have to remove it if doing dados etc

If I was doing it I would use a bandsaw.

Ross

Some thoughts that may provoke other ideas - are we talking about black poly pipe that farmers would use on dams etc or something stronger or weaker ? ie garden variety very thin poly or rigid and inflexible and very robust ? ie rigid like a white pvc or metal pipe

1. By hand with a very sharp knife - cut the pieces to 1m+ sit the pipe on some home made vee blocks and secure the ends down on the final blocks with nails. Its often possible to mess about too much with power tools and jigs etc when simple hand methods get the job done

1B .By hand with a short scrap of hacksaw blade ?

2. Somehow set up a jigsaw so that it only cuts the one side of the pipe ? use a piece of wood to limit the blade penetration

3. One of those fancy multi tool oscillating saws - should be easy by hand ot secure the pipe to a table top and use a wscrap wood straight edge to guide the saw ?

4. A dremel type tool with some sort of guide as above

...................

Bill

Dengy, do you wants to cut both sides or just one?

A handsaw should do the job for one side, or an angle grinder (be careful about melting it).

Or you could jam the piece between two pieces of timber and use a circular saw.

How many pieces do you want for cut. This is just the light irrigation poly pipe is it.

If it is something you want to repeat I would consider nailing 3 pieces of wood/MDF together to fit over the pipe and use this as a guide to run over the table saw.

You could even use a Stanley knife and cut along a guide using a similar principle to the above. If it is a one off I would cut free hand with a knife. You can get a hook blade for the knives that would likely do the job.

Have cut heaps of this stuff with a TS and BS depending on whether kerf losses were significant.
The TS blade blade I used had the same negatively raked teeth as used to cut hard plastics as most wood cutting blades will pull the material into itself and can make a bit of a mess.
I didn't use a giving knife with the TS and I never felt it grab the blade, probably because its too floppy.

Years ago I cut a slit along a length of 25mm conduit to fit over a guide wire. From memory I just used a hacksaw blade and lots of patients. Job could not have been too bad as the conduit is still on the wire.
If I had to do it again might pick up a hacksaw blade for a short length, or use a multifuction tool for a longer length.

Thanks Ross, but I only want to put a single cut down the length of it, not slice it in two

Originally Posted by Dengue

Thanks Ross, but I only want to put a single cut down the length of it, not slice it in two

Then a table saw is the go. To stop it twisting drill rightish fitting holes in 3-4 square wooded blocks and thread these onto the pipe and then align the blocks on a flat surface before passing the whole shebang thought the saw.

If you can find a scrap piece of timber about the same length, square in section.
Set table saw to 45 deg and run the scrap through the saw, flip end for end and run through again to create a V channel in the scrap making a long timber V block.
Hot melt glue the pipe into the V channel.
Reset saw blade to vertical, set fence so centreline of pipe is over blade with the V block on it's side and base against the fence (O>|[] where O is pipe, >| is V block on side, [] is fence). Set blade height to appropriate depth and run through saw using suitable pushstick.

I'd make a quick'n'simple (and temporary!) jig using two straight planks, scrap spacers and a few clamps; basically a cradle with a board on edge along each side of the pipe(s) - and slightly taller - to hold everything straight, then simply rip down the middle with a CS resting across the boards. Can use the CS's ripping fence on one of the planks if "dead straight" is a necessity.



I would not bother with a TS... it's easier & safer, IMHO, to guide a CS along a jig than to try and steer the pipe (and attendant support structure) over a TS.

Just sayin'

Lay it on a bit of board and capture it straight between either nails or narrow bits of off cuts. Then split it with a pull saw.

There should be a prize for the best suggestion. Something small. A new Powermatic lathe for example.