Tubing Recommendations

I’ve done a lot of searching and just want to get clarification.

 

I’ve seen some posts where they recommend 1" Outer diameter with a 0.65" ID for stainless, I’ve also seen others recommend something with a thinner inner diameter, and conversely others stating a thicker wall would be even better, indicating a larger ID would be best.

 

I guess I’m just asking what the latest recommendations are for:

Most affordable?

Most rigid / long lasting?

To start, it’s not 0.65" inside diameter, it’s 0.065" wall thickness. With a fixed outside diameter, a larger inside diameter has thinner walls, which is cheaper and lighter but also weaker.

Thicker will be stiffer but it’s diminishing returns. It’s just one of several parts that can deflect, and beyond a point there is no benefit in stiffer rails but there are downsides. Stiffer tubes are heavier, which can make the machine slower because the maximum acceleration without missing steps is lower. Lower feedrates can in some cases also shorten tool life and perform generally worse.

By the time the whole thing is built, the price of increased wall thickness is not that much higher. To me it seems the 0.065" recommendation is not simply a tradeoff between price and stiffness. It’s where stiffness is not really improving and the additional weight (and cost) are not buying anything.

This balance can also be influenced by the build size. Larger machines incur a stiffness penalty that’s larger than the weight penalty, so thicker tubes could make a difference. Smaller machines are stiffer to start with and thicker tubes might offer nothing but downside in weight and cost.

For the most affordable I wouldn’t go below 0.065" but you could get mild steel (non-stainless) and keep it dry. For extra stiffness you could get stainless with 0.12" wall thickness, and while you might never see the difference, you can sleep well knowing that the rails are not the limiting factor in the overall system stiffness.

 

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What sort of trade off’s would their be with Stianless vs Mild in terms of longevity?

I’m trying to source stainless locally but every place I’ve contacted has an MOQ which I don’t come near meeting. If I need to order online Mild steel seems to be much less.

 

Also thank you for the information on dimensions regarding the tube.

Jamie that was very well said, thank you. I might need to link that somewhere (linked on the parts page, thanks!).

 

The bearings have a crazy high point load on the rails. Stainless is a bit harder and rust resistant, for those reasons I chose Stainless. Usually it is not all that much more, if you want to try it the other way It will work, but stainless is a bit better. That might seem like a bit of a half answer but we have no idea how big your build will be, what you plan on using it for, or your expectations.

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I don’t really have expectations in mind. It will be my first cnc used. That being said the stainless quote I got was around $190 for a 4x5 work area. Trying to keep it cost effective for the wife lol

Try these guys. https://ecommerce.metalsupermarkets.com/Material.aspx?ProductId=STRO304/1065

Yikes. To give you an example, my local metal supplier has 1" 0.65"wall, Stainless-Seamless in 20ft length for around $50. More than enough to do a machine that size. Will Call MOQ of 1 piece (e.g. you must buy the entire 20ft).

 

I think MetalsDepot.com might have some decent pricing last I checked.

I found standard steel tubing on jegs for a reasonable price: www.jegs.com/i/Allstar-Performance/049/ALL22128-8/10002/-1

Hey guys,

I’m from Brazil, and down here I can’t find this OD tube with 0.065" wall thickness.
I have some wall thickness closer to this here, and I’d like to have some tips on which one will be better to follow with this project.
I can buy the 1" with 1,5mm (0.059") wall thickness OR 1" with 2mm (0.0787").

Thanks!

Fala Denis, Seja bem vindo! Eu também sou Brasileiro.

So you should go for the thicker tube if you can. It will make for a sturdy build.

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Yea, go with the thicker tubes, won’t be that much heavier.

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Opa GP, bom saber que temos mais BRs aqui!
Demoro, vou partir pro de 2mm então… Vc Tb montou uma usando esses tubos?
Abraços!

There you go!
Thanks Barry, let’s do it! :metal:

Fala Denis. Ainda nao, no momento eu tenho 2 MPCNC uma com conduite e a outra com 0.065" (1.651mm), Aqui no US e dificil achar tubo de 2mm e tambem tenho todos os componentes para montar a LR o que está me faltando e espaço na garagem. lol
Abraços.

A ta explicado, por isso vc consegue ter o tubo de 0.065" hahaha.
O que você acha das MPCNC? Vale a pena?
Eu foquei na LR por conseguir fazer algo com uma área maior e me pareceu ser mais baixo custo…
Abraços.

This is not what I expected my first post to this forum to be.
I would also like some clarification regarding the tubing requirement.
I think I’ve just ordered $150 worth of useless tubing.
The link on the lowrider-parts page points to “(Online Metal Supply 304 Stainless Steel Round Tube, 1/2” OD x 0.028" Wall x 72" Long, Seamless (3 Pack)) Further reading indicates 1" OD tube is required.
If the link to 1/2" tubing is wrong, I would suggest removing or better correcting it.
If the link is correct, I guess I dodged the bullet.
Regards,

Oh no. 1/2" is not the right size. That is a bummer. Sometimes amazon can change the description of an item and they sell something completely different, but with the same item number.

I just looked at the link, and at least for me, it is forwarding to 1" od tubing. The link is in the table here:

https://www.v1engineering.com/lowrider-parts/

I wonder if they did some shady stuff, or if they realized their mistake.

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Ouch… Save your receipt. That is an unfortunate link, as it’s just an example of SS tubing, and not the actual tubing you need, which is linked in the BOM above the link you followed. @vicious1 or @jeffeb3 or someone with the proper skills should either change that link or at least make it abundantly clear that it’s not the actual BOM item.

I’m really sorry that this is your introduction to the community, but like in The Money Pit, your Low Rider build has been pre-disastered! :grin:

For me it links to 1/2" tube too, but out of stock for 304 and recommending 316 stainless instead (also 1/2").

Specifically the link was https://amzn.to/32kZC45

No bueno!

Not only is the OD wrong but 0.028 wall is extremely thin, even 0.04 is thin. It should be more like 0.063 or more.

Also I should point out this was the link below the table (which I just happened to find first). The links within the table were 1" OD like Jeff said (but also out of stock).

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