Search
Forum
Wiki
Images
Files
Member List
Help
While designing the base for my treadwell, I'm simplifying the dimensions and angles a bit, just like I previously did for the head. Since I'm building it out of styrene, I'm using a tab and slot design and designing for 3/16" styrene, though one could omit the tabs and slots and just weld the edges together. If it works out, I plan to release printable plans much like folks do for R2.
![[Image: Z9O2qmF.png]](https://i.imgur.com/Z9O2qmF.png)
The intent is to skin the side panels and the sloped parts (not shown) with thinner styrene to cover most of the seams. The sloped parts will be removable panels (held in with magnets).
One side effect of Treadwell's design is that the slopes mean beveled edges. The only thing I've scratch built out of styrene sheet in the past is a shell for my MSE-4 out of very thin plastic. I'm still trying to decide how much of a pain making the bevels will be.
![[Image: rU0HR8o.png]](https://i.imgur.com/rU0HR8o.png)
For the stick portion of the Treadwell, I'm hoping to be able to incorporate a linear actuator in the base (if I can get one to fit) to get the extendible neck. The actual throw distance needed is 4.25" according to the plans but that's unlikely without modifying the throw somehow. More likely options are 4", 6", or 8".
The weight capacity of most of these actuators is generally far greater than what is needed to lift Treadwell's head, so the other important rating is speed. The ones I looked at in the $30 to $40 price point range from 5 to 14 mm per second.
Regarding the drive, I doubt that I can get away with driving wheels directly from a gearbox like the one previously mentioned, as the output shaft wouldn't be long enough for the pair of wheels on each side. Much like Paul, I'll probably have to transfer the power to the drive axles with a chain and sprocket setup.
This would, however, make it unnecessary to lift the drive wheels off the ground or even remove treads to enable the droid to be pushed if the gearing were too much; instead I could remove the chains, perhaps by building in a locking slider for the motor mounts.
Yes, I could also use a chain to do the gear reduction from the motor (saving the need to buy gearboxes), but 20:1 feels excessive for a single stage, and I don't want to make things too complicated.
The intent is to skin the side panels and the sloped parts (not shown) with thinner styrene to cover most of the seams. The sloped parts will be removable panels (held in with magnets).
One side effect of Treadwell's design is that the slopes mean beveled edges. The only thing I've scratch built out of styrene sheet in the past is a shell for my MSE-4 out of very thin plastic. I'm still trying to decide how much of a pain making the bevels will be.
For the stick portion of the Treadwell, I'm hoping to be able to incorporate a linear actuator in the base (if I can get one to fit) to get the extendible neck. The actual throw distance needed is 4.25" according to the plans but that's unlikely without modifying the throw somehow. More likely options are 4", 6", or 8".
The weight capacity of most of these actuators is generally far greater than what is needed to lift Treadwell's head, so the other important rating is speed. The ones I looked at in the $30 to $40 price point range from 5 to 14 mm per second.
Regarding the drive, I doubt that I can get away with driving wheels directly from a gearbox like the one previously mentioned, as the output shaft wouldn't be long enough for the pair of wheels on each side. Much like Paul, I'll probably have to transfer the power to the drive axles with a chain and sprocket setup.
This would, however, make it unnecessary to lift the drive wheels off the ground or even remove treads to enable the droid to be pushed if the gearing were too much; instead I could remove the chains, perhaps by building in a locking slider for the motor mounts.
Yes, I could also use a chain to do the gear reduction from the motor (saving the need to buy gearboxes), but 20:1 feels excessive for a single stage, and I don't want to make things too complicated.