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laser sight for square

Started by spencerhenry, October 02, 2006, 09:57:07 PM

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spencerhenry

i do alot of resawing, both new material, and reclaimed. almost all of it is used in beam form for decorative accents such as trusses. the people i mill for have EXTREMELY high expectations of quality, dimensional consistency, straight, and especially square. right now i use a "big foot" square to check the piece for square to the bed. has anyone ever put a laser sight on a mill that will show when the piece is square? not sure how to do it, but i need to find something faster than checking, and walking back the the controls, and then checking again.

DanG

Spencer, I guess I ain't understanding the question too well.  Not sure just what you're trying to square up. ???

I have played around with some mirrors and one of those laser levels that shoots a line, rather than a dot.  That worked pretty good for making a square corner, but somehow I don't think that's what you're looking for.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Tom

There is no replacing a square mill.  If your squaring dogs are square to the bed and your blade is square to the bed, and nothing gets under the cant, the beam has to be square.

Brucer

I'll second that, Tom. I've become the preferred supplier to the local timber frame business because my beams are so square. I rely entirely on the side stops -- but I make sure to treat them well:
- grease them every 50 hours so they don't wear and get sloppy.
- check them for square when I grease them.
- don't put too much pressure on with the clamp.

Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

DanG

I totally agree with Tom and Brucer, but I still think there's more to the question than that.  Spencer is an experienced sawyer with a good mill, so I figger he's up against something a little different, like resawing old beams that aren't square to start with, while trying to save as much of it as possible. ???  I get the idea that he's trying to square the top of the beam to the bed while the bottom side is irregular, or something like that.  Maybe you could just send the blade down there to check.  It may not be much faster, but would sure save a lot of steps.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Bibbyman

When Mary and I were touring the Wood-Mizer sawmill facility in Madisonville last month, I noted a vertical laser beam striking the face to the sawhead.   I asked the sawyer about it and he commented it was to check the cant for square. I think it was mounted in the ceiling. I don't know if I caught that in a picture or not.
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

spencerhenry

relying on the stops is not sufficient, for example say that i have one good face, and one bad face that is not flat which may or may not be parrallel to the good face. the bad face for whatever reason is against the stops. it requires a square to check the good face to the bed.
secondly, the stops are set for square when they are all the way up. when they are less than that, they can be slightly off of square, the height of the clamp also changes how much force is against the stops, and where in the piece the force is, both can change the amount of deflection of the stops. there is always deflection in the stops, unless there is no pressure from the clamp. the requirement for square dictated by the customer allows me virtually nothing out of square.
i have spent many hours periodically checking every adjustable thing on the mill. the blade is parrallel to the bed, the stops are square to the bed, the blades run true, and are sharp. this is not a question about mill alignment, but rather a way to CHECK if the beam will be perfectly square from face to edge.

Tom

I have sawed timbers in that condition and relied upon my eye.  Here is what I did to square it.

I put the twisted beam on the bed and, by sighting down the surface of the blade, got the top surface as level as I could.  I clamped it there and used scraps of wood under it if necessary to keep it steady.

I then Sawed a very thin piece off of the top to flatten it.

Now, having a flat surface, I turned it over, 180°, onto the bed and flattened the other side.

Once these two surfaces were flat, I turned it up,90°, agains the squaring dogs and flattened one edge. Sighting it, to level it longitudinally, made it square.

The last side was the easiest because I had two square surfaces against squared parts of the mill.

I know of no other way to square a bowed, crooked, twisted or cupped timber.  You have to get one side flat.

Now, I know that you know this, but that's all I can offer.  I use my eye because I'm not in possesion of a piece of technology that will do what I feel needs to be done.  Perhaps a laser will help.

For a customer to give a twisted 2x8 to a sawyer and expect two, square, 1x8's is pretty unreasonable to begin with.  To satisfy someone who is so meticulous that he wants perfection and doesn't understand the job, is a losing proposition. 

Even an edger or straight line saw will fail on occassion because the product moves.

An end-dogging scragg might be the fastest way if one had the money.

To do the job on a sawmill is still going to make you rely heavily on the squareness of the mill.  If your mill is square, then the rest is an art.  The more he complains, the more I would charge. :)

DanG

Quote from: Tom on October 03, 2006, 10:08:42 AM
The more he complains, the more I would charge. :)

That's sorta what I was thinkin', too. ;)
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

tcsmpsi

I've worked with a lot of lumber in a lot of building applications.  There ain't but just so much 'square' one should EVER expect in working with wood, most especially structural wood.   

Now, in a machine shop, working with metal, a little closer tolerance, even to an nth degree can be reasonably experienced. 

Wood moves under normal circumstances.  Even if one mills a precisely square board, the expectation of it remaining 'perfect' is not....reasonable.

In the building business, sure it would have made my life much 'easier' to get precise structural wood.   :D

If I paid $200 a bf for a 12"X24"X40' cedar beam, it would still be just a cedar beam.  ;)

I have found it more of a challenge to keep milling square, to keep up with log/cant movement than anything else.
\\\"In the end, it is a moral question as to whether man applies what he has learned or not.\\\" - C. Jung

Larry

I dunno...on my mill the blade is always perfectly parallel to the bunks and never varies.  My log stops are almost always out of square...guess from the beating and use they get.  Spencerhenry, I've thought about your question before, and never have come up with a good answer.  Laser would be to hard to see, most of the time outside.

