levelling a level

[David Wadstrup]

Hello,

I recently purchased a vintage 12" spirit, torpedo level made by Rabone of England. Here are a couple of pictures:


205741205742


I have no idea how old it is, but I'm guessing somewhere in the vicinity of 100 years. It's a beautiful level that appears to be out of true, and I'm not sure how to calibrate it. I'm particularly mystified by the fact that it does read accurate(my reference surface is dead level) in one direction but not the other. I would have thought that an out of level level would read OPPOSITE when it is rotated 180 degrees. Am I right in assuming that my results show that it is not the foot of the level that is at fault? Rather, that it is the seat of the vial? Or is it something else? Does anyone have any advice? Can the vial be adjusted in this kind of level? I bought this level to be a user. Is there any hope?

Thanks for your help, everyone.

[Robert G Brown]

I don't understand, if your reference surface is absolutely perpendicular to the pull of gravity, the bubble should not change positions whether it is in a North South orientation or a South North orientation. Or am I reading your post wrong?

[David Wadstrup]

Sorry. This is really hard to put into words. My reference surface is absolutely level. When I set the level on it it the bubble reads level. But when I rotate the level 180 degrees, it reads as if the left side is low. Does this make sense?

Thank you for helping. I'm about ready to start pulling my hair out!

[Robert G Brown]

How do you know your reference surface is absolutely level? Did you use another level and then rotate it 180 degrees?

[David Wadstrup]

I used a level known to be accurate to create the surface(a steel straightedge shimmed to perfectly level).

[Robert G Brown]

I sure hope that someone wiser than me jumps in because I don't have a clue. Good luck and please post the solution when you find it.

[Andrae Covington]

Sorry. This is really hard to put into words. My reference surface is absolutely level. When I set the level on it it the bubble reads level. But when I rotate the level 180 degrees, it reads as if the left side is low. Does this make sense?

Thank you for helping. I'm about ready to start pulling my hair out!

Hmm... the first thing that comes to my mind is to check that the case of the level is square and parallel all around.

[Paul Incognito]

David,

Check to make sure that the top and bottom of your level are parallel. Sounds like they may not be.

Paul

[David Wadstrup]

Thanks for jumping in. The bottom of the level is flat. The vial is set within a cavity of the wooden body and is covered by a brass top. It's not really possible to check it for parallel in relation to the sole.

[Brian Kent]

The most logical answer is that the universe is messing with your brain.

[David Wadstrup]

That's exactly what it feels like!!!

[Paul Incognito]

OK. Is the bubble adjustable? On some of the old levels the bubble sits in a ring that can be rotated. There my be a set screw holding it in place. The vial is definitely not parallel to the sole. Are you sure the body of the level isn't twisted or bent in any way? That will throw off the reading too.
Are you looking to make a user out of this? If you want a dead accurate torpedo level, I wouldn't bother rhabing this, just go and get yourself a Stablia.
2 more cents,
Paul

I like Brian's explanation better!

[David Wadstrup]

The bubble isn't adjustable. I removed the top brass plate, and the vial is cemented in place. The body doesn't appear to be twisted or bent. It's torpedo shaped, so I cant really reference it to a straightedge.

I did want to make a user out of it. Any hope?

[Paul Incognito]

Hang it on the wall as a decoration. Get yourself a Stabila. I've had one for 10 years, it's been dropped, kicked and run over. It still reads true.
Paul

[David Wadstrup]

Thanks for you help everyone. I just ordered myself a Stabila torpedo.

[Steve Friedman]

+1 on the Stabilla, but aren't there adjustment screws on the level?

Steve

[David Wadstrup]

No, no adjustment screws. There are 4 screws that attach the top brass plate to the wood body, and 2 screws each holding the brass feet on the bottom. NOne of them, as far as I can tell, serve to adjust/calibrate the level.

[Mel Miller]

I would doublecheck the reference surface by reversing your reference level, and if that level is very sensitive (like a Starrett 98) be sure to keep your warm hands off the vial in the process. I can think of no conditions when your torpedo level would read level one way, and off level when reversed on a true level surface.

Mel

[Gaz Palmer]

Hi David,

Rabone boat levels (Mahogany or Rosewood depending on age) are nice levels to use, but need a lot of tender loving care and the means by which they're best adjusted typically involves re-setting one or both of the brass tips to the underside of the level, unless the bubble is loose in it's bed. The underside of the level can certainly be re-faced or trued, but the two brass tips are the bearing surfaces/points on levels of this type and can be re-set by re-finishing, shimming, or replacement, but you need an absolutely level surface (Typically another level known to be true) on which to gauge and make your adjustments. Touching onto vial adjustment on levels of this nature (Rabone wooden levels) are set into a cured putty/plaster of paris-like material) tends to lead to a world of headaches.

As mentioned earlier, an alloy bodied Stabila will remain true throughout it's length during a lifetime of use and a Type 83S can serve as a reference when adjusting other levels.

[John Coloccia]

David: the situation you're describing doesn't really make sense (which is why you're posting here...it's confusing you too!). Something in one of your assumptions is off. If you're curious and want to get to the bottom of it, please post your exact procedure for doing this test. I know you're using a shimmed straightedge for a reference surface, and I can't help but think that something has crept into this that is throwing you off. Also, are you using a digital level as your reference?

