flandersflyer Posted May 9, 2016 Share Posted May 9, 2016 OK Nice work your doing ben Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted May 15, 2016 Author Share Posted May 15, 2016 I was fairly distracted by the Keeley auction this week but came back with nothing. There was a little bit of progress on the pedal levers as I finished welded them together. Followed by blasting and priming the throttle one and turning pieces of bar to link them to the treads. Cutting out some MDF rings and gluing them together has given me the blank for the transmission brake pattern. I will need to mount it up on the lathe to machine a taper on the diameters. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted May 22, 2016 Author Share Posted May 22, 2016 After turning the diameters of the transmission brake pattern I gave it a coat of primer. After sanding and a further coat of primer it looks like this. We went to Beaulieu auto jumble yesterday. Although this is not a Dennis pump I should be able to fit it in the available space. I have primed the pedal levers and drilled the treads. I drilled a number plate and fitted it to the brackets. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted May 22, 2016 Author Share Posted May 22, 2016 Having decided where the ball joint needed to go on the steering arm I thought about how to make the tapered socket. I was able to find the angle on the original drawing; 10 degrees and 52minutes. Why they chose such a strange taper I don't think we will ever know but I decided I should be able to make the taper on a Bridgeport milling machine (my mill is too small). The angle equated to slightly over 0.095" per inch. After setting the ball joint axis concentric with the rotary table and positioning the head on the same axis I tilted the head until raising the table one inch gave a deflection of 0.095" on a dial indicator. Then fitted a 3/4" end mill to machine the socket. Then checked the depth against the ball joint. Trying it on the chassis again showed the drag link was slightly too long as full left lock could not quite be achieved so the drag link was shortened by 1/2" The outside of the socket was shaped with a combination of saw, angle grinder and files. And when retrying the parts it was possible to achieve full lock in both directions. Quote Link to comment Share on other sites More sharing options...
GeePig Posted May 23, 2016 Share Posted May 23, 2016 A nice piece of work, you must be glad it all worked out. Is there some kind of bump stop that makes sure that on max upward deflection of the axle the steering arm does not contact the chassis rail? trev Quote Link to comment Share on other sites More sharing options...
David Herbert Posted May 23, 2016 Share Posted May 23, 2016 I think the steering arm IS the bump stop... On a more serious note, I am suprised that the drag link is not more horisontal, at least at some point in its action. Was this a typical Dennis thing or just this particular chassis design ? I would like to add my voice to those saying what a super job this is. David Quote Link to comment Share on other sites More sharing options...
andypugh Posted May 23, 2016 Share Posted May 23, 2016 I decided I should be able to make the taper on a Bridgeport milling machine That was rather a cunning bit of machining. I guess to an extent you were lucky that the part was small enough to swing on the rotary table. I wonder if a threaded and welded lathe-turned taper insert would have worked if you had not been able to rotate the work? Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted May 23, 2016 Author Share Posted May 23, 2016 Even with the Bridgeport milling machine it was not an ideal fit, I had to remove the handle from the rotary table as the arm did not clear it. I then operated the rotary table using a bolt through the spindle. I made the arm from EN3 so I had the option of welding if it all went wrong. However I did have visions of a welded on socket fatiguing through. The first attempt at bending the arm left it with about 3/4" of clearance between the arm and the spring retaining plate but there was not enough space left for suspension travel. I have now reduced this to about 1/8" to give maximum suspension travel. The drag link is at quite an angle but you can see this in the factory photos and it is unusual to this particular model. I did look at whether the ball joint could mount under the steering arm but then it would hit the leaf spring before full lock is achieved. Basically after many goes at making it work I think I must be within about 1/8" of where the ball joint was originally positioned. Quote Link to comment Share on other sites More sharing options...
