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Norm Voelzow
Norm Voelzow
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Spacer Shaft Tolerances Explained

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Question: From Sim Sze Tung – Singapore China. The tolerance card for spacer shaft is in mils/inch. Does this per inch refer to spacer shaft length or coupling diameter and, is this a gap or offset reading?

Explanation: Spacer Shaft Tolerances

To apply Alignment Tolerances to a Spacer Shaft (Jackshaft, Spoolpiece etc.) we multiply the length of the Spacer Shaft in inches times the speed related Spacer Shaft tolerance from the tolerance table shown below. This will give us a tolerance to be used to check against the actual offsets, both vertical and horizontal, that the Optalign® or Rotalign® will show us at each coupling center in the Coupling Mode. Note: Offset is the amount the two centerlines are separated (offset) from each other at any specified point. Normally, offset is measured at the center of the coupling(s) which is where the torque is transmitted. Typically we express alignment related offsets as VO for Vertical Offset and HO for Horizontal Offset.

For example, using a 60" Spacer Shaft which rotates at 1,800 RPM, we multiply the Spacer Shaft Length of 60" by the speed related Spacer Shaft tolerance of 0.6 mils/in. which results in an offset tolerance of 36 mils. This tolerance will be used to check the actual offset the Optalign® or Rotalign® will show us in the Coupling Mode and must be checked at each coupling center!


Tolerance Card
Tolerance Table (click)

The Optalign® or Rotalign® calculates the actual offset between the Stationary Machine and M.T.B.M. (Machine To Be Moved) centerlines, using the dimensions you entered. Also, the Optalign® or Rotalign® can show us the relationship or offset between Stationary Machine and M.T.B.M. centerlines anywhere along these centerlines. Even if you are using the older Optalign® IR (invisible beam) or V system you can still compare two points or both ends of the Spacer Shaft as shown below! (Note: To do this with the older Optalign® IR / V we need to change the dimension from Prism to Coupling Center after getting the results for the one end!)


You can see from this example illustrating the actual Vertical Offsets that by checking the tolerance at both coupling centers and correcting the alignment, we are actually controlling the angularity between the two machines centerlines and possibly preventing a catastrophic failure! With Spacer Shafts we do not need to look at both Gap and Offset as we do with Short Coupled machines since once we achieve Tolerance on a Spacer Shaft alignment the angularity will be very small and well below Tolerance.

Note 1: For Spacer Shafts under 6" in length, we would use the Short Coupled Tolerances which are found under the headings of Gap and Offset in the tolerance table shown above.

Note 2: Use OEM or in-house tolerances if available.

Have a Grand Day!
Norm & Bev Voelzow • Voelzow & Company, Inc,

© Copyright 1997 Voelzow & Company, Inc. Wingate, North Carolina


  Document
#1 Spacer Shaft Tolerances Explained
 
 

Two Commonly Asked Soft Foot Questions

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Question #1: What does the Optalign® or Rotalign® show us in the Soft Foot mode?
Answer: Shaft movement onlynot foot movement and not soft foot correction!

Question #2: Why doesn't the Optalign® or Rotalign® show the actual Soft Foot correction?

Short Answer: They are not designed to!

Long Answer: We do not enter a dimension from the base to the centerline of the motor shaft nor do we enter an inside dimension (side to side) of the feet! In order for any computer to "guess" at the actual soft foot fix, the computer would need the front to back foot dimension plus these additional dimensions. Notice I said "guess"! How many times do we have perfectly flat feet and a perfectly flat base — never or almost never! If we want a computer to calculate the soft foot correction — we would need to supply the motor front to back foot dimension, the dimensions mentioned above and the following information:

  1. Is the foot flat or bent? If bent, is it bent up or down — towards the outside of the motor;
    is it bent up or down — towards the front or back of the motor; or a combination of both?
  2. Is the base warped? If warped — which way?
  3. Is the base solid or corroded or flimsy?
  4. Are you using a stack of shims, a few shims or no shims when measuring soft foot?
  5. Are the shims bent? Are the shims dirty?
  6. Is there dirt under the motor feet?
  7. Etcetera, Etcetera, Etcetera !!!

