Making a straight line

[lotechman]

Often I am involved in making long straight lines. Chalk line is one way to go but the string supplied in construction chalk lines is much too wide. I have a spouse who crotchets and some of the threads are very strong as well as thin. I changed over and now my chalk line is the thinnest in the shop. People borrow it on a regular basis.... along with my salvaged speaker magnets to hold the other end of the string. Never throw away blown speakers. Tear them apart first.
Another way to go is welding wire. The best is fine stainless (.035) wound onto a boat trailer winch. One end is secured on the frame or beam then the winch is clamped or tack welded at the other end. When drawn tight the wire makes for a perfectly straight line. I have used this tactic when I am having to mount or locate multiple pieces all in line over a sixty foot distance.

[TEK]

It must work or you wouldn't be doing it but I sure would have thought that the wire would take a set from being wound up and wouldn't pull straight. Interesting.

[stick]

sure it would pull straight. ever watch pipefitters run copper tubing? They don't play around with sections like homeowners do, they get it in coilos, unroll it and pull it tight with a comealong. it winds up dead straight.

[lotechman]

I guess I should have added that a boat winch has enough pull that you can break the wire if you really try. You wind up to that sweet spot in tension where things straighten out but the wire doesn't break. :'))

[DDA52]

We used to use wire to set building fronts all the time. Slag will burn a string, but not a wire. Piano wire, stainless wire all work well. They stretch tight and straight.:cool:


For chalklines, the best I have found for thin lines is braided nylon fishing line. I used to be a layout mechanic for an interior finishout company. That was the best we found. I used 5# of chalk or more per week doing that. The chalk will eventually eat the nylon for some reason, but it would last several months. It won't hold as much chalk either, so double snaps don't work. I was using this on a huge job with zero tolerance. The thin line helped quite a bit. After nearly three million square feet of layout, I had changed lines maybe three times, and used up 60# of chalk!

[Ries]

I have a japanese "chalk" line- its actually an ink line, and it is finer than a US style chalk line- so for times when I need a line, I use it instead. Works better, nicer made, and the line is finer and easier to see, and doesnt wipe off as easily.
http://www.tajimatool.com/shopping/1inkchalksnap-lines.htm
Lasers work pretty well too- and you dont have to roll em up again when you are done.

[ZTFab]

I was using this on a huge job with zero tolerance.


Sweet...

[DDA52]

Sweet...

I didn't think so at the time. It was a huge pain in the butt.:realmad: All walls had to be perfect since all the marble was being cut and shipped from Greece. No field cuts were permitted. The place is in Centerville, Va. ...Used to be called Westfields Conference Center. May still be...just been a long time. 5 star hotel and the works.

[lotechman]

That ink line sounds interesting. Nothing like that above the 49th. Bellingham is the closest but it might as well be on the other side of the world since 911.
I have used laser but have not been happy with the size of the red dot once you get forty or fifty feet away. Is it because I am using cheap lasers???

[corvidcreations]

OK, a twist on this topic:

How do you draw a straight line down the length of a tube? I can get an approximate one by a number of methods, but I'm trying to get one within a degree. I'm going to be notching/fishmouthing both ends of the tube, and I need to be able to align the tube properly in the jig so that the notches are parallel when it's all done. I don't want to approximate. Anyone have any good methods?

I have been made aware of a good method for a short length of tube. Take a piece of paper, wrap it around the tube, making sure that the edges of the paper are all aligned. The lengthwise seam of the paper is then parallel with the edges of the tube, and you can mark the line at either end of the lengthwise seam. This is, of course, assuming that the paper is cut at right angles. But this doesn't work well for longer lengths because 1) I don't have a piece of paper 8' long, and 2) if you do this multiple times down the length of the tube, each time aligning the bottom of the paper with the previous mark, small errors each time will add up to a bigger error at the end of the tube.

Any thoughts?

P.S. my tube is 8' long, and I have four of them I need to notch.

[bruceb]

Lay of piece of angle iron on the tube and draw your line along the edge of the anle iron.

[mla2ofus]

I don't know what it's called. I'm sure at least one pipefitter or pipeliner on here knows what i'm trying to say. It fits on the blade of a tri square and has a center punch w/ it so you can center punch a mark one end of a pipe that is clamped/tacked so it can't roll w/ the bubble leveled on the square. Then move to other end or where ever you want a mark at the same point on the circumference of pipe by again leveling the bubble.
Mike

[corvidcreations]

You mean take one of these 20 pieces of angle I have stacked right in front of me? :sleeping:

Duh.

Thanks. That seems so obvious. I must be working too late. Or I'm not as clever as I'd like to believe.

I'll try to come up with a tougher question next time.

[lotechman]

"Dividing Head" is the Vee shaped piece in a machinist square set that can be used with the square head and bubble level to find the top dead center at both ends. Curvo-mark makes a unit with a center punch... All in one.
The angle iron trick is so much better!
For pipe around four to fifteen inches a square and bubble level works well. If your pipe was say 6.5 inches OD You would set your framing square on top and down one side then set your level on top. You level the square on the pipe and mark in at 3.25 inches. Without moving the pipe you go to the other end and repeat.
Snap a chalk line or use a long straight edge to join the marks. I use small diameter/strong crotchet thread.
Another good reason to be married :'))

[mla2ofus]

Thanks,Lotechman. I couldn't remember the name of it.
Mike

[TooManyProjects]

lotechman,

Take a look at this one

http://www.leevalley.com/wood/page.aspx?c=2&p=49715&cat=1,42936,50298&ap=1

I think that is pretty close to the ink line mentioned earlier. Canadian company, so you shouldn't have any hassles. It sounds like you must be near Vancouver and they have a store there.

I'm in Seattle, but I know Lee Valley for their woodworking tools. They make some pretty nice ones.