Laser Levels

[Bob Perkins]

Hi All,

I'm most likely going to pick up a laser level.

I'm looking at low cost (like everyone else..) $200-300.

Self leveling type:

-I've used an electronic self leveler - very nice! Very expensive :(
-Have seen the bubble type (I don't really like that style)
-Gravity/magnetic type (don't know how it works?)

Plus horizontal and vertical variations, etc. It will be used for boat setup, and other construction projects too..

Anyone have a favorite they have used?

Thanks

[Paul Denison]

There are a couple of good threads on the Fine Homebuilding web site. I purchased a 5 beam, self leveling, RoboTools laser level. I have been using it with much success on my back porch project. Self leveling is the way to go. It seems to be more accurate than the bubbles.

[Bob Cleek]

I, too, have been interested in the use of laser levels for set ups, etc., in boatbuilding. I haven't been able to get past the affordability issue. It seems to me the lower cost units aren't sufficiently accurate. They may be fine for house construction, and that sort of thing, but I'm reading specs that say the accuracy is +/- a quarter inch at 25 or 50 feet, which doesn't do it for me. What say you all?

[WFK]

Maybe the tolerances are a little different where you are, but Bob I'd say that if you think that + or - 1/4" in 25 to 50' is ok for house construction I'd never let you set foot on my property. ;)

[Bill Perkins]

1/4 in. in 50 feet would be excellent accuracy . That's .02 in. over 4 feet . How else would you you detect that ? Is your 4 foot level that accurate ? A long piece of clear plastic tubing used as a water level is remarkably accurate , and it sees around corners . You can't beat it for the price. I've sometimes suped mine up with a dash of dish washing liquid detergent which reduces the surface tension of the water so it levels more quickly and has a flatter surface where you read , or so I think .

I own what I think is the simplest TopCon sight level.The accuracy of it's circular leveling devise is listed as 2mm over 10 feet which works out to about 3/8ths in. over 50 feet . That's about .03 in. over 4 feet . Again , think your 4 foot level can pick that up ? Levels of up to 8 foot length placed on the work show the bubble between the lines . In the real world this is considered Level .

[Art Read]

What are you going to do with it? For a one-off boat project's waterline, it's hard to argue with a $.49 piece of clear plastic tubing, a helper and a cupfull of water...

[GROOVY]

What a good tip Bill ! Soap in the water !
I will try that next time, food coloring helps too

[Art Read]

Hmmmmm... Looks like we crossed posts there, Bill. Wish I'd thought about that dish soap idea when I was cutting my waterline. I did add a little food coloring to make the water level easier to see, but the "sticky" surface tension in the tube did make things a little "iffy". Ah, well... I probably didn't scribe an accurate/fair enough line between my marks to make a significant difference anyway. ;)

http://www.imagestation.com/picture/sraid19/pa00f4e0f1b89303f87730d9a0c1db4c6/fdc1e078.jpg

[Tom Lathrop]

I don't have either the cash or need for the latest high-tech leveling instrumentation and have a question for those who think that 1/4" accuracy in 50 feet is way too sloppy for them.

How would you know that something was out of level that much? Just how would you propose to check such tolerances and what tolerance would you think is acceptable.

Water in a clear plastic tube is pretty good but drag and inertia can have serious effects on the repeatability of these too. Soap or other wetting agents can help but they are still not perfect. Small diameter tubing is not very accurate for measuring in a reasonable time frame.

[ 03-05-2003, 10:01 AM: Message edited by: Tom Lathrop ]

[Bob Perkins]

I love the conversations on this group - Everyone has great ideas smile.gif

Last year I had to reposition the waterline on my 23' sailboat because the previous owner made it banana shaped and I got growth around the edge.

I rented a pro-quality laser level and put the new line on exactly where I wanted it. It was a lot of fun to do..

Now - I'm setting up my frames on my current project - there will be lot's of positioning, checking and fiddling. My hope is the better I get the parts in place, the less material removal in the fairing process. Moving the laser point around and rechecking my work will be very quick with this tool, especially when I bump into it and mess things up smile.gif

Plus - I'm a tool junkie. It will get used again for the water line - around the house and on my future boats.

[as Margo would say]
"Hi, my name is Bob and I am a tool-aholic"

ps. I considerd the water level, but didn't like the surface tension issue. But - I may revisit it with the soap. Good tip!

