Refurbishment of holes drilled in carbon steel.

[fergie86]

Hi All,

i'm thinking this may be a bit of a long shot but any ideas or suggestions would be much appreciated!

The problem I have is with machined calibration blocks that have been sitting in storage for a number of years unprotected.
Basically (for those that don't know) a calibration block in the my line of work is a section of carbon steel pipe which has flat bottomed holes machined into it at varying angles and depths.

I am looking for a way to refurbish the holes by hand to eradicate any rust or scale which has developed inside them.

It is imperative that the technique I adopt doesn't change the shape or orientation of the holes and the bottoms stay perfectly flat at the exact (or as exact as humanly possible) angle they started.

the holes are a mixture of 2mm and 3mm diameter and varying depths.

I've thought about various drill bits or pipe cleaners but haven't settled on anything yet.

As I say any info, suggestions or brain waves would be very much appreciated!!

thanks in advance!

[ultimatehandyman]

What about this

http://www.youtube.com/watch?v=NH9Cd-g23kw

[peter c]

I would certainly try using Coke as it contains a small amount of phosphoric acid that was used in rust removal for car bodies many years ago. Many years ago at Tilbury Docks we dropped a flask of Coke concentrate on the quay and it cleaned most of the rust from the inlaid crane tracks!

HTH

Peter C