Get the picture? That is a lot of information to try to get just to have a computer still "guess" at our Soft Foot correction! We recommend that you work on the foot that the Optalign® or Rotalign® displayed as having the most movement — using feeler gages! Fix that foot and recheck all of them again! (Some use shim stock to determine the correction but may not notice the taper!)

Here is another picture for you. This triangle graphically shows you how the Optalign® or Rotalign® is calculating the movement of the shaft centerline. The base of the triangle is where the motor centerline is with the all of the feet tight. The Hypotenuse is the motor centerline with one foot loose! Interesting — I think so!


This is the Angle measured by the Optalign®, Masterlign® or Rotalign®.


This is the number displayed on the Optalign®, Masterlign® or Rotalign® screen which is Shaft Movement at the shaft centerline and NOT Soft Foot shim correction!


This is the Front to Back foot dimension entered by you in the Optalign®, Masterlign® or Rotalign® dimension screen.


The number displayed on the Optalign® or Rotalign® screen in the soft foot mode is based upon a movement of the shaft — PERIOD! Again; Shaft movement onlynot foot movement and not soft foot correction! Go to the foot with the most movement and use feeler gages to determine the correction. With feeler gages you can also determine if there is any taper indicating a bent foot. Bent feet or rolled/bowed bases usually require step shimming. Don't try to short cut by "side stepping" soft foot! There are no short cuts with soft foot — just perseverance, determination and finally skill! Good Luck, Norm Voelzow

© Copyright 1997 Voelzow & Company, Inc. Wingate, North Carolina

Optalign® & Rotalign® are registered trademarks of Prüftechnik Dieter Bush AG of Ismaning, Germany

 


  Document
Two Commonly Asked Soft Foot Questions
 

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We have written the above Laser Tip about Soft Foot because checking Soft Foot with a laser is so misunderstood by so many people! We have explained what the laser "sees" in the Soft Foot mode since 1986, shown 1,000's of people in classes and in the field and we turn around and people go back to assuming the lasers show the Soft Foot shim correction! Go figure!

Do yourself a favor and don't complicate Soft Foot! Use the laser to ferret out the problem foot or feet and then use your head and a set of feeler gages to "really see" exactly what is going on under that foot!

Remember, I never said that doing Alignment or correcting Soft Foot was easy with the laser but I always have said that a laser made both much easier!

Note: This Laser Tip is two - sided with the Typical Causes Of Soft Foot graphics by Bev Voelzow shown on the reverse side! You will need to click on the "Two Commonly Asked Soft Foot Questions" PDF icon above to see Bev's work!

Have a Grand Day!
Norm & Bev Voelzow • Voelzow & Company, Inc,

© Copyright 1997 Voelzow & Company, Inc. Wingate, North Carolina


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Pruftechnik Laser - In the USA - Need a Calibration Check? Call 305-468-1908
In the USA - Need a Calibration Check? (CLICK)
 

Compact Chain Tool

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VCT-5 Compact Chain Tool - Call 704-233-9222
VCT-5 Compact Chain Tool - (click)

The VCT-5 Compact Chain Tool facilitates shortening or lengthening bracket chain without damaging the existing chain or special ends!

VCT-5 Compact Chain Tool . . $21.00 each
(Chain not included)

VCT-5 set Compact Chain Tool w/ two 30" lengths of extra chain . . $45.00 per set

Important: Do not insert the extra chain needed by taking apart the installed master link(s) but, using the VCT-5 Compact Chain Tool, skip over a link or so from the master link and insert at that point. Most of us will break the lightweight European master link – especially Norm Voelzow (me)!

We accept, Master Card and Visa! Call 704-233-9222 or request a Quotation by email.


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Sunlight and The Lasers

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Sunlight and The Lasers

Occasionally we have had customers tell us that they thought that Sunlight was preventing the laser system from taking measurements when the machinery being aligned was located outdoors and that they wanted a more powerful laser! We explained that a more powerful laser is not the answer but in fact they were getting interference from direct Sunlight or too much reflected light off of other equipment!

