Friday, 28 May 2021

Model A - front brake rod

 The Model A came with its original front brake rod, but none of the fittings. It's an odd design - the rod is 3/16" (0.1875") but, to prevent rotation in the brake arm, it's flattened at the end. This makes it larger - it's actually threaded 1 BA, on a major diameter of 0.209".

Of course, cleaning up the thread is a bit of a challenge with the flat since many dies will not bite having three sets of flutes, or very narrow flutes, as the thin rod disappears into the gaps. 

Here's my stock 1BA die:

See the narrow flutes? This next picture is another I bought:

The flutes are much wider on this one, and I managed to recover the thread and get my newly-turned adjuster knob to fit. It's made from 303 stainless steel on the lathe, milled for detent on a 1 BA mandrel in the toolpost:

The outside is cut with a deep straight knurl, slightly chamfered:

The next lathe job is the spring housing, copied from the one on the W/NG. It's a bit of 1/2" 303 round bar with a 1/4" CEI thread in one end, bored 9.5 mm for clearance on the 3/8" brake rod end:

Tuesday, 18 May 2021

Charlie's Shed - 276 air filter adapter

This is an exercise in turning as a favour for fellow AOMCC member Lee who is currently building a KH - a 500 cc twin. One of the delightful things that happen in the AOMCC is that members trade bits and information with each other - Lee gave me a new clutch adjuster for the W/NG recently, so it's my turn to return the favour and get some good turning and screw cutting practise at the same time.

His KH has a Vokes pancake air filter, which he wants to attach to a 276 carburetter. These are the dimensions:

They will be a 60° form - it's a CEI thread but in a non-preferred diameter.

We'll need a bit of this 2" brass bar:

I've faced this both ends and turned a section down to the required outside diameter of the larger thread: 

Next job it to cut the bore to the minor diameter of the inside thread, starting with drills up to 3/4" and finishing with a boring bar:

I'll cut the outside thread first - it's easier and I can test the setup. In this picture, you can see the thread is not fully formed - it's flat on the peaks:

I obviously didn't take too many pictures - I have finished both threads in this shot and have test fitted ot to a 276 of my own. I did actually turn a 1/2" length of the inner thread from a bit of thick wall tube to test it properly - this carburetter is in very poor shape so it's not a very good test.

Here's the finished adapter ring:

And here it is on Lee's carburetter. He says the thread into the filter is a bit tight - but we don't want it falling off now do we!

Friday, 14 May 2021

QR50 - Finished

Well, it's taken 18 months but the little beast is finished. The eBay picture looked like this:

What is only obvious after the event is that the frame is bent, the piston is cracked, the crank threads are all damaged, the kickstart splines are gone, the exhaust is missing, the airbox is missing, the forks are completely shot (the springs, for example, are rusted away to dust) and the tyres, tubes and tapes are ripped and mismatched. The kickstart pedal is wrong - it fits but is for a right-hand kickstart, so the pedal folds the wrong way; the handlebars are wrong and the levers and grips are all missing.

Oh, and everything is covered in red poster paint.

The good bits? the tank is solid, the front mudguard is solid, the seat base is good and the whole of the transmission is good. Most of the generator is ok apart from the pickup and the carburetter is repairable; the cylinder bore is good, but there is a fin missing. The wheels are round, the rims are straight and all of the brake parts are there - but the linings have come off.

This is how it arrived:

It's been a brilliant little project, and I have learned much. I've used the mini-lathe to repair the crankshaft threads, the kickstart splines and to make the fork sliders, stanchions and bushes. I've used the welder to make the silencer and the airbox, and to overlay the damaged kickstart shaft ready for new splines and to weld up the forks.

I've discovered how to weld plastic - there was a hole in the rear mudguard caused by the rear tyre wearing through. I've learned to look and to see the wood for the trees - I had painted the frame before I realised that the reason the rear mudguard was worn and the seat didn't fit was that the frame was bent.

I've learned how to wrap plastic parts - the tank, mudguards and number plate are polythene and impossible to paint.

After all that, it seems to work - it starts, drives and stops through I need a small person to test it.

I hope they like it.

Friday, 7 May 2021

Model A - toolkit

 As you well know I'm very keen to have a toolkit with me on a bike trip. I'm not one of those guys that uses a mobile phone and an RAC card - I like to be able to deal with roadside breakdowns and adjustments myself. It gives me a great sense of security.

