# A Variable Sensitivity Level.



## ariscats (Apr 6, 2015)

I have got an idea for a variable,calibrated, sensitivity level.Is this a useful instrument?Is any one
at any time wished to have one?Shall i pursuit the idea to prototype ?I am not interested in paten-
ding it.I don't even know if such a thing exists. I do not want to make money on it.It is just for
the fun of thinking and making things.Please share your opinions.
Ariscats


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## rgray (Apr 6, 2015)

I think that could come in real handy every now and then. I say build it!!!


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## JimDawson (Apr 6, 2015)

Sounds like an interesting project.  Go for it!!


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## 18w (Apr 6, 2015)

Aricats, what range of sensitivity would the level have? Length? Means of calibration? From seeing your other projects, I too would like to see what you come up with.


Darrell


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## Doubleeboy (Apr 6, 2015)

sounds great, please keep us posted on your progress.
michael


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## ariscats (Apr 6, 2015)

Thanks for the interest .I can feel now that it is worth the effort.I have to work out the maths but i believe a range between
1mm/m to 0.01 mm/m is quite achievable.Calibration will be by using a long sine bar.Also I have spotted a ready made vial
that is very appropriate for the purpose.For the time being the Orthodox Easter comes this Sunday and Spring is going
full blast here in Greece.So i will meet you after about a week.Thanks again
Ariscats


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## RJSakowski (Apr 6, 2015)

I saw a design on another site for what is essentially a variable sensitivity machinists level.  I did a search of my browsing history and have not found the site yet.  When I do, I will post it.

It works by placing a fulcrum under the center of a filled and sealed glass tube and applying a downward bias on either end.  The curvature will be slight  which is what you would want in a high sensitivity level.  

I had done up a design but am looking for a piece of precision bore glass tubing to complete it.  I have looked on e-bay and you can find 1 ml glass syringes at a reasonable price.  I am thinking that should be about the right bore diameter.  I my former employment, we made .25 ml syringes and they had a bore of .09".  Quadrupling the volume will give twice the bore diameter and .18 sounds good to me.  One other innovation the designer had was to use butane for the working fluid.  Butane has one of the lowest surface tensions of any liquid and I would think that would allow the bubble to move more freely.  He epoxied one end of the bore and put a fill port at the other.  I believe that he salvaged the fill port from a refillable lighter.


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## ariscats (Apr 6, 2015)

RJSakowski said:


> I saw a design on another site for what is essentially a variable sensitivity machinists level.  I did a search of my browsing history and have not found the site yet.  When I do, I will post it.
> 
> It works by placing a fulcrum under the center of a filled and sealed glass tube and applying a downward bias on either end.  The curvature will be slight  which is what you would want in a high sensitivity level.
> 
> I had done up a design but am looking for a piece of precision bore glass tubing to complete it.  I have looked on e-bay and you can find 1 ml glass syringes at a reasonable price.  I am thinking that should be about the right bore diameter.  I my former employment, we made .25 ml syringes and they had a bore of .09".  Quadrupling the volume will give twice the bore diameter and .18 sounds good to me.  One other innovation the designer had was to use butane for the working fluid.  Butane has one of the lowest surface tensions of any liquid and I would think that would allow the bubble to move more freely.  He epoxied one end of the bore and put a fill port at the other.  I believe that he salvaged the fill port from a refillable lighter.


I have seen this solution in another forum,may be 'Practical machinist' but i do not really remember.My idea is to use a ready made vial from,lets say,
http://www.leveldevelopments.com/products/ without stressing the vial in any way avoiding repeatability problems and temperature effects.The use of butane
gas (fluid) is a marvelous idea together with the lighter filling valve.I will use them if i decide to make my own vials and thank you for bringing this up.
You got it right that a bent and not a ground tube is involved.But allow me to keep the "mystery" till i will finish  the calculations.
Ariscats


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## RJSakowski (Apr 6, 2015)

ariscats said:


> I have seen this solution in another forum,may be 'Practical machinist' but i do not really remember.My idea is to use a ready made vial from,lets say,
> http://www.leveldevelopments.com/products/ without stressing the vial in any way avoiding repeatability problems and temperature effects.The use of butane
> gas (fluid) is a marvelous idea together with the lighter filling valve.I will use them if i decide to make my own vials and thank you for bringing this up.
> You got it right that a bent and not a ground tube is involved.But allow me to keep the "mystery" till i will finish  the calculations.
> Ariscats


I am looking forward to seeing your design!


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## randyc (Apr 6, 2015)

RJSakowski said:


> I saw a design on another site for what is essentially a variable sensitivity machinists level.  I did a search of my browsing history and have not found the site yet.  When I do, I will post it.
> 
> It works by placing a fulcrum under the center of a filled and sealed glass tube and applying a downward bias on either end.  The curvature will be slight  which is what you would want in a high sensitivity level...



I believe that was posted in a shop-made tooling thread that ran to over 200 posts on another HSM forum.  That thread included a lot of good ideas. (A bit of liquid soap in water will reduce surface tension in devices such as remote leveling tools, where two vertical, calibrated pipettes are linked with flexible tubing.  Might not be as good as using a liquid gas or even alcohol, however.)


