I am looking for a joint that will rotate 360 degrees and also rotate to any position within half a sphere. It needs to be relatively small, no more than 2 or 3 inches in all dimensions. Everything I have found has been way to big or doesn\'t go a complete 360 and doesn\'t move to positions within a spherical shape. I thought Legos might work but all of the hinges and joints have some limitation. Any help or suggestions are appreciated.
360 Rotational Joint
- Thread starter mrteal
- Start date
Shawn R. L.
New member
How about the limb\'s or head\'s of a Barbie or GI Joe doll?
\'m not sure what you mean exactly. Do you need:
- a 360 degree rotation that fits within a half sphere of a set size?
- a 360 degree rotation in the xy plane and 180 degree rotation perpendicular to it?
- as above but with a translation in the direction the joint is pointing at?
In the first case the joint is fairly easy. A pin/hole connection will do.
In the second you probably need a cardan style coupling. Lego has these (or at least while I still played with it).
In the third you\'ll need a cardan style coupling with a telescopic cylinder. It will have a min. reach though.
- a 360 degree rotation that fits within a half sphere of a set size?
- a 360 degree rotation in the xy plane and 180 degree rotation perpendicular to it?
- as above but with a translation in the direction the joint is pointing at?
In the first case the joint is fairly easy. A pin/hole connection will do.
In the second you probably need a cardan style coupling. Lego has these (or at least while I still played with it).
In the third you\'ll need a cardan style coupling with a telescopic cylinder. It will have a min. reach though.
Shawn R. L.
New member
A while back Lego\'s had a line of toy\'s called Connex or Robotix (?), cant remember which. They were sort of Lego\'s for adults. All sort\'s of stuff you could snap together to make some really impressive stuff. Mabey something there?
Z
ZeCorto
Guest
You need 2 joints: one will rotate 360deg horizontally and the other one on top of it will rotate 90deg (or 180deg front to back) vertically.
There is no solution with only one joint since having your full half-sphere liberty in only one joint would mean that you had a spherical mobile piece resting on half a sphere, which would not hold in place.
There is no solution with only one joint since having your full half-sphere liberty in only one joint would mean that you had a spherical mobile piece resting on half a sphere, which would not hold in place.
Nice drawing. Is it based on the idea of the P1500 monster that was proposed?
What scale will you make it?
As to the joints, they are fairly simple since it\'s only two rotation. You can make them yourself using some metal tubes. I\'m about to leave for work and will try to remember to post a drawing tonight.
What scale will you make it?
As to the joints, they are fairly simple since it\'s only two rotation. You can make them yourself using some metal tubes. I\'m about to leave for work and will try to remember to post a drawing tonight.
Well thanks. Although the drawing is not mine, someone posted it and I happened upon it. I wish I could draw that well. Yes, it is the proposed P1500. I have no idea how to scale it but it is 28 inches tall, 13 wide and 5 tall. With the gun carriage it is 8.5. I have posted some WIPs in the WIP thread but those were a while ago. Progress has been made, check there in the future as thats where I will post.
The drawing would be much appreciated. I figured out a way to do it with Legos but it is kinda expensive and will not provide the look I want.
Ok, in that case I hope you know how to read a technical drawing. I was counting on that. Here it is:
I\'ll first do the 360 degree rotation (items 3-7). What you need are two tubes of which one can slide into the other and a rod that can slide in the smallest tube. A good scale modelling store should have these in brass.
The joint is made of three parts.
- Part 1 (items 4+7). You cut off a bit off the smallest tube and solder this on the end of the rod. Make sure that burs are removed and there is only solder on the end site.
- part2 (items 3+5). Cut a length of the larger tube and about half that length of the smaller tube. Glue or solder the smaller tube into the larger like on the drawing.
- Part 3 (item 6). A separate bit of the smaller tube.
To assemble this: slide part 1 into part 2 and make sure they can rotate easily within eachother. Then slide part 3 over part 1 and glue it close to the end of part 2, making sure there is enough space to move.
In the free end on the tube you can drill a hole for a pin/hole hoint that can be used to give the foot a 180+ degrees rotation.
In reality the foot may have been mounted on a ball joint but that\'s a lot harder to make.
By the way, from what I understand from this article: http://members.tripod.com/~fingolfen/superheavy/p1500.html the P1500 was basically a Dora on tracks.
The drawing you have is quite nice (keep on building it. It looks cool) but it\'s likely to be fantasy.
Show us when you\'re done.
I\'ll first do the 360 degree rotation (items 3-7). What you need are two tubes of which one can slide into the other and a rod that can slide in the smallest tube. A good scale modelling store should have these in brass.
The joint is made of three parts.
- Part 1 (items 4+7). You cut off a bit off the smallest tube and solder this on the end of the rod. Make sure that burs are removed and there is only solder on the end site.
- part2 (items 3+5). Cut a length of the larger tube and about half that length of the smaller tube. Glue or solder the smaller tube into the larger like on the drawing.
- Part 3 (item 6). A separate bit of the smaller tube.
To assemble this: slide part 1 into part 2 and make sure they can rotate easily within eachother. Then slide part 3 over part 1 and glue it close to the end of part 2, making sure there is enough space to move.
In the free end on the tube you can drill a hole for a pin/hole hoint that can be used to give the foot a 180+ degrees rotation.
In reality the foot may have been mounted on a ball joint but that\'s a lot harder to make.
By the way, from what I understand from this article: http://members.tripod.com/~fingolfen/superheavy/p1500.html the P1500 was basically a Dora on tracks.
The drawing you have is quite nice (keep on building it. It looks cool) but it\'s likely to be fantasy.
Show us when you\'re done.
vincegamer
New member
Buy a cheap Gundam model. They come with a variety of soft-plastic or rubber joints. I\'ll check mine out to see if it can do what you want, but they aren\'t expensive and the parts are quite useful.
Thanks mini. That drawing is exactly what I needed. It is very understandable and I think a lot simpler than trying to buy somthing that will fit the bill.
Perhaps a bit more labor intensive than I realized but I think the overall look will be worth the extra effort and expense.
Keep an eye out for WIPs in the future.
Perhaps a bit more labor intensive than I realized but I think the overall look will be worth the extra effort and expense.
Keep an eye out for WIPs in the future.
@vincegamer: Yeah, I was thinking ofthat in the car. Some of the snap together kits have ball joints that could be usefull.
@mrteal: one advantage is that such a joint is stronger than most plastic ones. You can also use brass tubes/rods for the pistons in the constructions.
@mrteal: one advantage is that such a joint is stronger than most plastic ones. You can also use brass tubes/rods for the pistons in the constructions.
