BenHawkins

Thanks for all the comments on roofing methods. It is always good to learn about these techniques. The Dennis catalogues of this time suggest that they were actually covering the roofs with zinc sheet. Unfortunately there does not appear to be a zinc mill that rolls sheets wider than 1100mm so I will need to solder two sheets together. I know the radiator castings will ultimately need replacing but I have been doing a little more work on them to see if I can get a year or so our of them. I was interested to see if the corrosion pits could be filled by spraying molten metal into them. They needed to be prepared by sand blasting and then an oxy-propane nozzle was used to melt aluminium wire and compressed air used to propel the molten droplets. I couldn't get it to stick well in the craters as it was difficult to get a good blast profile in the craters. So in the end I decided to drill out the pinholes. Tap them out so I could Loctite in aluminium bolts Then cut the bolts off and grind them off flush.

I don't really know if I would notice, but it seems like quite a lot of imbalance to spin at up to 1400 rpm. All my Dennis flywheels (3) have holes drilled in them that I assumed were for balancing. None have more than two so they look less like Swiss cheese than mine (and it is much easier to drill two holes that appear to line up). The clutches tend to have a balance weight riveted on, probably because there is not enough material to drill. I don't know if the flywheels were originally dynamically balanced or just put on a 2" shaft and placed between two parallel horizontal rails so they could see which part rolled to the bottom.

I parted the bush off, using a piece of bar in the tailstock to catch it. Then remounted it in the chuck so I could face it off. Followed by chamfering the edges. And the (almost) completed bush. It still needs a small notch machining but I need to sort out a 7/16 slot drill for that. The flywheel will not fit in my press so I will probably make up some tooling to use with some M16 threaded rod to draw the bush into the flywheel.

I then machined the outside diameter down to 2.001" And started to bore the internal diameter out; using a stop on the bed so I stopped in the same position each time. Continuing until the bore was 1-3/8"

I remounted the phosphor bronze in the lathe so I could continue the machining of the clutch centre bearing that needs to be pressed into the flywheel. The first step was to machine the first 1/2" down to 1.995" diameter. Then cut the 16tpi thread. And try the collar on the thread to make sure it fitted.

On Monday I dropped the flywheel of at the nearest dynamic balancers. They had to remove 200 grams to sort it out. They mostly do work for aerospace companies so I thought they might get the hole spacing slightly more even. However, it is hardly noticeable when the holes are painted. I can't fault the 48 hour turnaround and it would terrible without balancing. Probably better balanced than Dennis would have managed.

I have fitted the remaining boards to complete the roof and applied some undercoat. Once all the roof boards were in place I screwed on the front board for the cab. And swapped the cross head screws in the window frame for the slotted ones I purchased.

This allowed me to accurately mark the length of the board for cutting. The first board was then screwed down. The process was repeated for 9 more boards. That is the limit for allowing be to fit through the gaps and the final boards will have to be fitted from a ladder. The coach building books suggest all gaps should be filled with putty so I looked in the shed and thumbed some into all the gaps. It needed warming in my hands before it was pliable enough but that might just be a sign of the weather.

I have painted the undersides of twenty lengths of tongue and groove timber. And marked the centre line on the cab. Then clamped the first board in place; it seemed to follow the arch quite well.

I scribed two lines where the clutch lever needed splitting and cut through with an angle grinder. I milled some of the shape into it before thinning it closer to shape with an angle grinder in the two positions where it needed to be bent. I then heated it with an oxy-acetylene torch and fitted some box section over the end to apply the bends. It needs to go back on the machines to finish it off. I dropped the front propshaft off with the gear cutters; hopefully they will sort it all out for me. I have finished painting the next two boards for the back of the cab so we fitted those. They had bowed a little so some big sash clamps were used to close up the join between the two boards. The cross head screws in the window frame a temporary fitment until I get some slotted ones.

After giving the arm a coat of primer and paint I tried it on the shaft. 1st-4th gear select well but reverse is not easy to select; I think the lever is just tight against the bracket and if so should be easy to fix. It clears the universal joint so it must be nearly right as there is not a lot of space.

I took the gear selector drop arm to work so I could borrow a larger rotary table. The first stage was to clock the rotary table so it was coaxial with the milling spindle. This was followed by clamping the drop arm to the rotary table and adjusting its position until the centre dot mark was also coaxial with the milling spindle. Obviously there would be quite a lot of torque applied to that clamp bolt so I pushed a couple of step blocks up against the arm and clamped those in place as well. Making the final stage of milling the radius on the end quite easy.

I hoped to mill the circular end on the gear selector drop arm this weekend but as I started to set it up on my 8" rotary table I realised it would not fit. I will have to borrow a larger one. Now the engine position is fixed I have slightly shortened the starting handle shaft and secured the handle with a taper pin.

