Parts for specific machines
Why won't my serger cut cleanly? Knife position and edge first
Read this to decide whether your serger needs cleaning and realigning or a new knife. It shows which knife five Janome, Brother and SINGER manuals give replacement steps for, the setting for a new one, and each maker's dealer or service network for the part.
The short answer
It may only need cleaning and adjusting. Janome's books for the 8002D, 1110DX and MyLock 634D list exactly two causes under "The fabric is not cut neatly": the upper knife's position is not adjusted properly, or the upper knife is dull. Only the second calls for a new part. So clean the knife area and check where the knife sits before you order anything.
Which knife a manual gives replacement steps for depends on the machine. Those three Janome books cover the upper knife only. They say the lower knife lasts over a year in normal use, though running over a pin or another hard object may mean replacing both. Brother's 1034D manual and SINGER's S0230 manual give steps for either knife, and SINGER's remedy for worn or damaged cutters is to replace one or both. Read the knife section of your own model's manual before you buy.
What five serger manuals say about a poor cut
| Manual | How it describes the problem | What it says to do | Replacement steps given for | Setting for a new knife | Width control |
|---|---|---|---|---|---|
| Janome 8002D, 1110DX and MyLock 634D | Fabric not cut neatly | Check the upper knife's position; if the upper knife is dull, replace it | Upper knife only. The lower knife lasts over a year in normal use; running over a pin or hard object may mean replacing both | Upper knife edge overlaps the lower knife edge by 0.8 to 1.5 mm (3/64 in.), with the upper knife at its lowest point | Cutting width dial moves the lower knife, with the upper knife locked down first |
| Brother 1034D | Says worn or blunt knives will make the material pucker or the stitches uneven | A knife that cuts a single strand of thread at its front or rear is sharp enough; replace the knives when they are blunt | Upper knife and lower knife | Upper knife down and in front of the lower one, 0.5 to 1.0 mm from the lower knife's edge. The figure on the same page also shows a 1.2 to 1.7 mm dimension; set the knife as that figure shows. Lower knife edge flush with the needle plate | Stitch width lever: R4.5 to 7 mm on two-needle models. The knife chapter also uses it to move the retracted upper knife to a fabric-guide position |
| SINGER S0230 (same manual as S14-77, S14-78, S14-79) | Irregular trimming | Check cutter alignment; replace one or both cutters if damaged or worn out | Lower (stationary) cutter and upper cutter, each when it becomes blunt | Lower cutter blade flush with the stitch plate; upper cutter front edge about 0.5 to 1 mm lower than the stationary cutter's cutting edge | Cutting width lever: 3 to 5 mm on the right needle alone, 5 to 7 mm on the left needle alone |
Check in this order before you buy
- Unplug the machine. The knife replacement and cleaning steps in these manuals start there.
- Clean the knife area. The 8002D book has you open the looper cover and brush the trimmings out toward the front, and says a vacuum cleaner may be used.
- Turn the handwheel slowly toward you and watch the upper knife pass the lower one. If it doesn't move correctly, SINGER's S0230 manual says to look for fabric or waste thread stuck between the blades.
- Check the knife position against the figure in your own manual; the table above gives the figures from these five. In the Janome books a wrong position is cause one, and the fix sits in the replacement steps: with the upper knife at its lowest point, loosen the hexagonal bolt, set the overlap, then tighten the bolt firmly.
- Test the edge. Brother's 1034D manual says a knife that cuts a single strand of thread at its front or rear is sharp enough.
- If the knife fails that test, or on a Janome the position is right and the cut is still ragged, replace the knife your manual names and set it to that manual's figure. On a 1110DX or MyLock 634D, check the standard accessories first: Janome lists a spare upper knife among them for both models, and both books have you keep the accessory box in the waste chip box.
- On the Brother 1034D and SINGER S0230, the manuals give steps for both knives but don't say how to tell which one is blunt. Brother says to replace the knives when they are blunt. SINGER's remedy is to replace one or both cutters, and its manual says to consult your service agent if a change gives you trouble.
