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Re: Chrome plate of press bushing housing
Re: Chrome plate of press bushing housing -- hak440	Post Reply	Top of thread	Forum

Posted by: Kelly_Bramble ® 04/24/2006, 12:47:55 Author Profile eMail author Edit

Ultimately, there is nothing wrong with a chrome plating specification, however the following are some challenges. When you plate a press fit hole, you introduce several manufacturing problems. Press fit holes are tight toleranced, and controlling the hole diameter and roundness can become a challenge. Plating is not as consistant as one may beleive. I don't care who's specification you use. The plating thickness is never as controllable as we would like or think it is. One challenge you can have is a phenomenon called "dog-boning". When applying chrome plating (or any metalized plating) there is a tendancy for the plating to be thicker on the sharp edge areas. This can cause size challenges with the press fit hole. Moreover, the plating tends to scrape away while pressing in the bushing. This can cause binding and galling of the hole surface and bushing (stress riser). The bottom line is that controlling the press fit hole diameter becomes twice (if not more) as diffulcult and the press fit installation becomes less predictable. A solution often incorporated is masking the press fit hole during plating operations. Some care should be taken to ensure that the chrome/material stop edges are properly manufactured and sealed. I have seen Zinc Chromate specification required between the bushing and press fit hole. This is a good ideal anyway, as the Zinc Chromate primer will help seal out the oxygen (corrosion) between the bushing and base material, as well, as help secure the bushing in place. Often, the Zinc Chromate is "thinned" using an acceptable thinner. This helps the primer to distribute evenly during the bushing press fit installation. In general, plating a press hole sounds like a good design/engineering ideal, however it virtualy always drives up cost, rejects, less predictable, and is just a general problem to manufacturing.

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Re: Chrome plate of press bushing housing
Re: Chrome plate of press bushing housing -- hak440	Post Reply	Top of thread	Forum

Posted by: Marky ® 04/24/2006, 12:43:41 Author Profile eMail author Edit

Mask the area of chrome in the area that is press fit. Is the chrome plating for aesthetics purposes? If so, leave the chrome off. I would like to know that if I were in a plane or helicopter and the landing gear failed it was because something with chrome plating failed....but looked nice. I would like to be the lawyer $$$$$. It will be the shinyist plane wreck in history.

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Re: Re: Chrome plate of press bushing housing
Re: Re: Chrome plate of press bushing housing -- Marky	Post Reply	Top of thread	Forum

Posted by: Kelly_Bramble ® 04/24/2006, 12:49:07 Author Profile eMail author Edit

LOL "It will be the shinyist plane wreck in history." Thats funny!

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Re: Re: Re: Chrome plate of press bushing housing
Re: Re: Re: Chrome plate of press bushing housing -- Kelly_Bramble	Post Reply	Top of thread	Forum

Posted by: randykimball ® 04/24/2006, 23:23:52 Author Profile eMail author Edit

It is sometimes necessary to chrome a hole or male part then grind to size. This is quite a lot of expense. Why are we applying chrome to these parts? There are several other ways to prevent corrosion. For example when pressing a metal part into mag. the hole and metal part are wet primed with XPD prime (green chromate). If we are looking for hardness with a controled size, consider nitride (very little external build up, very controlled, and can be as hard as the mid 60's RC). The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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