The authoritative public forum
  for Metal Finishing since 1989
-----

Electroless plating for over size bore

Can the nickel plating withstand being a wear surface for steel or will it tend to flake off with time? I will need to plate down bore size .001 to .003 in diameter. Material is 4140. The product is air tools with a loose fitting piston riding on the bore.

Thanks

Dave Hart
Manufacturing company - Minneapolis, Minnesota
December 20, 2009

---

Hi, Dave. I think hard chrome plating the bore would be a much better approach.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 21, 2009

---

December 23, 2009

Ted,
In what other ways, besides being an older and still more available process can chrome be superior to EN for this application? Is it because its harder or do you foresee other problems with EN? Certainly, EN has an advantage over chrome in that it does not require a post-grinding operation.
Regards,

Guillermo Marrufo
Monterrey, NL, Mexico

---

Hi, Guillermo. My reply was based on book knowledge that chromium has a lower coefficient of friction, is able to retain lubricants due to its cracked structure, and can be built up very heavy and without any practical limitation on thickness. If your practical knowledge and experience tells you that electroless nickel is likely be good for this application, and is more practical because grinding isn't required, I can't challenge it.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 28, 2009

---

First of three simultaneous responses -- December 28, 2009

Hi Ted,
Thanks for your reply, I was just trying to learn.
I thought you were anticipating adhesion problems with the EN over this type of substrate. Would you say an extra Woods strike would be required in such case? About the thickness, it doesn't seem too much for a conventional mid-phos EN bath.
My best regards and warmest congratulations to you and your crew for this excellent forum!

Guillermo Marrufo
Monterrey, NL, Mexico

---

Second of three simultaneous responses --

A friend as well as others use electroless nickel in model boat and airplane engines. These run in the 20 - 30 K rpm range, so EN does work in some places. Since the build that he asked for is so tiny, He would have a rough time trying to have the same amount on all sides and not have any break thru on his grind or hone step after plate. I would certainly give EN a try.

James Watts
- Navarre, Florida
December 28, 2009

---

Third of three simultaneous responses -- December 29, 2009

I read the question several times. Then I copied and pasted just to be certain.

"I will need to plate down bore size .001 to .003 in diameter"

I would like to meet the plater who can plate chrome down a bore this size.

Apart from this we have the usual problem of trying to answer a partly stated problem.

What is the piston material, design life, is lubrication possible, operating temperature, length of the bore etc.

To answer the original question, properly plated nickel will not flake off. Wear is a different question.

Geoff Smith
Hampshire, England