Model A - Fasteners on the Mini-Lathe

Updated: First published December 2020

After making some tank bolts for the W/NG, I thought I would make a start on all the missing fasteners for the Model A. After all, I like turning and I'm a bit fed up with welding after the QR50 exhaust. I'll need:

• 2 off E1/58 special bolts for the rear stand. I have the 1/2" Thackeray washers to go with them. E1/58 was renumbered to 5505-26, which is used on the W/NG and many other Ariels. I can copy these.
• 1 off E8/245 petrol tank bolt, like the one I made here.
• 2 off E8/921 special bolts for the rear mudguard stays, with their nuts. The bolts look like Ariel parts 5655-30, which is used on the W/NG so I can copy these; their nuts, E8/922 are not the same so I will have to find out what these look like. Looking around the reference pictures I have, it appears the hex size on these matches the stand bolts, whilst the hex on the W/NG ones is smaller and matches the bolt they attach to.
• E8/762, the big nuts for the top of the oil tank. These are different from the later ones as used on my W/NG and SQ4, because the oil tank bracket has a smaller hole as does the sidecar mount in the frame and the later nuts would not fit. E8/761, the stud that goes with this nut, was renumbered to 0182 and is a standard Ariel part. It's a 5/16" CEI x 1 15/16" stud.
• The lock nuts for the chain adjusters, E8/925 renumbered to 5744-30 and the the chain adjusters themselves, E8/924 renumbered to 5740-30. Both of these are used on the W/NG so I have patterns I can copy for these.

I'm making a start with the stand bolts, since I have the Thackeray washers, the stand and and the springs. All these bits will get lost if I don't make the bolts and get them attached to the bike.

I'm starting with a bit of 0.82" hex in EN1, since I will be chemical blacking these and don't want to use stainless. In this picture I have turned the 1/2" OD register for the washer and the 3/8" major diameter for the thread

Here's the thread going on using a 3/8" CEI die in the tailstock die-holder:

Here's one, mostly finished. I have to turn a chamfer on the other side, but I will make a few more bits before I rig up for that:

Turning the head chamfer, after facing off the head and discovering that my parting tool was not quite square!

Finished and ready for blacking:

I'm going to make the E8/921 special mudguard stay bolts next, by copying the ones on the W/NG. These bikes are so easy to work on, properly designed for easy maintenance:

Here is one of the bolts, with it's locknut and the special nut which fastens the moving part of the mudguard:

Post script note: years later, I realised the picture above includes the spacers used when there is no pannier rack fitted. I corrected this error in this post...

Using the same set up in the lathe, same turning and parting tools, the three jaw chuck and the tailstock die holder with the 3/8" CEI die, I'll make a couple of these bolts to this stage:

Since the next stage for both these and the stand nuts requires me to put the threaded end in the chuck, I will change over to the ER25 collet chuck to avoid damage. I only want to do that once, so with the the hexagon bar stock still in the 3 jaw chuck I'll make the two special nuts:

So in this picture, we can see one of the completed E8/921 special mudguard stay bolts with it’s E8/922 nut, which retains the detachable stay. Also pictured is the E8/761 (0182) 1 15/16 stud for the top of the oil tank.

These are the E8/762 nuts that retain the oil tank to the sidecar lug. The sidecar lug is much smaller on the 1930 frame than the one on my 1942 W/NG. 

Last thing on the list is the chain adjusters. The nuts are first, and these are made from a bit of 0.445" hex in the lathe. They have a short 5/16" BSC thread inside, and most of the outside is plain:

The adjusters themselves are a bit more involved. They are basically 5/16" round bar, but they will have a 1/8" BSW size hex (3/16" BSF) which is 0.34" across flats. This is unobtainium, so I will build up the rod with weld and mill the hex in. I'll start in the lathe, just to start the threads square:

The hex is not much bigger than the diameter of the bar:

Here they are again built up with TIG. The two tubes are the footrests for the QR50.