[David Wadstrup]

HI Gaz,

Thanks for sharing your thoughts. It is a nice, but delicate level that is in good shape. I believe it is mahogany. Any idea of the age?

Like you suggested, I had planned on adjusting the feet to recalibrate. With either shims or trimming. But when I found that I was getting different readings, one of which showed level, I couldn't figur out what to do. If I tried to shim up the low side when it read out of level, it would bring it out of level when it was oriented in the way in which it read true. Confusing!

I'm starting to assume that perhaps my reference surface is not as level as I think it is, so I ordered myself a Stabila torpedo level to make absolutely sure. Should be here in a few days.

I'd love to hear more about this company and the levels they made. Any sources of information that you could send my way?

I appreciate it,

David

[David Wadstrup]

Good morning, John,

Thanks for the offer of help. I've got a Stabila on the way to make sure my reference surface is absolutely level. It is not a digital one. Would you mind if I got back in touch once I've checked? I'll make sure to give a step-by-step recounting of my procedure if I'm still getting these non-sensical results.

Thanks,

David

[john brenton]

That antique is a very nice level. I also have a stabila that I used everyday and took some serious beatings. They are good levels. I would see what the stabila does on that surface, and if it does the same thing then you know your surface is not that great of a reference.

If you did decide to take on the task, I would use some sandpaper and stick it to that surface plate and see if a few very light passes wouldn't fix it.

[David Keller NC]

David - One aspect of this litte mystery is the color of the level vial in your picture. Old level vials were clear - the fluorescent green/yellow coloration is a relatively recent phenomena. J. rabone and Sons were in business a long time, so it's possible that your level is of 1960's or 1970's manufacture and the vial is original to the level.

But it's also very possible that the vial was broken at some point and replaced. I see that a lot on the antiques market.

All level vials are curved along their length to some extent, although that might not be immediately apparent by eye. This is the principal difference between a "fast level" (low curvature), and a "slow level" (high curvature) of the same length. It's possible that the vial in your level has uneven curvature, which would make it much more sensitive on one side relative to the other, and would potentially result in the effect that your seeing.

Unfortunately, if the level vial is mis-shaped, you can't fix the level by working on the two brass bearing points - you will have to replace the level vial. That can be done, and you can purchase spares from several antique tool dealers on the web.

[Peter Cobb]

All level vials are curved along their length to some extent, although that might not be immediately apparent by eye. This is the principal difference between a "fast level" (low curvature), and a "slow level" (high curvature) of the same length. It's possible that the vial in your level has uneven curvature, which would make it much more sensitive on one side relative to the other, and would potentially result in the effect that your seeing.

You beat me to the explanation... I was thinking along the same lines, or rather curves.
Cheers,
Peter

[John Coloccia]

If everything is truly level, the orientation if the level and shape of the vial shouldn't matter. Where it would matter us if you were trying to measure inclination. If something is shaped poorly, the markings will need to be calibrated and the rate of change will not be consistent.

[Brian Vaughn]

Actually, the situation makes perfect sense if the sole isn't parallel to the vial, and the surface is barely out of level. In one orientation, the skew of the vial counteracts the skew of the sole, resulting in an apparently level display. In the other orientation, the two skews add to each other, resulting in an apparent out of level situation. Think of it like this: > In one orientation on a sloped surface, the top line would be level. In the other orientation, on the same sloped surface, it would be twice as out of level.

[Brian Vaughn]

By the way, the best way I know to check levelness of a surface, in the absence of your new Stabilla, is a large glass marble. As an appraiser, I used to carry one with me to check floors, and it quick and easy to use.

[David Wadstrup]

Brian,

You're interpretation makes sense to me. It's the first possible explanation that I can actually wrap my head around. Thank you! The Stabila should be here on Wednesday, and I'll make sure to eliminate any errors in the reference surface.

David,

It is a yellow/green fluid(a color I strongly dislike). Does that date the vial to 1960s+? I would have thought it was an earlier level(although my assumptions were made without any real knowledge of the subject). I'm hoping that my reference surface is out of level and that the sole of the level is out too. Like Brian said. This would make it an easy fix. I don't know if I want to get involved with trading out the vial. Sourcing one and chiseling out the old vial seems like a major headache. Although if I could replace it with a vial with better looking clear fluid....

Thanks, everyone,

David

[David Keller NC]

The dye is apparently Fluorescein, which was first synthesized in 1871. However, it's apparent that it wasn't commonly used in levels until much later, as there are many levels on the antiques market with known manufacturing dates well after the 1870's. My guess (and I'm no expert on this - you would need to talk to someone that's really into collecting levels from the MWTCA) is that it was probably not commonly used until synthetic organic chemistry was industrialized in the 1950's.

[Paul Incognito]

A way that I learned to check a level is to put it on a flat surface and check the vial. Turn the level end for end and re-check. The bubble should be in the same exact place if the level is true. The flat surface you're using doesn't have to be level, but the bubble should show the same either way.

Paul