Oil seal holders Skewiff

[Neo from OZ]

Hi there,  I have a BSA Goldstar hybrid,  its has a scrambler motor and B33 frame,  done up in touring spec,  so looks the part.
I was refurbishing the forks and replaced the oil seal holders due to prior owner damage.....
Was a bit of a mission, stanchions stuck in the top of the gaiters (used a hot air gun,  worked a treat) new bushes a bit tight so had to hone the inside of the fork bottoms. Still; got to the end with everything working smoothly.
The replacement old seal holders (Chrome ones) looked great ,  the left went on OK but the right one appears to have had the thread machined a little off centre.
When its on, the fork the stanchion is not in the centre of the cover at the top,  out by a whopping 5MM.  So I cant get the spring in.  When I screw it in, the gap   goes around and around.  It screws smoothly right to the bottom so is not cross threaded.  I put the original (damaged) one on the fork and its perfect!,     
So I complained and they sent a free replacement, (Australian supplier),  but the replacement is exactly the same??
I was wondering if anyone else has had this issue.  Could be a bad batch? The supplier said he did have problems with tight threads but never with miss-aligned ones.

[Spaceman]

I have never come across a similar problem before with BSA fork seal holders. I would have expected that the seal holder would have been machined on a lathe even just to machine it to the correct length. Normally, the thread would be either turned on on the lathe or cut using a tap but still in the lathe in which case it would be almost impossible to cut the thread other than coaxially.
Even if you had cut the thread with a tap off the lathe, I would have thought it would be difficult for it to wander off axis.

That leaves the possibility of the machining being done on a CNC machine and someone has programmed in an angular error and ended up cutting the thread off axis. If this was the case, its likely that all the seal holders made in that batch and, possibly from that supplier, will have had the same issue. If so, you may need to go to a different supplier.

[Neo from OZ]

Thanks Spaceman

I took it to the engineers at work, after some measuring etc,  one of them held it up to the light and said, "you know its bent"
Then took out his steel ruler, one side was concave, the other convex, only slightly, but there, just the last inch near the thread.

They are pretty tough units so we could only surmise that they started slightly bent or it happened during the pressing or heat treatment.
(We think the threaded portion is pressed in, as the rest of the tube has a seam running down it.)
Although we only guessed at the manufacture
Just my luck, I get two of the buggers, no one else has heard of it.

[Spaceman]

Just looking at a spare seal holder that was lying around, it looks as though it is a 'seamed' tube - in other words, it started life as a flat sheet that was rolled into a tube and the edges then welded together. On my seal holder, the thread was definitely cut, probably on a lathe.

The part of the construction I can't quite figure out is how they engineered the internal flange that the seal butts up against. If they used heat in the process of fixing this in position then this could well have led to distortion just above where the seal sits. If this was the case, it is likely that all the seal holders made with this manufacturing method at this manufacturer probably suffered from the same problem.