Bob

[ 03-05-2003, 10:05 AM: Message edited by: Bob Perkins ]

[John Teetsel]

I recieved a RoboToolz three beam level for Christmas and I still haven't figured out an application in boatbuilding. Striking a waterline is the first thing that makes sense, but $200 for a single task? Anything else?

[whb]

John,

I would think it would be great for setting up stations as well. Not just as a level but as a straight line beamed through a small hole in each for side to side positioning.

Howard

[NormMessinger]

Twenty dollars at Harbor Freight! It sure aint gonna be the tool mentioned above but it might be good enough.

[pjwalsh]

I am a fan of the nylon tube water level. Have always found it quite accurate enough for any boat and housebuilding projects - I use 1/2" diameter nylon tubing for a 60' length and 3/8" for a 25' length. I fill them with that nontoxic antifreeze cause it gets chilly around here.

If you set up a resovoir with the surface at the desired height it can be a one man operation (though I do find myself running back to the resovoir to check all the time - paranoia i guess)

Have used the various beeping laser and water level variations too but I like the simplicity of the tubing.

On the desire for incredible accuracy I think the best solution is a transit - easily 1/16" to 1/8" over 50 feet or more. Of course getting two widely separated ends at the same elevation is not the same as getting every point in between there too.

[Bob Cleek]

Illuminating discussion, indeed. I tend to remain unconvinced that the cost of a decent laser level is justified for occasional use. I have found those cheapo lasers built into the end of a 2ft. level handy, though not for real critical stuff. Surely a quarter inch isn't a big deal if you are striking a waterline, but what if you are running a center line down the keel setup on a forty footer? You could be out 3/8" from side to side on your frames from one end to the other. That sure wouldn't happen with a wire run between the perpendiculars and the wire would cost you zip.

[Paul Denison]

Bob, if I understand you correctly about the keel, the laser is perfectly straight, you would center the dots or the line just like the wire. Level is the only issue here, and I believe mine is 1/8" in 100 feet.

I'm reading diferences in level between the inside flooring and the existing exterior porch at 32 stations. These stations are for the joists (sleepers) on the sloped concrete porch. I substract the height of the laser and the build up for the floor to know where to start scribing the joists.

All this so I can run porcelain (sp?)tile from the porch into the family room and have it look level. I think that my scribing the irregular slope of the concrete will produce more error than the laser level will.

[Bob Cleek]

Well, I gotta admit I'm not completely confident that I know what I am talking about when it comes to laser levels. I understood that the laser beam is perfectly straight. I also understand that the level part of the equation is a function of how accurate the level that the laser sits on can be. Maybe I misunderstood the little literature I've seen on them, but I thought that the "accuracy" part of it referred to the size of the "dot" at a given distance, or the spread of the beam. Lasers focus light waves, but the less the spread, the more expensive the laser. As I heard, these little "toy" lasers you see in the cheapo keychains and pointers and in the less expensive laser levels, originally (and maybe still for all I know) were actually REJECTS from CD laser reader production runs. They found themselves with a ton of CD lasers that didn't make the quality control cut (something about the production that is chancey) and some enterprising fellow found a use for them. Since the CD laser doesn't have to go very far at all, they aren't designed for a really tight spread (that takes a lot more power as I hear, too). So... I understood that a quarter inch at 50 feet meant the dot would be a quarter inch around at 50 feet, leaving you at best to shoot for the center of the dot... but whadda I know. I'll take my reply off the air. LOL

[Tom Lathrop]

Bob,

I am also working from limited knowlege of these automatic laser levels. You hit on the point that I questioned about their accuracy. The beam can be perfecly straight and colimated to a perfect point as small as you like and the accuracy would still be dependent on getting the thing level in the first place. How do they do that? Anything other than gravity and a sight bubble?

Getting an accuracy of 1/8" in 100 feet requires a method of setting up the instrument that I have no experience with. Are there sight bubbles in common use that are this good? I don't know but would like to hear from anyone who knows about this.

[ 03-06-2003, 12:06 PM: Message edited by: Tom Lathrop ]

[John M]

Couldn't resist.

The beam can be perfecly straight and colimated to a perfect point as small as you like and the accuracy would still be dependent on getting the thing level in the first place. How do they do that? They use the hose. ;)

John M

[Dave Fleming]

OK, up front this is before the Laser Level became so well known as it is today.

