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!

In this next picture there is a quarter inch end mill in the collet chuck and we are using the vertical slide to mill one of the retaining bolt holes into a slot, so that we can perfectly adjust the rotary table to align with the lathe centre.

What you can't see is that I have used a 3/8 inch end mill to clean up the bottom edge of the overlay weld on the other side. This is pretty much finished now, but it may require a couple more holes to bolt down to the cross slide. We will look at that when we set it up to mill the slots in the kickstart shaft.

QR50 - Tin bashing the Magneto Cover

This week, yet more QR50 parts, this time the missing magneto cover. I'm hoping that in a week or two there might be some exciting Ariel news, but more on that later if it all comes together.

For now, the QR50 needs a couple more big parts making, the exhaust and the magneto cover. The magneto cover is available from Honda for about £26, but I like sheet metal work, I have a suitable sheet in stock so let's make one instead.

First job is to measure up the diameter of the magneto housing in the crankcase and calculate the length of the strip we will need to make the cylindrical part of the cover. Then, we can use the bandsaw to cut a strip to length and to a suitable width to clear the rotor nut, with a bit to spare for overlap and errors. Secondly, we need a disc to make the top and a further strip for the gasket face as we shall see later. 

The parts can be deburred on the linisher or by hand. The ends of the strips need to be nice and square, so we will use the mitre attachment:

I'll bend the main cylinder around this bit of 4" tube. The finished drum will be about 6" in diameter, but of course the steel will spring back from the 4" cylinder:

I'm using a toolmakers clamp to ensure the starting edge is held tight against the steel tube - I do not want a flat in the cylinder. When it's bent fully round, I test it against the crankcase to ensure it is a snug fit; overlap is trimmed off with a hand shear and deburred. This takes several attempts removing a small amount at a time - we don't want it too short, as that means we will have to start again. When the fit is good, tape the ends close together with a bit of masking tape, before welding as an autogenous butt. You will probably lose the very end of the weld, but that is why we have spare length.

The weld is finished on the linisher and test fitted again. The outside edge is not parallel and is very long, but it's the fit of the inside edge that is important at the moment:

Next job is to raise the edges of the cover. Start with a disc marked with the diameter of the flat part, which is a little less than the diameter of the cylinder. Add maybe 3-4 mm to the radius to fold over as a raised edge:

Over a suitable dolly, raise the edge little by little, working around the edge moving the metal maybe 10° with each rotation:

Try to keep the edge even, and the disc will stay flat; raise it too much at once or move off the line and the face will distort:

Eventually it fits nicely in the cylinder. I put a blob of grease on the rotor nut and assembled the cover to the engine, pushing the disc in as far as it would go but keeping it square to the cylinder:

The grease witnessed that the disc touched the nut. I move the disc back out of the cylinder about 5 mm (for clearance) and marked the inside of the cylinder before cutting it with shears:

Next stop, it's the brackets to hold it in place. These are simply bent up from a bit of sheet - the holes are cut with a cone drill while the bracket is in the flat. There's a similar one for the bottom:

The original Honda version has a seal, which sits in a ledge formed by a second ring inside the main cover. I'll make this with another cylinder:

This too has a raised edge which will eventually carry the O ring:

The O ring is made from a 3mm OD Viton extrusion; I use Loctite 406 for rubbers and plastics. Buy more material than you need and cut it over length with a sharp knife - it took me three attempts to get the fit correct and snug:

Tacking the seal carrier in place. Unfortunately at this point I ran out of gas...

A short interlude while I travel to Ian Baird's Welding Services shop for some more Argon, followed by welding the brackets in place. I used a plug welding technique for this, carried over from when I used to use MIG for welding car body panels together. You drill a hole in one half, clamp the two parts together and MIG into the hole, creating a little plug that emulates a spot weld. Great! Except it doesn't work with TIG, with a fixed electrode which just burns the outer half away. It's better if you increase the current much higher than you would expect for that thickness, but it steel leaves you chasing a hole with the filler rod. I'll bring the MIG out of retirement I think, or use fillet welds.

With the brackets in place we can finalise the position of the disc. I'm stitching this in place, making sure that it is in right place before I make the weld:

Eight stitches later it is finished:

After a session on the linisher and the wire wheel, I use the usual U-Pol paints (etch primer and satin black) to finish the cover:

And that's it. Before I forget, after stitching the cover in place and trimming it back, I rolled the edge over on a dolly, to tidy it up. I think it looks OK:

QR50 Assessment - Missing & Broken

Today I had a chance to look at the boxes of QR50 bits. My oldest grandson is 5 in a few weeks and I need to get this bike together before he misses out. Lets see:

Frame

As I've shown in previous posts, the frame is in good shape. I need to finish the footrests, but that is in hand and will be completed when all of the other problems find solutions. As you can see, I have left the stubs (to which the folding footrests will be mounted) long enough to carry the footrest rubbers for the time being.

The centre stand and it's bracket are all there, though the pivot hole in it's bracket is pretty worn. It will weld up OK.

Forks

I've assembled the forks today. The fasteners are all there and the yokes and spindle are in good shape; the bushes are completely shot; I suspect the snubbers and rebound springs are missing; one of the main springs is missing and there is no wheel spindle, though this is just a long plain bolt that I can make easily.

There are no gaiters or shrouds for the top of the sliders either. The drawings suggest that the plastic bushes are held in by circlips in the normal way - I will machine some new bushes on the lathe.

Rear Suspension

The main concern here is the metalastik bush lugs on the crankcases - one of them is cracked. I will probably let that one go for a bit, to see if it becomes a problem.

There rear suspension strut is there and will just need painting.

Wheels

The wheels are both there and just need new tyres, painting and possibly new bearings.

