I’m sure I’m searching the wrong thing or calling it by the wrong term but I have a project in which I want to nest square tubing so that the inner piece can slide out and extend and I want to find the terminology or a source like a Grainger or Fastenal type place for them. (I already tried Harman Plastics and McMaster Carr and no joy)
I want the square tubing to be quieter when being adjusted, to take up the excess space for a stiffer connection and for it to protect the paint or powder coating while it’s being moved.
This is similar to what I’m looking for but it’s metric and I need SAE and a bulk source: Robot or human?
I don’t have a 3D printer, but more importantly I’m after a bulk buy of a high quality part like that that will be made of something really durable like nylon. I’m using 1.5x1.5, 14 gauge square tube for the outside and I’m hoping to size the inner tube based on what I find on the market for sleeves, but ideally relatively close.
I’m surprised you haven’t seen it. I’ve got a ton of stuff around the house with sleeves like that. One of those pop up tents for picnics with adjustable legs has it, I’ve seen it on gym equipment, it’s on a telescoping arm made by RAM Mounts, there’s even one on a really cheaply made adjustable height tablet pedestal thing, they’re all over.
If you check the posts above all the details are in there including a link to the sketchy Chinese ones in metric. The weld seams would have been removed prior to use.
As for the question you asked that I didn’t answer yet: as long as they’re injection-molded somewhere in North America and not 3D printed I’d be interested in purchasing some samples for a couple of different tube sizes and types (starting with 1.5" square and 1"X2" rectangle) and experimenting, then a starting order between 50-100 with hopefully more to follow and an option to order more.
maybe a trailer supply house ? torsion axles have sleave of heavy duty Ruber in them? or maybe find a junk trailer cut the axle into size specific peace’s then press out the pieces? ( it would appear my time is clearly worth nothing to me…)
But in reality, you need to source your tubing size first to determine the wall thickness and max height of each section of tube and determine the shear strength needed or rather the side load needed.
After that you can determine if you need a tight fit between tubes or plastic. If you have a significant side load the load can easily crush any plastic and create a the opposite effect.
Do a little research on Telescopic Tube and you can find the answers you are looking for. I have never used anything like you have posted as tighter tolerances were always used.
And when considering the tolerances you also need to consider the tolerances of the coating. If the person doing the PC puts too think of a lawyer on, even those protectors are going to scrub it off.
Metric/American is not really the issue. I have actually been involved with the ASME committee that clarifies that for US government contracts Imperial must be used. And it goes back to the Reagan years when he pulled the legislation to not go Metric for the Country.
Bottom line, in Gov Contracts it is a manufacturing advantage for maintaining our own equipment in times of emergencies as other “axis” countries would need to convert tooling to Imperial from Metric and would take them longer to repair/replace parts needed to repair/restore equipment.
Today, it is becoming less/less of an issue as I can enter a metric tool into a CNC machine and through software it interprets the appropriate offsets needed for the tool.
So while I hate to go buy lumber/material when it is listed as metric, it really is as simple of dividing/multiplying by 24.5 to determine the correct conversion. Unless you are dealing with the tolerances of screw threads or clearance tolerances it’s generally not an issue.
Yep, sliding tube inserts is what I was looking for. Thank you! I just didn’t post a pair of tube sizes since I wanted to experiment a little with different coatings and tube sizes/shapes and figured it would be more helpful for someone reading the thread in the future to read a more generic question that might apply to their situation as well.
It’s funny you mention that as I was thinking about several versions of welding spacers onto the insides. The only issue is I’m sure that would be just as likely to damage paint over time. I’m going to start playing with a few options soon.