Redherring Posted May 24, 2016 Share Posted May 24, 2016 Hi Ben. Thought you might be interested in this photo. This is the right hand front hub on the S type Leyland. Very similar design. The steering arm (missing) is bolted to the 'lower' hole in the hub. The cross-link attaches to castings bolted to the upper holes - on left and on right hubs. Robert Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted May 30, 2016 Author Share Posted May 30, 2016 Hi Ben. Thought you might be interested in this photo. This is the right hand front hub on the S type Leyland. Very similar design. The steering arm (missing) is bolted to the 'lower' hole in the hub. The cross-link attaches to castings bolted to the upper holes - on left and on right hubs. Robert Thanks for that, always nice to compare the different manufacturers methods. We went away to look at another unrelated project for some of the weekend but have still made a few bits of progress. I spent a few hours straightening the gills on the radiator tubes. Looks quite nice when pushed out in the sunshine. It was fun to let it roll down the slope and be able to steer it and stop it with the handbrake. I have removed most of the excess material from one side of the universal joint socket. I will swap to a long series cutter to finish it off then repeat the process on the other side. The foundry had problems with my MDF pattern for the rear brake drums delaminating when pulling it from the sand. As the transmission brake pattern is even deeper I have gone for a steeper taper (4 degree included angle) and turned some aluminium inserts. These are 12mm diameter on the other side, 9.5mm diameter through the bulk of the pattern and tapped M6 on this side so the bolts can be used to extract it from the sand. Hopefully this pattern will be less traumatic. Another rub down and coat of paint and it should be ready to drop off at the foundry. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted June 12, 2016 Author Share Posted June 12, 2016 All the service engineers have been away from work over the past couple of weeks so I have been standing in and travelling around the country. Last weekend was spent picking up parts and visiting an archive to try to find a registration card for when this chassis moved to Lincolnshire, we only got as far as registration cards for 1922 so we need to return to Lincoln at a later date. Milling of the UJ socket has continued. And once the rotary work was finished I bolted it to the table and roughly shaped the profile for the smaller front flange. Followed by a bit of final deburring and filing. And finally a clean and coat of primer. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted June 12, 2016 Author Share Posted June 12, 2016 A good friend of mine assured me he had a spare Dennis 2 ton clutch in his shed so we visited to have a look. After a couple of hours of shunting vehicles around and dropping the boiler out of a steam lorry we spent a few hours emptying a shed to find the clutch (and some parts for his projects!). The crack and broken rim was a bit of a concern and where the clutch stop acts it has worn down to less than 0.1" Removing the woven lining showed even more damage. I will have to decide if it is worth investing in an AC TIG welder to have a go at repairing it or just build it up into a pattern with ply and filler. I already have clutch stops and these have been blasted and primed. The friction linings need to be replaced. Quote Link to comment Share on other sites More sharing options...
Asciidv Posted June 12, 2016 Share Posted June 12, 2016 You know it has to be a pattern....but I wouldn't let it stop you from buying an AC TIG! Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted June 19, 2016 Author Share Posted June 19, 2016 More transmission parts have been blasted, primed and painted. I dropped the transmission brake pattern off at the foundry so we are slowly ticking off the missing parts. I have also drawn up the mudguards and placed an order for them, hopefully I can pick them up towards the end of July. Taking measurements from the clutch showed that in addition to the corrosion it was quite warped as well. This meant the only real solution was to build it up into a pattern. I started by gluing strips of MDF on and building other areas up with filler. It is marginally too big to fit my lathe so I mounted the rotary table on the milling machine and tilted the head to the 12 degree angle required. The clutch would not have been possible to pull from the sand so I decided to build up the inner surface as well with filler. Originally this would have been done with a core but this seemed a bit excessive for one casting and I can always mill the casting back to standard dimensions. I tilted the head 2 degrees in the other direction to get the draft angle. I have given these surfaces a coat of primer but I still need to add some threaded bushes into two of the holes so the pattern can be lifted from the sand and build up the mating faces to give me some allowance for machining. Hopefully I can drop this off when I pick up the transmission brake casting. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 3, 2016 Author Share Posted July 3, 2016 This vehicle was originally purchased by Ernest Shentall of Chesterfield; the other day I was visited by the son of one of the last owners of the company. He left me with five potato sacks as would have originally been carried (although these are a little later). I also have a fruit crate but I will need to find some more. I dropped the pattern for the clutch off when I collected the casting for the transmission brake drum. I don't have the drop arm for connecting up the gear linkage so I drilled the holes in some square bar. There is a slightly longer original to show how much of this piece of bar I need to turn into swarf. [ATTACH=CONFIG]116780[/ATTACH] I wanted to remove the flange for the rear universal joint so I brazed some 1/4 silver steel rod into a laser cut blank. All I managed to do was bend the silver steel so I might leave the flange in place as there is nothing really wrong with it. Quote Link to comment Share on other sites More sharing options...