The missing lever from the clutch cross shaft is similar to those that are already fitted. There is a 1" diameter hole at one end with a pinch bolt to secure it to the shaft whilst setting up; two taper pins are then also fitted to guarantee it will not move. At the other end is a 1/2" eye for a clevis & pin. I have started to rough this out by drilling 1" and 1/2" holes in a piece of square bar and then removing some of the excess material at that end. Whilst I was around the workshop this weekend on other tasks the shaper removed much of the excess from the rest of the length. Still plenty to do but starting to take shape.

I bought the cheap remains of a Lucas horn at an autojumble several years ago. This week I fitted a new reed, added a piece of brass tube, soldered up a crack, gave it a coat of paint and fitted a new bulb. The glamorous assistant has fitted the bracket I made to the cab prop. And then fitted the horn to the bracket. One step closer to being road legal.

I wanted to tackle the front prop shaft as I probably need to out source the manufacture of a longer one. The clutch release bearing arrangement cannot be removed with the knuckle joints fitted to the prop shaft. There is a grub screw that secures the threaded collar retaining the bearing. When this removed and the housing was unscrewed the bearing was in good condition. I tried to press the knuckles off the shaft but it was a bit more than my 10 ton press could manage (even with the addition of oil and heat) The ten splines are 1.5" minor diameter, 1/4" wide with parallel sides. It appears the press fit is on the minor diameter as the old grease wicks out of the gaps at the crests.

At times it is bearable. I have started priming some boards for the roof. But it is more satisfying when another board is finished and can be fitted. It was also nice this week to renew the insurance; double the value of this one and add road use. It added nearly 12 pounds to the premium!

Hi Dan, The Dennis two ton flywheel is 16" od, so it would probably work for your purpose. I don't know how similar the Halley flywheel/clutch is to the Dennis but I am sure we can arrange another casting if required. The flywheel & clutch has worked out to be one of the most expensive parts of this build; including lining and all materials it has probably worked out around 800 pounds. It looks like you may be able to machine the flywheel yourself so that might save you 200 pounds.

Working on my 1914 Dennis has depleted my stocks of Whitworth coach bolts so I was pleased to visit the garage of a local retired ironmonger and come back with a few boxes. I still hope a horse drawn van will turn up to fit to the chassis (as was done originally) but if not these will certainly help to build the body.

I used the lathe to face the end of the shaft, using a three point steady to support it. The length still needs reducing a little more to get a good fit between the mounting rails. As I am now fairly confident about the position of the engine I turned up a small bush to centre a 1/8" pilot drill in the engine mounts and drilled through at two opposite corners. Then opened the holes up to 3/8" and fitted some temporary bolts. Certainly an improvement on quick clamps and should make it impossible for me to drop the engine on the floor. And I have done bit more painting.

I felt strong enough to have another go at lifting the 40kg flywheel on and with the holes opened up slightly it fits well. This allowed us to centre the engine and clamp the clutch release parts in place. I must thank the Goslings for these parts but as they were off the fire pump. The fire pump did not use a foot pedal but instead a long lever on the end of the transverse shaft, therefore this shaft cannot fit between the mounting rails and cannot be mounted high enough to reach the centre line of the clutch. This clutch stop is from a 1920s Dennis lorry and although very similar to the original it does not end up in quite the right place as it is too low and will clash with the clutch springs (that fit around the hole shown in the photo). It is just the bracket part that appears to be different from the original parts so I should be able to use most of it. It was fairly easy to cut the end off the transverse shaft.

The rear end of the prop shaft tube was supported on a large revolving centre so I was able to machine the taper on that end by setting the compound slide at the 6.5 degree angle (the actual angle is not too critical). The drawing calls for most of the diameter to be reduced to 2-3/16". This picture shows how close it was to the capacity of the lathe (the reason the three or four jaw chuck could not be used at the headstock end as the tube would not fit through the bore). Another check of the fit. Both ends need to be pinned and brazed into the tube before reaming the holes for the drive pins.

I finished boring the prop shaft tube and checked the universal joint jaw piece fitted. I then drilled three holes equally spaced on a 100mm PCD in the mounting block I had made so that it could be transferred from the tool post to the catch plate. Then mounted the catch plate on the lathe spindle (and clamped the prop shaft tube into the block) and used a dial indicator to make sure I had it coaxial with the lathe spindle before tightening the bolts.

The other tasks for this week have been further boring of the propshaft tube. And roughing out the phosphor bronze centre bearing for the flywheel. And of course more sanding and painting.

There has not been the usual level of productivity this week as we went down to London for the Brighton run auction and Regents Street motor show. John Dennis drove us through London in the 1902 car which was an unexpected treat; it was running well on all of its (one) cylinders. I often make lorry parts in my lunch break at work, but on Monday the lathe and milling machine were busy so I drilled some holes in a block of steel to attach the bulb horn to the prop at the front of the cab. After drilling the 3/4 inch holes and the 5.1mm holes for tapping 1/4BSW the next step was to split it with a saw. I then milled some of the excess material away. It is still a bit heavy duty for a horn bracket (the kitchen scales say it weighs 338g). I will thin it down a little more next time I have nothing else to do. I have also increased the diameter of the mounting holes in the flywheel by 0.005" but have not yet tried fitting it to the engine.