3D printing Widgets

I looked at the videos Jon posted. Firstly, DO NOT EVER TRY AND EXTRUDE ANYTHING UNDER 190C! it puts too much tension in the Bowden tube and the the fittings start cutting into the PTFE tube, which translates to ever increasing backlash in the extruder system.
Second, I note that they recommend bed leveling cold, fine but it's better if you then do a pre-heat, 190C Extruder and 60C Bed. Then switch off and immediately do the bed leveling, I found these things out the hard way!

All the fixing bolts are M3 to suit the hole sizes on the motors.
I haven't had a chance to look at the videos & I haven't got any filament yet so only just powered up the printer.
On NC machines you had to reference the axes or Set Zero so that's the first question when I press the start button.
They use the term "Levelling", & what I've read so far is just setting the height above the bed, nothing about getting the axis movements parallel with the bed.

On the FreeCAD front it seems as if you can't easily modify one part to make another. It seems as if you have to erase some folders or even start again. I haven't managed to copy & paste (carbon copy) hole layouts from the sketch in one part to the sketch in another.

 

Magpie
In FreeCad you most certainly can modify an existing part to create a new one. In FreeCad any changes you make are not kept anywhere until you "Save" them. A simple "Save" will overwrite the original file with the modifications but using the "Save as" option means you can save the modified file under a new name. This way the file you started with will not be modified in any way.
If I am trying a modification to just improve how a part prints I frequently use "Save as" and use the sme file name but add a suffix like x at the end of the file name. That way I still have the original unmodified file in case the modification doesn't work!  By doing this it is quite possible to leave a "trail" of files but its down to you to remember what each modification was intended to do. Once you are happy with the changes it is good practise to do some "housekeeping" and remove any early versions of the file that you no longer need.
I hope this helps.    

I think its a case of you can modify an existing part to create a new one sometimes.
I have just edited a sketch of one of the faces which has five circles in it which gives five holes. I have added an ellipse, the sketch is full constrained, but FC doesn't generate an elliptical hole. Why?

I use the method you describe for saving earlier versions so you can backtrack.
I also clean up afterwards, its like the email inbox, if you don't you cannot see the wood for the trees.

I have just altered the diameter of the central hole, it hasn't updated that either nor exported the changes to the STL file.

Exploring FreeCAD as a self-learning exercise can take a lot of time - sometimes productive and sometimes down-the-rabbit-hole.

I know some folk hate YouTube.  Lots of so-called-experts who drive tools at full speed and do magic stuff so fast normal mortals have not a change to keep up.

There is an exception I make for one site:  https://www.youtube.com/@MangoJellySolutions

This guy knows FreeCAD and somehow maintains empathy for those who have not gotten a grip with the beastie.  He does scores of tutorials that focus on one or two things.  He does not speed.  He says what he is doing and often why.  He often starts with a discussion of the nature of the object he wants to create, what he might start with and then the steps he would use to adapt it and uses that to select the CAD functions.  He does tend to stick with the 'Part Design' more than I would but that might fit others quite well.

When I am about to use some part of freeCAD for the first time, or I am considering the design of an object I will often go looking for a tutorial that covers that topic.

I keep a list of those training videos that I have looked at and what the topic was and usually some notes about what I learned.  I keep going back to that rather than blunder around in the dark. 

Magpie, I'm sure your printer has some method of referencing (zeroing) the axis's. If you think about it moving the Axis by hand to 5 different points on the bed and adjusting the bed so that the nozzle sits 0.1mm above the bed will ensure that both X and Y are at 90degrees to the bed surface. A word of warning here, never try bed leveling without the paper on the bed, sooner or later you're going to scratch it if you don't. Remember back to leveling NC machines, one point is always the reference and is never changed once set. With the Anet I always set the left rear screw first, then leave it and do all the setting on the other 3. Any order you like but I always use RR, FR and FL. You'll find you own best way of doing things.

