Monday, November 5, 2012

Sourcing RepRap extruder springs in South Africa

Several RepRap extruders use compression coil springs to provide tension on the idler. While some companies exist that manufacture springs locally, they are not really conveniently located and might charge a lot if you are only interested in small quantities.

After search the internet and fastener / hardware stores unsuccessfully, I happened to notice that certain clothes-pegs have springs that seem perfect for the job.

Sourcing the clothes-pegs turned out to be relatively easy....

The ones that I found are:
Barcode: 6009695720525
Branded as: "You Save"
Pack size: 48 pegs (with one spring each) (Can't find it on their online shopping page)
Sources: Pick 'n Pay (~R26 per pack of 48)
Free length: 16mm
Wire thickness: 0.9mm
Turns: 9 (first and last one flattened)
Outside diameter: ~6.4mm (Fits M4 / M3 screws)
Turn "pitch" (relaxed): ~ 1.9mm (including 1 wire thickness)
Spring coefficient: Unknown
Material: Unknown ("rust free", looks like it might be zinc coated steel)

The pegs themselves seem to be made from PE and might be recyclable into filament with a filament extruder.

This thread on the RepRap forums seem to mention the same springs.

Tuesday, February 7, 2012

BitBurner - Download HTTP links using BitTorrent

BurnBit has a handy service that allows you to generate torrents for any directly accessible HTTP link.

They have some nice instructions to integrate it into your site. However, almost no big sites use these.

In order to easily use it for downloading Linux distributions (which are well mirrored, making BurnBit useful, even if just easily download from multiple mirrors simultaneously and to check that the file is not corrupted) I wrote a small GreaseMonkey script that injects their download buttons in some of the more obvious mirror sites / HTTP accessible FTP sites.

It is somewhat crude currently, but works well on sites that just contain directory listing.

Tuesday, January 17, 2012

Compiling CMake 2.8.7 on Solaris 10

Building CMake might fail due to incorrect environment variables.

If you already attempted to compile CMake, delete the directory and start again. It caches its variables for its own build all over the place.

A full Solaris 10 install has everything you need to compile CMake.

I bootstrapped it using as much system libraries as possible and assumed 4 CPUs / cores and set it to install to /usr.

Set up envirnment:
$ PATH=/usr/sfw/bin:/usr/ccs/bin:/usr/bin; export PATH
$ CC=gcc;export CC

$ ./bootstrap --parallel=4 --system-libs --no-system-curl --no-system-libarchive --no-system-expat --prefix=/usr

Compile according to Readme.txt:
$ gmake -j4
To install:
Change to root
# gmake install

To package:
$ bin/cpack
The generated package can the be installed as per the instructions on the download page.
The package will only work on other Solaris 10 (and possible newer) system running the same CPU architecture. Solaris 9 misses some of the libraries that it expects to find.

These instructions do not work on Solaris 9, due to the lack of a compiler in the default install. Installing Solaris Studio might work, but was not tested.

Update: I have a prebuilt version available here.