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4sc4n10

Hi people, my name is Jean, I'm 44 y o. I've been a Linux user for years now, and a Wikipedia contributor and translator. I'm a craftsman/artist, and this led me to learn how to use Qcad, in order to have DXF files waterjet cut for jewelry, lamps, etc, out of stainless steel or titanium. Then I discovered the RepRap and the world of open sour technology. I felt enthusiastic about this and started to make a RepStrap with a KT-150 drilling table (not finished yet).

I recently moved to a rural community here in the south of France ; we want to go offgrid both for ethical and financial reasons. We want a sustainable way of life, away from the threats of nuclear power and shale gas extraction, to name but a few. We're the very type of people who need OSE.

People living here are involved in organic farming rather than technology, so I want to build a few things like an electrical generator, using either woodgas, methane or hydropower.

I started to talk about OSE and the GVCS, but people here don't read English so easily, so I'll translate a few things for them.

By the way, could you use metric measurements in your designs along with the imperial ones ? We're not familiar with the imperial, almost nothing exists here like a "4x8" or "11 AWG", not to mention a " 3/8 nut"

mjn

> By the way, could you use metric measurements in your designs along with the imperial ones ?

This is an on-going debate inside of OSE. While it is true that virtually the entire world uses metric measurements, most of the OSE development work is being done (so far) in the U.S. Locally purchased materials are all in imperial measures, so going to the local lumber store and asking for a 2x6 (meter) sheet of plywood will only get you a blank stare. Some metric hardware is available, but that just leads to a mix of things. Eventually, there will need to be versions of the GVCS tools specified in metric measurements that use standard metric hardware.

- Mark

4sc4n10

Hi Mark, I'm aware of the blank stare thing ; it would be just the same here with the imperial. This is quite an issue, it means re-designing in some cases.
For example, the LifeTrac would be of much interest to us ; I guess we could just decide to round values to the next metric (in case we get, say, 25.4 millimeters, we'd use simply 25 mm). But such a device needs to be well balanced, shifting its center of gravity may be catastrophic.
Will there be a "metric" team ? Is it possible to just "scale" files ?
I've done this once with a plan I bought ( yes I did, 5 bucks :) ) to make a sloted plywood worbench. Fortunately plywoods are (roughly) the same size on both sides of the Atlantic, so it was not so tedious. But it was indeed a re-design, the original plans only served as a guide.

Jean

Mike_Apostol

Hi Jean, this will be one of the things I'm going to be looking into a lot more in depth when I head to FeF in November. Some of it will be just straight conversion however I imagine a fair amount won't be, it will more depend on the criticality of certain dimensions between the individual pieces and the and their assemblies/weldments as standard stock metal sizes do vary between the two systems. It'll be easier once we have some full drawings and models of the different designs which should be happening over the next month or so. Then we can have a team of people working on the conversions/equivalent metric designs.

I agree that everything should really be done in metric but hey, it is being pioneered in the states so have to go with imperial for now. The downsides of having it in both is that it really doubles the amount of documentation work that accompanies every change and iteration of the designs. Being open source projects like this, they are likely going to be changing often so it will substantially add to the total work. I guess we'll see how it all pans out!

4sc4n10

Well, maybe I can help with some kind of "bulk conversion" like open a file in QCad-scale-change from (say) 12.7 mm (half an inch) to 12 mm, plain metric bore size-save as-upload for engineers to check if it's stil sound ? By November I'll hopefully have finished my insulation work and I should have time to do that.
I understand it's difficult for you to work with metric as you can't get metric parts. Fortunately some sizes roughly match like 4 inches to 100 mm.

mjn

I think much depends on how international the project becomes. At some point, it will be useless to design/develop in anything but metric.

dorkmo

im never giving up on imperial :D

DreamBuilder

Compromise is: in UK or Australia one can buy a tape measure with both Metric + Imperial on it. Most Ex-Empire countries use both!? I have two sets of spanners etc.

Now lets mention bloody US bolt threads!!! LoL.

Talking bolts. FeF made some bolts with Brianna showing the threaded rod and nut welded on.. But bolts should be hardened? I buy bolts what stamped 8.8.

mjn

The substitution of metric hardware (nuts, bolts, washers, etc.) will likely be the simpler part of metric conversion. The difference between a half inch bolt and a 12mm bolt is not going to make much of a difference in strength. OTOH, the few hundredths of a inch difference between half inch steel plate and 12mm steel plate could throw off a CNC weld. Much of this will need to be determined by just trying it.

- Mark

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