bernette FUNLOCK threading, test sewing and care

Start with the right manual and needle system

Keep the exact manual beside the machine. The b42 is a coverstitch/chainstitch model, the b44 is an overlocker, and the b48 combines overlock and coverstitch operations. Their color-coded paths help identify threads, but each chart lists the correct order for a particular formation. The b48 manual names a mechanical threader for its lower and chain loopers; b42 and b44 instructions describe model-specific looper/threading aids and a manual needle threader. None of these 40-series pages describes the newer automatic air-threading system.

All three manuals specify ELx705 needles and caution against using a standard household sewing-machine needle instead. Check the manual for needle position and size before changing the stitch configuration. Disconnect power before changing needles, opening the looper area for service, or leaving the machine unattended, as directed in the manual.

Make a chart-driven setup, not a guessed one

For the b44, identify the desired overlock formation, needle position, upper-looper converter requirement and cutting width before threading. The b42 setup changes between its narrow and wide coverstitches, three-needle coverstitch and separate chainstitch. The b48 adds the physical transition between cutting overlock, coverstitch and its charted combo patterns. Use the correct insert or knife state; a chart row for the b48 overlock is not a coverstitch setup merely because both are on the same machine.

Start with the manual’s recommended tensions and stitch length for the selected fabric category, then sew a test strip. The b44 and b48 differential-feed range is 0.6–2.0; the b42 manual lists the same range for stretch or gathering adjustments. A feed ratio that helps a lightweight jersey may produce a different result on a stable woven. Tune a small amount at a time and inspect both sides of the seam rather than treating the dial position as a universal recipe. For coverstitch, the b42 and b48 manuals specifically call out a longer stitch setting than a short ordinary overlock stitch.

Finish and secure each seam correctly

Coverstitch begins and ends differently from ordinary lockstitch sewing. Both the b42 and b48 manuals warn that the looper-thread structure can unravel if pulled at the end. Follow the manual’s method for stopping, drawing the thread tails and tying off the needle and looper threads. For b42 chainstitch work, the manual describes a looper-thread loop that can be undone; that is useful for temporary work but does not provide the same locked seam structure as a conventional household straight stitch. Test the start and end handling before making a visible hem.

For overlock, check the cut edge and thread wrap together. On a b44 or the b48 overlock plan, pins must stay away from the knife path. The manuals advise testing tension on a sample; they do not guarantee that a particular thickness, thread finish or stitch will work without adjustment. Remove loose threads and inspect the trim bin before it overfills.

Clean and lubricate by the model’s instructions

Disconnect the power before cleaning. The b44 and b48 manuals point out that knife action creates lint and trimmings, so brush the looper and knife area often with a dry lint brush. The b42 lacks the overlock cutting knife, but still needs lint removed around its looper and needle plate. Use the lubrication points shown in the exact manual and the specified sewing-machine oil; do not improvise with household oil or spray products.

When comparing used or open-box listings, confirm that the specific machine includes its correct foot, tools, inserts or converter, needle set, dust cover and waste bin where those items are part of the product’s standard contents. The 42, 44 and 48 packages differ, and the accessory image alone cannot prove a seller has every item. Save the selected stitch chart with the machine so a later mode change does not require guessing from memory.

Sources: official b42, b44 and b48 support pages and their linked 2023 English manuals.