Gallery, Projects and General > How do I??

Accuracy of engineers level

(1/4) > >>

eskoilola:
I would like to reinforce the base of my lathe (the table it is standing on) from particle board to become something more rigid.
The particle board is by no means weak as it is a composition of two 30 millimeter thick boards which are epoxied together. It is just somewhat flexible and does not make the lathe as rigid as it could be.

A 25 mm (one inch) thick iron plate would certainly add some rigidity when bolted under the lathe. As a matter of fact, that lathe has the holes for the bolts already in place. That plate would then in it's turn be bolted into the particle board.

There seems to be several methods to check the levelness (not absolute but relative) of the ways. When attached to a rigid base like that the ways could be easily straightened by shimming the bolts.

So -assuming that I would check the ways with a machinist level, what would be the accuracy needed here ?
0.3 mm/m would tell 0.1 mm differences between the ways (they are about 15 cm apart). Is this accurate enough or do I need to go down to 0.01mm range in order to get any benefit of this procedure?
Are there any alternate procedures to check the way straightness ?

And Yes, I searched the forum with N/A.

chipenter:
An enginers level is usualy half a second  thats 120th of a degree , put across the ways at each end of the bed to check and ajust for twist .

eskoilola:
Actually - getting the lathe level with itself. The easiest (by far) way to do this is to make it level with the world. This is because the levels (not the digital ones, I hate them) usually work on a very limited range and tend to measure levelness with the wold ...

After browsing the World Wide Wait I figured out that nobody seems to be using more accurate device than about 0.4mm/meter. So 0.3mm/meter should be enough. Those are German millimeters, not the chinese ones ....

So, I went and bought one of these.

It is a machinist level with 0.3mm/m accuracy.

AdeV:
You should be able to adjust the angle of the vial on the level; so, put it across the ways at one end, adjust until the bubble is in the middle; move to the end of the ways, and any discrepancy should be in the lathe, not the world (unless you happen to be somewhere near an inconvenient gravitational anomaly - see numerous episodes of Star Trek to see how to deal with those).

Pete.:

--- Quote from: chipenter on March 21, 2018, 01:23:40 PM ---An enginers level is usualy half a second  thats 120th of a degree , put across the ways at each end of the bed to check and ajust for twist .

--- End quote ---

I think your maths is off Jeff. There are 3600 arc seconds in a degree so half a second is 1/7200 of a degree. A half-second level would be extremely sensitive - it would move as you walked around a concrete floor in your workshop. Two seconds is still very sensitive and your basic engineer's level is more likely to be 4-10 arc seconds.

Navigation

[0] Message Index

[#] Next page