BenHawkins

These patterns have been given a couple of coats of paint and will need polishing when the patterncoat has hardened.

I have added 3mm of ply to each stack of MDF for the header tank pattern to make up the thickness. I then drilled holes for dowels to line the two halves up. 

Before the rain set in today we were able to unload the generating set from the trailer. Whilst applying plusgas everywhere I came across these stampings of the broad arrow with WO. Obviously I have seen this with WD on many occasions but I am sure someone on HMVF can explain the why this was stamped WO instead.

The rocker cover has four Rotherhams of Coventry flip top oilers but only one has the lid so I was concerned the rocker chamber might be full of rust. To my surprise the oil I applied last week seems to have done the job and I was able to loosen the thumb knob that secures the rocker cover. 

Although it is obvious that some water has made it in through the three faulty oilers there is still only light corrosion so I am sure the rockers will free off

19 hours ago, Doc said:

Ben,

Pleased to see you've bought the Coventry Simplex generating set. I was under bidder on it at the Crawford reduction sale last year. Part of me wishes I had persevered, but you can't have everything. Good to know it's gone to a good home.

Andy

Thanks Andy,

Perhaps I am better off not knowing the hammer price but I am quite happy with my purchase. Although it is obvious the engine has spent some time outside and there were two spark plugs missing when we picked it up I did take some modern technology with me.

The first tool was a welding rod, I poked it into the sump and to my amazement all that came out on the rod was clean, clear engine oil. No black burnt sludge, water, emulsion or rust. That might still be in the bottom of the sump but decided it was a positive sign.

The second tool was a £20 boroscope. I poked this into the two open spark plug holes; it does not give fantastic images (partly due to poor illumination) but I could not see anything to worry about. The threads for the spark plugs only had light surface rust and being horizontal did not appear to have let any rain in.

I have not take the engine out of the trailer yet, it is too tall for the engine crane so we need to rig up the chain block and scaffold tower. Last night I put some oil in the bores and on most of the fasteners before covering it over with a tarpaulin.

The starting handle had been broken at some point; I suspected the drive dog was in mesh and the shaft was stuck in the carrier so I unbolted it this morning so at least I will not bend it any more when unloading the trailer.

I found a piece of bar that could be bolted to the flange on the crankshaft. This piece of bar has quite a few holes in it from some of the dismantling on the Dennis projects.

To my amazement the crank moved with light finger force at about 2' away from the axis. I don't intend to turn it any more than that but it is certainly a positive sign for disassembly.

From the same location as the Coventry Simplex I picked up this photo taken in Cologne, 1919

It has been quite slow finding parts for the Thornycroft with the three major missing components being the steering box, engine and gearbox.

I spotted this generating set online and we have been out today to collect it.

At first I thought it was one of the Thornycroft T4 generators. The engine is very similar but in fact this one was made by Coventry Simplex.

Looking at the engine numbers used in cars I think this dates it to around 1914 and makes it the 18.5hp model. I believe these generators were used to power searchlights, it ended up on a farm but from some of the lining on the paintwork I suspect it also found a fairground use at some point.

The inlet over exhaust configuration is the same as the Thornycroft T4.

Like the T4 it has only two main bearings and the crank has to be extracted through the hole at the back of the crankcase.

The spark plugs stick out the side too so it may be the closest match I can find.

Worth the 250 mile round trip! I will keep oiling it over the next few months before attempting to free anything off.

We are still mainly concentrating on other (long neglected building) projects but really enjoying getting back into this one after so long.

I have glued each additional layer of MDF onto the CNC cut templates and used the router to trim them with a slight offset to give 2 degrees of draft angle. Each is currently at 4 layers of 12mm and the final depth needs to be 4" so I need to add some thin ply or similar to the backs to finish them off. There are still a few more parts to print before moving on to the core box. 

The outlet is on the side of the radiator so a tight bend is needed. Three of the four parts of the pattern have been printed, rubbed down and primed; the other half of the core box is currently printing.

Yesterday we printed the first half of the core box for the water connectors whilst I was working on other projects.

The pattern had a couple of coats of bondaprimer and some rubbing back during the week and is starting to look good. The first half of the core box has had a light sanding and a coat of primer; the second half is hot off the printer.

When I was having MDF shapes CNC machined for patterns some time ago (for the 1914 Dennis) we managed to fit in a couple of profiles for the header tank into the sheet (but not a complete set for the pattern). I have quite a bit of MDF left over from the mock cab I built (also for the 1914 Dennis) so I have cuts some pieces out a little larger than the templates. After making a couple of aluminium top hat pillars to pass through them (tapped M6 to help extract the pattern from the sand) I glued a couple of them together on the table in my office (as that is reasonably flat and will not upset the glamorous assistant as much as doing it on the kitchen table).

