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Taut Wire Questions

Lumberjack

Lumberjack

Hot Rolled
Joined
Jun 3, 2006
Location
Sweden
Hi,

Am trying to find more info on taut wire method for future use.
Mainly regarding what instrument/microscope could/should be used, was it used some standard or for the task proprietary stuff?
Any modern approach to the taut wire? As in reading it.


Thanks for any input and happy new year to you all :)
 
Lumberjack said:
Hi,

Am trying to find more info on taut wire method for future use.
Mainly regarding what instrument/microscope could/should be used, was it used some standard or for the task proprietary stuff?
Any modern approach to the taut wire? As in reading it.


Thanks for any input and happy new year to you all :)
Click to expand...
.
i have only seen electronic type
.
Electronic Sensing Head
.
basically has a fine adjust either micrometer or screw with indicator when wire touches a light lights up. if it makes a tone it can be hard to hear and need headphones in a noisy area
.
often used on steam turbines and wood sawmill equipment. optics varies with temperature and if construction site cold i have seen reading change .030 or more with longer distances. actually with a laser and a nearby heater on i had objects within .020 and after heater turned off a few minutes later laser said they were 0.200" off quite a difference cause of temp differences causing air to shimmer
.
and longer wires if windy the wire vibrates. wire under good conditions maybe repeat to .001" but not always. still for rough alignment taking time under extreme conditions hard to beat using a tight wire. a wire often left setup for days weeks months where as optics we always put optics away for the night in a locked box
.
warning i have seen 200 feet wire when cut go flying and it can easily do some damage to a person. sure short setup you can use a finer smaller wire but longer distances going to need a big enough wire you can keep tight. if wire too small it stretches and gets looser over time. in general i have seen steel wire and tungsten wire used. edm wire is often small and maybe use for short distances. edm wire comes different alloys too. i have gotten used edm wire free before not perfect smooth but it was very small i believe .004" diameter. normally need wire .010 to .030" or bigger for longer distances
 
thin kerf website
.
TKT Engineering
.
has a lot of tools and info on sawmill alignment. i worked on papermill type equipment but still always had admiration for thin kerf web site. i have made custom tools before so i can appreciates someone else's custom tools
.
this old millwright and machinist thinks highly of thin kerf web site
 
We used to line up long bed lathes laterally using the taut wire and microscope method. The taut wire was held in " Eclipse " pin chucks fastened into pot magnets. One magnet was fastened to the chuck face and the other magnet was attached to the end of the tailstock barrel. You could then wind the tailstock barrel carefully to tension the wire. The microscope was held in the tool post.

You zeroed up the wire at either end and then worked your way down the bed using the side adjusters to bring the bed into line. It's an old method but quite effective.

Regards Tyrone.
 
Tyrone Shoelaces said:
We used to line up long bed lathes laterally using the taut wire and microscope method. The taut wire was held in " Eclipse " pin chucks fastened into pot magnets. One magnet was fastened to the chuck face and the other magnet was attached to the end of the tailstock barrel. You could then wind the tailstock barrel carefully to tension the wire. The microscope was held in the tool post.

You zeroed up the wire at either end and then worked your way down the bed using the side adjusters to bring the bed into line. It's an old method but quite effective.

Regards Tyrone.
Click to expand...

