Adler 69 skipping stitches

[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the needle as it penetrates the material and only slackens enough for the hook to slip behind it as the needle is withdrawn a bit - about the thickness of a nickel.