andypugh Posted July 3, 2016 Share Posted July 3, 2016 All I managed to do was bend the silver steel so I might leave the flange in place as there is nothing really wrong with it. At the risk of giving lessons in the sucking of eggs, you could try getting the ring nut all toasty-warm. Though that will still leave you with the flange taper(?) to loosen. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 3, 2016 Author Share Posted July 3, 2016 The next job I wanted to do was the "End for Arbor Shaft, Part Number 1333/4". Another part where the original drawing has survived. This is a fairly complicated part as it has a spherical end drilled for a drive pin and has to be able to articulate in the socket I made previously. I decided this was best done in the milling machine but first required me to machine a back plate with an 8TPI thread to fit my dividing head. Once again when setting it up with the blank I had machined previously I was right on the size limits for my milling machine and the tail stock had to overhang the table. I had to machine a left hand boring bar from a piece of 1/2" HSS as my boring head screws onto an arbor and would therefore unscrew if I reversed the direction. For those of you who have not seen this process before it basically works on the theory that if you cut a sphere in any plane you will end up with a circular cross section to the cut. The next stage was the cross drilling, starting with a stub drill and working up to the biggest drill I could fit on the machine (a 20mm reduced shank drill fitted in a 1/2" collet). I then refitted the boring head and opened the hole up to 1.120". Once the end is brazed into the prop shaft I will then run a reamer through to open it up to 1.125". The final machining stage was to swap to a fly cutter and put two flats on, using the dividing head to make sure they were 180 degrees apart and symmetrical about the axis. Polishing with some 800 grade silicon carbide paper improved the surface finish and finally I checked for smooth operation inside the socket to make sure I had generated a good approximation to a spherical surface. I need to lay all the transmission out soon to see what parts I am missing. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 3, 2016 Author Share Posted July 3, 2016 At the risk of giving lessons in the sucking of eggs, you could try getting the ring nut all toasty-warm. Though that will still leave you with the flange taper(?) to loosen. I need the tool to fit the universal joint to the 1908, but as I don't strictly need to remove the 1914 one I will probably do more harm than good in attempting any more progress on that task! Quote Link to comment Share on other sites More sharing options...
