Category Archives: Miscellaneous

FKM349VL Benchtop Mill: control, EMC2 LinuxCNC interface

The FKM349VL is one of many similar benchtop mills, Made in China. It’s size and power requirements make it quite suitable if you need a small machine that is still capable of machining aluminum alloy, and to some degree, even steel.

General characteristics – X travel = 490 mm, Y travel = 160 mm, Z travel = about 330 mm.
Table size is 700×180 mm

Spindle is MK3 with M12 draw-bar (this is the most significant limitation – only manual tool change!).

fkm349vl mill

The linear stages use 16 mm, 4 mm pitch ball screws. Motors are 4.5 Nm, 6 Amp nominal. These are quite powerful, plenty of torque for this machine. This allows velocities of about 1800-2200 mm/min with no steps lost.

The control electronics are all housed in a cabinet attached to the machine. All pretty nicely made (motors powered by roughly 50 VDC, from the toroidal transformer; the blue transformer provides 12 VDC for the control circuits):

fkm349vl control overview

The stepper drivers – Leadshine units, up to about 5.5 Amps, configured for 4.3 Amp peak, 3.1 Amp RMS. Type MD556, V2.5. The units are similar to the Leadshine M542 and M752 units. Aka, KL-5056, aka, Rhino RMCS-1102 – many similar units exist.
The stepper motors have 200 steps/rev; the drivers are configured for 8 microsteps per full step – this results in 1600 steps per rev.

fkm349vl stepper driver

By default, this machine came with a “CNC-Workbench” CNC controller, offered by W+W Automatisierung (www.ib-weigelt.de). I gave it a try but soon found out that it is not up to my requirements; it’s a nice little controller, for what it is, no complaints, but really only for very basic uses, and difficult to interface with other CAD/CAM software. Most of my other machinery either uses industrial control, or EMC2 (LinuxCNC), so the decision was soon made to adapt the control to EMC2.

EMC2 has a powerful hardware layer, using the parallel port for control input and output. To allow proper speed and noise immunity (very important if you don’t want to run into issues!), a little interface circuit was fabricated, on a piece of perf board:

fkm349vl interface brd

fkm349vl interface brd solder

fkm349vl control schematic

Nothing too fancy – low pass filter, Schmitt trigger, LED driver (the stepper driver use optocoupler inputs). The limit switches are combined by diode OR connections, switches are normally closed – to prevent machine damage in case of a broken wire.

The internal interface of the machine, originally used by the “CNC-workbench” controller uses a pretty uncommon high density D-SUB connector – 44 pins!

fkm349vl high density plug

First time I have seen this type of connector, but it offers a fair number of contacts, for a pretty reasonable price, and quite a bit of soldering effort!

The software implementation – let me know in case you need the EMC2 HAL files for reference. Also attached a little incremental encoder as a “handwheel”, using a second parallel port. Quite amazing what you can do with a second hand computer, a few parts, and free software!

German Bakery: sourdough bread, ‘quark’ variety

Living in the US, I don’t want to miss good home-style bread. Sure, all kinds of bread are available here, but at a price, and you never really know what is inside.

This bread is about 60% rye, 40% wheet. Rye flour always requires the use of sourdough, and we have to consider two cases:

(1) You are the proud owner of some sourdough, or have a friend that has some.

(2) No sourdough at hand. Don’t worry. Sourdoug can be prepared, without any starters, at home.

(a) mix 50 g of dark or semi-dark rye flour with 50 g of water; stirr; leave at room temperature for 24 hours.
(b) add 100 g of dark or semi-dark rye flour and 100 g of water; stirr; leave at room temperature for 24 hours.
(c) add 100 g of dark or semi-dark rye flour and 100 g of water; stirr; leave at room temperature for 24 hours.
(d) add 100 g of dark or semi-dark rye flour and 100 g of water; stirr; leave at room temperature for 24 hours.
At this point, you should have quite a bit of sourdough ready, with small bubbles, and with no mold.

Some key items:
(1) Use boiled or otherwise chlorine-free water; tap water is perfectly fine but boil and let cool before use to remove any chlorination
(2) Use very clean utensils; store at a clean place – away from any sources of mold.
(3) Use a plain plastic or porcellain dish; don’t cover it; don’t use a metal dish.
(4) Temperature is fairly important – not too hot, not too cold.

For later use, best put some sourdough (~100 g) into the freezer.

Now, as you have sourdough now, let’s get started.

