Cutting a Slot in Plastic Tube

PeteCooper

PeteCooper

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I need to cut a slot along the length of a piece of plastic tube - probably about 4" long. The tube diameter is about 1/2" and the slot width will be about 1/4".
Please can you advise the best way to do this? The slot must be straight and the sides must be parallel - it is to serve as a mast gate. It needs no real strength but must be able to guide the sail slugs pat the opening in the mast track where they normally go in and out.
Thanks.
 
sailorman said:
Router ????
material held in a workmate or chippys vice
Click to expand...

As sailorman says, but use a longer length say about 8 inches and start the cut a few inches in from one end and stop short of the other end. If not, the tube will collapse before you get to the ends. better to cut it to the it to the actual length you require afterwards.
 
Dremal territory. Mark off the outside of the area to be cut with plastic tape. I would also score the lines using a steel rule and a scribe before carefully cutting with the Dremel.
 
A few weeks ago I used standard 40mm plastic waste water pipe to make covers for turnbuckles, about 30cm in length. As I did not want to remove the rigging to insert through the pipe I cut a slot in the pipe so it could be slipped over the rigging wire.

The problem I found is that the pipe wanted to be smaller than 40mm so the slot starts to close up and pinch the cutting blade. I used a table saw to cut the slot, with the blade just higher than the wall thickness. I found the pipe was closing against the back (non-cutting) part of the blade. The cut was not clean although for my purposes this did not matter. I would not recommend using a table saw. I suspect a router would be better and better still a router mounted in a router-table.

If your slot only needs to 4" long then make the cut in the middle of a longer piece. The two non-cut ends of the pipe should prevent it closing up.
 
Think about this! You are going to use a Workmate, then you will need to raise up a platform on each side to use the router, a speed cutter and plunge action. With no dowel lightly grip the tube, then Dremel along it. No heavy tools, no faffing about, its a piece of plastic pipe, the Dremel will be like a cheese wire. Use a cutting disc for the long cuts.
 
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If the slot extends to the ends of the tube the easiest and simplest is to fit a dowel snugly into the bore and clamp the tube in a vise. Five minute job with a hacksaw will give you the slot without any aggro of plastic melting when being cut by a rapidly rotating blade.
 
Draw slot with marker pen.
Cut through the middle with a tenon saw or whatever comes to hand.
Trim with stanley knife. Or file, sandpaper......
 
Open the jaws of workmate or a vice so that the pipe just lays in it. Cut the slot with a fine toothed tenon saw. Once past 3-4 inches one can hold the slot in plastic apart with ones fingers or open it up with a small screw set in the slot. As suggested earlier make it a bit longer & trim to length after.
A tenon saw is better than a hacksaw but the dowel inside method is better if you can find the right size dowel
 
How about forming the slot by drilling a series of holes of the correct diameter along the length and then joining them with a fine toothed saw - probably easier to ensure that the holes are precisely in line and therefore that the slot is straight
 
PuffTheMagicDragon said:
For cutting wood, certainly, but I would suggest that the tooth geometry of an HSS metal-cutting blade - properly tensioned in a hacksaw frame that is used correctly - is better suited for the accurate removal of plastic shavings.
Click to expand...

A tenon saw will give better control over the direction of the blade.
I did have to cut 22 No 450 mm long 40mm diam waste pipe earlier in the year so i know it works
 
Daydream believer said:
A tenon saw will give better control over the direction of the blade.
I did have to cut 22 No 450 mm long 40mm diam waste pipe earlier in the year so i know it works
Click to expand...

I agree this is what I do but a rip saw teeth gives a better finish than a cross cut saw teeth.

There is a fitting for a dremel that allows it to be used in the same way as a router so the PVC tube could be clamped in a workmate vice and the guides clamped to the workmate top to run the dremel along the tube at the required distance from each side

This
http://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=565#.Ve8hYNKeDGc

Or this
http://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=335-01#.Ve8hitKeDGd
 
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Rogershaw said:
I agree this is what I do but a rip saw teeth gives a better finish than a cross cut saw teeth.

There is a fitting for a dremel that allows it to be used in the same way as a router so the PVC tube could be clamped in a workmate vice and the guides clamped to the workmate top to run the dremel along the tube at the required distance from each side

This
http://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=565#.Ve8hYNKeDGc

Or this
http://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=335-01#.Ve8hitKeDGd
Click to expand...

Will turn an easy 3 minute job into one taking ages

If using a powered saw then the finer tooth of a cross cut saw with a squarer tooth angle will be better than the coarse tooth of a rip saw with bigger teeth with tips with a sharper angle
Having cut a few thousand metres of plastic ( ranging from formica, to polycarbonate to perspex to Trespa etc etc) in my joiners shop over 25 years I feel fairly confident of that
 
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Whichever way you choose, do a trial run first with a bit of spare pipe.

(And, if using a Dremel type tool with cutting disc, keep your fingers out of the way in case the disc catches and jumps. I speak from recent, painful experience :( )
 
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