502b from Fasttech... very poor threads.

I recently received several 502b hosts from fasttech, to build some robust single mode lights for colleagues.

I’ve assembled only 1, and the threads at the drop in end are so poor I can push the thing together all bar the last couple of threads, which then only just tighten enough to hold against the spring pressure.

Anybody had similar, or have I been unlucky?

I purchased a 502B host from fasttech last year and I had no problems with it. I wouldn’t say it was Solarforce quality, but good enough for the 5.25 I paid for it. It might be the current batch fasttech is selling isn’t that great.

You might consider contacting their CS.

The 502 has always been hit and miss , so nothing has changed for half a decade ... ( oh well )

If you want more hit than miss ( far more ) a Solarforce host might be worth while considering ...


502B’s are about the cheapest 18650 host you can buy, most have crappy threads, have had them with threads like you describe before. I don’t buy them any more because of the low quality, spend a few more bucks for a better host. Wrap the threads in aluminum foil and it will make the light usable.

Dang…that’s sad. The 502B’s I got a while back had awesome threads, a very good GP host

Unfortunately, it seems a hit always goes to worse and worse quality…sad

To the OP…take pics, send ticket to fasttech’s support group…explain to them that the threads are horrible and get your money back (this is one of the main reasons I like fasttech, their customer support has always been spot on…no so much with other “wholesale” Chinese sites)

Agreed, the Convoy stuff ALWAYS seems spot on

Sucks that quality control is so squiffy…but what do you expect from China?

dont u get what u pay for? the QA in china is a hit or miss sometimes…

I have a nice Solarforce L2 that I use at home…too nice for work!

I currently have a 504b at work, but the bezel end suffers and peens over when dropped, which happens from time to time…so as the 501b seems to be slated I thought the 502 would be a safe bet!

Wish I’d gone for Convoy S2s now…

A good many 502B and 501B have passed through my hands, some were of excellent quality, some were crap, but generally speaking, these that are manufactured 5-6 years ago were better build than a recent production.

Miss installed rubber ring on the lens, it is pinched and there is no way to remove and reinstall without destroying the retaining ring.
Head threads are loose and if you tighten up, it slips and jumps. No way to improve it other than plumber’s tape.
Tail cap threads are loose and very very coarse. Came cross threaded from the factory. Threads on the body tube is goner!
Tail switch is stuck on “on” Cant be turned of.

Will need a replacement. |(

I do not recommand 501b hosts from FT at this point in time.


rather than tossing them away you can clean the threads up with steel wool then wrap it once tightly with electrical tape to smooth up the lines.

it usually helps making things “feel professional” in my case.

+1 on the tape idea.

I used to keep an iTP A3 with my keys, but the threads were crap and got destroyed simply by being carried with keys in my pocket. I applied a few layers of thread seal tape, and it tightened things up to the point where the head no longer skips threads or pops off on its own.

Yep, sounds exactly the same as mine. Cheap is one thing, but unusable is another.

I have a few. Copper line the P60 area helps secure things. Thermal paste helps too. But a bit messy when you go to change things. I also brush the threads with a copper wire brush and lots of Nyogel. Seems to help a tad. But still junky. I take the pocket clips off and fill the holes with silicon. I know, ghetto, but it works.
Now I like the Solarforce hosts for my builds. Much better quality and more customizing options.

Seems to me simon was selling some 502b's too so you might ask him if his are of a decent quality or not ... i have plenty of the older ones that are perfectly fine . i think it's just such a reproduced light that there are going to be good ones and ...bad fakes ..or good fakes and bad real ones ..Who knows ....

i got a 501B from dino direct a long time ago with a really old emitter in it on clearance for next to nothing ...and thought OH man ...Look it's a real ultrafire 501B ...not a clone of a clone of a clone .We're not talking a million times better but the anno was way nicer .. the knurrling much cleaner . the threads way better and over all just a much better light ///this was back in the day when about everything manafont ever sold was a ultrafake ..i think the MCU c-c88 was the first time I realized ultrafire actually makes a nice light ..same with the UF-980L.it was clear that it was in a league of it's own .

When people wanted to buy the ebay ultra-fire looking 980L's for about half price i knew there was no way in hell they were going to get a real one . the quality was so good you could even see it in the pics.

I would like to add one more thing that is wrong with the host I received. The space in the head where the drop-in sits…. it is too wide.
So in adding foil/tape to the drop-in is very inefficient due to having to wrap too many times around the drop-in. ;-(

Such a shame.
At this point in time, I would suggest everyone stay away from this.

Cheers folks.