Mini-lathe - angle plate

 Some while back we looked at an arrangement to use the compound slide vertically to cut some slots in some screw heads. At the time I had this angle plate with a shim to put the compound slide exactly perpendicular to the bed. 

Now that I have my MIG welder working again I have overlayed the angle to some extent and I'm using a fly cutter to create the perpendicular surface. It looks horrible at the moment because I did the overlay with the MIG at night, with the inverter protesting at the low voltage.

I've made a couple of passes with the fly cutter and we can see where the welding is low.

We will do some more passes with the fly cutter and then fill in some of the holes.

Meanwhile, we need to make this angle plate as stiff as possible so we will put a brace in each end:

One of the functions of the angle plate is to carry the rotary table. Whilst this has its own 90° mount, it takes up a lot of space and for the purposes of the kickstart shaft we would have to extend the cross slide considerably to get it in the right place. A better alternative is to use the angle plate to mount the important part of the rotary table like this:

We will progress the rotary table mounting a bit further when we have finished making the back of the angle plate flat:

Flat, cleaned up and almost finished. The surface is perpendicular to the cross slide top!

There's a couple more bits to do - I'd like to take an end mill to that bottom edge and tidy up, and one of the rotary table holes needs elongating for adjustment. I'll do that when I set up for milling the kickstart shaft.

Model A - kickstart shaft

 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.