# Using the PLS5 to find square off of an existing wall.



## chrstphrab1 (Nov 9, 2006)

Does anyone have any good tricks using the PLS5? Specifically, I was looking for an easy way to use the PLS5 to layout a perpendicular line off of an existing wall.


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## Bone Saw (Feb 13, 2006)

a squared+b squared=c squared is the only method I'll use, construction master calculator makes it quicker:thumbsup:


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## Teetorbilt (Feb 12, 2004)

In most situations the perpendicular wall is relevant to the adjoining wall assuming that the original wall is flat. If you really need to be particular, pull a very tight stringline about 1/2" off of the wall and work from that. I triangulate with string often, use 130# Spiderwire, very little stretch over home sized distances and, as long as the same guy is setting the tension, it's pretty accurate.


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## K2 (Jul 8, 2005)

2 random points, 4 arcs= 2 intersecting points = line perpendicular to the first line. No math required.


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## Teetorbilt (Feb 12, 2004)

2 set and equal points from center = 2 arcs = perpendicular. The closer to 45*, the more accurate.


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## K2 (Jul 8, 2005)

Teetorbilt said:


> 2 set and equal points from center = 2 arcs = perpendicular. The closer to 45*, the more accurate.


That's good too but 4 arcs will find your center.

I always draw arcs with a wind up steel tape. Set a nail through the hole on the hook. No reason to be set at zero when drawing arcs.


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## Teetorbilt (Feb 12, 2004)

I'm somehow losing you and I'm pretty good at math.

Say I'm going for an 8ft. wall. I run my string to establish a flat surface, pick my center for the new wall, measure 8 ft to either side and pull my arcs from there. That should be the center of the wall at the far end. Another arced measure would only confuse the issue for me.

Relative measures to other walls would also be taken which, generally, leaves you with a 1/2 -3/4" bullseye to work from. Way too much for my business.


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## K2 (Jul 8, 2005)

Take a straight line. Pick any two points on that line. Say you picked two points that were about 15 or 16 ft. apart. Pick a number on your tape about more than half the distance. So say pick 10. Draw a 10 ' arc and then say an 18' arc from one point. Go to the other point and draw another 10' arc and another 18' arc. The line determined by the intersection point of the 10 ' arcs and the intersecting point of the 18' arc is perpendicular to the original line and is also the midpoint between the original points.

This only gives you a perpendicular reference line and does not position a wall. I've always worked off of bench marks and reference line so this seems natural to me. Your way might be better but I'm to old to change.

I tried doing it on sketchup but I need more practice. 

If the original line is an existing wall you would have to bring your points out equally an inch or so to draw the arcs.


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## Teetorbilt (Feb 12, 2004)

Gotcha now! You didn't explain it too well in the original version, the keyword was 'random'. The random point will work as long as it is constant.


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## chrstphrab1 (Nov 9, 2006)

Bone Saw said:


> a squared+b squared=c squared is the only method I'll use, construction master calculator makes it quicker:thumbsup:


Bone Saw,

Thanks for the tip, but any multiple of a 3-4-5 triangle will eliminate the need for a calculator. For example:

3^2 + 4^2 = 5^2
6^2 + 8^2 = 10^2
9^2 + 12^2 = 15^2
12^2 + 16^2 = 20^2
etc.

Chris


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## chrstphrab1 (Nov 9, 2006)

Teetorbilt said:


> In most situations the perpendicular wall is relevant to the adjoining wall assuming that the original wall is flat. If you really need to be particular, pull a very tight stringline about 1/2" off of the wall and work from that. I triangulate with string often, use 130# Spiderwire, very little stretch over home sized distances and, as long as the same guy is setting the tension, it's pretty accurate.


Teetorbilt,

Thank you for the information about the string. I'll have to get some Spiderwire.

Chris


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## chrstphrab1 (Nov 9, 2006)

K2eoj said:


> Take a straight line. Pick any two points on that line. Say you picked two points that were about 15 or 16 ft. apart. Pick a number on your tape about more than half the distance. So say pick 10. Draw a 10 ' arc and then say an 18' arc from one point. Go to the other point and draw another 10' arc and another 18' arc. The line determined by the intersection point of the 10 ' arcs and the intersecting point of the 18' arc is perpendicular to the original line and is also the midpoint between the original points.
> 
> This only gives you a perpendicular reference line and does not position a wall. I've always worked off of bench marks and reference line so this seems natural to me. Your way might be better but I'm to old to change.
> 
> ...



K2eoj,

That's an awesome technique! I never thought of that! You also gave me an idea of how I can use my Hilti PD28 laser distance finder to find perpendicular off of an existing wall. Thank you very much.

Chris


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## Joe Carola (Jun 15, 2004)

chrstphrab1 said:


> Does anyone have any good tricks using the PLS5? Specifically, I was looking for an easy way to use the PLS5 to layout a perpendicular line off of an existing wall.


I have a 5 point Robo laser and I place it in the center of the room off the wall about 6" and turn it on and then measure on each end from the wall to the line until it reads 6" on both ends. Where the center laser hits on the opposite wall is where I mark that center. Then you can square up from there.


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## chrstphrab1 (Nov 9, 2006)

Joe Carola said:


> I have a 5 point Robo laser and I place it in the center of the room off the wall about 6" and turn it on and then measure on each end from the wall to the line until it reads 6" on both ends. Where the center laser hits on the opposite wall is where I mark that center. Then you can square up from there.


Ok, thank you everyone. You helped me come up with a fast way to find 90 with my laser. This should work with the Robo laser, too. Here's what I came up with. Thanks again.


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## Teetorbilt (Feb 12, 2004)

I'm still really not big on lasers even though I own a few. Not accurate enough for me. Sometimes older is better, being off 1/4" can really suck.


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## chrstphrab1 (Nov 9, 2006)

Teetorbilt said:


> I'm still really not big on lasers even though I own a few. Not accurate enough for me. Sometimes older is better, being off 1/4" can really suck.


There are some pretty accurate lasers out there, but they are pricey. The PLS5 is only off by 1/8" at 100ft, but costs about $400.

Chris


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## K2 (Jul 8, 2005)

Probably best to know 5 or 6 ways to do the same thing. A wild beam on a military base could get you a couple of m-16's in your face with a couple of 18 year olds behind them.


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## theworx (Dec 20, 2005)

We have three different laser systems but still find the fastest is masking tape, tape measure and use 3-4-5. Have found that by the time you get the laser out of the case, set it up, and do your measuring and adjusting I already would have my bottom track shot down. For a long wall coming off perpindicular a string line (snap a chalk line) works best to give you a nice straight wall.

K2 that's funny (a stray beam):laughing: !!! Ever used a Hilti powder actuated gun on a Military base (when they weren't expecting it)??? I did and was met with some MP's pointing rifles at me and got in big crap because I didn't register the fact I had and was going to use such a tool  !! I guess the Mp's got reports of gun shots and rushed down to check it out!!!


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## Teetorbilt (Feb 12, 2004)

We always call out "Shot!" prior to firing a Hilti fastener. It's best if everybody knows what is going on. We started doing it after nearly scaring a HO to death. It helps some sensitive workers too.


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## snapper21 (Mar 13, 2006)

6 8 10 triangle? I know alot like to say 3 4 5, but a 6 8 10 should get you on it, if you have room. Like Teetor mentioned, you may want to chalk a straight line to pull from, rather than the wall.


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