I've been having a go at referencing or homing the printer. The first thing to say is that the only mention in the manual is to the Home page on the screen.
Once there there is a Move button which takes you to a screen which has a Home button which puts the machine into the usual homing routine.
There are X,Y,Z indicators on the screen which turn from green to red after homing.
However the actual home position on Z varies depending on where it started from. There are scales which give the absolute position, I think Heidenhain use them.

There are the usual buttons for jogging the axes but their function depends on whether you've homed or not & they are not just simple, X,Y,Z moves, they seem to move two axes at a time & not in the expected direction.
There is nothing in the manual.apart from one button which moves the Z-axis up.
I'm going to have to write it down!

Do you jog the head down to the printing height & then home it?
I homed it about 60mm above the bed & started a program from there. It started to print the bottom layer at that height.

When a print finishes the head will be well above the bed. It cannot just return to the start height as it will hit the part.
That means you will have to clear the bed & reposition the Z-axis.
When homing it moves X & Y a few centimetres but only a very tiny amount in Z.

Where the Z is when you switch on is Z zero. When you switch on you have to carefully move the Z axis down to the bed with your sheet of paper on it. Level the bed, then switch off, then switch back on and reference the X and Y axis. Make sure you have the correct bed size selected in Cura, your print should start in the middle of the bed and your Brim should be 0.1mm thick

I've tried a number of different nozzle sizes and found that 99.99% of prints are fine with the 0.4mm nozzle and 0.25mm layer height. I have populated spread sheets with all the settings I use for the 4 main print types, would you like them?

It seemed I would have to do something like that, a very primitive procedure.
The seller just said he couldn't remember, the joys of online shopping.

I also ordered two rolls of filament from somewhere else, according to Ebay they were posted on Sunday! & delivered yesterday by Royal Mail who don't recognise the tracking number.

We'll see what tomorrow brings!
A mate is a postie, I'll send him a text.

I'm still struggling with FreeCAD.
Working with a sketch & Pad there's no problem but using the revolver tool & trying to use different hole sizes in the sketch just makes every hole the same diameter & ignores any additions.

I'll message you with my email, I just love spreadsheets!
 

I had a word with our postie, (my mate is on leave), he remembers a parcel in the van on tuesday but when he went to get it, there it was - gone! His co-worker (different from today) on the van must have taken it & delivered it somewhere, or anywhere!
I went on Royal Mail Tracking & it said it was delivered to an address about 200 yards away on a different road.
So I went round there, a neighbour said they had moved out tuesday/wednesday. There was a bag in the porch but nobody answered the door.
So how do I get it? Legally of course.

Magpie
I think you may be expecting more than the "Revolve" tool actually does or are you trying to do something else?
Whatever 2D sketch you have displayed "Revolve" simply tries to make a solid object by rotating it around the chosen primary axis. It follows that the sketch must not cross the selected revolve axis. Really only good for making circular or part circular objects.

This is the sketch for the wheel of my Fokker V25.
 
Using the Revolve icon gives this solid representation when rotated 360 degrees around the vertical axis.
 
As the sketch itself crosses the Y axis FreeCad gives an error message if the horizontal rotate axis is selected.

I would expect that once Home Z is set on your printer then that will be the nozzle starting height automatically selected above the bed for any future print. When a particular print is finished the printer returns to a Home X & Y but leaves Z height alone to ensure it cannot hit the print on the bed.
Does your printer has automatic bed levelling adjustment? If not then you have to adjust the bed height at each corner so that the nozzle maintains exactly the same distance above the bed over the full range of X and Y. 
Certainly on my A8 this is a tedious and entirely manual operation. With the nozzle set at Z home adjustment of the bed is made to ensure a piece of printer paper just slides between the nozzle and bed when positioned anywhere over the bed. This bed gap is important as if the first layer does not stick uniformly to the bed it is quite likely the print will fail.
Hope this helps.   

Ideally the selected axes should be Z and X or Z and Y