I open one face, rotate 180 degrees, make my second cut, rotate 90 degrees to the log stops, and check for square.  At least this way I only have to check one time per beam.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

DanG

I can't think of any way to employ a laser for this, either.  But, the main goal was to save having to walk back and forth to make the adjustments, wasn't it?  Maybe a low-tech solution would be more practical.  I'm thinking that some sort of manual adjustment for the fine tuning, located at or near the point of checking might be more practical.  Maybe a manual hydraulic cylinder(bottle jack) or some sort of screw assembly clamped to the mill would allow you to cut down on the trips.  You'd still have to walk down there, but only once.

Spencer, I agree with the other guys that your customer's expectations seem unreasonable, but judging from your past posts, I'm not sure "reasonable" is a part of the language out there. ::) :D :D
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

tcsmpsi

If one, as you mention, has parallel blade to bunk, cuts two bunk sides...then what?

If one already knows the stops are out of square with the bunk/blade, does one shim the log/cant?  Or, would one compensate their stops to bring them into square (welding/adding material, adjustment, etc.)?

I understand that working with hydraulic stops is a bit different than manual, but if I couldn't depend on my stops being within tolerant square, that would be a required fix.


Even with some type of laser sighting device that would somehow give a consistently accurate 90 degree 'plane', how would one compensate the log/cant?  And would it stay and be accurate during the sawing process the full length of the cut?

Tilting bunks?  But then, the potential of misalignment would be the same as the log stops, wouldn't it? ???

\\\"In the end, it is a moral question as to whether man applies what he has learned or not.\\\" - C. Jung

beenthere

I'm wondering how a laser might me used to help keep the third cut square (Following Tom's procedure, after two cuts one should have two parallel sides, and getting the third cut 90° to those sides seems the trick, as the forth cut will be parallel to the third).

If there is slop in the back stops, and they are not square, then some physical form of measuring and truing up one of the parallel faces would be needed. Be it a square or a level, either should work. Re-clamping if the cant is out of square for the third cut.  I can't envision how a laser would help do this task.  ???
I'm with DanG, that something to contact the vertical side of the log, to view when clamping, might work (I am thinking of a short level on a spring-loaded arm that holds the level against the face). Or spring-loaded contact points that can provide a visual reference when clamping and sawing. (and like tcsmpsi says, fix the non-square stops  :) )

Now, running that two-sided cant off to a swing mill, with a vertical saw square to the bunk, it'd be a piece of cake.  :)

But, how can a laser help ???


south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Modat22

If you figure out how to use a laser to do what you want. I would recommend looking at Ebay for a 500mw green laser diode. They are bright enough to see in daylight and will melt holes in black plastic bags (thats about it though)
remember man that thy are dust.

Tom

The "stops", "log-dogs", are actually by use "Squaring Dogs".  They need to be square with the bed to cut any type of lumber relatively accurately.  If they aren't square, they need to be fixed.  

They should be stout enough to stand a cant being turned against them, but care should be used, for the sake of the dogs as well as the clamp, to keep pressure only as a tight as necessary to keep from pushing the mill out of square.


The short-cut way of getting by out-of-square squaring dogs is to use a known square item as a fence.  A piece of steel square tube, or a square beam you cut earlier.  Place this against the dogs and resting on the bunks, put the cant against it and use its vertical surface as a squaring dog and then clamp the cant against it hard enough to hold it, but light enough that you don't tilt the fence.

The squaring dogs should have some kind of adjustment to tune them back into square.  Tilting the bed is attacking the symptom, not the problem.

Welding the dogs surfaces would be a last resort.

Either look for adjustments, or, design dogs that have them if yours doesn't.


spencerhenry

the method is use for resawing beams is just as mentioned, one flat face, rotate 180, mill second face, turn parallel faces perpendicular to the mill. as noted, the 3rd cut is really the only one of any difficulty. by applying a moderate amount of pressure with the clamp, and then running the clamp up or down ever so slightly, will move the cant a significant amount. probably on a big piece that was relatively square to begin with, the amount of  "adjustment" is easily + or - 1/16" on a 10" beam. while i do think this guy is a little too anal, he has hired me to do what he wants, it also can be done, though his requirements will make his bill rather large.

Tom

One no-no is to move the cant while it is clamped.  This is a good way to twist it out of square and put undue pressures on the dogs too.

I you are creating "diamond" cants (unsquare parallelograms) then you need to find out what is unsquare about your mill.

If the difference is a big-end/little-end thing, then you need a planer.

1/16 is hardly the width of a bandblade's kerf.  This guy doesn't want timbers to build with, he wants an erector set.  Is he the nail-hammerer or the architect?  I'll bet that he would really be lost if you took his pencil away and made him get out of the air-conditioned car.