I then took them out into the yard and used some plastic strips (printed to the correct thickness) to offset the router cutter and make the second layer slightly larger than the first and give the pattern a sensible draft angle so it should pull from the sand. I need to repeat this several times before I can screw and glue the printed parts to them.

On 5/31/2020 at 7:32 PM, andypugh said:

Don't forget to leave a hole to glue a dowel in so that the moulder can insert a screw to pull the pattern out of the sand.  (CAD makes it trivial to put that at the exact centre of gravity)

I picked up a free sample bag of threaded inserts at a engineering trade show and have been using those in the back of smaller patterns. I decided to print little handles to fit to M4 set screws as well.

The project is not so much of a rush that I need to get something printed every day so I am printing small items in the evening and get a couple of the larger parts at the weekend. I am using a relatively small layer height (0.15mm) and thick walls so could print faster with thicker layers.

Yes, they were from Ben. I need to organise a trip to see the Fowler next time I have an excuse to be in that area.

14 minutes ago, Citroman said:

I did a find lot of wooden forms on a Belgian fleamarket once. I did buy an bearing of an overhead driveshaft from a factory. It was painted to look like cast iron even the screws putting the halves together were made of wood. 😊

We refitted a lineshaft to our kitchen last weekend; currently it is just ornamental and there are no plans for a flat belt driven apple lathe or mixer but I like to keep option open.

I have made a few BS190 bolts and slotted nuts to secure the steering box this week, once painted I will fit them.

So far I do not have the confidence to leave the 3D printer going when I am out of the house but some more of the radiator pattern parts are finished.

I need to get the router out to shape the bits of MDF but we hired a skip this week so I have been moving large rocks and soil and every opportunity.

Three of the water connections between the cylinder blocks are corroded away or broken. I made a CAD model of the pattern and core box. The pattern took around 13 hours to print, the core box will take about double that.

On 5/25/2020 at 9:34 PM, David Herbert said:

I like the left hand fitting on the radiator top tank. Those 3D printed details are very nice.

David

The pig was a test print. I think the castings, tube plates and tube will cost more coins than it can hold.

This week I purchased a set of patterns for the Austin generating set cylinder blocks. These blocks were also used on the early (1910-1912) Austin 10hp car. There is frost damage to my blocks but they are probably repairable (as the engine runs I doubt they are cracked through to the bores). It seemed too good an opportunity to pass up and they are a great example of pattern making.

Front half of the cylinder block. There are lots of core prints for the cylinders and water jacket. Note the loose pieces to make up the flange held in place with bent nails. The sand will be built up over the loose pieces and the nails removed before the box is completely filled; otherwise an additional core box would be required for this feature.

The back side of the cylinder block. If both sides were the same this one would not be required.

This core box makes up the cylinder bore, valve ports and combustion head.

These two make up the core boxes for the water jacket. No sand goes on the green prints; which shows where the two loose pieces go; note the small loose piece at the bottom left of the upper box. These cores would be challenging to pack and quite fragile when completed so must have taken a skilled moulder.

They came from a foundry in Kings Heath when it closed some decades ago so could be the originals used to make my engine.

I thought other people who have resorted to making their own patterns could learn a lot from these! If anyone wants a dummy generator we could cast some blocks for mounting on a wooden crankcase (or make all the other parts if you like a real challenge).

On 10/11/2019 at 11:41 PM, lynx42 Rick Cove said:

I have one of the Austin engines.  It is No. 136 with a hand etched ID plate.  It has a cast steel engine base so probably was not a generating set.  I found it in Mallacoota Victoria in 1976 and only managed to acquire it last year.  It is complete but I haven't got it rinning as yet.  Not sure what the radiator should be like either..  The generator is just sitting there to fill up space.

Thanks, I missed this at the time you posted it. Another interesting project.

There is still some detailing to do on the gearbox before I can consider making any more parts. I have decided that the priority tasks should be getting the steering and handbrake linked up to make it easier and safer to roll the chassis in and out of the garage.

The top of the steering box needs to be fixed to the dash. Although I started fitting the dash over a decade ago I left it 2" tall and didn't finish the dash irons as most other commercial vehicle engines would sit higher in the chassis. Now the project has the correct engine (thanks to Hedd and Ken!) I was able to finish the dash irons to the correct height by warming them up and bending them to match the original drawing (it is great how many of these have survived).

I then trimmed the bulkhead and cut the opening for the flywheel. Once the 14 holes were marked up and drilled I sorted out 5/16 BSW coach bolts and modified them in the usual Dennis way (filed three corners off the coach bolts and filed one corner into each hole in the dash.

The radiator pattern making stalled around 6 years ago for the same uncertainty about engine fitment. I have no drawings for these parts, just an idea of the overall dimensions and some cross sectional drawings of the Hallford horizontal tube radiator that also appears to have been supplied by Coventry Motor Fittings. I also have plenty of photos and these have also been very helpful.