Asciidv Posted July 4, 2016 Share Posted July 4, 2016 Ben, When you were machining the ball, what step size did you take? How long did it take to machine the ball? I do admire your determination to chew through large lumps of steel just with a HSS bit Are you going to harden any of the components in this assembly? The sacks are wonderful! Barry. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 10, 2016 Author Share Posted July 10, 2016 When machining the ball I raised the table by about 0.010" each time, running the boring head at 200 RPM and each revolution took several minutes. I am not sure exactly how long it took but I would guess a minimum of 5 minutes per revolution (on the final pass, much quicker when roughing out) and therefore given it was a 3 inch diameter a feed of less than 0.009" at the centre and 0.0045 at the edges. The drawings do not ask for the ball or socket to be hardened, but the drive pin is again "UBAS Steel Case Harden". I have chosen to use EN24T and have it nitride hardened. This called for spherical ends so I have used the same method but required a way of holding it so I took a scrap of aluminium bar, bored it through at 1-1/8" and used a hacksaw to cut a slot so I could use a pinch bolt to secure the drive pin. Finally I put the drive pin in the lathe and polished up the ends. I need to make a few more parts for hardening so I can justify the minimum charge. Phosphor bronze blocks fit on the end of the drive pin and run in the slots in the socket. Having struggled to find a metal merchant to supply some at a reasonable price I ended up purchasing some from an online auction. It should keep me busy for a while when it arrives as there are a number of oil grooves to cut in the blocks. I cut the slot in the gear selector drop arm so I could clamp it to some 1" bar and machine the boss on with a ball nose slot drill using the rotary table on a milling machine. I then transferred the blank to the shaper to remove some of the excess material. This is usually a great machine as I can leave it running whilst working on other jobs. However the magic smoke escaped from the 20 year old variable frequency drive that I use to run this machine. I found it in a skip and it was only just rated for this motor so I have ordered a more appropriate one but at present no further work has been done on this component other than order some HSS to make a slotting tool to put the keyway in. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 10, 2016 Author Share Posted July 10, 2016 The flywheel is too big for my machines but I didn't want that to stop me making the pattern. Using Draft Sight (a free 2D CAD program) I sketched a set of rings and discs that would fit into a standard sheet of 12mm MDF and sent them off to be cut. One week later these arrived. I made four rods with a 16mm head, 12mm shaft and tapped M6 at the other end to aid assembly and removal of the pattern from the sand. The CNC router was able to put the holes accurately in position so that each ring (gradually getting bigger in outside diameter and smaller on internal diameter) could easily be glued into position. Once the glue was applied a number of clamps held everything together I still need to make and glue on a central boss for the clutch bearing and a ring on the back face to accommodate the crankshaft flange before applying filler to smooth out the steps. I have also pressed the bearing off the gearbox output shaft as I will need to machine out the rusty split pin, tidy up the thread and make a replacement nut (as I had to split the nut to get it off). Quote Link to comment Share on other sites More sharing options...
andypugh Posted July 10, 2016 Share Posted July 10, 2016 However the magic smoke escaped from the 20 year old variable frequency drive that I use to run this machine. I found it in a skip and it was only just rated for this motor so I have ordered a more appropriate one but at present no further work has been done on this component Why not run the motor DOL? Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 17, 2016 Author Share Posted July 17, 2016 I quite like being able to change the speed of the shaper with the VFD. It would work without it straight off the three phase but I would at least need to fit some fuses and a start stop button. Anyway the shaper is turning lumps of metal into swarf again. As the dividing head was set up on the milling machine I used it to machine a hexagonal blank for the transmission brake hub nut. Filler was applied to the flywheel pattern. Followed by sanding and painting. Some discs of MDF have been glued together but still need to be machined to the right shape for the central boss before gluing in place. We removed the existing flywheel with some difficulty, it seemed quite heavy when I lifted it to the floor so I put it on some bathroom scales (85kg). Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 17, 2016 Author Share Posted July 17, 2016 I went up to Manchester on Thursday to collect the newly made mudguards. I had previously made the brackets for the rears so I was able to rest one in place to see how it would look. I then spent some considerable time getting them fully degreased. And applied a coat of primer. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted July 24, 2016 Author Share Posted July 24, 2016 I have been around the edge of the mudguards a couple of times with primer just to make sure there is no crevice for water to sit in. After measuring many times and quite a few trial fittings the rear mudguards are now drilled to suit the brackets. The next task will be to modify some 3/8" BSW coach bolts to replace the temporary fasteners. I machined the central boss for the flywheel pattern and gave it a coat of primer. Before gluing it into the main pattern, sanding everything down and giving it a coat of paint. Quote Link to comment Share on other sites More sharing options...
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