Lotus 25 Coventry Climax - Tamiya - 1/20

[gulfclk]

So, after finishing some projects at home, it is time to start another kit.

This time, I grabbed the Lotus 25 Conventry kit, not Tamiya's best. Some major mistakes like the roll cage position which is far to much to the front and not a lot of place for details, although this type of car is nothing without this extra detail.

I started removing the front water reservoir so the front bulkhead can be sanded. I'll need to make some PE front bulkhead with fixation supports for the radiator stands, but that's for later.



On the rear, I removed the fixation points for the roll cage and made new ones with PS.





Next step is sanding and removing all rivets as they will be replaced with after market ones, removing the suspension points as I'll turn and mill uniballs on my Sherline, ...

[endac]

Looks like you're off to a good start. I was considdering buying this kit myself so i'll definately keep an eye on this

[gulfclk]

Much has not happened in recent days, or nothing too visible. First of all, I removed ALL the rivets and then the front suspension + rear suspension points were removed.

The aim is to rebuild the complete suspension because the pieces are not to accurate I think. Too little detail, and some things are wrong.
First of all, the front wishbones were removed. After that, the rear suspension point were cut away and I started redrawing parts to be etched to rebuild the rear suspension points.
Along with this, I drew the front bulkhead and added some other parts. I want to do the front bulkhead as there are some brackets for the front radiator stands. Making those in plastic would make them too fragile.

As I was drawing, I also added the pedal supports because the kit parts are bulky plastic blocks and therefore not 100% correct. So, ready to etch ... but then the printer cardridge is empty!

Ah, the engine mount! Tamiya has two fixation points under the engine. Good solution, but not correct!. The engine is mounted onto the rollcage fixation points. Tamiya makes the engine support, but provides no engine mounts. Instead of a star shape they make a triangle. So ... even a new engine mount will be etched.



As we can't etch, we'll work on the underside. The 2 coolwatertubes are integrated in the plastic chassis. A 2mm mill and some setup work is required to remove everything so some new tubes can be made afterwards.



As the lathe and mill are up and running, we'll make some engine parts. Tamiya paid some great attention to some engine details like the waterpomp, but the upper polley that I presume is for the fuel injection pump has not been made. In stead, you only find a trace of the belt.
I started with a small aluminium rod that I turned to 4mm diameter. Than, using a 0,8mm drill, 8 holes were drilled.



After that, a 0,4mm mill was used to make the pulley theet on the outside. 1 hour after I started, this baby is ready!



Next will be the brake discs. The drawings are ready, making them will take a couple of hours. I'm wondering whu this car has 6 wheelbolts ...

[MPWR]

Originally Posted by gulfclk

Right, now this is my kind of building!

But I've learned the hard way- superdetailing is not a crime, it's a disease....

[Jamme]

:worshipp y
Greetings,
Jamme

[ScratchBuilt]

Mmmm....love that turned pulley! Will be watching this one with interest, Gulfclk.

Why six wheelstuds? I may be wrong, but I suspect it is due to the design of the 'wobbly web' wheels Lotus had been using on their racecars for some time - since the Mk12 in 1956. Tyre wear wasn't such an issue on these cars, so there wasn't much need for a quick-release-style wheel arrangement - why use a heavy centre-spinner when you can use small studs and Austin Seven wheelnuts? A wobbly web with fewer spokes probably wouldn't work, so six spokes with six studs inbetween was just fine!

All the best!

SB

[PJE48]

One of my biggest challenges with my Lotus 25 projects has been the scratch building of the shifter linkage at the transmission. I will be following closely to see how you handle this. Have you decided which race you are replicating?

Paul Erlendson

[gionc]

Wow!!!!

[klutz_100]

This is going to be awesome to follow

[gulfclk]

Originally Posted by PJE48

Have you decided which race you are replicating?

Unfortunatly, I can't find any good pics from races and details in the past. I have about 60 pics, 8 to 10 rather detailed, but not more then that. So if anyone has more ref material ...

[PJE48]

Originally Posted by gulfclk

Unfortunatly, I can't find any good pics from races and details in the past. I have about 60 pics, 8 to 10 rather detailed, but not more then that. So if anyone has more ref material ...

The three best books with lots of photos are:

"Lotus 25 & 33" by John Tipler

"Jim Clark and His Most Successful Lotus" by Eoin Young

and "Lotus 25 Climax FWMV" by Ian Bamsey

If you love the Lotus 25, they are well worth the cost.

Paul Erlendson

[cinqster]

Nice!

[racer1]

Very nice what you're making.
Scale 1/20 no scale 1/200

[gulfclk]

So, the first test of etching did not seem to positive after moving places. The parts were not perfect, so I'll do them again once the etch tank is properly installed.

So, to kill time, I started making the brake discs, well, one of them at least. To get the most realistic result, I decided to make them in metal. I normally use resin bars like on my MP4/8, but for this one, metal was the only way to go as the brake disc itself is very simple and no holes, ... are present to catch the eye.

First of all, I turned a bar on the right diameter. A 2,6mm hole was made.



You'd expect to do the front first, well I did the rear side of the disc first because of the way I would need to fix it afterwards to make the other side.
I first made the conical 'chamber' and then drilled the 0,8mm holes on the devider table. 'Polishing' was done using a #200 sand paper. It looked like this ...



After parting the part however, the front didn't look to good. I knew this would happen so oversized the front by 0,1mm so I could finish it afterwards without losing the right thickness.



OK, now you have 1/2 a brake disc, but how you work on the other side, how do you mount that thin part in the chuck? Well, quite easy. I made a special holder with a chamber in exact the same diameter as the disc but less deep than the disc thickness so I could work on the front side without touching the holder.



To keep everything together, simply remove all grease, oil, ... and use a drop of superglue. It'll keep it all together. To remove the part afterwards, just heat it and the part will come loose!



So, the next step was taking 0,1mm off the front side of the disc to smoothen it up and make the conical front part.



So, 1 finished brake disc looks like this ...



Normally, I use 2 chucks to make brake discs so I can make exact pairs, but as one chuck is used now to make and use the holder, I only have one chuck left to make discs, which means more time. Making tools and holders is time consuming but it needs to be done if you want to achieve good results.

[ScanmanDan]

Super craftsmanship on the Lotus. I am very much enjoying watching it come together. Thank you for sharing how you machine the detail parts. I've been stumped as to how to turn replacement disks for my 1/12 scale chopper. With your help I now have a work method to kick start my stalled project. I'm going to be following along closely on your build. If you have time could you give some more detail as to how you go about etching parts?

Thanks again for taking the time to show how the magic is done.

Dan