Step (1) – Take 100 g of sourdough, add 200 g of rye flour, and 200 g of water; leave at room temperature for 24 hours.

Step (2) – Add 400 g of rye flour, 500 g of water. Leave at room temperature for 24 hours.

Step (3) – Add 750 g wheet flour, 200 g of (warm) water, 30 g of salt (measure accurately!, mix in with the flour), 1 cube of yeast (available mainly in Europe – 42 g each; can be substituted by one package of active dry yeast), 500 g of ‘quark’ = curd cheese – low fat type.

Step (4) Knead properly, using your hands or strong machine; cover the dough with a towel, let the dough sit for about 1 to 1-1/2 hour to rise.

Step (5) Form any shape and size of bread. I prefer multiple small pieces. Use some wheet flour – the dough is fairly sticky.

Step (6) Let rise for about 30 minutes; preheat oven to 220-230°C.

Step (7) Bake. After 10 minutes. Reduce temperature to 170-180°C (depending on oven; I use a forced convection type: 170°C). Bake for another 45-60 minutes, depending on size of loaf. If you prefer a shiny crust brush with water (with a bit of corn starch added) immediately after removing from oven.

Step (8) Let cool. Don’t cut off pieces for at least 1 hours – other wise, steam will escape.

Enjoy!

Note – rye flour refers to semi-dark rye flour (not whole grain). In Germany, known as Type 1150. Wheat flour – best use any ‘bread flour’, in Germany, known as Type 1050. I use Type 405 because it is commonly available and it is amazingly cheap (currently EUR 0.32 per kg!!).

bread full

bread cut

Xmas Bakery: Nougat Plätzchen(=small cookies)

These are one of my favorite Christmas “Plätzchen”(=small cookies). A kind of nougat shortbread, covered with chocolate.
First, prepare a dough by thoroughy mixing/kneading (no machine needed, best use your hands):


250 g nougat (soften in microwave)

80 g butter (soft)

60 g sugar

300 g plain flour, German Type 405

1/2 teespoon baking poweder (throughly mix with flour)

a little bit of salt

1 egg

some vanillin powder (or vanilla essence)

Once properly mixed, make two rolls, and wrap in some plastic foil:
nougat

Let rest for several hours in the fridge, or overnight.

Then, form nice cookies, either manually, or by rolling it to about 3/16″-1/4″ thickness. Don’t roll too thin!

nougat ausstechen

nougat ready for oven

Bake in oven at medium temperature. For best result, use 165°C circulating air. Baking time is 10-12 minutes.

Let the cookies cool to room temperature. Eventually, your efforts will result in a pile of cookies ready to be chocolate-coated.
nougat baked

Then, melt

200 g baking chocolate

150 g of really dark chocolate

using a water bath (also to keep the chocolate warm during the coating process).

nougat chocolate application

For guests that are worried about too much chocolate, it always is a good idea to leave some of the cookies partially covered.

nougat final steps

Use non-stick paper, and let the cholocate solidify for at least 18 hours before packaging.
Store in odor-free, dry place. For best taste, let them rest for at least a few days.

Xmas Bakery: Christstollen

The time is right to get started with some Christmas bakery. Stollen, a long standing German Christmas tradition. It comes in various kinds and modifications, but there is only one truely original recipe.
Don’t use any self-rising flour, or baking powder – really Stollen always uses yeast to rise.

1 kg plain wheat flour, Type 405 according to German industrial norm (DIN) no. 10355

60 g of baking yeast (about 1.5 regular yeast cubes), can be subsituted by active dry yeast, but the real thing is always baked with fresh yeast, commonly available at all German supermarkets.

250 mL milk (warm up; not too hot!)

First, to get the yeast started, put all flour in a suitable bowl (plastic bowl most prefered), make a hole in the center, put in the yeast and mix with some milk to form a semi-liquid dough. Cover with some of the flour, and let it sit for 30 minutes.

stollen yeast

This is how it should look like.

Add:
1 egg, 1 egg yolk (some traditional recipes don’t use eggs, but I highly recommend it, otherwise, it will be a pretty ‘flat’ Stollen, unless you have a suitable mould)

180 g sugar (extra pure saccharose – just kidding; refilled with ordinary, plain sugar)
stollen extra pure saccharose

200 g butter (room temperature!)

and, the remaining part of the milk.

My traditional recipe doesn’t need any almonds – but these are common additions to other Stollens. Therefore, you might add 125 g of ground sweet almonds, and 50 g of ground bitter almonds, along with some more milk.
Also, you can add mace spice, but not too much!