Brakes

Brake plates and components are all there and will just need a clean up

Engine

The engine is in a bit of a state, though nothing really serious:

• The crankshaft has the usual mushroomed thread 
• There are several (about 6) cylinder head fins broken off. I'm hoping to use the AC MIG set on this and learn to weld aluminium...
• One of the barrel fins is broken, which is not really a problem.
• One of the oil pump castings is broken. Unfortunately it looks like this is special to the QR50, so we will have to get inventive... Perhaps I can machine a replacement from a slice of aluminium bar stock?
• One of the crankcase lugs, used to mount the exhaust, is broken out.
• The ignition sensor is toast. I may need to buy a complete new stator unless I can rewind the sensor coil.
• The generator coil appears to have no leads
• The generator cover is missing. Old saucepan anyone?

This is the broken part of the 2-stroke injection pump. I guess that what is missing here is a facility to operate the pump from the throttle cable, to vary the injection rate - I may elect to run the bike on premix initially.

This is the crankshaft. I'll set this up in the lathe with the fixed steady and machine it true. hopefully there will be enough length for the nut to fit?

Transmission

The transmission looks like it is all there, though the rear drive shaft bearings are missing.

Despite the empty cases in the picture, I have all of the transmission components and have had them assembled.

The kick start quadrant splines are, as usual, completely knackered. Fortunately we have an NC50 transmission with a good one.

Electrics & Controls

The coil is there and in good shape; the small main harness is also there with the CDI unit. The handlebar switches are all missing - I have the left hand lever but not the right one. There's a lot of this sort of thing available very cheaply on eBay though, so that's easily sorted.

The handlebars are a puzzle in that they have conventional clamps and conventional clamp on levers - i.e. the bars are plain. All the parts list illustrations I have seen show bars with a welded lug for the left hand lever and a welded lug for mounting the bars to the top yoke.

Given that these bars look a bit high and wide for the bike - the originals appear much lower to the yoke in some pictures. I may cut, slug and weld them up:

Or this:

I might also make a welded bracket to attach them to the yoke, per the originals:

Then again, it might be an optical illusion. The cables are all there.

Mudguards & Bodywork

The front mudguard is there and in good shape - it's bolts are also present. The rear mudguard/seat unit is holed (looks like a heavy rider wore through the mudguard with a tyre) and the seat will need a new cover.

The number plate is probably damaged beyond repair.

Fuel and Exhaust

The fuel tank is as yet unseen. The exhaust pipe is there but the silencer is missing; the carburetter is there and looks OK.

The air filter is missing, but I can easily find a pod filter.

Summing Up

This is quite challenging. The little bike is financially not worth a lot - you see them for sale at £500-600 or so. Parts are available but very expensive, so this will be a labour of love for a grandparent wishing to extend his restoration skills - this might be a 1982 bike but the skills I will learn could be used on a 1920's bike.

In order of importance:

1. I need the crankshaft thread fixed in order to assemble the engine
2. I need the missing bearings to assemble the transmission
3. I need the forks fixed in order to get the bike to roll around, and I need at least one tyre
4. I need the generator stator in order for the engine to run
5. I need some handlebar controls to be able to stop the engine and to be able to brake
6. I need an exhaust

Everything else I can get around - the engine will run with a shortage of head and barrel fins; it will run on premix with no oil pump (and I don't have to find all the oil lines); one tyre is probably OK since this is not a road bike; I can find an air filter from eBay; the bike will be fine with fixed footrests for a while.

QR50 - Aluminium Welding

A brief look at the crankcases for the QR50 mini-moto reveals that we are either going to be buying some new cases or learning to weld aluminium:

One example of the generator side case has a mounting missing:

The other has damage around one of the casing screws:

Fortunately this has the missing mount present, so there may be some cutting and welding on the cards:

This appears to be part of the exhaust mount:

Rusty metal

While it doesn't look too bad from this angle, the battery tray on this MZ TS125 is falling apart due to acid damage. There is a crack from one of the hooks for the battery retaining strap which means that that tab, with the M5 hole for the side panel is quite floppy.

Since it was only going to cost me a few minutes, I tried to braze it up but in practice it is all too thin to have any strength, so the easiest thing to do is cut it off and make a new one. The bracket used to mount the battery tray on the frame is sound, so we can cut the tray away from it retaining as much as possible of the old tray to provide a pattern for a new one.

I have some 18 SWG cold rolled sheet in the shop, which is a good deal thicker than the original which looks like 22 SWG. You can see the extent of the damage in these pictures.

The new one is very simply folded from sheet, cut out with the jigsaw & hacksaw and with 5 mm holes drilled into the corners for clearance and drainage. We'll tack the corners together with the MIG welder.

Here's the hooks folded down and around the old strap.

So now I have transferred the side panel tab to the new tray, and brazed it in place in case I have to move it again. Next, to weld up the corners and finally weld the tray back to the frame:

Welding the outsite of corners is tricky if you are not to blow the material away completely; my welding needs a lot of dressing! Corners done, we'll tack it in place using the old one as a guide:

We'll need to fit some other parts around it to confirm that the side panel mount is in the correct location, and then we will complete those welds underneath. Removing it with those fully welded would probably destroy my new tray.

Just a little U-Pol etch primer to avoid rusting...

A few days later I have the cast aluminium rear mudguard and the coil bracket to mount up and test my new battery bracket. I'll put the lot in the vice and mount the rear end with some 10 mm pins, that are a close fit in the holes and don't allow any wobble:

You can see the three M6 mounting holes for the side panel - one in my battery bracket, one on the coil bracket and one in the mudguard. Here's the side panel mounted up:

Perfect! now we can weld up and apply some paint.

And that's it, ready to be returned to its owner.