Besides chosing the 'bold' option (if available) when workiing with text, is it possible to widen the stroke of a letter or figure, without widening the letter as a whole? 

Adding a stroke of the same color perhaps?

Sorry, but I don't understand how adding a stroke of the same color will widen e.g. a letter? Please see the attached document showing what I am trying to achieve.  Thanks.

Adding a stroke is easy but no way to achieve the result to the right exactly:

Thank you Polygon, that clarifies the matter.

The result is strange in the bottom left because of the clipping path I forgot to remove. Here it´s without:

Thank you, no problem, I understood the process. I must apply this and test what happens when cutting out text with a plasma cutter. I suspect that it will follow the outline with the nodes, in which case I will have to manually move the nodes to widen the text - a VERY tedious and time-consuming process!

You can apply stroke width to a whole selection or text object - important is the convert with Stroke to Path then Ungroup then Path->Break Apart then Path->Union to maintain the outer "rim".

Yes, I do follow these steps, but as you can see from the attached example, the outline with the nodes appears to be at the same dimensions as the original letter. Converted to G-code ('machine language'), the result will be that this line with the nodes will determine the cutting path, and not the outermost black edge of the letter.

Path->Stroke to Path is the key. Not Path-> Object to Path. Please read closely:

1. Type text

2. add stroke

3. Path->Union to convert to Path

4. Path->Stroke to Path

5. Ungroup makes 2 new groups for Stroke and fill so

6. ungroup again and 2 objects are selected then

7. Path->Union

8. Apply stroke, kill fill

Hello Polygon. Success at last, thanks you very much for your guidance And thank you also for your patience with me.