vial for a machinist's level

[jcs0001]

Pete

Thanks for the information and link.  I guess I'll have to go to the "golden arches" for a coffee and get a drink "straw".  That should work ask I believe they are fat enough.

John.

[Pete.]

This guy is now selling them by the handful. I have got my own order in already..

http://www.homeworkshop.org.uk/index.php?option=com_adsmanager&view=show_ad&adid=28147&catid=2

[RussellT]

I don't need a handful and already have more than enough clutter.  Would anyone like to split an order?

Russell

[jcs0001]

The level is finally back together with an intact main vial (the other two were good and still are) and is calibrated.

I bought a 2 kg box of plaster of paris (POP) and have about 1.99999999 kg left   Any ideas for using the remainder are welcome.


I found some fairly thick (like poster paper) acid free white paper for backing and the vial still had a very small amount of room (diameter wise) with one layer of paper so that worked out well. 


Transparent tape was used to temporarily hold the vial.  The groves for the two circlip springs can be seen here:


I had several plastic drinking straws ready to cover the small "tit" on one end of the vial but found that I did not need to use them.  Instead I applied POP in small amounts with a bamboo skewer and kept it away from the "tit".  The other end was easier although I used the same method.  I did 3 applications of POP to get both ends nicely anchored and was quite happy with the final result.  The pointy end of the skewers was used to wedge the vial up towards the opening at the top.  A very small amount of cleaning up was done at each end.


I put the two spring wires in place and with great difficulty finally managed to get the protective cover over them.  This was likely the most difficult part of the process as they did not wish to sit in their respective groves.

Putting the plugs in each end was causing me a lot of headaches, trying to figure out how to keep them properly aligned.  I have a surface plate along with a decently flat piece of glass and a pair of 123 blocks so checking them was easy.  I was thinking of making a jig with the 123 blocks - basically bolting the plugs, one to each block and then pressing the blocks together on the surface plate.  This idea was abandoned as too complex plus my larger clamps did not want to cooperate.

Finally I decided do the following:
1) press one end in as close as my eye would allow.
2) align the two plugs resting each on a 123 block on the glass.
3) squeeze them together as much as possible by hand while aligned on the blocks
4) do the final compression in my rather decent sized wood working vice checking the alignment regularly as I pressed them together.

I found that the plugs required a lot of pressure to press into the tube.  Large C clamps and other types of clamp either could not provide enough pressure or were to wobbly to be effective.  My large wood vice is lined on each side with plywood and the plugs ended up pressing into it without any damage.  Here is a mock up with a piece of similar sized brass - I don't have photos of the tube in the vice.


And a final couple of photos with the level back in operation.




John.

[Pete W.]

Hi there, John,

I'm pleased you eventually got the level repaired and back to a functional condition.          

Getting the vial aligned with the tube window and then getting the two end plugs fitted and aligned with the window and each other are more tricky than it sounds - there isn't a lot to get hold of!!  I have a level repair project that's stalled at that stage.  I have it in mind to make a special clamping jig but it's a lot of work for a once-off operation!

How did you calibrate your level?  There's a relevant Youtube video by Stan Zinkovsky (aka Z ) in which he shows that even on a tilted surface plate there's a line that is level, i.e. at right angles to the line of maximum slope.  However, you do need another level to find it but that one can be borrowed from a friend!  You place a parallel along that line and then set the level under test against it.  That certainly gets you near enough for most of the calibration.  Then you do the final trim by comparing bubble positions when the level is turned end-for-end.

Maybe you should make your penultimate photo your Mad Modders avatar?             

[jcs0001]

Pete

I agree that making a fancy jig for a one off is a bit of work.  I had no trouble with my method and it was fairly easy to do.

As far as calibrating the level here is my method - more experienced members feel free to point out any errors omissions or screwups.  My method will get the level very close to level - for final tuning I will use a surface plate (see why I did not below).

I left the non adjusting side of the level a bit less than snug and each time I checked the level I tightened the adjustment nuts just moderately.  Once I was happy with the position of the vial holder I tightened the nuts and screw and checked it again.


1) you need a fairly level flat surface - use a carpenter's level to find one - it doesn't have to be perfectly level - just enough that the machinist level will register once calibrated.  If the machinist level (ML) rocks on the surface use a bit of tape to "flatten" the surface so the ML does not rock.

2) use masking tape or a marker to mark the end and side of the area in which your ML will sit.  You will be placing your level in the same spot each time you rotate it 180 deg.  You can also clamp two straight edges at right angles and place your ML against them.


Note adjustment nuts on the left side.  Note bubble is against the far right mark on the vial.


Rotated 180 degrees from the first photo.  Note bubble is also against the far right mark on the vial.  It is now calibrated - very close anyway.

3) adjust the ML so that the bubble shows.  Don't try to get it centred.  Rotate the ML 180 deg. and see where the bubble is now.  It will likely be different than the previous position.  Before rotating the level adjust it so that the bubble is moved towards the first position, about 1/2 way.  Turn 180 degrees and note where the bubble is and adjust again.  You will need to do this a few times.

4) the goal is to be able to rotate the level 180 degrees and have the bubble in the same position.  For eg. if the right side of the bubble is against the far line on the right side of the vial in one position then it needs to be against the right side of the far line when the level is rotated 180 degrees - you can see this in the two photos.

If your surface is closer to level than mine then the position of the bubble in the vial will be closer to the centre.  I suspect the carpenters who installed my window did not use a fine machinist grade level.

I hope this makes sense - it was a quick process and not very difficult.

In my case it is quite cold in my shop and not conducive to doing fine work.  I used a window ledge and got the level very close - I can fine tune it when my shop is a bit warmer and I can use my surface plate.

John.