Slow Monster rebuild

[350TSS]

In the above photo is today's effort at a male mold for the instrument nacelle which will attach to the underside of the two bolt lugs on the leading edge of the top yoke originally also holding the instruments. The skirt around the edge I hope will marry up with a supporting "shelf" inside the fly screen (hopefully with enough space to put a voltmeter and possibly an oil pressure gauge if I can find an electric one that will work from the current pressure switch position on the clutch casing.

[350TSS]

I have come to a conclusion concerning the rear brake hanger. The issue I have been struggling with is that the original S4 (fixed) hanger has a 12mm inward displacement from the inner-most edge of the casting at the wheel spindle to the two holes where the caliper is attached. With the 25mm spindle the OD of the wheel bearing is 52mm with a machined boss in the wheel casting that holds the bearing about another 8mm outside that on each side. The diameter of the boss in total is therefore 52mm + 8mm + 8mm = 68mm. The distance between the centre of the wheel spindle and the caliper bolt hole centres on the casting is 106mm.
My original intention was to machine a hub that had a bearing onto the wheel spindle out of 60mm bar and bolt a 10mm plate onto the inside edge of the hub. This will plainly not work as the size of the wheel boss and the 12mm inward displacement means that the hub would have to be machined from much larger bar. (clear the 68mm wheel boss say 72mm, allow 6mm either side for structural integrity then a 12mm either side to take 8mm bolts to attach the swivelling 10mm hanger plate so my hub would have to be machined from 72mm + 6mm + 6mm + 12mm + 12mm = 108mm bar. It would weigh a ton and all un-sprung weight as well. The hub would need to be 32mm widthways
The real issue/problem is the inward displacement of the hanger, my solution is to spacer the disc out by 12mm from the wheel, meaning that the hub can be as small as the bearing I can buy/make + say 6mm each side for structural integrity + 12mm each side for attachment of the plate by 8mm bolts.
I have located some single row sealed ball races with 25mm bore x 37mm OD x 7mm wide, I intend to use two inserted from either side of the hub with a 6mm division in the middle of the hub so the inner races bear against the swinging arm on one side and the wheel bearing on the other. The hub need only be 20 mm wide and 37mm + 6mm + 6mm +12mm +12mm = 73mm.
Upside is that the rear disc will be out of the lee of the tyre and so should be better cooled also the turning forces transmitted through the reaction rod to the frame will be through the centreline of the inner bearing (rather than 12 mm inboard of the centre-line of the bearing. The downside I can think of is that the bolts retaining the disc or rather the threads retaining those bolts will suffer a much higher shear load. The spacers obviously will have to be accurately made to prevent disc run out and exacerbation of that shear load. The reaction rod end at the crank case may also need a spacer/ bracket, subject to exhaust pipe and brake pedal clearance issues. Can anyone envisage any other difficulties with spacing the disc out from the wheel?

[utopia]

A bell has just rung and I now remember that you asked for some dimensions in this area from my Dymag wheels.
Sorry, it slipped my mind .. been desperately busy with my own rebuild.
I'll have a think, measure up where necessary and get back to you.
And/or I have scoured my old emails and managed to track down my communications with HPS when I bought my wheels, and these include many dimensions that I measured on my existing wheels as well as production drawings from Dymag.
If you would like me to forward those, pm me your email address.

On the shear stress thing, the bolts should not experience any shear load unless they loosen off.
When fully tightened they are in tension, which in turn exerts a clamping force which lock the two components together such that they behave as one solid component.
As long as the bolts are capable of withstanding the tensile force necessary to exert the appropriate clamping force, there will be no shear load on them.

That said, I haven't yet quite got my head round exactly why the extra disc offset is required .. but I will presumably understand better once I do some measurements.

[350TSS]

