Fixation from the spindle of the front wheel

[AdrianJ]

My Plunger A10 has a bottom slider with a lug for the brake cable like Lippi’s but the fork bottom is threaded. I have assumed that it came off a B something. As it is fine in all other respects it seems sensible for me to keep it, the lug is redundant.
When I bought the bike the spindle that was in was straight with no step and packed with about 5 washers on the left hand side. It was a wonder that the wheel turned at all.

[Lippi]

Hi all

Thanks for all your inputs. It seems to be difficult to get a fork slider. Nevertheless I still search, but I have maybe a solution which should work.

I plan to turn down the spindle approximately 1 - 2mm in the diameter and make a fine pitch thread on it. To fix the spindle to the fork slider I will turn a stainless steel counterpart. Also with a fine pitch thread to fix it to the fork slider. From my point of view it should work and it is easier to get a new spindle instead a fork slider.

Attached you will see how I planned it. It would be gread if you can give me some input. This is just an idea without any dimensions.

Cheers Lippi

[chaterlea25]

Hi Lippy,
The only "snag" I can see with your plan is that the outside of the fork leg is not flat for the nut to sit against
This why I suggested a threaded sleeve
Is the spindle thread damaged?  If it is OK the tap for the sleeve is the same as old type bicycle pedals so taps are available (Try a long established cycle shop)
Keep the spindle size as large as possible if you go to machine it originally 9/16 =14.5mm

John

[Lippi]

Hi John

What do you mean with a threaded sleeve? I can't imagine, sorry, different languages :-)

Could you make a sketch for people like me :-)

Thanks and cheers

Lippi

[chaterlea25]

Hi Lippy
Something like this image, threads inside and outside of a steel sleeve
Tap out part of the fork leg and screw in the insert with loctite on the outside threads to secure it

John

[AdrianJ]

Just curious. Would both threads need to be left handed?
Adrian

[berger]

i think the left handed thing was good old fashioned engineering and if the bearings locked for some reason it wouldn't undo the spindle , but there is little chance of that happening present day also the other side has a pinch bolt to nip the left fork leg to the spindle, notice the clue in the word pinch, not 65ftlbs and possibly smash the leg, that was a mistake some people made on the ally notrun legs

[Lippi]

Hi all

I checked the surface from the fork slider. It looks there was a machining work after casting. The surface looks milled. I assume the flatness is sufficient for a sleeve nut. Do you agree?

Cheers Lippi

[Swarfcut]

 
 Lippi. The crankshaft has a left hand thread on the oilpump drive, so the locking nut used here, part 67 643 could be used to fit on the end of the wheel spindle as it is the same thread.

 Do not remove metal from the fork leg, just turn down a few mm from the large diameter on the spindle so that if fits further into the wheel hub, and the spindle sticks out a little bit more to take the nut. The thread showing is not enough to take a nut safely.

 Some folks may not think this a good idea, altering spindle, but you should be able to get this left hand nut easily from British Bike suppliers and is an easy fix and better than what you have. The proper fork leg is what you really need.

 Here is a link for a UK supplier:  https://www.feked.com/bsa-crankshaft-timing-side-pinion-drive-nut-a50-a65-a7-a10-models-lh-thread.html

  The company name is a variation of the English slang term meaning "broken, ruined", as in kaput.


 Swarfy.

[chaterlea25]

Hi All,
Swarfy, The threaded end of the spindle looks loose in the fork leg so a plain nut would not really work????

John

[Swarfcut]

 CJ.  Yes I can see that, and  the spindle end needs supporting with an insert into the fork end. The problem is the geographical location and the unusual thread required. Not easy for Lippi to sort.
   
    As I see it, any fix is better that what is there now. The spindle is supported poorly by the top hat bush in the hub, where it enters the fork slider.  You could grind down an old oilpump scroll (if you had one) to make a matching internally threaded  sleeve to suit the  spindle thread and the hole in the fork end.  Just thought  nut 67 643 would be easier to obtain than the correct fork slider, and in the short term get the bike back in use with a greater degree of safety than before.

 Most practical answers are a custom spindle, with a longer thread to suit a modern fine thread nut, and your threaded sleeve solution.

 Swarfy.

[Jules]

Hi Lippi, seems like we are all suggesting similar things to what you are proposing that you think you can do! I would have thought that  machined surface on the side of the slider should work ok to seat the sleeve you are proposing (no different to Swarfy's idea of seating a nut against it) which seems to all intent and purpose what John is proposing too, its just how your sketch is drawn (very thick sleeve) vs John's pic of a thin sleeve....
in the meantime fyi, I've dealt with this company in the past for bits and they may be a bit more local to you, I cant comment on their quality now though, sorry....
https://degroot-bsa.nl/
Lets know how you end up  , cheers

[Lippi]

Hi all

First of all, thank you very much for your effort and your inputs.

I think I go for the solution which I sketched before. The main reasons are:

- I just have to modify the spindle (if I will find a fork slider, I just Need to exchange the spindle)
- A friend of mine is design engineer and I have relations to a machine shop with expierience with Stainless steel

I will measure all the parts and my friend will make a drawing for the sleeve. In parallel I will search a fork slider. Thanks for the link to the dutch men :-)

I will Keep you updatet!

Cheers Lippi

[RichardL]

Lippi,

Sorry to enter the discussion late, after you've seemingly settled on a fix. If this were mine, I would look hard at Swarfy's method with his additional suggestion of a plain insert (bush). It looks like there is already enough gap to fit one. If the bush has quite a thin wall, that would likely be OK, as it only has to stabilize the spindle as it passes through the leg. One thing I would change from Swarfy's thoughts would be to machine the large end enough to allow a washer as well as the nut. To me, creating the bush and turning down the large end of the spindle seems like less and easier machining than turning down and rethreading the spindle, then creating a thin-wall shoulder nut, not to mention internal and external left-hand threads (if left-hand was your intention).

Whatever method you choose, we will be most interested to see a bunch of photos of it.

Richard L

[RichardL]

Oh, one more thing about this. While, at first blush, it looks like there may be some concern about how far back you can turn the large diameter without obscuring the lever hole, the lever hole is really irrelevant in this method (that is, the "Swarfy Method").

Richard L.