I was working at Campbell Shipyard here in San Diego and we were setting up to build 7, approx. 250' long Tuna Seiners.
New yard supervisor was a fanatic on modulars and jig setup. Had an engineering contractor come in and set steel plates at precise level uniformly throughout the yard. We, Layout and Lofting, were to use these as bases for setting up a transit and aligning the jigs and then the modules built upon them. It was an absolute disaster. Imagine trying to maintain a line of sight in a working yard with mobile cranes, people going to and fro about the place,t'was a mess.
A meeting was called and the air became blue with invectives and blame callings. In walked the owner and in a quiet voice asked if anybody had a solution to the problem. A voice was raised with the reply....Water Levels.
Ayup the age old water in the hose thingy.
Clear industrial grade thick walled ( so cranes could run over it) tubing. Petcocks on either end, blue food colouring and a dash of glycerine to cut surface tension. We did some marks and on a overtime Saturday broke out the transit to 'check' the marks. Within an 1/8 of an inch in 60 feet was the result. Not too shabby, or so says I.

[Matt J.]

Never used a laser level for boat building. Indeed, I've never used on for anything, though I've witnessed people using them for construction of storm drain, stormwater, and sewer pipes. They're OK, but not my choice.

Contractors tend to use them regularly, and they use the high dollar ones. The damn things are nuisances as far as I'm concerned, becuase they are not guaranteed to hold level or to stay accurate. We've had contractors build pipes with the wrong slopes, with in-line dips, valleys, and high points; all because they assumed the damn laser was accurate and precise.

It's a waste of time and money, if you really want to be accurate. For boatwork, I don't think there's anything wrong with using one for striking a waterline.

Being a surveyor, I'd prefer to set up an automatic level on a tripod and get my wife or friend to help me by sighting or marking. It's more accurate and not actually more expensive than a "good" laser level (about $735 for a good autolevel + $150 for a decent set of legs versus about $1100 for a construction grade laser level).

On top of the cost of a good auto level and tripod versus a "more" reliable laser level. The auto level can be sold, or used for home construction projects with far greater adaptability and range.

Again, for just marking a line +/- such as a waterline, yeah, the laser's easier and probably faster, but for longer lines, greater accuracy, and more adaptability, I'd use an auto level without hesitation.

But I'm biased. Our auto level proves laser levels to be inaccurate on different jobs every few months.

-Matt

[whb]

The guys who set up our pool table had a bubble level that was supposedly good to 1/10,000 of an inch over the length of the level. About 18"

He said it cost 4 figures and he treated it like a baby. Foam case, the whole nine yards.

Howard

[Dave Fleming]

Probably a Starrett, Precision Machinists Level.

Similar to one of these. http://www.starrett.com/catalog/images/objects/2100/2022.jpg

[Tom Lathrop]

Dave,

The water tube is probably at least as accurate (and maybe more so) as the transit. How did you set the transit level to begin with, a sight bubble? No possibility of human error there?

[Dave Fleming]

Tom, it was not so much an accuracy issue as a congestion issue.
We used the transit on those steel platforms or I heard them called "monuments" early in the morning before the shift started to set marks on vertical steel posts just out of the way beside each jig and from that mark, punched into the steel post and bullseyed with flourescent paint, to start with the water level. I guess we could call those marks our reference points?
1800 workers, mobile cranes, trucks,yech! That was the biggest yard I ever worked at and it was some experience. But, me I like a 10 to 20 man crew or me up in a shop or loft out of the way of the thundering herd, so to speak.

[Matt J.]

Bullseye bubble are as accurate as a tube bubble. It depends on the accuracy and precision of the bubble arc. Cheaper instruments have higher arcs in the glass, whereas better ones have small angles... we've got a Leica handheld rod bubble for holding the rod plumb cut to 8' and it's a real b***h to hold plumb.

Level is check against known benchmarks, and the ability to accurately reach out at great distances makes, IMOO, transists more reliably used and checked. It's nothing to move 100's of feet and check to less than 1/8" or 0.01'.

Besides, our old level / transit equipment would look more appropriate next to old wooden boats smile.gif .

-Matt

[whb]

Dave,

That Starrett looks an awful lot like the one the pool guy had.

Howard

[Cedarhill Boatworks]

You can buy lots of laser levels. Cheap ones have a large dot that gets larger as the distances get longer. A good one, a really good one will run more than a thousand dollars. They a re self levelling and are extremely accurate over long distances. Most of them can be set up to scribe compound slopes in two planes as well. Great for road building, great for pipiline installations and train tracks. But for a grand? Not a small investment unless you are using it every day.
A good transit is even more accurate and even more expensive. Aggod transit in the three thousand dollar range is self levelling and will have an optical plumb feature for setting up over a monument as Dave Fleming described. In the old days we used a plumb bob over the monumetns and it always worked fine for me. The difference between a good transit and a really good transit is the machining of the levelling posts and the quality of the vials that house the bubbles. Like a really good machinists level the stadia in the vials is what you are paying for. A perfectly good transit can be had for less than a grand and will be more accurate than anyone needs to lay a keel and station molds on any boat less than a super tanker.
The simple water level available at any decent lumber yard is as good a level as anyone needs to build a house or a boat. Fabric softener does a better job of reducing the height of the miniscus and will keep it from freezing as well. Glycol is toxic, fabric softener is not.

[Dave Fleming]

Glycol is toxic, fabric softener is not.Fabric Softener is interesting. As I said we, at that time, used food coloring and a bit of Glycerine drug store variety in the water.

[capt jake]

OK, FWIW, I have used many of the high end construction laser levels in the past. The ones I am familiar with are set up just like a transit. Tripod and a level to set it all up. You must be just as carefull with the set-up as with a transit.

The 'diameter' of the 'dot' is adjustable on some models as well as the rotation speed (we are talking quality).

These ones were very acurate! The building we built was probably 400' x 300' and I remember the laser to be acurate within about a 1/4" plus at roughly 1/2 those spans.

Nice thing about a rotating laser is it gives a nice line to follow. For instance, setting a suspended ceiling grid; work from the outside inward, and the ceiling is perfectly level! smile.gif

We set all of the windows, walls, grid, and more this way. Of course this was a large commercial job, but what a difference from the previous job which was done with 'regular' levels, etc.

Knowing how to use one of these, and the proper set-up is crucial to success.
I am always keeping my eyes open when I am at the rental place. Looking for a quality used unit to purchase. Not much to go wrong with them.

To each their own. smile.gif

[Dave Fleming]

Oh Capt.

Nice thing about a rotating laser is it gives a nice line to follow. For instance, setting a suspended ceiling grid; work from the outside inward, and the ceiling is perfectly level I quickly learned to hate doing soft or dropped overheads in vessels! With stanchions and other obstructions in the way you were lucky to be able to string a line from point to point to begin with.

[capt jake]

Dave, this was just an example. I would think that careful placement of the laser would clear 'most' of the obstructions. smile.gif

To each their own. smile.gif

[Dave Fleming]

Capt, no argument but, in the early 1970's we didn't have such space age tools, sigh.

[Tom Lathrop]

I think some of this may be getting through my rather thick skull. Not much good to me though since the expense is way beyond my needs. I did buy a cheap laser level which has the limitations already mentioned but will work fine for boot top and other reference lines. Otherwise I will stick with the water tube with the suggested fabric softener and a borrowed transit when available.

[Bob Perkins]

Hi All,

Figured I would post my conclusion:

I actually went to HD and picked up 20' of tubing to go the water level route, but I still wasn't crazy about the idea since I had such good luck in the past with a rented laser.

I finally found a place nearby that had a selection and people who knew something (go figure...)

After messing with a few different ones, I ended up with:

http://www.plslaser.com/level/laser/prodspecfs.htm

The PLS2 (if the link doesn't work right).

It does exactly what I needed it to do.

I got my motor stringers on the same plane and all of the frames are exactly on the setup level. A water level would have worked to, but the laser allowed lots of double checking that would have been a hassle with a tube that I would have dropped a lot.

Also, I can shoot a straight line down the center for alignment purposes instead of rigging up a string.

I (of course) recommend this method with the laser. Admittedly it is overkill smile.gif

Cost justification: The money I spend is a rounding error compared to what the finished cost is going to be.. This tool will get future use.

Thanks for all the feedback. I'll be posting pics of the setup soon.

Bob