Defective Barbs

[101]

I got a mixed bag of 3/8" fat boys from Petra's a while back, and wondering if anyone else has seen this issue. The problem is the diameter of the fitting after the machined threaded portion stops. On some of them, the diameter past the thread is at the thread minor dimension, as it should be. On others it is much larger and closer to the thread major diameter.

This causes a problem as the fitting cannot be fully threaded into anything unless the thread in the block/etc. is reamed out near the opening. Obviously this is an error, but I am curious how wide spread it is as I have not seen it mentioned. It is difficult to search for this issue as you would imagine, and I have not found any other references to the problem.

I just emailed Alex and have not heard back yet. Keep in mind the fittings shown are from the same order, so a mixed lot or something. Additionally, I have removed the o-rings from the fittings to more clearly illustrate the problem.

Any thoughts? All of my older typical 1/2" fittings all stay at the minor thread diameter as they should. I have never seen this problem before, but it could certainly be a huge issue given how little compression occurs on the seal.

http://img225.imageshack.us/img225/3280/barbs2textwn0.jpg

http://img508.imageshack.us/img508/2323/block2textfk2.jpg

[sirheck]

Wouldnt the (bad) ones use an O-ring?
Or did they come with the wrong size O-rings?

[IanY]

I would call PTS and I'm sure they'll replace the barbs.

[skinnee]

good catch! Definitely call PTS about the problem.

Hell, you could point Alex or Quoc to this thread, they'll correct it for sure.

[eXa]

Wait... dont the Fatboys have a countersunk O-ring?

[skinnee]

Yes, but there is still o-ring compression.

crap...lemme go get the camera and end the speculation. :rolleyes:

[101]

The recessed o-ring is very minimal. I didn't take a whole suite of pics showing various stages of seal compression. The point of the pics is to clearly illustrate that the one on the right would be stopped by the o-ring compression, and the one on the left would be stopped by the poorly machined fitting. I clearly state I removed the seals for the pics.

[eXa]

Ok... just looked like it wasnt anything there in 101s picture

[Zaskar]

Ive gotten screws like that before, definitely something that needs to be checked on any threaded item, good catch.

[sirheck]

Yes, but there is still o-ring compression.

crap...lemme go get the camera and end the speculation. :rolleyes:

The (bad) one looks to me like it is suppose to have a certain
size and dia. O-ring. Hence why it has the smooth spot and stops
(positive stop) style, after being snugged down for compression of said O-ring
so one cant split or push out the O-ring if tightened too much.

:shrug:

[eXa]

It just look like bad work\QC to me... even barbs without countersunk O-rings usually screws all the way down.

[101]

As a side note, I am surprised at how poor the machining quality is in general on these fittings. Just look at the flats on the hex nut area, or anywhere for that example. Extensive machining marks on everything, extremely low quality compared to the typical "high flows" that come with just about everything these days.

[Zaskar]

Ehh for 3-4 bucks, cant expect more :D

[Lloyd]

looks to me like on hasn't been finished properly! Defo RMA IMO