Using steel conduit instead of the solid rods used currently would change the Darwin in several ways: Neutral The outside dimensions of the unit would be larger to still have the same work area Positive Weight savings (or is this actually a negative?) Conduit/pipe is easier to cut than solid rod Material is more readily available Negative Might "cheapen" the appearance? The brackets would have to be quite a bit larger to accommodate 3/4" or 1" conduit requiring more plastic and print time to create Has this been considered? https://reprap.org/forum/read.php?14,13039,13039#msg-13039 Fri, 12 Jun 2026 16:29:18 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?14,13039,14207#msg-14207 https://reprap.org/forum/read.php?14,13039,14207#msg-14207 -------------------------------------------------------
> I'm all for an SAE version. Would it really be
> much more difficult to provide two sets of CAD
> drawings. The cost saving would be significant for
> those in the U.S.A.

Not if you order your parts from McMaster, MSC, or another similar industrial supplier. Most of them will actually be quite happy to take your order, and if you start doing any sort of serious tinkering you will find their selection to be enormously beyond even the best HW store. You might also have an industrial supplier in your area where you can do cash and carry.]]> Colin K. Mechanics Thu, 10 Jul 2008 23:24:12 -0400 https://reprap.org/forum/read.php?14,13039,14093#msg-14093 https://reprap.org/forum/read.php?14,13039,14093#msg-14093
The only place you'd have a problem would be if you have a set of Ian's cast parts with the captive nuts cast in place, like my Darwin - then you'd have to find metric grubs for those parts, but that's not a lot. I think he's switching to laser cut parts though, so I can't comment on the new kits.

I used all metric parts because I like working with them better, but even in Canada I had a little trouble sourcing stainless steel metric drill rod. I ended up finding a box full of old printer guide rods at a surplus store cheap, which worked perfectly. I was really, really disappointed when I found out McMaster Carr no longer ships to Canada, but I'm making do.]]> Wade Mechanics Tue, 08 Jul 2008 18:07:03 -0400 https://reprap.org/forum/read.php?14,13039,14080#msg-14080 https://reprap.org/forum/read.php?14,13039,14080#msg-14080 Squintz Mechanics Tue, 08 Jul 2008 15:26:56 -0400 https://reprap.org/forum/read.php?14,13039,13829#msg-13829 https://reprap.org/forum/read.php?14,13039,13829#msg-13829
or was it a steel braided screened cable ? Interesting and I would like to know more.]]> Lampbus Mechanics Thu, 03 Jul 2008 06:13:28 -0400 https://reprap.org/forum/read.php?14,13039,13809#msg-13809 https://reprap.org/forum/read.php?14,13039,13809#msg-13809
Turned out that we had accidentally--how I don't know--magintized the wires and they were acting as an inductor and causeing all those problems. Re-did the wiring harness in shielded cabling and the problem no longer exists. It was, I think, all due to the steel frame. No good but with the right cable--ie shielded--not a problem.

Demented]]> Demented Chihuahua Mechanics Wed, 02 Jul 2008 14:20:51 -0400 https://reprap.org/forum/read.php?14,13039,13579#msg-13579 https://reprap.org/forum/read.php?14,13039,13579#msg-13579
Metal on metal loose connections can create lots of interference too; make sure everything is tight, and poke around with a scope.]]> Wade Mechanics Wed, 25 Jun 2008 15:01:11 -0400 https://reprap.org/forum/read.php?14,13039,13571#msg-13571 https://reprap.org/forum/read.php?14,13039,13571#msg-13571
oitreprap.googlepages.com

but it turned out bad. The wiring, I think, has gotten a bit of interference from the steel frame and maybe from the other wires. Not so good as you can't drive the motors. Perhaps using shielded cat cable?

