Wilson Steel Bushing vs Redding Nitride

[ireload2]

You can check out PVD TiN coatings around the web and some vendors will list the thickness. I am pretty sure Redding knows nothing about the process and contracts it out.

Here is Endura coatings
>>>Our proprietary PVD coating systems possess precision thin film architectures. The average thickness of our various PVD coatings range from 2-5 microns (0.00008" - 0.0002") per surface. http://www.enduracoatings.com/vapor-hard-thin-film.html

http://www.tincoat.net/tin.html
>>>>Properties:

• Thickness: .0001" - .0002"

 

[ASbobcat]

So, with your set, is there no correlation between which end is stamped and which is smooth?

Also, does every bushing have one, and only one, smooth transition?

Finally, how do you tell the older bushings from newer ones? (I have a couple with a different looking stamping - the numbers are "thicker" and the stamping more pronounced or deeper. The others look more like they were etched rather than stamped.)
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I cannot find any correlation between stamped side and smoothest bevel side. Seems about 50/50. Also, some of my stampings are huge and some are so small I have trouble reading them even with glasses.
If you hold the bushing at an angle with very good light and a good magnifier you can see either a smooth radius (old) or a sharp bevel (new) on each end. I have found a significant difference between the size of the bevel at each end in every bushing I've inspected.

I am just about to abandon TN bushings for another reason. The TiN, as with the TiC in their pistol dies, has an affinity for brass shavings. I'm really getting tired of having to polish my bushings. TiN is not significantly harder than hardened steel (Rc 85 vs Rc80-82), but it is self lubricating. That is the main difference. But you pay a penalty for this because brass also galls into it easier.

 

[ASbobcat]

Quote
In most applications a coating of less than 5 micrometres (0.00020 in) is applied.
I think you will find you cannot measure the thickness of the coating. These coatings if applied by PVD or CVD are very thin ceramic coatings.

I have no use for the coated bushings. If there is a problem with one it can only be polished with diamond paste (which removes the coating) or it has to be returned. The steel bushings can be polished oversize, chamfered, radiused or tapered as required.

I am considering going back to steel bushings, but for a different reason.
I bought a set of Redding TiC pistol dies and returned them because the "self lubricating" surface was also a magnet for brass chips. I was literally having to remove the galling every five pieces. The TiN in their S bushings shows the same property. I've had it with scratched necks and repeated polishing. Applying and removing a small amount of case lube is a lot less trouble. And with Lee lube you get the added benefit of a very thin protective carnauba wax coating. This film minimizes tarnishing and adhesion of carbon residue.
Another option I'm considering is converting to Forster FL sizing dies and having the necks honed to my spec. Best of all worlds.

 

[ASbobcat]

So, with your set, is there no correlation between which end is stamped and which is smooth?

Also, does every bushing have one, and only one, smooth transition?

Finally, how do you tell the older bushings from newer ones? (I have a couple with a different looking stamping - the numbers are "thicker" and the stamping more pronounced or deeper. The others look more like they were etched rather than stamped.)
-

I have discovered the cause of the scratched necks with TN bushings (disregarding the one faulty bushing that I had replaced).
I annealed the necks and forgot to polish them before resizing. A thin layer of Copper/Tin oxides is formed on the case when heated to annealing temperatures and these oxides are extremely abrasive.
I polished the bushing and the necks and that fixed the problem.

It then occurred to me that if there is oxidation on the outside of the necks, obviously it's going to occur on the inside as well. This explains why I was seeing scratches on the inside if the necks, even after passing over a carbide expander button. Normally a carbide button would "iron" clean brass smooth. So now I'm going to polish the inside of the necks as well as the outside after annealing.

I have found Flitz LIQUID media additive (not paste) very effective at polishing brass without tumbling when applied with soft cotton cloth.

 

[MTSLW]

Great info! I really appreciate all the knowledge on this site.

 

[centershot]

I use Barkeeper's friend.

 

[DocDoc]

I have discovered the cause of the scratched necks with TN bushings (disregarding the one faulty bushing that I had replaced).
I annealed the necks and forgot to polish them before resizing. A thin layer of Copper/Tin oxides is formed on the case when heated to annealing temperatures and these oxides are extremely abrasive.
I polished the bushing and the necks and that fixed the problem.

It then occurred to me that if there is oxidation on the outside of the necks, obviously it's going to occur on the inside as well. This explains why I was seeing scratches on the inside if the necks, even after passing over a carbide expander button. Normally a carbide button would "iron" clean brass smooth. So now I'm going to polish the inside of the necks as well as the outside after annealing.

I have found Flitz LIQUID media additive (not paste) very effective at polishing brass without tumbling when applied with soft cotton cloth.

Ti is titanium not tin.

 

[ASbobcat]

I use Barkeeper's friend.

Good idea, I'll try it.

 

[ASbobcat]

Ti is titanium not tin.

I wasn't referring to the bushings, but I'm sure others appreciate the chemistry lesson.
Point is, virtually all metal oxides are abrasive, some more than others. That includes Copper, Zinc, Iron and Tin, among others. Which one, and it's symbol on the Periodic Table is not important to the discussion. The point that they scratch our bushings, and that it is preventable is.

 

[Webster]

Quote
In most applications a coating of less than 5 micrometres (0.00020 in) is applied.
I think you will find you cannot measure the thickness of the coating. These coatings if applied by PVD or CVD are very thin ceramic coatings.

I have no use for the coated bushings. If there is a problem with one it can only be polished with diamond paste (which removes the coating) or it has to be returned. The steel bushings can be polished oversize, chamfered, radiused or tapered as required.

Just Googled TiN coatings on machinist cutting tools. The thickness is typically 0.0001" - 0.0002". The bushing manufacturers probably hone the bushings 1-2 ten thou over to account for the coating? Don't understand the need for TiN. It's main purpose is wear resistance for tool life and anti galling when cutting steel and other metals that might gall and adhere to the tool bit. I don't think either is an issue sizing brass. Don't think it's self lubricating. I would lube even if it was. You have to lube the case body so it only makes sense to lube the neck. I don't think your going to wear out a hardened steel bushing? I have seen brass adhere to my FL dies once in 45 years. The problem occured from not chamfering the neck O.D. and FL sizing. Small raised pieces of brass broke free from the O.D. of the case neck mouth and got dragged into the body area of the die. Never checked TiN. The coating doesn't have to be thick to work, it needs good adhesion to the tool. One of my jobs was QC on Cr, Ni and Cd plating on military parts.