Here's the setup in the Mini-Lathe. Usual vertical milling slide replaces the compound on the cross slide, and the rotary table is attached to the vertical slide. The saddle is locked to the bed, and the tailstock backs up the vertical slide:

We are passing the work over the cutter, to avoid making climb cuts; the plan is to make a pass, turn the table 60°, and make the next pass. After one turn we will advance the work using the vertical slide - otherwise the vertical slide is locked. I've also tightened the lock screw on the cross slide gib a bit, to take out as much play as I can:

Here's the first one. The target is a 0.340" hexagon, which is 1/8" BSW. It's barely bigger than the 5/16" bar (0.3125" diameter). Currently it is 0.007" oversize.

Next step is to tidy up the hexagon  and face the end to length, adding a small chamfer. 

Next, we'll cut the rest of the thread:

And that's it, apart from the finish:

Model A - First Impressions of a Clutch

Isn’t it a bit early to be looking at the clutch on that bike, when you have so many others in the pipeline I hear you ask? Well, yes it is, but a while back I lost one of the tank bolts on the W/NG - you might remember I made a new one; I am diverting myself with lathe jobs as a distraction from all the welding on the QR50, and part of the lathe work is to collect the bits for the gear control on the Model A, and to do that I need to mount the tank - which is another lathe job, as one or two of the bolts are missing - so I need the tank mounting rubbers for that too, and I also want to trial fit the tank on the FH and I have no rubbers...

So what I need to do is to get an order for Jeff Hunter Engineering, who will supply all the rubber bits and what I am going to do is order as much of the rubber as I can, for all three Ariels. And this is where the clutch comes in - the Sturmey Archer clutch in the Model A has a rubber shock absorber in the clutch and this is bound to need some attention:

So let’s have a look. It’s very easy to get to as in 1930 Ariel were not using the fully enclosed and sealed primary drive, and my primary cover is off awaiting time on the welding bench:

Clearly, two of the retaining bolts, springs and spring cups are missing. Those bolts actually have screwdriver slots under that muck.

Under the pressure plate, the basket and centre are very good indeed:

The plates are reasonable too, but I wasn’t expecting Ferodo linings:

The parts list clearly shows a cork lined clutch:

Yet if we look in the Sturmey Archer book from the period, there is a Ferodo option for the three plate clutch. Interesting.

We’ll have to replicate these parts, though I wonder if they have been intentionally omitted. Ferodo clutches of the period can be quite heavy - the one on my W/NG is much less pleasant than the cork clutch on the SQ4, for example.

Still, it will be a long time before we have to deal with that problem.

QR50 - Oiling System

The little QR50, as a two stroke, has an oil injection system consisting of an engine driven pump supplying metered oil direct to the carburetter float chamber from a reservoir in the frame spine. Keen readers might recall the stopper I made for the oil filler behind the headstock.

As we near the end of the project we need to think about hooking up the system; the pump has been ready for a while and is a replacement for the original which had a smashed casing. I’ve got a twist grip with the two into one cable which operates both the throttle and the oil pump, so we just have to pull it all together.

The first step is the banjo which takes the oil from the frame tube to the pump, and to a tube leading back to the headstock as a visual indicator of oil level:

Typical of Honda, this couldn’t be anything easy could it - like a standard banjo that I could buy. No! The fitting in the frame is M9 x 1.0, so I have to make the banjo bolt from scratch. For me that is the tricky bit as I don’t have much experience cutting threads on the lathe and I am certainly not going to buy an M9 die that I will never use again.

Next, we need a banjo to go with it. Tricky again, because the banjo needs an internal annular groove for the oil to run around. We need a tiny boring bar, like this one:

This is ground from a blunt 5 mm twist drill and mounted in a bit of 1/2” bar, retained with an M4 grub screw.

Using the new tool, the interior is bored to give an annular space:

When the internal features are ready, I put the banjo in the tail stock v-block to drill the holes for the oil line connections:

With the banjo parted off I can do a trial fit on the bike to think about where the lines will route:

I’d planned to use 3/16” hydraulic tubing, which I had knocking about:

Whilst this was functionally a sound idea, it transpired that the feed to pump and the connection to the filler neck were going to need 5 mm bore line, so these 3/16” stubs were too small. I went home for tea, as it was below zero outside and I couldn’t feel my fingers.