.
any time you can look through a optical scope or use magnifier with a reference scale then you can estimate a gap distance and its usually faster. but i believe if you can use electronic gage and as you adjust closer then the light lights in contact you are not really looking for a number.
.
basically the screw adjuster is to adjust closer to wire. if you bring gage to one end of machine wire end adjust to wire so gage light lights up and then you slide gage to other end and see light go out and adjust machine til other end the gage light goes on then go back and reset gage and check if readings repeat.
.
hard to describe. depends it using a screw adjuster to move machine or putting in or taking out shims. but electronic gage is useful cause sometimes as you tighten bolts the machine moves as you go from 1/4 tight to 1/2 tight to fully tight. hard to describe. sometimes that is called soft foot. wouldnt be the first time bolt torque was adjusted to get alignment to move .0005", hard to describe. i often shim and align parts weighing a ton to .0001" usually to get below .0005" you need a torque wrench and often vary bolt torque. for example 25 ft/lbs and 35 ft/lbs rather than every thing 30 ft/lbs. you get below .001" and even oil on shims and even finger prints can effect shim thickness.
.
sometimes 5 each .001 shims is better than 1 ea .005 shim as the 5 each shims often can be fine adjusted or squeezed a bit. hard to describe. sure you can mix feeler gage shims
.0010", .03mm(.0012"). .0015" so 2 each .0012 is .0024" and 1ea .001 and .0015 is .0025" or .0001" difference between the ends of a part. but without ultra clean shims and using a torque wrench you can be alike a dog chasing its tail cause things move slightly (.0005")as you tighten quite often. soft foot is angular rather than parallel contact at shim areas. as you tighten you are bending part til the angular gap goes down to parallel contact. where shims are its not unusual to have a angular gap or out of parallel .0005", just got to watch distorting the whole part. obviously taken to extremes you literally can warp or bow a part as you tighten bolts. some use .0001" indicator and magnetic base to watch part distortion as bolts are tightened
.
by the way electronic light often doesnt instantly light up often if within .001" you might see it dimly lighted and it goes fully lighted with more pressure or another .001. obviously requires a clean wire and clean gage if you want good electrical connection. just like electronic edge finder on a mill you can get electrical contact issues the last .001" and get false readings if part dirty that light doesnt light up when it should. just saying dont expect miracles and working to millionths from a wire. and dirty hands leaving no finger prints thats easier said than done keeping everything clean
.
with longer wires over 100 feet even wind inside a building can cause wire to vibrate. if you in area thats 6 stories tall and there is a temperature difference you can get a chimney effect or wind. on a 12 story building literally i have felt a 20 mph wind when a outside door was opened. hard to describe. dont expect miracles from longer wires. often on a turbine adjustments were like +/-.005" and wire 50 foot and wire worked ok
 
Thanks DMF TomB for the extensibe description!

I will look for a wire source and make some tensioning / adjustment devices for starters.
 
lasers are nice as some beam receivers have a digital display. so a rotating laser can have 4 beam receivers each with digital readout and 4 people each leveling a different sole plate by adjusting screws and each watching the numbers on the individual displays while adjusting
.
with electronic tight wire indicator you adjust a screw or nut until light goes on or it makes a beeping noise. nobody got to look through a scope. often job becomes a one man job instead of a 2 man job. often when tightening from 1/4 tight to fully tight a machine section can continue to move. its nice to have light or noise so when tightening you dont have to move or look through a scope. there are advantages to the tone producing tight wire gages even when ear phones are used in noisy areas. you look at wrenches you are using to tighten looking at some sort of display or tone maker many feet away all without moving back and forth to look through a scope and move over to adjust and move back to look through scope
.
or when you use multiple tight wire sensors at different locations. often you can see while adjusting one spot it is effecting other positions. hard to describe
.
i have seen where a man walking on a sole plate it would go down .0001" (using laser) from his weight and go back up when he got off of it. just saying continuous reading or indicating gages that dont require moving and looking through a scope often have advanages
 
We were lining up some linear bearings on a very long bed ( 50 ft ) with a laser. The laser was being operated by a specialist operator. He'd set the laser up on a pretty sturdy tripod style stand at the end of the machine bed. The expert and myself had got about 2/3rds of the way down the bed when all of a sudden the readings started going well off line. We were concentrating on what we were doing and we hadn't noticed that the shop foreman was leaning on the laser stand whilst chatting to one of the labourers !

Regards Tyrone.
 
I had one of those. Long bed Landis Cylindrical grinder. 16 -20 feet between centres. New customer that lashed out on one of those Hamer Laser things.
I'd levelled it the best I could, half to a quarter division at my 0.02/m levels.

He tells me I'm 0.6mm out. (24 Thou) end to end. I'm thinking I'm under 2 (Christian Numbers.) That's quarter + of a millimetre. I could lay bricks more accurate than that when I left the farm, 30 years ago.

Suggest to him that he sets up his laser tripod on the back side of the machine. So we don't interfere with the laser. Dr Marko was involved. We didn't touch one jack, only to be told we were out 0.6 millimetres the other way.
 