On these Janome models, the width dial moves the other knife
On the 8002D, 1110DX and MyLock 634D, the cutting width adjusting dial moves the lower knife, not the upper knife that works up and down as you sew. Janome's steps: unplug, open the looper and side covers, lock the upper knife down, then turn the dial. Clockwise moves the lower knife right, for a cut that is too narrow; counterclockwise moves it left, for one that is too wide. Then lock the upper knife back up. The 8002D and 1110DX books give a range of about 3.0 to 5.0 mm from the right needle.
The lock is the upper knife release knob, item 23 in the 8002D's parts list; the dial is item 24. Pushed right and turned toward you, the knob locks the upper knife down and out of use. Pushed right and turned away from you, it locks the knife up and cutting. Items 27 and 28 are the upper knife and the lower knife, two separate parts.
Width is not one of Janome's two causes of a ragged cut. It is for a cut that sits too narrow or too wide against the seam. And don't assume the Janome arrangement holds on another machine. Brother's 1034D manual sets width with a stitch width lever, R4.5 to 7 mm on two-needle models, and its Stitch Width section names no knife. The lever comes up again in the section on retracting the upper knife: the retracted knife's top sticks out above the needle plate as a fabric guide, and the manual says the stitch width lever moves it to the guide position you want. Check your own manual.
Which knife to order, and where
None of the five manuals prints a part number for either knife. Order by model number and by the manual's name for the part: upper or lower knife on the Janome and Brother machines, upper or lower cutter on the SINGER. A listing that says only that it fits most sergers does not show that it fits yours.
- Janome: Janome America says it distributes sergers and accessories through authorized dealers and does not sell directly to the public by mail order or online. Its online serger accessory catalog lists no knives. Ask a dealer for the knife your model's manual names; on the three Janome models above, that is the upper knife. Janome's manuals page, linked below, also links its Find a Dealer search.
- Brother: the Consumables & Options page for the 1034D lists only optional serger feet. Brother's Store Locator, linked below, finds its authorized dealers and service centers.
- SINGER: SINGER's help center says many spare parts are sold on singer.com and that its authorized dealers carry a wider range, but its online accessory collection lists no serger cutter. The S0230 manual says to consult your service agent if a cutter change gives you trouble, and SINGER says its Warranty Centers in the US and Canada supply SINGER parts and repairs. The Warranty Center search is linked below.
Traps
- Pins. Janome says running over a pin or another hard object may mean replacing both knives at once. SINGER warns that sewing over pins will damage the cutter edges, and has you place pins to the left of the presser foot.
- No schedule. None of these manuals gives a replacement interval; each ties replacement to a dull or blunt knife. The only durability figure is Janome's, for the lower knife: over a year in normal use.
- The thread cutter is a third blade. The 8002D's separate thread cutter, for the thread chain, goes blunt as loose threads build up, its manual says; clear them out. A new knife won't fix that.
- Not every bad seam is the knife. Janome puts skipped stitches down to the needle (bent, blunt or wrongly inserted) or to threading; see how to read a needle's system and size. Brother says worn or blunt knives will make the material pucker or the stitches uneven, but its troubleshooting table lists thread tension and threading for those same symptoms.
What to check on your own machine
- The model number, to find the right manual and order the right part. Check the machine's labels: Brother says the 1034D's serial number is on a silver sticker on the back of the machine, and SINGER's S0230 manual refers to a plate under the machine that gives its voltage. Then get the manual for that exact model.
- The knife section of that manual: Replacing the Upper Knife and the separate Cleaning Upper Knife Area in Janome's Care of Your Machine chapter; Replacing the knives in chapter 15 of Brother's 1034D manual; Replacing the Lower Cutter and Replacing the Upper Cutter under SINGER's Machine Maintenance.
- No manual? Janome's manuals page is linked below. If your machine isn't on it, the page sends you to Janome's list of retired machines, which includes discontinued MyLock sergers such as the 134D, 334D, 434D, 534D, 644D, 734D and 744D. Brother's 1034D User's Guide is also linked below. SINGER's serger manuals, the S0230's among them, are on the Manuals page at singer.com.
Check it on your own equipment
These take you to the manufacturers and standards bodies the page draws on, so you can look up your exact model.
