Not sure what diameter tubes are being used in LR4 builds in Australia but I am finding two sections are possible contenders:
31.75mm OD x 2.00mm wall, seamless stainless tube
30.00mm OD x 3.00mm wall, seamless stainless tube
The V1 website suggests 32/30mm OD with a tolerance of +/-0.20mm. So #1 is just outside of this. #2 with its 30.00mm OD is perhaps better because of this but with a 3.00mm wall maybe a bit heavier than it needs to be.
Which option do you suggest I put on my xmas list? Or is there a better option someone in Australia has found?
That said, I built my LR4 using 31.75mm (1.25" OD) tube. Some parts are a bit loose, but overall, I had good success. I think the general imprecision of 3D printed parts allows that 0.25mm to fly, but if your 3D printer is out the other way, making holes a bit bigger, it is possible that you coukd have trouble. After all, there are different parts for 29.5mm and 30mm, so while .25 may be fine, .5 is enough to warrant different parts.
If you are OK with the risk, 31.75mm tube is stiffer, but the 30mm tube is a more certain path.
I guess that I wasn’t clear - I have seen a few suppliers (in Australia) describing their tube as 32mm or even 31.8 when it is actually 31.75. If you are building a fire sprinkler system or a handrail that doesn’t matter, but it really pays to check.
Currently 31.75 is all that we can easily get, 30mm is commonly available in a square section though!
Interesting, I had assumed (wrongly) that 32mm was just 1.25 inch.
Is it worth scaling prints, though that would surely cause plenty of other issues.
Come to think of it my Primo had some slight issues with tube diameter being a touch small. Can’t remember what I bought for it but I think was a similar issue of .2mm small. Maybe that was just bad beginner prints.
I wasn’t criticising, just trying to be clear myself.
My calipers actually say my nominal 31.75 is 31.73mm, but I got acceptable results. Some caveats: I can spin my Y rail in the clips by hand, indicating that the tube isn’t tightly held. Can’t do that with the conduit on the LR3.
I did need to pinch the braces on the X gantry, but I think that turned out well. I dont have a comparison to the conduit there though. It feels solid enough, when cinched down.
I did not scale prints at all. I printed everything for 32mm, and used it as-is
In the wonderful world of marketing, given what @bitingmidge said, it probably is actually 1.25 inch marketed as 32mm as “close enough” in the same way I see 12mm llywood sold as “1/2 inch” here, or 18mm sold as “3/4 inch” for most uses, the difference isn’t important, but for us, we kind of need to know what we’re getting.
Scaling brings out a world of hurt - the holes in those aluminium plates won’t line up for a start - so you scale them and then discover you can’t bolt to the rails.
Don’t scale prints people!
In reality, a single wrap of sticky tape would fix any perceived problem I am sure.
Some great feedback here and I definitely wouldn’t start trying to rescale the printed parts.
It is interesting that 29.50mm OD tube uses different printed parts to 30.00mm OD tube. Where I think it might make some difference is the rolling bearings within the printed core that supports the router. Maybe a little more “play” as the core sits on slightly smaller diameter rails than the ideal (i.e. 31.75mm vs 32.00mm).
I don’t expect it would matter much for the printed braces as they clamp down onto the tubes and we are only talking about 0.25mm across the diameter.
So for us here in Australia perhaps the 30.00mm OD x 3.00mm tube is the better option, even though there is a weight penalty.
The braces that hold the tubes are different, but the core remains the same. The braces also move the different sized tubes so that the bearings ride in the same place.
The clips that hold the Y rail do the same.thing so that the rail side rides at the same height. This needs to align with the rail side Y belt.
As a result, I suspect that I needed to make a bit more adjustment to the core tension than I would have otherwise, and probably my rail side Y belt sits just a touch higher (or the rail side YZ plate rides a little lower.) I calculated it out and it can safely be ignored, it’s into the realm where I don’t expect that kind of total accuracy from the machine.
The size dependent pieces are the braces and the Y rail clips. Everything else remains the same regardless of the size tube used.
Lol. Well, for rigidity, I think so. Between the 31.8/2mm and the 30/3mm, I’d bet on the 31.8 for rigidity, though maybe not for ultimate strength.
Ok I see the core remains the same and the rails are positioned to match the core. So the better option for us here is the “big boy” 31.75mm OD tube.
I noticed the 31.75mm tube is available with a 1.60mm wall also, so 31.75mm x 1.60mm it is. Almost perfect!