Tyrone Shoelaces said:
We were lining up some linear bearings on a very long bed ( 50 ft ) with a laser. The laser was being operated by a specialist operator. He'd set the laser up on a pretty sturdy tripod style stand at the end of the machine bed. The expert and myself had got about 2/3rds of the way down the bed when all of a sudden the readings started going well off line. We were concentrating on what we were doing and we hadn't noticed that the shop foreman was leaning on the laser stand whilst chatting to one of the labourers !

Regards Tyrone.
Click to expand...

They always make the leaners a Forman. Either leaning on coworkers or machines. :D. Sorry, I couldn't help it
I always thought a lazer would be best for alignment. Not so much for short distances.
 
mllud22 said:
They always make the leaners a Forman. Either leaning on coworkers or machines. :D. Sorry, I couldn't help it
I always thought a lazer would be best for alignment. Not so much for short distances.
Click to expand...

I usually Managed OK with the Stone Age tools - taut wire and telescope for lateral and spirit levels for horizontal. Box level and big square for uprights.

Regards Tyrone.
 
We used the "tight wire" method for turbine and generator alignment. The way I was taught (pardon the pun) to setup a tight wire was to make a set of guides which were actually rollers with a small vee groove in them. This vee groove was machined in the lathe with a sharp vee toolbit and was not more than maybe 1/32" deep. The rollers were mounted on adjustable supports with screws for elevation and lateral motion. One end of the wire was pulled over its roller and fasted solidly to the frame supporting the roller (which was bolted fast to the machinery being aligned or anchored into the concrete floor depending on the job). The other end of the wire passed over its roller and was made onto a weight of about 30 lbs. This was often made from heavy round stock with fins welded to it. The weight was hung in a pail of heavy oil. This was to dampen the natural oscillation it would have.

By adjusting the wire guides, the wire could be aligned or centered to some reference. On turbine and generator work, the centerline of the shaft was what we built off of.

As for means of "reading the wire", we used what we called a "wire mike". This was made right there in the field. What we did was to get some hollow fiberglass archery arrows and cut off as much of the tubular shank as we needed. This gave us an electrical insulator and also a thermal insulator from the heat of our hands. On one end of the fiberglass shank, we fitted a steel extension as long as was needed. This was drilled in the lathe so it was concentric with the bore that fitted onto the fiberglass shank. It was fastened with a couple of small set screws. The other end of this steel extension was drilled with a wire size drill to accept an old style phonograph needle, and later on, a cut off sewing needle. It also got a small set screw to clamp the needle in place.

The business end of the wire mike was at the other end of the fiberglass shank. We machined a steel extension to fit snugly onto the fiberglass shank and mounted a Starrett inside mike off of it. Effectively, we had built an electrically insulated extension for an inside mike. On the steel adapter which mounted the inside mike head to the arrow shank, we attached a very fine gauge flexible electric wire. This ran to a pair of earphones. The other wire from the ear phones was connected to a 9 volt transistor radio battery. The remaining terminal of the battery was then wired to the machine or part being aligned to the wire. The person using the wire mike had to have a very light touch or "feel". The wire mike was started off shorter than the distance to be measured, and carefully extended while the needle end was swung in an arc making a radius that was square off the surface being measured from, and this was done with the mike being opened a thousandth or so at a time when the needle got close to the wire. When the needle contacted the wire, you'd hear a very distinct "click" in the headphones. It helped to have another person hold a piece of white paper as a backdrop behind the wire/needle area. This seemed to give a bit clearer view. No two people had quite the same feel for this sort of work, so on something like a turbine with multiple bearings to align to shaft centerline, we'd have one person take a complete set of readings and keep them folded up and not made known until a second person took their own readings. If the differences from surfaces measured to the wire were the same across the two sets of readings, even if the actual readings deviated slightly but consistently, we knew we had good data to move things into alignment.

We used the tight wire on vertical hydro turbines as well, but it was a major PITA. If the shaft and runner and generator rotor were not in the unit, we used a single wire. If the shaft/rotor/runner were in place in the unit, we hung 4 wires around the shaft and took readings to check the shaft for plumb. This was a bigger PITA. Then, we go into using an "electronic square" which gave very fine resolution. So fine we often found ourselves chasing our tails, or, as one fellow used to put it:
"picking fly shit out of the pepper with boxing gloves on". We traded one set of PITA's for another.
 