Has it been explained to him what the difference is between a Sawmill operation and a Millworks?
Is he expecting you to be a millworks?
Are you a millworks?

spencerhenry

my mill is NOT out of square, the issue that i have is a quality control issue. i was looking for a way to not have to walk around and put a square on the piece to the bed. i can mill the product desired, i just want to be more efficient. the people that want the precise dimensions are the craftsmen. i have done a fair amount of timber work myself, and i know how much easier it is to make perfect joints when the material is "perfect". the amount out of square that i am trying to perfect, is usually less than 1/16" in about 10". most people who mill, most people who use material, and all people without a keen eye will never see the "defect"

Tom

Sounds like you're getting ready to invent something.  I don't have a clue. :)

I misread your 10" as 10' and supposed it might be a longitudinal problem.

You're right, 1/16 across is manageable.  I still don't know how you can fix it without doing what you are doing. 

That is what we call a diamond cant and the only way to fix it is to jack up the low side.  That usually makes your product smaller by twice that thickness, Because you have to do it to both opposing sides.

Tom

I just thought of something else.  The new log lathe that Wood mizer builds might work.

It is indexable.

pigman

spencerhenry, I fully understand your problem. I run a WM super with the two plane clamp. On large logs I have a hard time getting the third face cut to be exactly 90 degrees to the  first face. Since I don't cut beams it is no big deal if the edge of the boards are not exactly square. On a few occasions, I have squared small ERC for posts and likewise, I have difficulty squaring the cant. Some of my customers don't like it when their fence posts are nor perfectly square. ::)  I see no reason why a laser could not be mounted on the mill head to shoot vertical line on the very edge of the log or cant that is in line with the backstops.
Bob
Things turn out best for people who make the best of how things turn out.

Brucer

I've wondering what I'm doing different here. I square up those twisty cants the same way everyone else seems to. I've asked the shop foreman where I saw to let me know whenever any of my timbers are out of square -- he figures it's OK if there's only 1/64 of an inch showing under the square on an 8" face. I don't hear complaints very often.

The side stops/squaring dogs are adjustable in two planes, and that should be enough to keep them square in any position (at least in theory). One thing I do to reduce the sideways force on the side stops is to keep the clamp low.

The one thing I just realized is that both spencerhenry and pigman have Super Hydraulic mills and it may be harder to control the clamping pressure with the boosted hydraulics on those machines.

But to deal with the original problem, one idea is to use two lasers to check the outboard face for square. One laser is mounted below the bunks pointing directly across the mill so it projects a vertical line on the outboard face of the cant. This line will be vertical no matter how much the face is tilted. A second laser is mounted outboard on the saw head, pointing forward and in at about 45 degrees. This will project a line that is vertical only if the face of the can't is vertical. Move the sawhead back or forward so the two projected lines coincide. If they align perfectly, the cant is square. If they form an "X", a "V", or an "A" shape, the can't isn't square. As long as the lasers have sharp edged lines of uniform thickness, you should be able to tell when they diverge even slightly. You'd need some kind of device to calibrate the lasers: probably a vertical board with perfectly square braces that would sit on the bunks.


Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

LOGDOG

Spencer,

   I know exactly what you're trying to describe. Even though I run a swingblade now and I can square three sides without moving the cant, I remember seeing my squaring arms move under pressure from my hydraulic clamp on my other Bandmills.

   I've done a fair amount of resawing and dealt with beams that were twisted and the like. I guess when faced with that challenge I'd approach it like this to make my life easier. Put your first good face up. Saw it flat. Roll the cant 180 degrees (freshly flattened side down). Clamp just barely tight so as not to lift the cant with the clamp. Saw the side you have up flat. Now you have two sides flattened that were not effected by your squaring arms because they were squared between the bed and blade. Now I would take and turn the cant 90 degrees towards your squaring arms. With arms all the way up snug the clamp up just barely and lower the arms to desired height for cutting. If more pressure is needed on the clamp give it after your arms have been lowered. If you don't (as you well know) you'll see that the resistance of the arms being lowered will often roll the left top corner of your cant downward.

   What really makes the process faster is having a helper. I've got a 12" speed square that sits nice and flat on the bed. You could easily have a helper hold that speed square on the outside of the cant (clamp side) after making the first two cuts I described and check for square as you make fine adjustments with the controls.

   Lasers are cool, and I have several, but they're not a cure all. Excess light is your enemy with a laser. If you're outdoors, you won't be satisfied with the results you get from the laser. It's also difficult to get them to project across multiple axis's (sp?) namely x,y and z. Sometimes there is no substitute for hands on manual checking.

   A job with specs that tight would require me to charge by the hour. Obviously they can afford it using that type of material and your time is money. Unless of course you own the wood and are selling it. Then you have to build your cost of time into the selling price per foot or piece. I appreciate your effort for excellence though and wish you luck. As my motto to the left indicates, I too appreciate things being square. :)

   Just my two cents.

LOGDOG

tcsmpsi

There's where my lack of knowledge comes into play.  I wasn't aware that hydraulic squaring dogs would give under the pressure of the clamping force. 

If I couldn't depend on my squaring dogs to be square, I would find a way to fix that before anything else.

\\\"In the end, it is a moral question as to whether man applies what he has learned or not.\\\" - C. Jung

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