Next day, I made some 6 mm stubs from some brass round bar and sweated them into the banjo:

That looks much better.

Regular readers might wonder why this takes so long. Look closely - with the oil pump in place, the dummy swinging arm doesn’t fit properly:

Inching closer, I made this brass fitting to hold the cable adjuster. I'll slim that nut down for appearances sake.

Model A - holding the back end together

 It took a few days, but with the help of the guys in the AOMCC I finally got the rear mudguard to luggage carrier bracket right! 

W/NG - getting rid of the fouling problem

A week before Christmas I needed a haircut, so I took the opportunity of a sunny day to take the W/NG on its first decent run since the engine rebuild, having replaced the 0.107 needle jet with a (correct) 0.106. It took me 30 miles to foul a new W8AC, instead of 3; for the trip back I changed to a used B5HS which took me another 30 miles until it too showed signs of fouling.

It was all my fault. When it arrived from Italy, the W/NG had a 276 fitted and I renewed the needle jet for the 276 because the one in it was knackered, and all was well. Then I found a really good 275 body, marked for a W/NG and I swapped the needle jet and main jet into it with a new slide and needle. Of course, the 276 uses a 107 needle jet and the 275 needs a 106 so I had unwittingly installed the wrong one, so finding that improved the situation.

Back to the present, and with hair trimmed, I rode back to the coast and it was surprisingly dark when I got home. On the way, I pondered other elements that I had swapped from the old carburetter and realised I had no way of knowing whether my main jet was indeed a 120 (it is stamped 120) or had been tampered with. I ordered a new main jet when I got back. I suspected someone had attacked the 120 since it was smoking when I took this picture and had fouled the Bosch plug on the way down. 

It was a good run though and she was humming along getting to 50 easily on the flat, though of course I am being very careful not to stress the newly rebuilt engine.

A few days later, a package from Hitchcock's arrived - I have taken to buying Amal spares from Hitchcock's, since their postage and packing costs, a flat fee, are more reasonable than Burlen's. 

It's a matter of a few minutes work to change a main jet, and have a look at what I found. The question we have to ask ourselves is when is a 120 main jet not a 120 main jet? And, as you can see from the picture, when someone has stuck a drill through it!

Afterwards, I took the old W/NG on a short run to Cromer and it has now stopped smoking and is much more sprightly. I'm hoping the fuel consumption might be better, and it will stop eating spark plugs! I've done about 35 miles on the old B5HS so far, so it's definitely improving but I've installed an old Lodge HN out of the Huntmaster to see what happens. The B5HS is certainly not as light as I would expect it to be when you consider that it is too hot a plug for this engine.

QR50 - Frame: can't see the wood for the trees

Something has bugged me about this bike for a while, something I couldn't quite put my finger on. It started with a Honda publicity picture showing an exciting red dirt bike, typical of their 80's dirt bikes, and a dirty old relic in an ebay picture which strangely gave no hint of Honda's magic.

One day, fitting the silencer and trying to determine the right position relative to the frame and engine I saw what I had been missing. Take a look:

I had been using this picture to scale the size of the silencer:

Seeing it for the first time, I realised why the seat didn't fit properly and how the rear wheel had come to wear a hole in the mudguard. It took half an hour to get the bike off the bench, lift the frame off the engine and remove the forks. 

I put the frame in the vice, holding the rear frame loop on one side and applied some heat - the frame soon moved, and I flipped it over to bend the other side. I made the bends gradually, turning the frame each time so that I could be sure that the bends were going in the right place and that I did not overdo it. 

The seat now fits properly, with the rear bolt holes aligned with the frame lug. 

Mini-Lathe - Cutting fluid feed

Doing a lot of parting for the various fasteners I am making at the moment led me to contemplate improving the manual drip oil bottle approach I have to feeding cutting fluid, which led me to eBay and YouTube to see what others were doing. A bit of slow-time at the computer led me to a simple drip feed oiler solution and as I’m lucky enough to have a lifetime of oddments knocking around the workshop, I thought I could easily build something without spending any money.