Lots of different activity today, it was cold this morning and rather than freezing my nuts off in the garage I thought I would devote some time to working out the electrics/as is and to be wiring diagrams/connector strategy and cable routes. At regular tea breaks I trotted out to the garage to check locations and types of connectors and consider cable routes, but mostly in the warm. I am one of those people that when confronted by a wiring diagram I first of all lose rational thought, start mentally skipping about and eventually become irritated at my own incompetence. Today I thought I conquer this and work through each circuit one by one on the original wiring diagram and decide where I would put connectors, what wires would be incorporated in the main loom and what would always be kept separate.
With connectors there is a real dilemma as they:
1. are always a potential failure point, too many and you have a risky system, too few and it is a pain in the arse when the box at the end goes AWOL and you have to dismantle half the bike to unplug the faulty bit of kit;
2. take up scarce space and need to be kept away from heat and moving parts;
3. need spare loom either side to ensure they are not in tension with the loom, and obviously also lots of gash wiring everywhere is unsightly.
After a couple of hours I had just about worked out a strategy for replacing the “as is” wiring when I thought I had better check how my MUV2 control box fitted into the equation. When I first got the MUV2 control unit, I glanced at the instruction manual and after about 5 minutes my eyes glazed over and I put the manual back in the box. In my ignorance, I had assumed it just replaced the fuse box. Oh no! It changes the whole way the bike will have to be wired. In all cases the switches instead of being on the power side of the active component move downstream of the active component to become effectively an earth switch. No relays required anywhere (except possibly one for the starter solenoid). Brilliant, because I never understood relays anyway or more particularly how to wire to them. Having spent another hour pondering what this meant I am far less daunted with the prospect of the rewire and I am pretty certain with my positioning of the unit directly underneath the ignition switch that I can dispense with about half the connectors on the bike without too much loss of maintainability. “Do the thing you fear most and the death of fear is certain” somebody once said.
After 3 hours or so of studying electrics I felt I had to get my hands dirty and the garage had warmed up a bit by then. I thought I would make the hub for my rear brake hanger which I spent last evening drawing out and defining the sequence steps to machine it with the fewest movements of the workpiece in the chuck and therefore the greatest chance of a concentric /successful outcome.
Some while ago I bought some 3.1/4” offcut aluminium bar about 150mm long. I have a 3 jaw chuck in my lathe but it is not big enough to hold 3.1/4 “. With the lathe when I bought it I got a load of other kit including a plate with 4 jaws that would certainly take 3.1/4”. I spent the next two hours not succeeding in getting the 3 jaw chuck off the lathe and I broke my 5/16” chuck key in the process. It looks as though I shall have to make a tool to hold the drive shaft (3 peg holes 5/16” diameter 5/16” deep on the circumference of the 40mm drive shaft, 120 degrees apart) and may be use a chain wrench to undo the 3 jaw chuck
Feeling I had to have something tangible to show for the day, a bit more filling got done on the molds. I also made the elastic bushes for the exhaust hanger bracket using clear silicone bath sealer. The central aluminium bush is held in with place with 6, 8 and 12mm washers. I just hope enough air gets to the silicone so that it goes off.

[350TSS]

Picture of bearings acquired for brake hanger hub 25mm x 37mm x 7mm

[utopia]

I think I see the "plate with 4 jaws" on the shelf above your lathe.
But is that not a conventional 4-jaw chuck next to it ?
Is that not big enough to take the 3 1/4" ally bar ?
You should be able to take each jaw out and reverse it, creating the scope to hold bigger diameters.
This is not possible with a 3-jaw, self-centring chuck because the jaws are driven by a single "scroll gear" so their driven teeth are curved and can therefore only fit one way round.
On the 4-jaw chuck, each jaw is driven independently by its own worm gear and the driven teeth on the jaws are straight-cut, allowing them to be reversed.
Sorry if the above is all old hat ... but better safe than sorry, eh ?

ps. ....just to dot the i's and cross the t's .....
If it does fit in the 4-jaw, you may need to also use a centre to steady the free end of your 3 1/4 inch bar.

[350TSS]

My - what sharp eyes you have!
I looked at the 4 jaw and thought as it was same OD as 3 jaw chuck in the lathe it was therefore no good - I never knew the jaws came out and were reversible. I would think a better solution than the "plate" but a bit academic if I cannot undo the 3 jaw chuck. Thanks for the "heads up"
It will take a bit of bodging but I am sure I will eventually manage to get the 3 jaw chuck off

[Mr Gazza]

A lathe chuck would be left hand thread, no?

[utopia]

No, right hand thread .. so the force of the cut tightens the chuck, or at least doesn't loosen it.

In fact as far as I'm aware, there should be a short, very accurately machined shoulder at the headstock end of the thread, and a matching perfectly flat, square face on the end .. to precisely locate the chuck on, and square to, the lathe spindle axis.
The thread, although accurate, does not precisely locate the chuck, it merely draws these features together.

