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Old 09-02-2009, 06:43 PM
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Question How do I Maintain a Straight Cut on a Very Large Tube?

Well?


Okay, so maybe some detail would help. I need to cut up a concrete form tube to make a bunch of small concrete form tubes which are to become important parts of a big cat tree. What I can't figure out is how to mark the tube so I can keep the cut straight.

Help, please?













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Old 09-02-2009, 06:49 PM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

I would get a cheap wooden yard stick and put a nail though the end. Drill a hole at the size you want and put a sharpie in the hole and rotate the tube. The hard part is following the line

Les...
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Old 09-02-2009, 06:53 PM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

Okay, that sounds like a good plan - thanks!

Actually, I'm very good at following lines... It's figuring out which line to follow that usually gets me in trouble.
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Old 09-03-2009, 12:27 AM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

Another method I use to mark a cylinder so that it can be cut a true 90 degrees to the axis of the tube is to wrap the tube with a piece of paper. I use something like brown wrapping paper for big tubes. Simply tape one end of the wrapping paper near the middle of the end of the sheet with a small piece of tape to the large tube. Then wrap the tube with the paper and adjust so that the paper wraps evenly on itself, so its edges align. That edge is part of a plane thru the cylinder at 90 degrees to the tubes axis.

Now tape the trailing edge upon the rolled up paper (you have basically created a cylinder over another). Tape it well and carefully rotate the outer cylinder over the inner so that the small piece of tape you used to hold the paper initially to the tube is broken or losses it attachment. You can now slide the outer cylinder up and down the cylinder and mark the cylinder anywhere along it's length knowing that each line will be parallel to the others.

Not that the other method doesn't work, just that you are working on the assumption that the end of the tube is originally cut at a true 90 degrees to the axis. And if you are cutting one then marking and cutting another any variance in each cut will compound and soon you will be way off 90 degrees to the axis. That may or may not be a problem, perhaps just having each ring with parallel ends is close enough.

Hope this helps,
Wiley
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Old 09-03-2009, 05:08 AM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

Thanks!

I want to keep the cuts as true as possible since I expect at least 6 per tube (our Lowes only carries the six foot tubes). After covering them in carpet I'm going to bolt them together into a big triangle. Any really bad cuts will cause major headaches then.
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Old 09-03-2009, 05:33 AM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

I usually mark the tube in three or four places, and wrap with electric tape.. I also use my bandsaw which has a 12 inch cut which also makes it easier...
Mark
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Old 12-04-2009, 02:37 PM
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Default Re: How do I Maintain a Straight Cut on a Very Large Tube?

If you have access to a laser level, it would allow you mark a few spots on one side and then turn and mark the other side.

Just make sure that the tube is level or plumb.

Chris
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