I thought i would take a second to do a little write up on this subject.
I am often asked weather or not Chronos can be modified to work with a belt drive system.
The answer in short is YES!
However, why would you want to? This is an important question to consider.
Obviously I like the lead-screw design. You can get levels of accuracy off the Lead Screw design that a belt-drive system cannot get close to. But does this matter?
To most people who do timelapse, the answer is No.
To me the answer is YES. because i am looking forward to exploring the world of motion controlled macro timelapse. I want to be able to shoot 1000 movement intervals in 1/8th of an inch. I have specific needs for this and plans for this. Most others do not.
I also like the fact there is ZERO setup time. You dont have to break it down, put it back together, it is tough, durable, lightweight, does not use much power, and works wonderfully. I have taken it hiking, camping, it has done its job in the heat of the summer, in a snow storm, in rain, and even in some hail.
The DC motor / belt driven systems are not as accurate, but that does not mean they are not accurate enough. if you are not doing macro timelapse they have more than enough accuracy. They are also very reliable, very robust, and they can take some abuse. If you are interested in a belt driven setup, i recommend you look up Dynamic Perception and check out thier products. They offer a high quality belt driven setup that has been proven in the field in all sorts of harsh conditions. They are inexpensive (compared to other systems) and there is a lot of online support for these rails from all the users. Plus, they can be longer than 4 feet, which is probably about the limit for a screw-driven system without some sort of moving supports for the screw. AND they move fast enough for video work.
So if i have so many great things to say about the Dynamic perception stage zero dolly, why did i go through all the effort to design chronos?
simple. I want to do macro timelapse, and i dont like menu systems, i can pack as many features and control into 4 buttons and a pair of knobs, and i dont want to have to set things up and tear them back down. I dont want to be carrying around extra tripods, i dont need 6 feet of rail, and I am a big into the "Do it yourself" mentality, and i did not find any well documented DIY solutions available online. So i figured this would be a good chance to change that.
The use of the lead-screw instead of a belt was was thought out and planned. If you are considering belt vs lead screw, you really need to determine your time lapse goals.
The problem with making a sort of hybrid with the Dynamic Perception dolly and Chronos is you lose the best parts of either system and end up with something somewhat limiting. You lose the long distance movement, you lose the excellent accuracy of the lead-screw, and you have a lot of work to change the coding to control the DC motor, or if you want to use a stepper instead you still have to make a gearbox for it, because if using the rail for a veritical lift, without a gearbox with some sort of self braking mechanism the motor may break hold and drop all your gear.
If anybody wants to try to do this and they want help, ill do what i can to assist as much as possible. But honestly i dont think there is much to gain by converting something like Chronos to a belt drive, but i like a challange.
I hope this helps folks