Even though all of the Pruftechnik laser systems filter out all light except for 670nm frequency used by the Rotalign and Optalign lasers – the Sun generates all of the frequencies of light! Another important point is the fact that the Rotalign and Optalign lasers power are designed and rated as Class 2 lasers - for Safety reasons!

Even if the factory went to the next class laser, Class 3, you can still can experience the direct or reflected Sunlight issue as the photocell in the Rotalign Receiver or Optalign Transducer will still see a lot of the lasers 670nm frequency from the Sunlight. Important: Anything above a Class 3 laser could not be used in the open because of the chance of an individual being blinded.

Here's another way to look at the Sunlight issue. Imagine that you were using a camera mounted where the laser's Receiver or Transducer is and were trying to take a picture of the other component with the Sun in the background. . . . . ! You would have the same problem with the Sunlight unless you had a hood on your camera's lens – get the picture!

When doing alignment outdoors you most probably will need to use a Sunshade! But, not just anything you have laying around as you must be careful not to put any excessive weight on the Rotalign Receiver or Optalign Transducer – and that is why the older Sunshade we had previously was so light but fragile!

In order to overcome this inconvenience and fragility the US Pruftechnik Distributor, Ludeca, developed the L 660 Sunshade which helps the user to overcome the Sunlight issue outdoors during the initial set-up and when measuring! Much like a camera with the attached hood used on large diameter lenses – this Sunshade is designed for Rotalign style Receivers and Optalign style Transducers as shown in the photos to the right.

If you are using your laser system outdoors we recommend you get a Sunshade! You can order an L 660 Sunshade from Nils Heilemann at Ludeca (305-591-8935) – please tell Nils that Norm and Bev said hello - thanks!

 


L660 Sunshade mounted on a Rotalign Receiver.
L660 Sunshade mounted on a Rotalign Receiver (click)
L660 Sunshade mounted on an Optalign Plus / smartALIGN Transducer
L660 Sunshade mounted on an Optalign Plus / smartALIGN Transducer (click)

Laser Enhancement Glasses

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Laser Enhancement Glasses
Laser Enhancement Glasses (click)

Laser Enhancement Glasses

Some users complain that when setting up their laser system that they cannot visibly see the laser hitting the systems Red cap because of the bright Sunlight. If this is an issue for you read on!

There are special Red acrylic glasses that help you see the laser dot better and are especially helpful in bright light conditions. They were designed specifically to match the laser wavelength color 635nm to 670nm, were made in my Grandmother Emma Rinderknecht's country, Switzerland, and are Z87.1 Safety glasses. (These fit over any existing glasses and are made just like regular safety glasses.)

Important Note: These are not Laser safety glasses but are conventional safety glasses that only enhance the laser and do not protect the wearer’s eyes from the laser. You should not be looking directly into the laser Transmitter at any time – EVER. These glasses were available many places but now cannot be found! If you find them – please let us know where by email – thanks!

July 14, 2008 Note: Thanks to William Ruting of Mount Gilead, NC we now have a source for you to go to for these particular Glasses! VERE, Inc. # 900 Large Fitover Laser Enhancement Glasses www.vere.com

Also: Be sure to read Sunlight and The Lasers explained directly above this section – thanks!

 


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Hello,

If you want more information, wish to comment on a Laser Tip, request that a Laser Tip be made or request a previous Tip - please use the Request Form link below, call us at 704-233-9222 or send us an email.

Thanks - Norm & Bev

Laser Tips © Copyright 1997 Voelzow & Company, Inc. Wingate, North Carolina


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Links

The following are some very good links for you to visit and well worth your time!
Just click on the graphic and be sure to check back as more great links will be added very soon. Norm

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We ship daily by the Big Brown truck on orders received as late as 5:30 pm EST!
We ship daily by the Big Brown truck on orders received as late as 5:30 pm EST!
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© Copyright Voelzow & Company, Inc. - Wingate, North Carolina USA. Reference the Digital Millennium Copyright Act Of 1998.

Top Gun®, when used with Laser Shaft Alignment, is a registered trademark of Voelzow & Company, Inc Wingate, North Carolina USA.

Note: We have not given anyone or any company permission to use any text from our website on their website or in printed material!

 


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