The solution started with a bit of 3/16” copper brake pipe, which I bent into a ‘question mark’ shape, squaring one end and filing a shallow angle on the other. It’s held by a piece of black Acetal round bar, cross drilled 3/16”. The plastic bar is very short, about 3/4”, and has a strong circular magnet attached to it with an M5 countersunk screw which is threaded directly into the Acetal:

The copper pipe is shaped so that the magnet can sit out of site behind the splashback. There is a pvc tube (fish tank air line) attached to the copper tube which leads to a valve, again a fish tank component: 

The valve is metal, to avoid any compatibility problems with cutting fluids and plastics and is there to shut off or restrict the flow of oil. The fluid comes from a washing up liquid bottle (told you it was cheap) hanging on a hook on the wall and full of oil:

 Fully open, the oil drips at a reasonable rate:

FH - Swinging Arm bushes

A while ago, last May in fact I removed the SilentBloc swinging arm bearings and I wrote about it here. Since then, lots of things have got in the way - not only the Honda stuff, the QR50 and the CX500 but also the rear mudguard and the oil filter for the FH and of course the W/NG engine rebuild. Anyhow, as regular readers will know, the oil filter is done and I am on to the swinging arm. I'm doing this next as I want to check the oil filter will fit (and can be re-fitted) with the FERC in place and I can't do that without the swinging arm fitted, so here goes.

Before I start, the inspiration for this job, the details of the bushes and indeed the spindle (and it's machining) came from Steve Carter, who's done more miles on Huntmasters than probably anyone alive today and who is a stalwart member of the AOMCC and a daily contributor to the AOMCC forum.

Thanks Steve.

So, I have two oil filled bronze bushes measuring 22 mm ID x 32 mm OD x 50 mm long that I bought from Simply Bearings under the part number AM2232-50. The cleaned out journals for the old SilentBloc bushes measure exactly 1 1/4", which is 31.75 mm and we will want an interference fit of maybe 0.002" or 0.05 mm.

Well, you know what is coming next don't you. Charlie will start banging on about the virtues of his mini-lathe. What puzzled me for a while was how to hold the bushes to machine the outside diameters to size - I considered expanding mandrels, grub screws in a mandrel and Loctite. I was nervous of using Loctite as the these bushes are porous and I was worried about getting the bush off the mandrel.

As it happened, I just went for it and did it. This Ever Build cyanoacrylate is old and cold and may not work very well but I put a 1/4" wide ring of it around the 22 mm mandrel and slid the bush on - in a few minutes it was set.

I machined the bushes quickly and easily to size using the power feed and a carbide tipped left hand tool running at about 400 rpm. and it cut beautifully with no complaints from the glue. Actually, the cutting forces probably don't test the glue very much as this bronze is quite soft.

When considering fits, I had thought about cutting a clearance fit and using Loctite 603 Bearing Retainer, but discarded the idea as I should be able to machine a reasonable interference fit and not require a liquid retainer. As it turned out, this worked beautifully with the first bush which had a medium driving fit, but I cut the second one slightly undersize so I used some retainer with that. They both held up to the reaming forces.

The mandrel knocked out very easily and the bushes were pushed in flush with the end of the swinging arm tube, since I knew that there was minimal end float with the swinging arm in the frame:

The spindle material I got from Steve was 7/8", which is about 22.25 mm so we needed to ream the bushes. The spindle needs to carry the original stud through the middle, which created a problem - my lathe is not long enough to drill out a suitable round bar, nor does it have the capacity to pass such a bar through the lathe spindle. This is where Steve comes in again - he had a bit of bar long enough to provide spindles for two of his bikes, mine and another friend’s so he ended up making four. All I had to do was trim it to length to suit my frame, which I could do with a fixed steady. 

With the reaming done, I could oil and fit the spindle - fortunately it fitted both sides simultaneously with out any adjustment, so I was lucky - I had taken no precautions to align the bush I was reaming with the other bush.

The fit is great - there is no play that I can feel on the bench, though it may be a different story when the bike is on the ground.

Last thing I need to do is fit a grease nipple, though I want to assemble the arm back in the bike so I can see where to put the nipple for best access.