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## randyc (Apr 6, 2015)

Post 1883 is the level with butane liquid:
http://bbs.homeshopmachinist.net/threads/39202-Shop-Made-Tools/page184

Several versions shown here:
http://bbs.homeshopmachinist.net/threads/39202-Shop-Made-Tools/page167


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## RJSakowski (Apr 6, 2015)

randyc said:


> I believe that was posted in a shop-made tooling thread that ran to over 200 posts on another HSM forum.  That thread included a lot of good ideas. (A bit of liquid soap in water will reduce surface tension in devices such as remote leveling tools, where two vertical, calibrated pipettes are linked with flexible tubing.  Might not be as good as using a liquid gas or even alcohol, however.)





randyc said:


> Post 1883 is the level with butane liquid:
> http://bbs.homeshopmachinist.net/threads/39202-Shop-Made-Tools/page184
> 
> Several versions shown here:
> http://bbs.homeshopmachinist.net/threads/39202-Shop-Made-Tools/page167


The first link is the post that I saw.  The second has some intersting feature as well.  Thanks.

Bob


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## randyc (Apr 6, 2015)

RJSakowski said:


> The first link is the post that I saw.  The second has some intersting feature as well.  Thanks.
> 
> Bob



The ingenuity displayed by people that practice this craft - whether professionally or out in the garage - NEVER fails to amaze me.  I think that a certain type of person is attracted to machine tools and generally these folks are probably a combination of artists and mechanics, LOL.  We like to know how things work and fix them plus we like to create things


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## ariscats (Apr 8, 2015)

First i would like to thank you for encourage and good words.I have made a free hand sketch to explain the idea.


I am using a Bent Vial. If you rotate the vial around an axis parallel to the diameter of bending,the effective radius,and
therefor the sensitivity,will vary.The effective radius will go from initial bending radius to infinity for a rotation of the 
vial (angle θ)  from zero to 90 degrees.The sensitivity can be defined as a= l/r where l is the movement of the bubble and
r is the effective radius of the vial.I have arrived at a grafic solution for the expression of F(θ) but the analytical solution
escapes me at the moment.I have to express the radius of curvature of an ellipse at the point of minor semiaxis intersection
to the periphery as θ increases.The ellipse is the projection of the vial circle to the XY plane.It has the major axis constant,that 
is the diameter of the bending circle an the minor semiaxis goes from r to zero analogus to cosθ as the vial is rotated. In the 
end ,at 90 rotation,this ellipse reduces to a straight line and therefor the effective radius goes to infinity.
An approximate expression for F(θ) might be as in the sketch above.
Anyway if calibration is done after construction by an indepented means(e.g. a sine bar) it has a small significance,
but is satisfactory for the completeness of the solution.
I hope that this small presentation is clear enough.I will await your comments.
Ariscats


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## randyc (Apr 8, 2015)

That seems a very good idea !  One of the earlier executions that I saw on the internet flexed the vial and that concept is a little troubling.  Your design is certainly stress-free   I'll be interested to see the finished result -


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## ariscats (Apr 9, 2015)

randyc said:


> That seems a very good idea !  One of the earlier executions that I saw on the internet flexed the vial and that concept is a little troubling.  Your design is certainly stress-free   I'll be interested to see the finished result -


Thanks randyc It was 3:30 in the morning when your response arrived.I do appreciate the"stress free"
Ariscats


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## RJSakowski (Apr 9, 2015)

ariscats said:


> First i would like to thank you for encourage and good words.I have made a free hand sketch to explain the idea.
> View attachment 99175
> 
> I am using a Bent Vial. If you rotate the vial around an axis parallel to the diameter of bending,the effective radius,and
> ...


ariscats, I left a message for you on your profile page under profile posts yesterday. Let me know if you are interested.


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## ariscats (Apr 9, 2015)

I just emailed you


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## Optic Eyes (Apr 28, 2021)

Levels can be hard enough to use for beginners and you want to make it more complicated, please fix something else.


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## ariscats (Apr 29, 2021)

Optic Eyes said:


> Levels can be hard enough to use for beginners and you want to make it more complicated, please fix something else.


Are you a beginner? Please explain.
Ariscats


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## Optic Eyes (Apr 29, 2021)

ariscats said:


> Are you a beginner? Please explain.
> Ariscats


I started my apprenticeship as a Millwright in 1969, Journryman in 1972, I worked at Mpls Honeywell 19 years as a machine repairman in the Avaionics and Ordnance divisions, then worked as a field service tech for the Engineering Dept at 3M as an
Optical alignment and mechanical tech. I retired as the instructor for the Millwrights Union.  I had my own shop making straight edges and precision squares for machine rebuilders, I even made a few levels. I teach Hand scraping and machine rebuilding.
In my experience levels are at a stage that needs no improvement, you're making something more complcated that's already at a stage of very good. 
Levels are a QUALITAVE tool, additions to make them QUANTITIVE exist but suffer from temperature changes to much. Optics began to be used in industry in WW2
to build aircraft ect. and have been used since, however the instruments are expensive at $33,000.00 for a basic scope. The reason optics are used is they provide a datum over a distance, something a level cannot do.


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## ariscats (Apr 29, 2021)

Impressive curriculum indeed!
Ariscats


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## Optic Eyes (Apr 29, 2021)

ariscats said:


> Impressive curriculum indeed!
> Ariscats


Thanks, But I was always interested in accuracy in layout and alignment


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