Fork drain screws ( 1965 B40F)

[Phil C]

Hello everyone, I drained the oil from my forks, and ordered some new drain screws from Draganfly. Hard to be sure, as it's so small, but  as far as I can tell, the pitch on the new ones looks the same as the old (2BA?) and the thread dia measures the same (0.183".) I noticed the new ones were a bit longer than the old, but went ahead and tried to fit one of the new ones. It was a little bit tight going in, which I was a bit uneasy about, but I was very disappointed when it bottomed before it was fully in, so the fibre washer is loose.They new screws are cheesehead and the thread length is about 10mm ( from under the head) whereas the length of the old ones is one is about 8 + 8.5 mm. Does anybody know what length they should be please? I'm a bit worried I've got the wrong screws and that the slight tightness as I screwed it in might have damaged the internal thread. Hopefully not.  Nothing in life is straightforward!  Phil

[Phil C]

I've just noticed my receipt identifies my new screws: 2BA X 3/8 . Phil

[Phil C]

I've also just noticed that the crest of the thread on the new one I tried to fit has flattened off. Hence the tightness, I guess. Any advice please? Phil

[Bess]

Hi Phil,
    Part number 02-1309, dimensions should be 2BA 5/16" long.

Best wishes...

[Phil C]

Bit disappointing. My receipt says part number 02-1309 superseded to 12743-54.    2BA X 3/8.
Draganfly suggested I cut them shorter, but I explained that's very fiddly with such a short screw. Anyway, they wouldn't refund me unless I return them.

[Phil C]

Small screw, I meant to say.

[Phil C]

Bess, You're obviously right, but where do you get the info that they should be 5/16"?  I see the part on the parts diag but I don't see the length given.  Phil.

[chaz]

a familiar problem, as others may say, M5 is close to 2BA, Drags supplied a M5 screw for the 2BA on the rocker cover on the B40.
you could get a M5 with a nut , screw the nut up to the head, saw off and file the end so the nut moves easy.
alternatively, run a 2ba die down the thread....
I wonder, if the screw supplied is a M5?

with regards to thread length, I refer to Baxters..
https://www.baxtercycle.com/product/02-1309/
or Ive got a table of bolts and screw threads from somewhere

[chaz]

for reference

[Bess]

Hi Phil,
           I had an incomplete list of all BSA fasteners and spacers. Over the years I have been updating and filling in the missing information etc. From that I have started to add the fastener dimensions to the parts manuals which saves time when building/maintenance etc. The A10 for my year is finished and going to start on the A65 for my year sometime.

At a guess, Draganfly have bought the standard manufacturers supply length of 3/8" and passing it off as the correct fastener. If you google 2BA screw you will probably get lengths of 1/8, 1/4, 3/8, 1/2" etc. If you're not too fussed on originality use a dowty seal in place of the fibre washer, you may not need to shorten the screw as the dowty seal is thicker (and better). I use them with cap head screws, which are easier to locate and tighten than the normal cheese head screw.

Best wishes...

[Phil C]

Thanks very much. Ordered a couple of 2BA x 5/16 from BA Bolts.  Phil.

[Phil C]

I confess I was a bit annoyed when Draganfly wouldn't refund me unless I returned the parts, but on reflection I guess it's fair enough. Otherwise I suppose some people might abuse the system.  Phil

[Phil C]

List looks very useful, Chaz. Thanks.

[DAVE BRADY]

Hi,

I think the supply of 'superseded' (superseded by who) numbered parts is a bit of a copout and is an excuse for a lack of diligence.
If Phil can find the correct length screw then why can Draganfly, professional suppliers of long standing, not do this.  If they were upfront and explained that a bit of shortening may be needed then fair enough but the wrong thread, no matter how close it is, should not be accepted.  We deserve better.

Dave.

[Phil C]

I don't know that the thread was wrong in my case, in fact no thought the tpi looked okay and the dia okay for 2 BA, but for some reason there was something amiss when I screwed it in, and it came out with flattened crests. I wasn't cross- threading it, by the way. Could be the female, in which case the screws I've ordered will show that I guess. But the length was wrong: I need 5/16, it was 3/8 and bottomed out in the hole before the fibre washer was compressed.