When parts like shafts, rods and bearing surfaces are worn to beyond tolerance, part disposal is not always necessary. The wear can be reversed by chrome plating and subsequently grinding back to the original dimension of the part. Often this can be done for a fraction of the cost of new parts.
Assessing Whether the Part Is a Viable Candidate
First we check for any surface damage on the base metal. This could include cracks or deep pits as well as possible corrosion. Any of these could prevent a good bond between the new plating and the metal. We find that parts that have only minor wear (typically being a few tenths of a mm undersized) make good candidates for chrome plating. Items that have suffered severe material loss or structural damage are generally not suitable for repair by plating.
Preparing the Surface Before Plating
First the old chrome surface needs to be completely stripped back to the base metal. This surface will then need to be ground to remove any fatigue layers and cleaned to remove any grease, grime or oxide. Any surfaces that are to remain un-plated (such as threads and bores) will need to be masked up before the stripping process.
Building Up the Chrome Deposit
Chrome plating builds up the chrome surface slowly in an electroplating bath and it is important to control the thickness of the deposit. For Chrome Plating, see https://www.poeton.co.uk/advanced-treatments/apticote-100-hard-chrome/.
Grinding Back to Tolerance
Post-plating the part is ground on a cylindrical grinder to remove the excess chrome until the part is at the required tolerance as specified on the drawings. Because of the very consistent hardness of chrome it can be ground to give a very fine surface finish.
Final Inspection
The repaired part will perform as well as new components. As with newly plated components, dimension is checked and the part will be tested for adhesion and hardness.
Provided the part is worn but still sound, chrome repair offers a highly cost effective solution to returning the part to full service.