SnakeOil-XY Preparations: Metalwork

4 minute read

DIN Rails

The DIN Rails are used to hold the electronics in the two compartments and allow quick modifications of the electrical setup. The holders do tolerate a bit of play, but from experience I can say it’s way nicer to have the cuts as straight as possible. Mark the length (depends on your build size) and use a coping saw to make a clean cut. Remove excess material using a file to prevent injuries.

Table shows the required lengths for a standard 180mm beta2 Version (should also match beta3):

Length Quantities Notes
305mm 2 -
282mm 1 Both ends need to have the cutout to allow for mounting

DIN-Rail Cutting

3030 Aluminium Profiles

Blind joints use a button head screw inside the profile to connect two profiles perpendicularly. For each joint, you need an allen key access hole and a thread.

This may or may not be the most challenging part of the build if you don’t have the right equipment. I tried to drill the holes for the blind joints on leftovers first, and with an electric screwdriver this can become very sloppy quickly. Luckily my uncle has a milling machine, so it was a breeze to drill the holes accurately and cleanly. Due to the increased precision, I went down to a 6mm drill, but adjust accordingly.

Find the measurements on GitHub. Do note the extrusion length apply to different versions of the build, so only choose the ones you need. Also, please note the measurements indicated with letters don’t always start at the end of the profile!

Allen-Key Access

Again, apply common practices and remove burrs. Next are the threads in the profiles. All 30mm profiles need threads, except one. I was told to use IPA instead of cutting oil and this trick worked wonders, because it evaporated quickly and all the chips fell off.

Level threads are required for your frame to be perpendicular - in short: take as much care to cut threads straight. Remove burrs and let the IPA dry. I used a rag on a stick to clean out the shavings because I don’t want them to fall on my table when working on the Printer.

There are printable jigs in the STL-Folder, but I didn’t have them handy and it did work out okay.

Thread Cutting

I placed the profiles from workshop into my room to temper them. I don’t know if it makes a huge difference, but I hope this will prevent the frame from warping after assembly.

Build Plate

It is very important that you buy a cast aluminium plate instead of rolled, because it will warp less when heated to high temperatures. It should ideally be precision milled, so you have a nice first layer. I bought one from a local CNC-Dealer and they do work fine for the price. But I believe you can get even less variance with more expensive pates.

The hole pattern accommodates the three mounting points and two M3 threads to act as a limiter for the steel build plate using some grub screws (inspired by Prusa). I will have mine cut on a CNC by a friend, but I don’t see any problem doing this manually with enough precision. Note, not all the bores are through the full thickness!

Linear Rails

After watching many videos about the cleaning and greasing of linear rails and their carriages (ranging from “wiping down only” to full reassembly), I came to the conclusion that there is no one correct way of doing it. I don’t know if my method works well enough, but I felt it was a good compromise.

Have enough towels and gloves ready because linear rails are messy to work with!

Linear Rail Mess

Be very gentle with the carriages, as the small bearings fall out easily. Luckily CNA included a small bag with some spares. I removed the carriage from the rail, wiped the rail down with a paper towel and cleaned the bearing groove only with IPA. After that, I applied Ballistol, which should prevents rust on the non-stainless rails.

The carriages are also wiped down loosely to get rid of the shipping oil, and then every small bearing is covered with some LM50 Litho HT bearing grease (again, there are different opinions on the suitability of those greases - do your own research).

For applying grease a small zip tie turned out to work excellently, and freshly sanitized tweezers work well to move the bearings by hand.

I don’t think it’s a good idea to remove all the shipping oil and leave it untreated, because it will likely catch rust bloom. But in the end, only time will tell how well this method works.