Demented]]> Demented Chihuahua Mechanics Wed, 25 Jun 2008 13:55:43 -0400 https://reprap.org/forum/read.php?14,13039,13546#msg-13546 https://reprap.org/forum/read.php?14,13039,13546#msg-13546 mimarob Mechanics Tue, 24 Jun 2008 14:57:57 -0400 https://reprap.org/forum/read.php?14,13039,13293#msg-13293 https://reprap.org/forum/read.php?14,13039,13293#msg-13293
I suspect someone could assemble a super-rigid repstrap by welding tubing together.

EMT/conduit may not have the proper ratio of strength/size but I'd be curious to see how it measured up.

How much does a completed reprap weigh anyway? Weight may not even be an issue.

Another thing to think about is that once these things start branching out for other applications someone is going to make a larger version. What will its frame consist of? 2" conduit or even better 2 5/8" steel fence post material would be much cheaper than rod of equivalent stiffness over multi-foot runs.]]> rodzite Mechanics Sun, 15 Jun 2008 06:30:41 -0400 https://reprap.org/forum/read.php?14,13039,13276#msg-13276 https://reprap.org/forum/read.php?14,13039,13276#msg-13276
This will be less expensive and much more efficient than going to a hardware store or buying online. It is unlikely the hardware store will have enough on hand for the project; it would be best to call beforehand.

*Assuming this works with your mode of transport.]]> SebastienBailard Mechanics Sat, 14 Jun 2008 21:15:21 -0400 https://reprap.org/forum/read.php?14,13039,13265#msg-13265 https://reprap.org/forum/read.php?14,13039,13265#msg-13265
I've already had problems with my 8mm stainless steel threaded rod bending inadvertently on my Darwin, despite being pretty careful with it. The 8mm smooth rod I found is extremely tough and strong though; I found a box of old 8mm inkjet printer rails at a surplus shop, it's a very tough alloy, not stainless as it's magnetic, and perfectly smooth. A bit of a pain to cut, but a Dremel did it with some effort.

A dumpster tour could find a lot of inkjet printers these days, if you really want to save money. You might find 5/16" rod cheaper too - it's more readily available in North America, and close enough to 8mm.]]> Wade Mechanics Sat, 14 Jun 2008 12:29:07 -0400 https://reprap.org/forum/read.php?14,13039,13238#msg-13238 https://reprap.org/forum/read.php?14,13039,13238#msg-13238
That is a pretty good cost savings.
Thanks for edumakatin me.]]> criswilson10 Mechanics Fri, 13 Jun 2008 15:34:19 -0400 https://reprap.org/forum/read.php?14,13039,13166#msg-13166 https://reprap.org/forum/read.php?14,13039,13166#msg-13166 -------------------------------------------------------
> The Darwin needs about 8.5 meters of rod so close
> to $60 worth of 8mm rod vs. about $12 worth of
> EMT... Seems like a reasonable cost savings to
> me.

Short pieces of conduit are readily available as construction site waste. i haven't seen much 1/2" being thrown out but 3/4" is readily available. I have a bunch in my garage right now as a matter of fact.]]> rodzite Mechanics Wed, 11 Jun 2008 22:28:25 -0400 https://reprap.org/forum/read.php?14,13039,13155#msg-13155 https://reprap.org/forum/read.php?14,13039,13155#msg-13155
By way of comparison the 8mm 12L14 Carbon Steel rod is $11.72 for a 6' length. Even 5/16ths "High-Strength Easy-to-Machine 1144 Carbon Steel" in Unpolished (Mill) finish is $6.00 for a 6' length (give or take 6 inches!).

The Darwin needs about 8.5 meters of rod so close to $60 worth of 8mm rod vs. about $12 worth of EMT... Seems like a reasonable cost savings to me.]]> JohnWasser Mechanics Wed, 11 Jun 2008 20:05:10 -0400 https://reprap.org/forum/read.php?14,13039,13147#msg-13147 https://reprap.org/forum/read.php?14,13039,13147#msg-13147 I forgot to divide by 2 when I measured the conduit beside me - duh! ;-)

I'll agree that it could be used and if you can find someone that does conduit work to give you their scrap pieces for free it would be great; otherwise, conduit can get expensive.