On my 1914 Dennis the radiator flanges match the flange size on the White and Poppe engine so I have used the same for this design and also match the tie rod mounting detail. I have purchased one of the cheapest 3D printers to help work through the long list of patterns for this and other projects; it only has a 220mm x 220mm bed but can still do a lot of the detail work.

It is a horizontal tube radiator mounted on shackles. These features seem to have been in fashion for a year or so either side of 1908 before the vertical tube radiators mounted on trunnions became standard.

On 5/18/2020 at 9:15 PM, nz2 said:

Do any of the gears or shafts from the latter gear boxes measure up to be the same size as needed?

 

The later gearboxes are stub tooth 5dp 20 degree pressure angle. The original was 6dp 14.5 degree pressure angle; shafts, covers etc. are all different but I may be able to use some of the transmission brake parts.

On 5/21/2020 at 12:43 AM, andypugh said:

As-drawn the torque times the tangent of the angle of the face from a line from the centre point. (times  µ)  

If you sweep the extension of the pawl face to the other side of the centre point, just a bit more than the weight of the pawl. 

I keep meaning to design and build a CNC slotting head for my mill. Perhaps this is the excuse? 

The ratchet detail is one of the drawings that survives. The tip angle of the pawl is 77 degrees and therefore I expected them to lock in when the hub is being driven. 

10 hours ago, rog8811 said:

Interesting design, unlike a sprag clutch  only two pawls will engage at any time, the springs will not need to be at all heavy as the shape of the pawls will self lock when in the detents.

Are you heading toward having all the parts for the gearbox made or hoping to find the right one or something of the era that will work?

I have a couple of 1920s Dennis gearboxes I could fit but I would prefer to put the correct version in. It is probably too much to hope that the correct gearbox will turn up so my only option will be to manufacture one. I don't like the idea of paying someone to have all the fun even if I was able afford it.

I have made a few of the simple components already but it is certainly going to be a challenging project.

We have been tidying the garage so we can get back into this project soon.

I have been working through the information I have found on the gearbox and started to model it in CAD. There are 39 parts listed in the catalogue but there are no diagrams and it does not list things like bolts, keys and taper pins.

Drawings have survived for 14 of the components; this includes the four shafts but does not include the selector rods or gears. Much of this detail can be guessed at from the drawings in the patent.

One of the novel features is the freewheel mechanism. What force do you think the springs need to apply to the pawls to make it work reliably?

We decided to have afternoon tea with the working vehicles to celebrate VE day; this was the second drive for the 1908 Singer but as it is only 15 metres between the garages it really needs a run out on the road to get a better idea of the performance.

Tinkering has continued on the Dennis and we have added a felt seal to the back of the fan pulley as it leaked a fair bit of oil. If a road test shows it to be relatively leak free I can swap the modern belts over to Whittle belts.

I have also found a Powell and Hanmer self generating headlamp (as shown in the in-service photo) but it needs a clean up before fitting.

The correct size of tan canvas sheet was available off the shelf but I can't get a good photo of it in the garage and I probably need to improve the way I have tied it down.

As these three are moving from rebuild into the tinkering/maintenance phase I am starting to think about the project plan for the 1908 Dennis. 

I have blasted the ironwork and really liked how the blacksmith tidied up the corner by forge welding a triangular piece in. 

They have cleaned up well. Repairing the threads that have been cut off will have to wait for a later date. 

I briefly looked at how much it would cost to reproduce the body in oak as used originally. Some shopping around will certainly be required.

This project has been on hold for too long, we hope to restart it later this year.

The current project is a 1908 Singer (I could not come up with even a tenuous link to military for that one). I had one of the wheels rebuilt by an excellent wheelwright; he brought me a present for this Dennis along with the Singer wheel.

Back in 1976 he rescued a dilapidated horse van that appears to have been identical to those used by Carter Paterson and as originally repurposed to the body for this 1908 Dennis project.

The four parts are (top to bottom):

1. Shore Staff

2. Timber Standard

3. Tilt Hoop Iron

4. Outrave Stay 

I offered them up to the chassis and they look to be of the correct proportions so will be perfect to scale the body from.

He does not remember using any of the other parts to repair any other waggon so they are probably in the spares stock somewhere. I am now really looking forward to another visit to the wheelwright during the summer to hopefully collect a boot full of other rusty treasure.

31 minutes ago, Surveyor said:

Just seen this, stupid question but during that period would they secure loads?

I have photos on the day it left the factory and one in service and none of them show anywhere to tie ropes. 

In order to rectify a slight coolant leak I removed the water pump to add more gland packing.

Whilst the coolant was drained and the pump was off I machined a boss, silver soldered it to the coolant pipe that feeds the cylinders, then drilled through and tapped it 1/4" BSP for a tap. This was in preparation for providing water heating to the carburettor.