Black Leather & Black Thread - Just Wont Sew

[TR6]

Can anyone help me to understand what is going on with my machine, thread, needle etc.

As you will see I am new to sewing and leather. I am in the UK and restoring an 1973 TR6 sportscar, horrified at the price of a vinyl interior, wondered if it might be possible to do it myself.

Managed to get a walking foot machine.

It looks just like a Consew 206R – a mini zig-zag machine but I think mine hails from China, originally from a UK distributor, I have seen a lot of machines like this branded differently, REX 601Z,.Thompson Mini PW500, Omega WF222, etc.

I have made most of the novice errors and learnt a lot from this site and others, so that I think I can rule out the following:

• Timing
  
• Hook to needle proximity
  
• Needle bar height
  
• Tension
  
• tried different needles
  

But please don’t let that stop you making suggestions, because at one time or another I will have had all of those wrong.

I can sew perfectly onto Calico as a test piece. Short stitch, long stitch even zig-zag using 40s bonded nylon thread and a size 18 (110) needle. Needles are 135x17 or DPX17.

The interior will be two tone with a beige leather used for the pleated parts and black for the remainder.

All the beige parts are done and worked fine using the size 18 needle and 60s nylon thread but beige.

Then I tried to sew using 60s Black thread – no good – dropped stitches and even the thread fraying through the needle, I suspect because one strand broke.

So suspecting that the needle/thread combination was the problem got a spool of 40s Black nylon and have had exactly the same problems.

Calico fine – black leather no good. I have some grey leather that I had been making up test pieces to work out the joins and had better success with that but still dropped stitches and the beige seemed slightly better than that but the black leather was a no no whatever I did.

So just before I dumped the machine I decided to try some old black polyester (Guterman) thread that I had and it sewed the black leather perfectly without any problems – a bit of tweaking to the tension and that was it.

So what is going on – I am confused?

I only paid £52 for the machine so it really owes me nothing, but when it's working it's a great bit of kit.

Any help gratefully appreciated. Thank you.

[dirtclod]

Try another size bigger needle and see if that helps. I have some white thread and some tan looking thread that just won't sew. In the past i have sewn a couple hundred spools of thread and i will get a spool that won't sew now and then.

[TR6]

Thanks for that. I tried a 19 and it has made a difference. I used some good quality leather samples and the stitches were good, even long zig zag ones.

Not only that but I think I can see what is going wrong. I am not sure what it is called but the arc'd bit of the shuttle race that rotates with the hook and forms the other half of the circle with the hook is just catching the thread as it returns the hook before picking up the loop and I think this is what is fraying the thread sometimes, as I guess it must be nicking one of the strands.

To get the hook to catch the loop consistently I set the shuttle so that the hook was as close as I could make it to the scarf on the needle. It looks as though the race part is as proud (close to the needle) as the hook itself, so to get the hook right, I have to have the race too close and the thread catches.

I have now backed it off a little but now I'm back to missing the loop.

I think I need to get the eye of the needle slightly higher so that the eye misses the arc'd bit of the shuttle race at the same time as trying to keep the hook in the scarf and close enough to pick up the loop without the race catching the thread.

Is it just a case of trying to find the sweet spot?

I think I read on the forum that Schmetz needles give the best loops, so maybe that might help?

[TR6]

I think I can answer my own question as to why its happening, but I dont know how to fix it.

To get the hook to pick the 40s or the 60s thread, it needs to be very close to the scarf.

To get the eye of the needle below the hook, I have had to drop the needle bar.

The problem is the eye passes too close to the race and the thread gets damaged. It doesnt happen with the polyester thread because it is much thinner and passes unscathed.

So using the 40s thread i get good stitches but the thread gets damaged and eventually snags up in the needle and or breaks.

Or I have the thread unscathed but no stitching.

I need the hook to be slightly bigger than the race so that it can get close to the scarf but still have the eye and thread miss the race.