Is my machine a bad design?

[Vezelay]

Sewing two highly visible parallel rows of a brightly contrasting colour isn't easy! Even the smallest divergence will stand out. Many of us would find that a challenge so don't let it bash your confidence in your competence or your machine. Personally I would unpick that and re-sew with a matching thread, using as few parallel rows as I could get away with.

[BrendaP]

If two parallel rows of topstitching is what you want try using a twin needle.  If there are any wobbles both rows of stitching will wobble in the same direction but they stay the same distance apart.  Any machine which can do a zig-zag should be able to take a twin needle.

[KayK]

I did once have a machine purchased from a certain 'Mr Cooper' that certainly wouldnt sew a straight line!  If you let a piece of fabric go through on its own it would gradually go on a curve - I had a good look at it and the feed dogs were very slightly set crookedly!  (Yes, I caught him in decent mood and he changed it straight away!)

However, please don't be harsh on yourself about it, sewing a dead straight line isnt that easy!  The best machines for this are the old fashioned straight stitch only, with narrow feed dogs and and a narrow foot.  The next best is a machine with a changeable straight stitch plate and straight stitch foot.  Otherwise, use the tried and tested method that all the other good souls have mentioned, and just take your time!

[Sara-S]

A little trick to try if you just want to practice sewing straight, but don’t feel like wasting fabric.  Take some paper and rule, or print straight lines on it.  Run it’s through the machine with no top or bobbin thread.

After doing this, hold it up to the light & see if the holes in the paper are all along the lines.

[Iminei]

Anyhoo, I'm scrapping my machine cover project as I've decided I bit off more than I could chew.
 
Nooooooo!!!    Dont do that ... its only a box cover ...

I dont know what fabric you are thinking of using .. your pic looks like leatherette (wwwaaaaarrrm leatherette ... Ah such a mis-spent youth!!!)  but a heavy cotton with a wadding would do the job excellently and allow you to enter the water at the shallow end!

Ah yes @KayK  ... the infamous Mr Cooper!!!! 

[Bill]

Nooooooo!!!    Dont do that ... its only a box cover ...

Yeeeeeees!!!  It's only a learning experience 

Too late now anyway, most some of it has already been destitched. Is that a word?
The material is cotton offcuts. No idea of it's thread weight. Bought a bag of it from a certain online retailer to mess about with before I break out the cashmere 

[William]

Hello-

Your stitching does not look as bad as you think! It took me quite a while to stitch a straight line. It is actually one of the more difficult beginner skills. Sometimes I still wonder about a line I tried to stitch...

And by the way, You did a good job lining up the points! :thumbsup:

William David