Knead to a firm dough. If too dry, add some more milk. Don’t add too much, dough should not be sticky or too soft! Properly knead with your hands. No machines are required for this recipe.
Let this dough raise for at least 60 minutes at a warm place.

In the meantime, we prepare the additions:
200 g citronat (rather finely cut!) – candied peal of a special type of lemon
100 g orangeat (finely cut!) – candied orange peal
500 g raisins (wash throughly with at least 1 liter of boiling water, and pick out any that don’t look 100% perfect)

stollen ingredients

Key thing is that the citronat and orangeat are finely cut, nothing is worse than big chunks of this in the final Stollen.

Once the dough has rested long enough, the citronat, orangeat and raisins are added – best by flattening out the dough to about 3/4″ thickness, additing the ingredients, and then folding the dough – this will reduce the effort to form a uniform dough.

Finally, form a Stollen:
stollen ready for oven

Make sure to remove any raisins from the surface (these will scorch and give bitter taste) – just push them in, or remove and eat.

Let the Stollen raise for about 30-45 minutes (avoid air drafts, keep in well-heated room).

Then, bake in a pre-heated oven. Temperature: For best result, an electric baking oven is much prefered, circulating air type. Pre-heat to 200°C.
Insert the Stollen. This will help with retaining the shape.
After 10 minutes, set temperature to 165°C, and bake for another 60 minutes (cover with a piece of aluminum foil after 30 minutes).
Test with a wooden stick – if no dough adheres, everything went fine. Otherwise, leave for another 10-15 minutes.

stollen baked

While still hot, apply about 200 g of molten butter with a soft brush.
Cover with a layer of powdered sugar (prefereably, use pure powdered sugar without any other ingredients that are commonly use in ‘icing sugar’).
Carefully wrap in aluminum foil to provide a good seal.

stollen ready for storage

Now, the most difficult part, let it rest for about 4 weeks at a reasonably cool and dry place (guest bedroom, corridor, or similar place that is free of strong odors and free of damp).

Note: this recipe is all in metric units, rather than cups, ounces, etc, because this is about exact replication of a traditional Stollen. This will only work if done accurately, with precise weights, and well-controlled temperatures all throughout the process.

Dell PowerEdge SC1425, 2x Seagate 3 TB NAS S3000VN000, Ubuntu 14.04.1 LTS: server upgrade

Over the years, a number of manuals and datasheets have been accumulating, also because of my inclination to keep a copy of more or less every document I have used for repair jobs, etc. – sometimes servers go down, and the files disappear in the vastness of the internet.

For some years, I have been dealing with USB drives and NAS storage devices, to keep local copies, and to keep files accessible, but this has become troublesome with space running out, and multiple copies, on multiple drives. Time for a better solution.

(1) A Dell PowerEdge SC1425: 64-bit dual Xeon 2.8 GHz processors, 2 GB RAM. Available surplus, essentially, for the cost of shipment.

poweredge sc1425

(2) 2 pcs Seagate 3 TB drives S3000VN000, these are NAS-optimized drives – essentially, the same hardware as common desktop drives, but targeted for 24/7 operation, with specifications that correspond to long-lifetime “medium”-performance requirements. Performance – this is a private fileserver, and reading rates of 20-40 MB per second are plenty, you don’t need any 10K/15K drives to achieve this.
The drives are operated in RAID1, full redundant.

seagate st3000vn000

(3) Ubuntu 14.04.1 – server. This is a common solution that can provide both Samba (Windows shared folder) and web (Apache) server functionality, at no cost.
Also, it provides the RAID1 functionality (software raid).

Putting these things together, not a big deal – one should think. It took quite some hours to figure out all the settings to get the RAID1 working, and all the files transfered from the old harddrive (~150 GB, the essentials).

Another item to consider, the noise. The SC1425 will be put in the attic, so there is no issue, but don’t consider having this machine anywhere close to where humans reside – it is noisy. 4 fans, cooling the dual CPU, right in the middle of the case (red frame).

poweredge sc1425 2

Some performance stats:

raid1 performance read

raid1 performance write

Roughly 100 MByte/s read/write on the RAID1 pair – perfectly fine to support a 1 GBit/s network speed. Over Samba, I get about 25 MByte/s.
Maybe you noticed the name of the machine – arctur – wondering what it is? – a star, quite a bit bigger than our sun, and not too far away – just about 11 parsec, or 37 light-years! Glad that data server is just a few nano-seconds away, at least, counting the light path.