Model A

 We're making chips! After a few test cuts, I've settled on a spindle speed of 750 rpm using carbide with oil mix cutting fluid and I'm getting a great finish. 

Depth of cut is 0.5 to 0.75 mm, and the feed is probably something like 0.002"/rev. The lead screw gives you 0.004"/rev and it's much slower than that, but unfortunately I have to manually feed at the moment.

There are a couple of upgrades you can do to reduce the feed rate, but they both need 3D printed gears which I don't have...

FH - not charging...

 Having learned that the FH will drain it's oil tank through the gear pump into the sump, I try to run it once a week or so during the winter. It was on one of these occasions that I noticed it wasn't charging and my first thought was to look at the dynamo to see if it had broken another chain.

Fortunately not - so I left it alone for a dose of thinking about.

Coming back the next day, I worked through the other electrical systems to see if anything jogged my thoughts and found the rear light wasn't working either: given that the ammeter and the rear light connect through the lighting switch I had a look under the top yoke:

Two wires had pulled out of the five way connector. Harness too tight or connectors not assembled properly in the first place?

Model A - Making the kickstart shaft

From the features and dimensions in the previous post, we have some idea of what we have to make - if we are to avoid cutting the excess length out of the old shaft and welding it up again, with the cotter flat in the correct orientation.

This would be a waste of an original part and wouldn't be half as much fun, but it is worth remembering that what we are trying to here is produce a replica of the 'Panther' shaft we have, but shorter and with the kickstart lever cotter in the right orientation.

We'll start by defining a list of features, so we can talk about making the shaft sensibly and without getting confused. Here we go:

• A - the pawl carrier minor diameter
• B - the hole for the pawl spring
• C - the holes for the pawl pivot pin
• D - the larger 'stop flat'
• E - the smaller 'stop flat'
• F - the bore for the layshaft bearing, and the bearing itself
• G - The flat the pawl sits on
• H - The kickstart lever diameter
• I - The main shaft diameter - 1 1/8"
• J - The flat for the kickstart lever cotter
• K - The pawl carrier major diameter, 2"

Of course the key question is in what sequence do we machine these features?

This is what I'm thinking at the moment:

1. Face and centre both ends of the 150 mm chunk of EN16 round bar (diameter 55 mm) that I've bought from eBay.
2. Holding the stock in the 3-jaw with the end supported in a live centre, machine away the material to make diameters H, J and K
3. Reverse in the chuck and machine a flange on the waste end, with a 5mm hole to register with the pin in the centre of the rotary table.
4. Hold feature I in the milling vice and use the vertical slide and an end mill to machine feature G.
5. Clamp the waste flange to the rotary table and use an end mill to machine features D an E.
6. Use the rotary table to machine feature A.
7. Use a slot drill to machine the tangential hole B.
8. Hold feature I in the chuck and machine off the waste flange.
9. Machine feature F.
10. Hold feature I in the milling vice and drill feature C.
11. Last job will be the flat for the cotter. We'll assemble the shaft into the box and then work out where the lever wants to be.

The blank we will have after step 3 will look like this:

Excuse the mixed units, and remember that these are approximate dimensions for roughing out only!

Model A - Kickstart Shaft

 The Model A arrived with a complete gearbox, apart from the kickstart spring, cotter, and spring shroud. The kickstart shaft was also strangely long and fitting the lever left the kickstart pedal very low, since the flat for the cotter was in the wrong place.

What we are trying to here is produce a replica of the 'Panther' shaft we have, but shorter and with the kickstart lever cotter in the right orientation.

A close up of the pawl, the pawl spring with it's plunger and the two-diameter pawl pin:

This is the flat for the kickstart lever cotter. The shaft I show here allows the kickstart to sit too low - it's for a bike that has the gearbox fitted horizontally, rather than at the angle used by Ariel and Brough Superior. The shaft is possibly from a Panther, who used these boxes horizontally in 1929.

The flat will have to move for the new shaft.

This is the flat where the pawl sits, with the axial holes for the pawl pin and the tangential hole for the pawl spring:

These two flats engage with the two plates in the gearbox that stop the pedal travel and disengage the pawl:

This is the bore for the layshaft, with it's bush:

A few dimensions to help us choose the stock for the new shaft:

We see here that the total length of the 'Panther' shaft is 164 mm or thereabouts.

This is the 'Panther' shaft fitted to the bike. This is the excess length - just over 47 mm. That means the total length of the new shaft will be 164 - 47 = 117 mm. Our blank is 150 mm long.

Lastly, here are a couple of pictures from AOMCC member Michael, showing the original arrangement:

Model A - sorting out the footrests

 The footrests on the A are a bit of a mess. One is thoroughly non-original and is probably homemade, the other has been shortened radically, to the extent that it is useless. Also in this region - the spacer between the engine plates (that prevents tightening the footrests from squashing the engine plates) is missing, the brake lever return spring is missing and the brake lever spindle has been recut with a BSW thread - it has obviously been stripped at some point.

Ariel footrests don't change much and I have a new set from club spares:

The rod is bent, but worse the threads are worn on one end and recut to 7/16" BSW. I've got a large piece of stainless steel to make a new one. In that package of spares was a brake lever return spring.

The two footrest supports were also bent but a few minutes with the MAPP torch sorted that out:

Next, we need a bit of time on the lathe to make the spacer that goes between the engine plates. We'll use the manky foot rest to provide the material: 

With the power feed on, it doesn't take long to clean up this bit of bar:

It's turned down just enough to fit inside the brake lever spring, bored 11.5 mm to clear 7/16", and parted off at 2" long. It's lightly chamfered at both ends, inside and out:

So that is that for the moment. The bar is a little bit long and one of the nuts is very loose and needs replacing, but we will sort that out when the rear brake pedal shaft is finished and it all comes apart again.

Model A - broken threads in the gearbox

 Blog posts these days seem to veer between a little part manufacturing, perhaps on the lathe, to reporting on something else that I found broken. This post is one of those. 

Pulling off the primary drive and clutch to gain access to the area behind the engine where the footrest spacer lives revealed a couple of problems with the gearbox. There is a little plate with three holes which ties the gearbox to one of the frame studs - there are two 5/16 BSW studs in the gearbox, with CEI threads outboard holding this plate to the gearbox .

Or there should be:

In this picture you can see the 5/16 BSW hole for the top stud, but it looks like the bottom stud is broken. We would have to get the gearbox out to have a look at that properly and remove it, but after a clean and a poke around it looks like the stud was lost years ago and the hole was just full of gunge. They clean up good as new with a 5/16" BSW tap:

While we are at it, we can bend this bracket back into shape - it retains the primary chain adjustment bolt which moves the gearbox forwards and backwards to tension the chain. Guess what? Can you see a broken bolt in that hole? I do have a new chain adjustment bolt because I thought it was missing but now I can see the remains on the old bolt stuck in the gearbox housing...