Today's newbie question: how to get things level

[Deadeye]

I have a yard-long spirit level. It seems to say the kitchen top is level and certainly a marble doesn't roll on the surface.

However, if I take a straight bit of wood (strip of ply with the factory edge, for example) and use it to judge when the strip is level, and then stand back.... it's wonky.

Am I just not getting the bubble centred correctly (it was just touching the lines each side and I thought it was in the same place when I rotated it to swap the ends), or is the eye better at spotting small skews, or what? And is there a knack or a better way to get, for example, the table saw top level?

 

[mhannah]

I don't think you can guarantee the factory edge of a board will be straight.

Could your eyes be deceiving you into thinking that it looks wonky when in-fact it is straight?

 

[Fitzroy]

Not sure I understand precisly your issue. But when using your eye to gauge a flat level surface it’ll always be referencing off other things in the vicinity, are these things truly flat and level? Ie a painting may not appear level as the floor, door frame, skirting board etc are actually out of plumb, level etc.

F.

 

[Racers]

If every thing in your house is out apart from the worktop then it will look wrong.

Pete

 

[will1983]

Have you checked that your spirit level isn't knackered?
If you're not sure how to do it, here's how;

Use the level to draw a level line on the wall.
Turn the level end for end and offer it up to the line, the bubble should be in the centre again, if it isn't, the level is kaput.

Some expensive levels allow you the option to adjust them with a small screwdriver.
If yours has this facility draw a second line with the level reversed, measure the difference between your two lines and draw a third line bisecting the angle between the first two.
Offer the level up to the new third line and adjust the screw until the bubble is centred.

Double check after the adjustment by switching the level around a few times and checking it always gives a correct reading, if not repeat the above until it does.

Another tip is buy yourself a bag of assorted plastic shims from screwfix/toolstation. I use these all the time when trying to work out how much something needs adjusting by to make them level.

For example a table saw top, I place shims between the table saws surface and the spirit level until it reads correct and then put them under the feet. Remember though that the ratio between the distance between the feet and the length of the level will affect the actual amount of packing the feet will need. I.e. if the feet are twice as far apart as the length of the level apart they will need twice the thickness of packing to make them level. Likewise half the packing if the level is twice the distance between the feet.