hi everyone,
would you happen to know the exact threads on the bolt 66-4168 and 15-4169? These bolds go through the gearbox and frameplates to fasten the gearbox. I also like to know if there special "thoothed" washers were used to prevent these bolds from shifting ?
hope that you can help me out.
Hi Arnold
The gearbox bolts, long & short - nuts, and most of the adjuster mechanism parts are available relatively easily nos bsa - except
27-5710 gear box adjuster
This is available in repro form but some are truly awful in manufacture terms / finish
The other parts which are very hard to find are the large serrated washers used to stop the gearbox creeping on the adjuster grooves - just now I cannot find the part numbers for these /
some stainless steel suppliers provide some these - some a lot better made than others -
Barleycorn corn engineering make all this in st steel - so a good place to stop & look
Mark
As I said - most of this set up is available with exception of the gearbox adjuster/ eye & the serrated washers - these I think would be welcome from you as most of the serrated washers found these times are worn & have little or no effect on hold the box in place
Rigid and plunger tele fork models use a serrated washer on the front stud...Swinging arm serrated washers are thicker but I've turned them down to use them on earlier bikes..I usually fit serrated washers to WD bikes but the thickness is an issue that needs to be addressed...I've also made longer studs in the past so the nuts can be made thicker and they can be tightened more without fear of stripping the threads..Clearance on the front stud can be a problem in that case...Ian
okay, I get the picture... thank you all for your more then complete hub of answers....I'm happy to learn that indeed some kind of washers were used to prevent the gearbox from "shifting" forward.....the modern sharp serrated washers I can use on front and rear bolds as these bolds have original NOS-length.... I also have been busy making new bolds 12mm length overstock wich will alow thicker washers anyway. hope to find the No: 65-4189 as I expect them to less damage lthe paint of the plates and therefor limit the challange for corrosion as this all happens in an almost unreachable downsection of the frame.
I have seen bsa riders who had keggs of wood between gearbox and frametube to keep the gearbox in place..... any other suggestions...welcome
Arnold
A stock standard serrated shake proof washer does the same job
Down side is it will dig into the steel &/or paint and may leave dimples
A std BSA M20 is no challenge for the box bolts
Now a 50-60 Hp Goldie is a different story
If you use a serrated washer you have to fit a thick high tensile washer between it & the nut
Never thought about longer studs & double width nuts
The adjuster would be fun to thread John. Being made from a casting I guess that would lend itself to being turned in a centre lathe. I expect our resident tool maker Ian might have a better idea.
As for the washer I guess it's the one in the technical section. No problem getting it hardened and tempered.
At the moment I'm buried in aluminium turning with the billet pile growing every time I turn my back. As soon as I'm back on steels I'll run off a few more trinkets.
The gearbox adjuster is available in stainless steel from Barleycorn Engineering (as are all the other gearbox mounting parts)...I've made one for myself in the past and machined it from solid as he has done, though that does require some hand finishing...To machine a casting I'd imagine machining the 'eye' would be the first operation using a jig and then a (lathe mounted) jig to hold it whilst the other end is threaded...I haven't studied one closely to detail that though holding it is obviously the issue... Ian
has anyone got a website address for Barleycorn? My link seems to have been discontinued and I can't find a current site for them.:white_frowning_face:
thanks, thats the same link that I have....and now mine is working as well.....wierd, it kept coming up as discontinued before
must be another consequence of Brexit (I'm in Germany) :slightly_smiling_face: