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1914 Dennis Lorry


BenHawkins

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Nice work as usual Ben, always look forward to seeing you progress the build up, and I usually pick up a little tip or two, thanks for sharing it with us.

 

 

Thanks, I just make it up as I go along so it is always nice to know other people get something out of it!

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I have done a little more on the king pins by tapping the tops 1/4BSP for the greaser and cutting the 1-1/8BSW thread for the adjuster nut. I purchased a new tool for this as you can't get 7TPI insert for my 16ER holder and have to move up to a 22ER. Certainly a few more hours required to finish them off. Later king pins have a finer thread for adjustment but as always I am trying to copy the original design as closely as possible.

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The shoulder screws for either end of the track rod are unusable do to heavy corrosion (and I had to cut through one to free it all off during disassembly. A bit more work on the lathe to turn a piece of EN24T into the right sort of shape.

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The next part was to cut it off the bar, face the ends, mill two flats and drill/tap the grease holes to give this:

IMG_0419s.jpg

Once the second one and the king pins are finished I will take them all for nitriding.

 

So I can use the old cracked water jacket top as a pattern I have built up the surfaces with MDF and filler.

IMG_0404s.jpg

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When the weather is reasonable I like to go outside and get on with fabrication work. I had been thinking about the rear wing brackets for a while. I turned down the end of some 7/8" steel rod.

IMG_0405s.jpg

 

The boss located the rod in the flange. I left it shorter than the thickness of the flange so I could puddle some weld in from the back face.

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With it all securely in position I could then fillet weld the other side and dress everything back with the angle grinder.

IMG_0408s.jpg

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Without drawings for the wing brackets the only sensible solution was to draw them out full size. I am lucky to have a photos to scale from so I know the wing came close to top of the bearers (these appear to be approx. 6"x2"). The bracket on another chassis I was able to measure appeared to have a 22" radius.

IMG_0412s.jpg

 

These dimensions all seemed to work gave a nice even 45 degree angle between the mounting flange and wing so this may have been the original design intent. It also allows for a little over 6.5" suspension travel. I had left the rods 1/2" too long so I could cut the angle into them.

IMG_0410s.jpg

 

Then clamped everything up and welded them.

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Then dressed it all back with the angle grinder and repeated the process to create the mirror image.

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I am still undecided about how to 22" radius into the full length of the front bracket and the top half of the rear bracket. Bend them cold with the press or hot around a timber form I cut out with a jigsaw?

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I am still undecided about how to 22" radius into the full length of the front bracket and the top half of the rear bracket. Bend them cold with the press or hot around a timber form I cut out with a jigsaw?

 

I would do it cold, then there is no rush. It's a small degree of bend. It might still be worth jigsawing the template just as a reference.

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Thanks for the suggestions. I went with bending them cold in the end.

IMG_0429s.jpg

 

The first one is now blasted, primed and put in place to see how it looks.

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I have tacked some of the foot pedal profiles together. The plan is to line everything up on the chassis and then decide how far they need joggling over and how big to make the bosses. Some of the surviving drawings for these parts suggest it was up to the fitter to put the bends in the levers to make them work with the chassis layout.

IMG_0427s.jpg

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The water jacket top that has been built up with MDF and filler has now been sanded and given a coat of paint. Almost ready for the foundry to use.

IMG_0424s.jpg

 

I put the king pins back on the lathe and left them a few thousands of an inch over size (to allow for grinding to the correct size to press into the axle). Then I machined the oil grooves.

IMG_0420s.jpg

 

The next job was to cross drill the holes to link the oil groove with the central hole. I marked the ends for the spiral grooves with a small detent at the same time.

IMG_0421s.jpg

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I made the king pins from EN24T as this can be nitride case hardened and this process should not change dimensions. EN24T is a really tough steel so well suited to this application but I struggle to achieve really close tolerances and a good surface finish when using it. For smaller components I have often left them very slightly over sized and then polished them back to size with some wet and dry (SiC) paper.

 

For the king pins I want a reasonable interference fit in the axle beam but for the pin to be around 0.001" smaller at the top so it starts off as slight clearance fit. It would have been quite a large surface area to polish back but I have access to a Jones and Shipman cylindrical grinder at work. Despite being over 60 years old this machine is still a pleasure to use; it is easy to achieve a very slight taper, can work to tight tolerances and leaves you with a mirror finish.

IMG_0431s.jpg

 

After grinding I wrapped some wet and dry paper around a pen and used it to polish out any sharp edges on the oil grooves. Once this was completed they looked like this and I was able to drop them off for a 90 hour nitride cycle to give a case depth of around 0.028".

IMG_0432s.jpg

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I forgot to mention that the threads get protected with a special paint before the nitriding process. This prevents the ammonia gas from coming into contact with the metal and therefore the threads will remain in their soft state. Hardening the threads reduces their toughness and gives them a tendency to snap off.

 

The gear has now been finished to we put it on the hub and tried it on the shaft to check the gears meshed in a satisfactory fashion. As the gear seems to work I should probably go back to the supplier and pay for it in case I ever need them to make another gear. Hopefully I will have the courage to start work on the gearbox casing repairs soon!

IMG_0443s.jpg

 

I have turned some bosses from 2" steel to fabricate pedal shaft brackets. To get the alignment right for the one that fits in the chassis rail I milled a recess in the middle of the base plate.

IMG_0441s.jpg

 

A similar boss was welded to the other bracket.