My thinking is that machine tools are dense lumps of metal with a very high thermal mass.
If they ever get cold, they take ages to fully warm through and, in the meantime, the condensation just drips off them.
Maybe your machine has experienced such conditions in its past and now has a little corrosion in the threads ....?
The chucks on my Southbend come off with a sharp bash with the flat of my hand on the chuck key, having first locked the spindle gearing ... easy peasy.
I would therefore be a tad wary of using much force .. at least at first.
On the other hand, if you do resort to a bit more welly, it occurred to me that you could grip some sort of bar-and-lever arrangement in the chuck itself, rather than do it via the chuck key .....?

[Mr Gazza]

Originally Posted by utopia

No, right hand thread .. so the force of the cut tightens the chuck, or at least doesn't loosen it.

Yes I worked that out about 2 seconds after posting it, and thought; Better to remain silent and seem a fool, than to speak and remove all doubt!

Just a thought - are you sure the 3-jaw chuck did not come with a set of external jaws as well?
Every 3-jaw that I have ever bought always had both sets

[utopia]

Good point .. dunno why I didn't mention that myself.
And of course that would temporarily avoid the need to remove the 3-jaw chuck.
In which case its worth pointing out that, if you don't have any, it may be possible to buy some additional external jaws to fit your chuck.
I believe the scroll gear details etc are semi-standardised so many aftermarket replacement jaws will fit.
Try RDG tools.

Incidentally, it is also possible to buy soft jaws (rather than the normal, hardened steel items) which can then be bored to any size you like.
This is also a method of ensuring repeatable concentricity when parts are removed/replaced from the chuck.
But note that when you bore them, you first need to tighten the chuck onto a suitable packing piece (short round bar) placed at the back of the jaws while you bore the front section.

[350TSS]

Good few hours in garage today, I made a retainer for the lathe shaft so I could get the 3 jaw chuck off. Spent an hour or so looking for some suitable steel that I could craft it from but it was all either too thick or too thin. Reluctantly I decided to use some pristine 10mm plate aluminium. I want to make the rear caliper carrier from this plate and I only bought just enough to make 2 (I have a propensity for buggering up the first one I make (of everything)).
Pressure will be on now I guess when I go to cut that hanger plate.
Anyway the trusty Milwaukee jig saw did the business but I broke 3 blades and had to go out for more halfway through the afternoon. Two holes were drilled and tapped at 120 degrees apart through the arms and 2 x 6mm cap screws threaded in to provide the pegs to align with the holes in the shaft. Good news it fitted, bad news I had to spend an hour filing a square on the chuck key end (which I broke yesterday) so I could open the chuck jaws. It came off without much of a struggle but I did find why it was on so securely – some aluminium swarf had got into the thread at the centre of the chuck and was acting like a locknut.
The four jaw chuck went straight on. My initial attempt at centre-ing the work piece was not a roaring success.
I gave up at this point as arthritis dictated I needed a sit- down job so I sanded out the most evident (easily accessible) casting lines on the fork leg bottoms. In think I will probably paint these as bare aluminium polished will be high maintenance. I will finish the rubbing down of the fork leg ends tomorrow and pop them on a courier to Maxton’s.

[350TSS]

Looking at the photos and only just reading your replies above I have wasted a day - the three jaw chuck looks to be reversible - bugger!!!!!!

In any event I cannot start the hanger hub as I need a parting off tool that will cut 3.25in aluminium, which has now been ordered

[350TSS]

The Fastbikegear ignition system arrived yesterday, but only after I had paid an extra £109 to cover VAT, customs charges and handling fee (also with VAT).
The kit comprises an Ignitech box with wires to coils and to the Hall effect sender/receptors with a diagnostic lead/connector that should plug into a PC (open connections with no means of sealing it), a hard plastic belt cover 3 D printed, an aluminium hub for bolting to the camshaft sprocket shaft, 2 x 3 D printed plastic clips to be screwed to the belt cover and that holds the Hall effect receptors (two chips 3mm square with 3 x 20mm prongs off each) which have to be inserted into the plastic clip and soldered to wires that go to the Ignitech box and a circular plastic part that holds 2 x 3mm dia magnets.
Seems a lot of money for not very much. I hope it works as well as they claim and reliably. I obviously now have to find somewhere to put the Ignitech box, presumably away from heat and moisture and possibly distant from magnetic interference from the coils. So far, I have found no recommendations in the paperwork sent with the kit – doesn’t mean it is not there – just I haven’t found it yet
I have also been reading the installation manual for the electronic control unit and found a recommendation that this is mounted at least 300mm away from the coils, my current design is about 100mm away. I am thinking that I will have to make a Faraday cage around the coils so as not to interfere with the control unit and / or Ignitech box.