Borbin the 🐱

The oil catch disc is located between the 1st gear and the bearing on the input shaft.
Needs to be fabricated because there would be too much damage to the old one when pulling off.

The disc gets fabricated from a piece of sheet metal on the lathe:

To get started, the 4th gear needs to be pulled off the input shaft. This is done with a standard gear puller. But what was not that standard, was the force required to get this actually off.

I ended up putting the puller’s screw in the vise, and used a long bar to rotate the gear around it for extra leverage. The deformation of the rather solid plate give a glimpse of the applied forces. Once this was finished, I was done for the week with any physical activities.

With the 4th gear off, the next step was to fill the gap between the 3rd and the 4th gear.

I used an older input shaft to try the brazing. Brazing involves applying just enough heat to melt the filler material without affecting the base material, allowing capillary action to bond the parts together.
I tried welding, but it put way too much heat in the part that it would change the metallurgical properties and the hardening of the part.
Using a TIG welder, brazing with Silicon-Bronze rods was actually quite easy.

The input shaft used for the project.
I used water to keep the material temperature low.

The gap is all filled with Silicon-Bronze.

The 3rd gear was removed with a grinder.

The input shaft had a severe runout at the bearing. To fix this, I machined the front part and created a bronze bushing. The bushing for the bearing is pressed on in a machine vise and secured using Loctite 638 (green colored glue).

The shaft is machined to its final dimensions.

The old and the new input shaft.

The new 4th gear is secured with a key, while the 3rd gear locks into the 4th gear.
A standardized key is not wide enough for the slot and is padded with two small metal parts.

My CJ750 motorcycle has a BMW R100 engine, and driving with 100km/h (60mph) on the freeway requires almost 5000rpm. This has to be changed.

The gearbox for the CJ750 (and the M72) has the following ratios:

With a tire circumference of 26 inch and a final drive ratio of 37/8, the rpms require to drive 100km/h (60mph) in 4th gear for all available gear ratios 26/20 (1.30), 25/21 (1.19), 24/22 (1.09) and 23/23 (1.00) are:

4050rpm is good for 100km/h with a sidecar, so the 24/22 for the 4th gear is selected.
The change from 1.3 to 1.09 is actually the same as using a high speed final drive with a 35/9 ratio instead (1.09 * 37 / 8 * 9 / 35 = 1.3). I'm using an EU quality final drive with a 37/8 ratio to avoid the russian and chinese junk, so thats why I need the adjustment in the gearbox.
To only change the 4th gear to 24/22, the ratio changes would be 1.57 - 1.34 - 1.42

The change ratio decreases with increasing gear number for all gearboxes I checked.
For example, one BMW gearbox had 1.51 - 1.37 - 1.25:
1st: 3.90 - 1.51 - 2nd: 2.58 - 1.37 - 3rd: 1.88 - 1.25 - 4th: 1.5

But 1.57 - 1.34 - 1.42 (with only the 4th gear changed) is not monoton decreasing.
The only possible replacement for the 3rd is a 28/18 from the DNEPR MT804. Fortunately, this gets a ratio change of 1.48, and the sequence is now monoton decreasing. And it almost matches the ratio if a high speed drive would be used (1.71 * 35 / 9 * 8 / 37 = 1.437).

So the new 3rd gear is a 28/18.

But the CJ750 input gear shaft is designed have only the 4th gear changed. This requires that the 3rd gear needs to be removed and the input shaft modified so that the new 3rd/4th gear can be pressed on.

The inner diameter of all output shaft gears are 26mm with a 10.5mm tooth width and only need a new spacing. Leszek from oldtimergarage.eu has verified the measurements for this unique project, and now it’s all set to launch! 🚀

First, the gearbox needs to be disassembled.

Exploded CJ750 Gearbox, Type 52:

Gears on the upper output shaft are all free spinning and can be replaced easily, while the lower input shaft has only the 4th gear pressed on. The 1st, 2nd and 3rd are fixed and part of the input shaft structure.

Project plan

For the upper shaft, new spacers will be created to align the new (free spinning) gears, and for the lower input shaft, the 4th gear is pulled, the 3rd gear removed and the shaft machined for the new gear set to be pressed on.

Opel is celebrating its 125th anniversary, and I recently watched a documentary about its history: 125 Jahre Opel - Kultautos und Krisenjahre.

The documentary highlighted many significant milestones and innovations from Opel over the years, making it a great watch.

In one of the historic clips, a Citroën DS was seen driving past the entrance of the Opel facility. Being a big fan of the DS, I noticed it immediately. It was interesting to see such an iconic car from another brand. I was anticipating an Opel in this context!

Historic clip:

This is where the clip with the Citroën DS was filmed: Marktstraße 35, 65428 Rüsselsheim am Main, Deutschland, Google Map

PS: Vier Rädder un eh Brett - Opel Kadett

Uses the Gamepad Input shield and Arduino Uno R4. Wiring info is in the src.
Up/down button/joystick changes task, and left/right button/joystick changes state/setting.

With the first 8x8 LED block to illuminate the darkroom.

Implements 5 tasks
- LEDBrightnessTask
- EnlargerOnOffTask
- EnlargerTimerTask
- DevelopStopFixTask
- GeneralTimerTask

LEDBrightnessTask

Sets the brightness of the 8x8 darkroom illumination LEDs from min 0 to max 15.

EnlargerOnOffTask

Manual enlarger switch switched on.

EnlargerTimerTask

Timed enlarger switch.

DevelopStopFixTask

3 timers for develop, stop bath and fix.

GeneralTimerTask

General timer starting from 0s.

Arduino Darkroom Timer Github Project

This is the sunset that occurs closest to the Autumn equinox, which is the point in the year when the sun crosses the celestial equator heading southward, marking the transition from summer to fall. This event results in equal lengths of day and night, creating a unique and balanced twilight experience.

But with so many trees around, the experience is limited to a narrow field of view towards the sunset. Nevertheless, the experience remains wonderful.

This panorama is the September 2024 Equinox contribution for the 'September Wrinkle' event of WorldWidePanorama.

Interactive Panorama Equinox-Sunset

The Making

Automated control points aren’t an option here because the individual images are predominantly black:

There are 6 pictures taken every 60°, including Zenit and Nadir (6+Z+N). To establish the control points, the brightness in PTGui was increased by +5EV.

Without precise control points, a 360°x180° panorama can become warped and distorted. It might seem that creating panoramas with large areas of uniform dark color would be easier, but unfortunately, there are no shortcuts in this process. Accurate control points are essential for maintaining the integrity of the image.