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
I've just noticed my receipt identifies my new screws: 2BA X 3/8 . Phil
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
Hi Phil,
Part number 02-1309, dimensions should be 2BA 5/16" long.
Best wishes...
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 My receipt says part number 02-1309 superseded to 12743-54. 2BA X 3/8.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.
Small screw, I meant to say.
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.
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
for reference
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...
Thanks very much. Ordered a couple of 2BA x 5/16 from BA Bolts. Phil.
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
List looks very useful, Chaz. Thanks.
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.
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.
I meant to say "I thought", not "no thought". Big fingers, small phone.
I should perhaps just clarify that although, at the time, I was a bit annoyed about Draganfly wanting me to return the items before refunding me, I did try not to show it. I didn't have a go at him or anything like that. He was just doing as his boss had advised him. And, as I say, on reflection I guess maybe it's fair enough. Just seemed they were such small items, one of which by then was damaged, that the trouble and cost of returning them would be silly. And they were semingly the wrong item, ie too short. I'm not sure he was convinced they were wrong. Phil
Is it really 2BA? Checked the spare parts manual for the -67 B40 Mk1. It states the screw #41-5141 is a "SCREW, MACHINE BSC, steel, cadmium plated, 3/16 in. x 11/32 in." It should have 32 tpi.
Though the -65 B40 parts manual has part number 01-02-1309. No mention of dimensions.
2BA and 3/16BSC are quite close in dimensions. o.d 4.7 to 4.762 mm. thread 31.36 vs. 32 tpi or in metric 0.81 vs 0.79mm.
Of course BSA could have changed dimensions, but for what reason?
Very interesting, Mike. Thanks very much. Having read this I've had another look at the screws, old and new, armed with my 0-1mic, my tpi gauge, and my 6" rule. As best I can tell (whilst cursing the fact that my eyes water more and more as I get older), the 32tpi gauge fits the old screws better than the new ones. And the length of the old ones does actually look more like 11/32 than 5/16 as I previously thought. The dia of the old ones is about 0.183" towards the shoulder and about 0.177" towards the end. They are loose in the hole when screwing in, very loose to begin with. The dia of the undamaged new one is about 0.187" towards the shoulder and about 0.182" towards the end. I believe 2BA should be 0.185". Presumably 3/16 BSC should be about 0.187". So considering all that, I guess you could be right; maybe they should be BSC. But then Bess seemed pretty confident they should be 2BA. I've attached a photo showing the old and new. You can see the damage on the new one I screwed in. All very interesting. And frustrating. And a bit concerning, worrying I might have damaged the female thread by screwing in one of the new ones. I wonder if BSC screws are very available - I'll have a look online. Might be worth trying them as well as the BA to see which is the better fit. Phil
Hi,
Here is the part drawing from the member area showing part number for your year, if you google the part number the dimensions come up as a 2BA.
https://www.bsaownersclub.co.uk/members_area/parts_page.php
Best wishes...
Been looking online. 3/16 BSC screws are a bit like hens' teeth.
I think the old screws, rightly or wrongly, are 3/16 X 32 BSC. But I can't find any. Phil
Phil
when you compare your sizes, 32tpi =0.031" pitch, 0.7mm =0.027" 2BA = 31.4tpi , 5mm threads are normally topped so 4.8 or 4.9mm diameter.
5/16" =0.312" or approx 7.928mm, thread angles are 60 degrees so all points to metric 5mm supplied , its the easiest option to supply nowadays.
Just to let you know what I did in the end. The 2BA x 5/16 cheesehead screws arrived promptly from BA Bolts and I have fitted them. Very slightly stiff, but only very slightly. They are mild steel and don't appear to have any kind of plating on them, so I just gave the heads a smear of grease. Put the oil in (10w30) and all okay. Thanks again. Phil
PS after what seemed like six months of constant rain until spring came along, this sunshine is very nice, isn't it?
But actually I think I'll replace them next time I change the oil with some plated or stainless ones, which I see are available online. Phil
Don't worry Phil, being in contact with oil they shouldn't rest, well not internally.