155 hole to 159 S/S tank?

[vic008]

Drilled 155mm hole in ss fuel tank. Need to open out to 159mm. (For vetus inpection port). Best easiest way please. Obviously a die grinder but dont have. Something to fit a drill, or disc grinder? Or do I have to file? Bought a holesaw off AliExpress, very impressed by quality.

 

[Klausen]

why did'nt you use the original holesaw?

 

[Norman_E]

First thing you need to do is mark it out so that you only take off metal in the right places. Attach a sharp scriber to something you can run round the inside of the hole so that a clearly visible scribed line is 2mm from the edge all the way round. After that you have a choice. either file it (slow and laborious) or try power tools. You could try a flap wheel in a power drill and see if that works, doing a small section at a time.

 

[waynes world]

a good size drum sander attachment will do it, like a 25 or 50mm.

 

[andsarkit]

If it is acceptable to open out to 160mm and you can get a holesaw that size then this might work. oops use your first holesaw in the centre to locate the larger one.
Alternatively a jigsaw with metal blade and cutting fluid or a grinding wheel on a drill. That will take a long time.