Adler 69 skipping stitches

[Sasho]

Hey, lately I've been experiencing strange skipped stitches, this happens very very rarely, but especially when doing a reverse. I've checked timing properly following the manual and adjusted it correctly. 

This still happens on some occasions, mostly when I transition from a thicker section to less bulky one. 

I sew canvas and Cordura with a 100/16 needle and size 50 thread. 

Can the skipping be due to the thicker material deflecting the needle? 

There's a little play in my need bar that might be doing this, but I am not 100% sure. 

Hook seems in a very good condition. 

Any suggestions is very welcomed, thank you

[Northmount]

@Sasho Moved your post to leather sewing machines.  You'll get more response here.

Pictures might help.

 

[Sasho]

Timing and space between needle 

[leerling]

The picturs look ok to me. Are they taken as the needle is lifted 2 mm from the deepest point ?

[kgg]

11 hours ago, Sasho said:

I sew canvas and Cordura with a 100/16 needle and size 50 thread. 

Can the skipping be due to the thicker material deflecting the needle? 

How thick is the material? Have you tried using a 110/18 needle? Is the thread a bonded nylon or polyester?

kgg

[Sasho]

2 hours ago, leerling said:

The picturs look ok to me. Are they taken as the needle is lifted 2 mm from the deepest point ?

Hey, I've followed very pricesly the manual, using a caliper. Timing seems perfect

[Sasho]

1 hour ago, kgg said:

How thick is the material? Have you tried using a 110/18 needle? Is the thread a bonded nylon or polyester?

kgg

Usually 2 layers + 2 layers of inner lining and occasionally webbing between that, my skipped stitches are extremely rare, but happens 90% of these rare times when doing a reverse. 

 

I am using gutermann Tera which is

100 % polyester continuous filament 

[Garyak]

If your needle is set correctly and bobbin is feeding the right direction, tighten down on the presser foot. The project needs to maintain contact with the needle bed at all times. Not maintaining contact when the stitch is being made causes skipped stitches. 

[Michiel]

With triple feed and needle feed machines very often the side “play” from the needlebar can be removed very easy

see the picture

the part my screwdriver is on should move a little bit to the needlebar assembly 

the screws are on the backside

do not make it too tight ! (A litle bit of play is better for the machine)

[Wizcrafts]

21 hours ago, Sasho said:

Usually 2 layers + 2 layers of inner lining and occasionally webbing between that, my skipped stitches are extremely rare, but happens 90% of these rare times when doing a reverse.

If you already timed the hook and needle as good as possible, experiment with changes to the check spring. There are usually three adjustments:

1. You can change the distance the spring travels down to its resting position. The longer the throw, the longer the thread stays taut. Normally, the bottom stop is set to bottom out just after the needle enters the material. Its purpose is to prevent loose thread from getting split by the tip of the needle. Try more or less throw.
2. The spring itself is attached to a split shaft that can be rotated for more or less spring tension. There's a set screw that holds the shaft in the preset position. Loosen the screw a little and try more or less spring tension.
3. There is a screw inside a curved slot that lest you move the entire assembly to left or right. Typically, turning it all the way counterclockwise tightens the lay of the stitches. Turning it full clockwise loosens the lay of the thread. Normal is centered in the slot. Experiment!

[DonInReno]

On 4/11/2023 at 11:08 PM, Sasho said:

Can the skipping be due to the thicker material deflecting the needle? 

Yes, sort of.   Going up in needle size would be a way to test if this is what is going on if it’s a minor problem, but going over thick seams has always been the poster child for needle deflection and breakage.   Cordura and other synthetics can be very slick and sometimes the operator will be inadvertently putting side to side pressure on the material causing it to slip under the pressure foot, especially with larger projects.   It greatly increases the chance for needle breakage, but a needle plate with smaller hole will quickly show if the needle is being bent due to too much or not enough operator guidance of the material.   A looser belt will allow slippage if the needle actually impacts the needle plate.w 

Perhaps the feed dog and moving foot are slipping while the needle feed is bending the needle - or the shape of the item is catching on the machine bed or needle plate rather than feed correctly.  I like a much more aggressive feed dog, serrated presser feet and extra pressure with synthetics - not to mention it requires a lot more concentration to provide the correct guidance compared with heavy cottons.

Your hook doesn’t look bad and I’d be very surprised if it didn’t feed heavier thread perfectly, but thinner thread does need minimal clearance between needle and hook, and the hook point needs to be sharper to cleanly scoop behind the thread, pulling it away from the needle rather than scrape it off with a blunt tipped. Comparing an otherwise decent looking hook with a first quality one that’s factory fresh will often point out slight issues that otherwise get overlooked.   Replacement hooks or hooks that have eaten a number of needles are often a little blunt, but for instance, a new Juki hook is very sharp and crisp.

I have to keep in mind thread is stretched tightly against the needle as it penetrates the material and only slackens enough for the hook to slip behind it as the needle is withdrawn a bit - about the thickness of a nickel.