I've heard of 1/4" ID aluminum conduit, which should have an OD close to the M8 rod that darwin uses, but I have no idea how much it costs. Maybe you should give it a try.]]> criswilson10 Mechanics Wed, 11 Jun 2008 16:37:33 -0400 https://reprap.org/forum/read.php?14,13039,13108#msg-13108 https://reprap.org/forum/read.php?14,13039,13108#msg-13108
[www.wheatlandtube.com]

This page lists the wall thickness for 1" as 0.126" or 3.20 mm.

All the steel conduit I have ever seen has been galvanized so it wouldn't work for sliding rails. I was mainly putting the idea forward for the structural frame (uprights and cross braces) as it is light and inexpensive and ought to provide good rigidity.

An even lighter model could use conduit for the uprights and small cables with turnbuckles as diagonal tensioners.

The RepRap is either going to become more complex or the $400 price is going to continue to come down. Actually both at the same time would be best!]]> rodzite Mechanics Tue, 10 Jun 2008 21:55:44 -0400 https://reprap.org/forum/read.php?14,13039,13099#msg-13099 https://reprap.org/forum/read.php?14,13039,13099#msg-13099
With that out of the way, the exterior finish of the conduit is smooth, but not as smooth as the solid rods. So there could be some issues with the z axis slider.
The only other problem that immediately comes to mind is that conduit tends to carry vibrations - which may or may not be an issue.]]> criswilson10 Mechanics Tue, 10 Jun 2008 16:37:46 -0400 https://reprap.org/forum/read.php?14,13039,13095#msg-13095 https://reprap.org/forum/read.php?14,13039,13095#msg-13095 Steel tubing would probably work pretty well with the current darwin design, as I would have thought it would still be strong enough]]> greenarrow Mechanics Tue, 10 Jun 2008 16:10:00 -0400 https://reprap.org/forum/read.php?14,13039,13094#msg-13094 https://reprap.org/forum/read.php?14,13039,13094#msg-13094 -------------------------------------------------------
> Is conduit an american name for pipe, or is it
> something else?


Typical usage in the states refers to piping, plastic or plastic-lined metal that contain electrical and communications lines. Specifically, though, it can also mean a pipe that carries one or another type of fluid.]]> Forrest Higgs Mechanics Tue, 10 Jun 2008 15:27:02 -0400 https://reprap.org/forum/read.php?14,13039,13085#msg-13085 https://reprap.org/forum/read.php?14,13039,13085#msg-13085 greenarrow Mechanics Tue, 10 Jun 2008 10:55:54 -0400 https://reprap.org/forum/read.php?14,13039,13060#msg-13060 https://reprap.org/forum/read.php?14,13039,13060#msg-13060 -------------------------------------------------------
> Another negative:
> Having to support an imperial and a metric
> variant.

If this thing is made in the US there will be SAE versions no matter what. It might not be the "offical" version but it will happen. The only way I see metric gaining the upper hand here is if the entire populace were compelled to take a year of college level physics :)]]> rodzite Mechanics Tue, 10 Jun 2008 00:45:09 -0400 https://reprap.org/forum/read.php?14,13039,13040#msg-13040 https://reprap.org/forum/read.php?14,13039,13040#msg-13040 Having to support an imperial and a metric variant.

But if it gives us the rigidity to also do CNC routing, we should consider it.]]> SebastienBailard Mechanics Mon, 09 Jun 2008 13:12:01 -0400 https://reprap.org/forum/read.php?14,13039,13039#msg-13039 https://reprap.org/forum/read.php?14,13039,13039#msg-13039
Neutral
The outside dimensions of the unit would be larger to still have the same work area

Positive
Weight savings (or is this actually a negative?)
Conduit/pipe is easier to cut than solid rod
Material is more readily available

Negative
Might "cheapen" the appearance?
The brackets would have to be quite a bit larger to accommodate 3/4" or 1" conduit requiring more plastic and print time to create

Has this been considered?]]> rodzite Mechanics Mon, 09 Jun 2008 13:06:40 -0400