IMG_0442s.jpg

 

The bores have been left slightly undersize and once everything else is done on these brackets I will use a reamer to make the bores the correct size and correct any distortion from the welding process.

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I made the king pins from EN24T as this can be nitride case hardened and this process should not change dimensions. EN24T is a really tough steel so well suited to this application but I struggle to achieve really close tolerances and a good surface finish when using it. For smaller components I have often left them very slightly over sized and then polished them back to size with some wet and dry (SiC) paper.

 

For the king pins I want a reasonable interference fit in the axle beam but for the pin to be around 0.001" smaller at the top so it starts off as slight clearance fit. It would have been quite a large surface area to polish back but I have access to a Jones and Shipman cylindrical grinder at work. Despite being over 60 years old this machine is still a pleasure to use; it is easy to achieve a very slight taper, can work to tight tolerances and leaves you with a mirror finish.

[ATTACH=CONFIG]110657[/ATTACH]

 

After grinding I wrapped some wet and dry paper around a pen and used it to polish out any sharp edges on the oil grooves. Once this was completed they looked like this and I was able to drop them off for a 90 hour nitride cycle to give a case depth of around 0.028".

[ATTACH=CONFIG]110658[/ATTACH]

place i once worked at had Churchill cylindrical grinders ..with a few Lumbsden surface flashers and a Prince crank grinder..

 

getting on but all good machines

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The next step with the pedal shaft brackets was to flush off the welds. Then I could counter bore them and turn a boss for the greaser to fit to.

IMG_0444s.jpg

 

I then drilled through the boss, blasted them and gave them a coat of primer.

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Reaming through the bores to make them the correct size and correct for any distortion due to the welding.

IMG_0447s.jpg

 

Checking the alignment on the chassis and measuring the gaps for the pedals.

IMG_0448s.jpg

 

Tapping 5/16BSW for the greasers and painting will complete the job.

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King pins and shoulder screws back from nitriding. A step closer to having the wheels on!

IMG_0451s.jpg

 

Talking of wheels, a fleabay purchase has just arrived. A pair of period bronze chocks; they were on buy it now for a little more than their scrap value.

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I was away for the weekend so the final task for the week was pressing, blasting and painting the other pair of wing brackets.

IMG_0450s.jpg

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Dennis originally fitted "Rotherhams of Coventry" greasers. There were a couple left on the chassis in hidden locations when I collected it but most had been removed over the years. I have been collecting these over the past eight years and have two biscuit tins full; one tin came pre-filled from the good friend who also supplied the chassis (thank you!). However when I looked at fitting them most of the parts are tapped 5/16BSW and require quite small greasers. I counted the tapped holes in the parts fitted so far to show I needed over twenty 5/16BSW greasers just to fill these. There are further parts to fit and I would need some more for the 1908.

 

I knew there was a parts supplier with some of these exact greasers in stock (although they were more expensive than I wanted to pay). It had been a good year at work and the Directors have given me a bonus so I phoned the supplier, negotiated a discount and purchased their entire stock of 30 greasers!

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I turned up some bosses to weld to the laser cut profiles for the pedals. I put a slight taper on the outside diameter to match the originals. These were then tacked onto the profiles. I think I made them from EN3 steel but it came out of a skip so I cannot be completely certain.

IMG_0459s.jpg

 

The next job was to v out with an angle grinder where I would later want to flush the welds off flat.

IMG_0461s.jpg

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It was then just a case of welding them up.

IMG_0462s.jpg

 

After roughly grinding the welds back I drilled and countersunk the oil holes in the clutch and accelerator pedal (the brake penal gets pinned to the shaft).

IMG_0465s.jpg

 

I then tried the parts together to see if it looked plausible. I thought I had made the throttle pedal in brass for the 1908 before, but then realised it was not meant to be bronze finish. This gave me a pattern for the cast iron pedal and a spare to use on this project. John Dennis (grand son of the original John Dennis that started the Company) gave me a pair of cast iron pedals to use on the 1908 so I used one as a pattern for the brake and clutch pedal for the 1914 (generous friends certainly help in this hobby and this help is much appreciated).

IMG_0466s.jpg

 

Still a bit more to do on this assembly but you can see the idea.

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These are the original cast iron pedal treads.

IMG_0490s.jpg

 

In order to use up my holiday entitlement my last day at work for the year was Monday. This means I have been able to get on with making new bushes for the steering.

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Followed by pressing them in.

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This left them slightly undersize so I ran a reamer through.

IMG_0480s.jpg

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The tapered socket for the other steering arm was quite corroded as there had been no arm fitted for many years. It appeared to be six degree included angle.

IMG_0474s.jpg

 

I turned up a mandrel from a bar end of aluminium and cut a slot in it using a hacksaw.

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By feeding the leading edge of some abrasive paper into the saw cut I could spin the mandrel using a battery drill.

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This has left a much improved taper.

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When I make the steering arm it needs to look something like this one on a 1914 fire engine. Another part that requires a fair amount of engineering.

IMG_0433s.jpg

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By resting the slot in the king pin on a drill bit of the same diameter I was able to mark a line parallel with that axis on the ends.

IMG_0473s.jpg

 

This made it easy to make sure the king pins were aligned correctly as I drove them in with a mallet. I had made the king pins slightly smaller at the top end so they would get tight for the last couple of inches.

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We then pressed them in but as the glamorous assistant was holding the other end of the axle there was nobody to take the photo. Then it was just a case of gently hammering in the locating bolts and fitting their nuts.

IMG_0484s.jpg

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