morrisman 8th September 2012, 07:50 PM If one buys a machinist level new or used . How do you know it is within specs . Older levels might be of better quality e.g., Moore & Wright or Starratt . Or , the new Asian made levels .
Is there a method of determining how accurate they are ? Mike
.RC. 8th September 2012, 08:16 PM Well if it is 0.05mm/m get something a metre long and place a 0.05mm shim under one end...
Also be aware that most usage of a level is only as a comparator, so the graduations or accuracy are not even needed... All you are doing is comparing one section to another and getting them all looking the same way...
Also if you turn a level end for end will tell you if the vial is in tune with the base.
azzrock 8th September 2012, 08:27 PM hi mike i think you just find a nice sturdy spot to place the level that is reasonably level.
take note of the position of the bubble. and then pick it up and turn the level 180 deg.
let it settle and then compare the bubble position to where it was befor you rotated the level 180 deg.
if the bubble is in the same position both times id say its dead on level. if not the level may need to be adjusted.
its a very simple check. It may not be so simple to find a level spot to check the level.
if need be you can shim the level at one end to create a level serface.
hope this is of some help
morrisman 8th September 2012, 08:55 PM OK that is a logical check , the 180 degree turn and check .
Thanks
.RC. 8th September 2012, 09:50 PM If it is out when you end for end it you can adjust it with the adjusting screw...
Sterob 8th September 2012, 10:10 PM hi mike i think you just find a nice sturdy spot to place the level that is reasonably level.
take note of the position of the bubble. and then pick it up and turn the level 180 deg.
let it settle and then compare the bubble position to where it was befor you rotated the level 180 deg.
if the bubble is in the same position both times id say its dead on level. if not the level may need to be adjusted.
its a very simple check. It may not be so simple to find a level spot to check the level.
if need be you can shim the level at one end to create a level serface.
hope this is of some help
The spot does not need to be level. If the level is reading correctly, it will display the same reading in both orientations, regardless is the test spot is level or not.
morrisman 8th September 2012, 10:35 PM Hi
Yes I see that the machinist levels normally have an adjustment on one end to either raise or lower the glass vial containing the bubble . Thanks again :2tsup:
tanii51 8th September 2012, 11:13 PM getting the last little bit right will drive you crazy :C think its something to do with the heat off your hand makes the bubble expand
john
azzrock 9th September 2012, 02:16 AM The spot does not need to be level. If the level is reading correctly, it will display the same reading in both orientations, regardless is the test spot is level or not.
yes true but how pertinent is the calibration check if the bubble is jammed down one end and not in the graduated area?
Steamwhisperer 9th September 2012, 07:48 AM yes true but how pertinent is the calibration check if the bubble is jammed down one end and not in the graduated area?
Hi Aaron,
I think Sterob means level enough to have the bubble close to the marks but not necessarily dead level.
Phil
eskimo 9th September 2012, 12:56 PM i didnt care if my level read true for levelness.close enough was good enough for being level
I just made sure I used the orientation of the level at both ends of the lathe the same way..ie did not rotate 180...if the level was close to reading "level" ie the bubble read close to centre on a object known to be level or even one graduation or two off then being "level was close enough for me.
as long as the bubble reads the same at both ends the bed must be in the same plane??? doesnt it????
MuellerNick 13th September 2012, 12:02 AM Well if it is 0.05mm/m get something a metre long and place a 0.05mm shim under one end...
I think starting with gage blocks under both ends of that "something" will be more stable and accurate. One end 1 mm, the other 1.02 mm. Then replace the 1.02 mm with 1.04 mm. Or something along that line.
Machinist levels here have 0.02 mm / m.
I have seen an actual calibration diagram of a level. They are quite inaccurate over their full scale.
Nick
peterb62 13th September 2012, 02:16 AM All I do to check a level is stick a peice of steel in the vice and get it level by rotating level and adjusting steel until level reads the same both ways, then when steel is level adjust buble to read level, works on any length level and can be used horizontal or vertical, dont usually worry about tolerence. Spot on is close enough!!!!!!
morrisman 13th September 2012, 12:06 PM I actually took the plunge and bought a British 'Rabone' brand machinist level on ebay .... don't know if its going to be of much use as its a 6" version. I see most of you guys use the longer types , either 8" or 12 " . Is a 6" level any good ? Mike
pipeclay 13th September 2012, 02:23 PM why didnt you ask before you bought if you were concerned.
Length will only play apart when calculating shims or amount to raise jacking bolts.
RayG 13th September 2012, 02:48 PM I actually took the plunge and bought a British 'Rabone' brand machinist level on ebay .... don't know if its going to be of much use as its a 6" version. I see most of you guys use the longer types , either 8" or 12 " . Is a 6" level any good ? Mike
Hi Mike,
6" is fine, it's sensitivity that's the important factor, if you want a quality level, i'd be looking at a Wyler like one of these, Swiss Quality Discount (http://www.swissqualitydiscount.com/index.php?cPath=16&osCsid=9e92a768f838f0f9c1374985c38390b8)
As far as calibration goes, most of the time you'll only use the level at one point, that is close to zero ( perfectly level), linearity at points away from zero is hard to measure unless you have a pretty good metrology setup.
Regards
Ray
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