Needle size

Have a question or want to show off your project? Post it! No Registration Necessary.  Now with pictures!

Threaded View
We are building a boat bimini (a fabric shelter that shades the cockpit)
out of 8 oz. Sunbrella fabric. The thing is about ten feet by ten feet
and is made up of several panels with full width zippers at each end. We
are using a Yamata staright-stitch industrial machine, which has taken
us a very, very long time to get set up properly. So many dials to
twiddle! We are using DB 92 bonded polyester thread and Innnova DBx1 #18
needles. It seems to be working. Our greatest problem, actually, is
controlling the speed of the machine. It takes an extremely light touch
on the treadle indeed. One slip and it runs away, breaking and snarling
threads and sometimes needles too. That is one humongous motor!

Is there a better thread/needle combination? Various trouble-shooting
guides we have seen say "Use proper thread or needle" or "Replace needle
with correct size" or "Choose correct size needle for thread and
fabric." No argument here. But how does one determine what the correct
sizes are?

Re: Needle size
What is the model of the machine?
Not all industrial machines are capable of handling that thread.

To slow the maximum speed you can put a smaller pulley on the motor but
learning to feather the treadle is your best bet.
An experienced operator can make a machine like that sew at painfully slow

Ron Anderson A1 Sewing Machine
PO Box 60, Sand Lake, NY 12153
We've slightly trimmed the long signature. Click to see the full one.
Re: Needle size
Quoted text here. Click to load it

Is the thread coming off the side of the cone, or off the top?  It is
supposed to come off the top.  If it doesn't, it doesn't stay twisted

Also, I have found el cheapo thread  frays easily.  Once, after a
needle break, I had a sharp edge at the top of the bobbin cage which I
filed smooth with emory paper.  I understand very high speed machines
like to have silicone oil applied to the thread before it gets to the

If that machine has a brush type motor (probably not, Ron can tell
you) you can put an in-line "speed controler" (available from Grainger
and other places) in the power cord.  A speed controler can give you
full power at most any low motor speed you want to dial in.

Re: Needle size
Where have I run across before?

The machine is a Yamata GC8500 with a half horsepower clutch motor. We are
getting very good at feathering the treadle.

From all I have read so far it would appear that the #18 universal needle
and the 92 polyester thread are correct when all the other variables are
set correctly, which is pure trial and error. This machine will sew though
eight layers of 8 oz cloth like a hot knife through butter. But the
settings are supercritical, especially the needle to bobbin timing. I think
we have it now. Practice, practice, practice.

Re: Needle size
Size 92 is borderline to heavy for that machine. With a lot of coaxing you
might get it to sew right but that is not the machine for that type work. A
walking foot machine is preferable.

Ron Anderson A1 Sewing Machine
PO Box 60, Sand Lake, NY 12153
We've slightly trimmed the long signature. Click to see the full one.

Site Timeline