Level machine is using a lot in site finding dumpy level machine fault  that’s way it is very important practical if you are using the machine first time your result were wrong then you will do all procedure again .so first read this article to finding level machine fault.

HOW TO FIND DUMPY LEVEL MACHINE FAULT

First of all open tripod then set it on ground where you want to set level machine
then keep Level machine on tripod and tight it with plumbing fork
Now bubble the level machine from leveling screw
When bubble come to center then leave it
now you instrument is ready for work

first of all you must check machine fault

that is very essential because if you have at least (0mm- 9mm) error then it is permissible if you have more than form 9mm then you must change the instrument because it is not suitable for work
first of all how can I check machine fault

When instrument become ready then select two point

Like
A and B
keep the staff rod on A point and target it trough cross hair then keep the staff rode on point “B” and target staff rod
now take reading on cross hair
and note both A and B reading
then change level machine to another point . you can change to any place but only to that point from where you can see point A and B.
now bubble your instrument same like you doing for first point
then take reading on same point but you must change point name like A’ & B’ first take reading on A’ and then take reading on B ‘ through cross hair and note it.

Now you have four reading and you can find easily machine fault

After that change the instrument to another place bubble it and select a point and take reading this will be your Point A’

And select another Point and take reading that will be your Point B’
then calculate it on below formulas.

Formula for finding Dumpy Level Machine Fault.

A – A ’ = C
B – B’ =D
C – D = Result

if you have 1mm – 9mm then you can work on instrument
if machine fault I mean (C-D) result more than form 9mm you can’t work on this instrument
you must change it

9mm is permissible error

Thank you for reading how to find dumpy level machine fault practical . if you have any problem then comment us in comment section or contact us . if you need any type practical works note .