Author Topic: Fixation from the spindle of the front wheel (Read 2344 times)

RDfella · « **Reply #30 on:** 11.06. 2020 19:19 »

Been thinking about this a bit more deeply this afternoon. I have to say a bush would be my first choice were the spindle threading into a substantial casting, but it isn’t. Fitting a bush in the context of a slider and spindle means boring out the slider AND reducing the dia of the spindle, thereby weakening both. Were I doing it, I’d go for one of the following, in descending order:
1.   reduce head of spindle enough to get a half nut on the threaded end. If I was feeling particularly fussy, I’d slightly counter-bore the slider from the outside and give the nut a shoulder to enter the counter-bore.
2.   check to see if the present slider hole is of suitable size for a helicoil (I believe the original thread diameter is 9/16” – LH) If that is correct, I’d go for 9/16” UNF – RH on the basis there’s no close metric size and helicoils / taps and dies are available in those sizes. I wouldn’t worry too much about using RH thread. As berger says, it’s best engineering practise, but if a front wheel bearing seized you’d probably be coming off anyway. More likely insurance against an apprentice forgetting the pinch bolt. As an aside, Jaguar uses RH thread on its LH wheel hub spinners, and LH on the RH side! In that case, if your splines fail a wheel coming off is guaranteed.
3.   if (2) isn’t possible, I’d open out the slider hole to the next thread size (5/8” or M16) which is the size you’d have to go to for a threaded insert anyway. More than I'd like to remove from a slider, but we are where we are. Then, rather than using a bush and machining the spindle smaller to suit, I’d turn up a new spindle with thread to match the slider.

RichardL · « **Reply #31 on:** 11.06. 2020 21:16 »

RD,

I'm pretty sure you have your own machine shop and awesome machining skills, but what you've described just sounds sooo much harder than just buying one of these (see link) for about $2.50 (or making one), then, turning the outside of it to fit the inside diameter of the leg. It looks like there is about 1/16" of radial clearance all around the spindle, which I believe is more than enough for the static purpose it needs to serve.

https://www.mcmaster.com/6391K233

Plenty of other sizes and materials available through McMaster.

Lippi,

If you need a U.S. go-between that will mail it to you I can handle that. I don't know the EU equivalent to McMaster. (Does EU still include UK?)

All this said, it would be interesting to hear if my preference is blessed or cursed by others.

Richard L.

RDfella · « **Reply #32 on:** 11.06. 2020 22:00 »

Afraid you’ve lost me, Richard. First of all the hole in the slider will in all probability need machining (who knows whether it’s round or parallel?) And then I’m stumped as to how an oilite bush (as these are known in UK) is going to hold the spindle in place, or are you proposing threading it into the slider and tapping it to suit the spindle thread? That’s more work than I envisaged and, if I may say, unsuitable material. Oilite tends to be 'crumbly' so I doubt it would be possible to use it as a 'reducer' bush. Lippi does say he’s got access to excellent machining facilities and my option (1) for example should take a turner less than five minutes.

RichardL · « **Reply #33 on:** 12.06. 2020 00:34 »

RD,

For the record, because I am neither the most expert member here with regard to every possible A7/A10 nuance, and probably 100th in line for best machinist, I started my recommendation by saying I thought Swarfy had it about right. Here is part of what he said (with date and time, for your reference):

Re: Fixation from the spindle of the front wheel
« Reply #23 on: 10.06. 2020 10:23 »
Quote

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 it 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.

Swarfy's idea is, turn down the large plain diameter of the spindle so the thread sticks out further, then, put a washer and LH nut on what now sticks out. The PLAIN sleeve (be it oilite or steel, doesn't really matter) does nothing but stabilize the lateral or up and down movement of the spindle in the leg hole. As I see it, no threading is involved, no abrasion occurs and less wear than an oilite bearing would see when it's actually working as a bearing.

I also threw in that obscuring the lever hole should not matter with this fix.

Even though I'm a crappy machinist. I think I could have completed the job in the time we've spent talking about it. You could have done the same, with lunch and a smoke thrown in.

Richard L.