In making up a tool kit, I like to start with the tools originally supplied by the works and add to them through experience with the machine as I have done for the Square Four tool kit. The starting point for the bike's original kit is the parts list, which prewar carried pictures of all the tools. The parts list for many Ariels are available for download at the AOMCC website. In addition to the parts book, club member Ray Tolman has prepared a booklet illustrating the tools for the singles and a second volume specifically for the W/NG. This excellent volume shows some key pieces of information:
  • a photograph of each tool, and the tool roll
  • the works drawing for the tool
  • identification of the vendor of some bought in tools
  • the part numbers for the tool
Using the information available, you can piece together a tool kit - or at least, you can for most of the tools. Some of them are as rare as a rare thing, and have to be made...

Here is the basis of the tool kit illustrated in the 1930 parts book:

Tools part numbers:

Here is the list shown above, retyped so that I can edit it and with some extra notes:


Tool Box with fixing strips, Models A., B., F.Make at home


6600-26Double-ended Spanner (fits 3/16 in. x ¼ in. bolts)Found in stock; these come up on eBay from time to time




Double-ended Spanner (fits ¼ in. x 5/16 in. bolts)





Double-ended Spanner (fits 5/16 in. x 3/8 in. bolts)





Double-ended Spanner (fits 7/16 in. x ½ in. bolts)

eBay - regularly available




Double-ended Spanner (head nut and wheel cone nut, 5/8” & 7/8” BSW)

eBay - regularly available


G1/55a6606-30Single End Spanner (engine sprocket nuts)Buy/Make. Part number later used for a double ended spanner.


G1/94 6614-29 Abingdon Spanner (3/8 in. x 7/16 in. nuts) Make at home




Tube Spanner (hub spindle nut) Buy/Make at home




Tommy Bar

Make at home




Valve Cap Spanner





Screw Driver

Buy - eBay




Spanner for Cylinder Base Nuts

Make at home




Valve Spring Compressor (complete), S.V.

Make at home.




Arm for Valve Spring Compressor

Make at home.




Screw for Valve Spring Compressor

Make at home. Ariel drawing available.




Magneto Spanner





Pinion Extractor and Set Pin

Make at home. Ariel drawing available.




Sprocket Extractor and Set Pin

Make at home.  Ariel drawing available.




Sprocket Extractor, Set Pin and Adaptor

Make at home. Ariel drawing available.




Adaptor for Sprocket Extractor

Make at home. Ariel drawing available.




Set Pin only, for Extractors

Make at home. Ariel drawing available.




Tyre Lever

Buy - eBay




Tyre Inflator, 16in. x 7/8 in.

Buy - eBay




Grease Gun

Buy - eBay




Canvas Tool Roll

Make at home




Set of Tools only, in tool roll, S.V.


What has always puzzled me with these kits is why is there no spark plug spanner?

So here is my starting point, a not-so jumbled collection of tools, some Ariel & some unknown...

And here we go, collecting tools. This post is likely to evolve over a number of months if not years...

Starting with a genuine Ariel part:

Item 2, G1/28 Double-ended Spanner (fits 3/16 in. x ¼ in. bolts)

Here's one that is commonly available on the world's favourite auction site:

Item 5, G1/66 Double-ended Spanner (fits 7/16 in. x ½ in. bolts)

Another genuine part, the common head nut and wheel cone spanner. I have 'adjusted' this one as it had been stretched by someone:

Item 6, G1/55 Double-ended Spanner (head nut and wheel cone nut, 5/8” & 7/8” BSW)

I happened upon these next two - they look very like the illustration in the parts book and they fit the wheel nuts, so they are good to go as far as I am concerned:

Item 9, G1/58 Tube Spanner (hub spindle nut)

It came with a tommy bar:

Item 10, G1/57 Tommy Bar

The valve cap spanner comes from AOMCC spares:

This one is a bought out item. It's a nice Terry's example I bought from eBay:

Item 12, G1/33 Screw driver

Another eBay find, a common magneto spanner:

Item 17, Z/20 Magneto spanner

And another - the Tecalemit grease gun:

Item 25, Z/21 Grease Gun

There's always little bits you need to carry - cigarette papers, solderless cable nipples, a spare plug or a main jet - and of course, you may need some laxatives:

Period Tin for small things

Monday, 3 May 2021

QR50 - first start

Son Thomas came up to North Norfolk on his RE Interceptor for a play with the Ariel Huntmaster kit. After a spin along the coast (during which he managed to find  pre-installed fault on the W/NG's throttle cable nipple - we came back on the choke cable and a hand throttle) we repaired to the workshop to take a look at the QR50, which is almost finished.

I'd assured myself that the electrical system worked:

I used the big power drill to spin the generator and to prove the sense of the kill switch and the rear brake switch, and to prove the CDI unit worked. As I suspected, the kill switch and brake switch wires are both earthed to kill the engine - though the position of the brake switch doesn't seem to affect the spark. And how do I know this? Because it works!