I'd like to find a wire sag table if anyone has one. Forrest posted one once but I neglected to grab it and now it's gone.

Sent from my SM-G930R4 using Tapatalk
 
If I remember right, that is the table you were looking for:
Tight Wire Sag Chart - 1

It's possible to calculate the sag online.
Formula:
Matroids Matheplanet - Die Mathe Redaktion

Online-software for calculating:
Octave Online Editor - Octave Online IDE - Octave Coding Online

Insert:
Code: 
output_precision(9);
F = 9.81*0.319;
s = 1;
q = ((0.2e-3)/2)^2*pi*7852;

K= sqrt(4*F^2-q^2*s^2)
sag = K/(2*q)*(cosh((q*s)/K)-1)
Click "Execute" to see the sag for that values.

Units:
F [N] = 0,319 [kg] * 9,81 [m/s²]
s [m] = 1 [m]
q [kg/m] = (0,2 [mm] / 2)² * π * 7852 [kg/m³]



To get a table, install the free software "wxMaxima" and insert the lines:
Code: 
F:9.81*0.319;

s:1;

q:((0.2e-3)/2)^2*%pi*7852;

K=sqrt(4*F^2-q^2*s^2);

X: matrix(
    [0], [0.01*s], [0.02*s], [0.03*s], [0.04*s],
[0.05*s], [0.06*s], [0.07*s], [0.08*s], [0.09*s],
[0.1*s], [0.11*s], [0.12*s], [0.13*s], [0.14*s],
[0.15*s], [0.16*s], [0.17*s], [0.18*s], [0.19*s],
[0.2*s], [0.21*s], [0.22*s], [0.23*s], [0.24*s],
[0.25*s], [0.26*s], [0.27*s], [0.28*s], [0.29*s],
[0.3*s], [0.31*s], [0.32*s], [0.33*s], [0.34*s],
[0.35*s], [0.36*s], [0.37*s], [0.38*s], [0.39*s],
[0.4*s], [0.41*s], [0.42*s], [0.43*s], [0.44*s],
[0.45*s], [0.46*s], [0.47*s], [0.48*s], [0.49*s],
[0.5*s]);

y(x) := (sqrt(4*F^2-q^2*s^2))/(2*q)*(cosh((2*q*x)/(sqrt(4*F^2-q^2*s^2)))-1);

float(y(X));

Result for this example:
Code: 
0.0
3.94082787503408*10^-9
1.576612838925357*10^-8
3.547026776442397*10^-8
6.306169666789703*10^-8
9.8531964432321*10^-8
1.418867048359303*10^-7
1.931231009896079*10^-7
2.522439697824708*10^-7
3.19246494325402*10^-7
3.941306746184012*10^-7
4.76899327550586*10^-7
5.675468193437215*10^-7
6.660816006651598*10^-7
7.724980377366662*10^-7
8.867961305582407*10^-7
1.008975879129883*10^-6
1.139037283451594*10^-6
1.27698316041249*10^-6
1.422813510012572*10^-6
1.576522698473605*10^-6
1.738116359573823*10^-6
1.907594493313226*10^-6
2.084951465913581*10^-6
2.270192911153121*10^-6
2.463318829031845*10^-6
2.664326402660639*10^-6
2.8732156320395*10^-6
3.08998651716843*10^-6
3.314639058047428*10^-6
3.547178888454728*10^-6
3.78759755772298*10^-6
4.035900699630417*10^-6
4.292085497287922*10^-6
4.556154767584612*10^-6
4.828102876742253*10^-6
5.10793545853908*10^-6
5.395652512975092*10^-6
5.691248406272055*10^-6
5.994731589097321*10^-6
6.306093610783538*10^-6
6.625340105108939*10^-6
6.95246825518441*10^-6
7.287480877899065*10^-6
7.630372339474672*10^-6
7.981151090578582*10^-6
8.33980868054344*10^-6
8.706350743147487*10^-6
9.080777278390717*10^-6
9.463082652494899*10^-6
9.853272499238266*10^-6

I don't remember, if the values in this example are for steel wire or fishing line.

Cheers,
Karl
 
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