Jules · « **Reply #34 on:** 12.06. 2020 01:52 »

So there you have it Lippi, sooooo many choices and I'm sure you will work out what suits your circumstances the best lol. One of the best things I find about this forum is the depth of knowledge and understanding of these old bikes PLUS the depth of general knowledge that always helps when things look "bad", as Richard said earlier, lets know how you end up, cheers

Lippi · « **Reply #35 on:** 14.06. 2020 20:19 »

Hi all

Ok, so many solutions and I have to do the choice. But thank you so much for your inputs!

What I'm a little confusing, I don't think it is a left hand thread on the spindle! But let me doublecheck. Unfortunately this weekend I did not had time to work on my bike.

I think I will go for the solution from John with the threaded sleeve. I don't have to modify the spindle (adding weakness by reducing material) and the fork slider is not original anyway. I will take out the spindle and try to identify the thread dimension (not that easy in our metric environment). If I have everything, someone of you could help me to find a shop where I can get the sleeve and also the screw tap? Then I will make a thread and fix the sleeeve with Loctite 270.

Cheers Lippi

chaterlea25 · « **Reply #36 on:** 14.06. 2020 21:07 »

Hi Lippi,
Get an accurate measurement of the spindle hole in the fork leg
This will be a guide to selecting a thread for the outside of the sleeve,
I have left hand taps that suit the original spindle size, so could tap a steel piece for you or make the insert if you can decide on the external thread needed

John

Lippi · « **Reply #37 on:** 29.06. 2020 16:17 »

Hi all

First of all sorry for the delay. I had some other activities which I had to set priority on it, i think the name of it is job :-)

Today I measured all the parts and took pictures. The problem is, I'm (actually) absolutly not familiar with BS thread family. Therefore I measured everything. I fitted a BTH Magneto to my bike and the nut on the pic was also delivered but it was not necessary to use it. But now I'm happy to have it. It has exactly the same thread as the spindle. The borehole in the fork leg has 16mm diameter.

Guys, if anyone can help me to get a thread sleeve and someone could borrow a tap in the right dimension that would be great. Here in this area it is almost impossible to find something liket this.

Attached you will find the PDF with the pictures I took. Thank you so much in advance and cheers

Lippi

chaterlea25 · « **Reply #38 on:** 29.06. 2020 21:54 »

Hi Lippi,
Can you measure the total length of the spindle? and the male thread diameter?
Either it has been shortened or there is a thin sleeve added to the threaded end ? as the thread is shorter than the spindles I have
If there is a sleeve threaded on, is there enough length of spindle to stick out through the fork to add a nut if the threaded sleeve was shortened or removed?

Here is what I think has happened ???

A previous repair attempt was to put a threaded sleeve into the fork leg, over time and brute force the sleeve has been pulled into the end of the thread , then the clamp bolt on the left fork was not tight and the spindle worked its way to the left

John

RDfella · « **Reply #39 on:** 29.06. 2020 22:08 »

The way that thread runs into nothing makes me agree with John - that spindle already has a bush on it

Lippi · « **Reply #40 on:** 30.06. 2020 08:37 »

Hi all

I will measure the spindle after work. The length of the spindle is not enough to add a nut. I will come back to you this evening with a total Picture of the spindle and the length.

Cheers, Lippi

Lippi · « **Reply #41 on:** 30.06. 2020 17:18 »

Here we are...

Attached the pics from the spindle and the length over all. I added also a picture of the profile from the spindle.

Cheers, Lippi

RDfella · « **Reply #42 on:** 30.06. 2020 20:44 »

Have you tried unscrewing what looks like a sleeve on that thread?

Lippi · « **Reply #43 on:** 30.06. 2020 22:18 »

Wow! Good input, never thought about it!

I will let you know tomorrow!

Cheers, Lippi

chaterlea25 · « **Reply #44 on:** 30.06. 2020 23:41 »

Hi Lippi
That spindle is standard length (230mm) and the threaded section should be 28mm approx
I definitely looks as though a sleeve has been threaded on (left hand thread)

If you can refit the sleeve to the fork and it is still tight It might be possible to loctite it in place ??

John