For plating (trivalent 8-10micron) , there is regular nut can be used or there is special nut available in a market to qualify the thread plug gauge after platting
1. You won't need a special THREAD to allow for 8-10 microns of plating. The standard 6H (Medium) fit is designed to accommodate this and is normally ok up to at least 15 microns with a corresponding Medium fit bolt.
2. As far as a WELD nut goes, there are several types and it's "horses for courses" as far as selection goes. My company sell a range of what are called "Slab Base Teenuts" which offer a choice of projection or traditional weld fixing. These types are regarded as the best for strength and durability (i.e. don't fall off if welded correctly) and are used by the million by the top automotive manufacturers. They can be plated before or after welding, 8-10 microns Zinc with Trivalent Passivate is very popular. See them here http://catalogue.jetpress.com/Industrial.aspx?intGroupID=14035&strProductID=nzodctnx12&strWebTemplate=F
1) For plated parts (say fasteners) - we regularly use cadmium plated fasteners and nuts. These are made precisely to size before plating and after plating also these are to size - ie a 1.5" fastener will suit to a plated or unplated 1.5" Nut (as well as 1.5" Gauge) and same for the Nut.
2) Weld nut is totally different ball game.
3) And welding a plated fastener to nut - I have never heard. may be permitted but..
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I agree that the question is not very clear but I have to disagree with your suggestion about CADMIUM plating! This has been restricted (actually banned in many areas) for many years see The Environmental Protection (Controls on Injurious Substances) (No. 2) Regulations 1993 and I would certainly not suggest using it on a welded part as the fumes (cadmium oxide) are hazardous to health.
Also I do not understand where you have decided that this query involved "welding a plated fastener to a nut". A nut is a fastener.
Also, how can you make a fastener "precisely to size before plating" and it still be precisely to size after plating? This does not make any sense.
Sorry for the contraversy, but I think that you may be misleading the original poster. (See my previous post/rant regarding giving incorrect or misleading information to a naive poster who doesn't know better).
1) Cadmium coating might be restricted but it is permitted based on usage. refer BS 7371-3 1993 and also EN ISO 4042 - 2004
2) Refer my last comment (And welding a plated fastener to nut - I have never heard. may be permitted but..). And this comment is not only for Cd Plating for any type of plating.
3) Also I do not understand where you have decided that this query involved "welding a plated fastener to a nut".
The OP Title and the language give an indication to this effect that a welding is being carried out on welded components. So it was only a caution.
4) Also, how can you make a fastener "precisely to size before plating" and it still be precisely to size after plating.
It was never said that the size before was the final (after size). When a component is plated (not to be subsequently finished by metal removal) these are first finished to a size, obviously which is not the final size (or dimension)
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Fantastic ideas for a Fantastic World, I make the illogical logical.They put me in cars,they put me in yer tv.They put me in stereos and those little radios you stick in your ears.They even put me in watches, they have teeny gremlins for your watches
Cadmium plating is difficult to find these days. None of our suppliers has offered it for commercial applications for many years and it is basically only allowed for military purposes. (I am in the UK). Also why bother with restricted substances when there are so many other finishing options that are less expensive, easier to get and (supposedly) safe for the environment? I strongly suggest that Anush Kishor stays with his original plan to use trivalent passivate. The corrosion protection required will dictate the thickness of zinc and subsequent trivalent film and all platers will tell you what protection is required for a given salt spray rating.
A good engineering reference book will also confirm that medium fit threads will accommodate plating thicknesses up to approximately 15 microns on each mating part (i.e. nut and bolt) so 8-10 microns is well inside this limit.
Also, (off topic) bearing in mind the discussion regarding "Good Answers" on another thread, why has sb's post #5 achieved 5 "off topic" scores when it is so clearly very much ON topic?
Welt Nut for Plated Parts
Re: Welt Nut for Plated Parts
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