- Official support page
Janome serger instruction books (Software & Manuals) (opens in a new tab)Janome's manual library, with direct PDF links for its serger models, including the 8002D, 1110DX and MyLock 634D. In each of those three books, the troubleshooting table lists the two causes of a poor cut, and the Replacing the Upper Knife section gives the 0.8 to 1.5 mm setting. If your machine is not listed, the page sends you to Janome's list of retired machines, and its Find a Dealer link searches the authorized dealers Janome distributes through. — www.janome.com - Official support page
Brother 1034D manuals (opens in a new tab)Brother's download page for the 1034D User's Guide (PDF, 8.79 MB). Chapter 15, Upper Knife and Lower Knife, has the single-strand sharpness test on page 55, and the steps and figure for replacing either knife on page 56. — support.brother.com - Official support page
Brother Store Locator: dealers and service centers (opens in a new tab)Brother's search for its authorized dealers and service centers. Choose Home Sewing and Embroidery as the product type, then Dealer or Service Center and a distance. Ask for the knife by your model number and the manual's name for it. — www.brother-usa.com - Official support page
SINGER Warranty Center Locator (US and Canada) (opens in a new tab)SINGER's search for its Warranty Centers in the US and Canada, which SINGER says provide repair services and SINGER parts. The S0230 manual says to consult your service agent if a cutter change gives you trouble. — www.singer.com
What this page does not tell you
- Every figure on this page comes from the named maker's manual or website. Set any knife to the figure in your own model's manual.
- The table covers five manuals from three makers. Other models, including other models from the same makers, can differ in which knife is meant to be replaced, how the width is set and the alignment figure. Your own model's manual governs.
- No part numbers are given because none of these manuals prints one for either knife. Order through the maker's dealer or service network, using your model number and the manual's name for the part.
- These manuals give no replacement schedule for the knife they tell you to replace, so this page can't say how long a knife should last. Go by the symptom and the checks above.
- Brother's 1034D manual doesn't say what the 1.2 to 1.7 mm dimension in its knife figure measures. Set the knife as that figure shows.
- If you can't tell which knife is blunt, or setting one to within a millimeter is more than you want to take on, SINGER's manual says to consult your service agent, Janome directs service questions to its authorized dealers, and Brother's locator lists its service centers.
Sources
19 documents, each with the facts on this page it supports. Manufacturers revise specifications, so every source is dated — open it before you buy.
- Janome's 8002D troubleshooting table lists exactly two causes for 'The fabric is not cut neatly': the upper knife's position is not adjusted properly, and the upper knife is dull, for which the remedy is to replace the upper knife.
- Of Janome's two listed causes, only the dull upper knife is paired with replacing a part; the position cause points to the adjustment on page 36.
- The 8002D Care of Your Machine chapter has a Replacing the Upper Knife section and a separate Cleaning Upper Knife Area section, both on page 36, and no section for replacing the lower knife.
- The 8002D book says the lower knife will last over one year in normal use, and that running over a pin or hard object may require replacing both upper and lower knives at the same time.
- When fitting a new upper knife on the 8002D, turn the handwheel until the upper knife is at its lowest position, loosen the hexagonal bolt, set the upper knife edge to overlap the lower knife edge by 0.8 to 1.5 mm (3/64 in.), then tighten the bolt firmly.
- The 8002D cutting width procedure: unplug, open the looper and side covers, set the upper knife to the down position, turn the cutting width adjusting dial to position the lower knife (clockwise moves it right when the width is too narrow; counterclockwise moves it left when too wide), then set the upper knife to the up position.
- The 8002D's cutting width can be adjusted approximately 3.0 to 5.0 mm from the right needle position.
- Janome's cutting width adjustment is for a cutting width too narrow or too wide against the seam width, and width is not among the two causes listed for fabric not cut neatly.
- In the 8002D Names of Parts list, item 23 is the upper knife release knob, item 24 the cutting width adjusting dial, item 27 the upper knife and item 28 the lower knife.
- To deactivate the 8002D's upper knife, turn the release knob toward you while pushing it to the right, which locks the knife in the down position; to activate it, turn the knob away from you while pushing it to the right, which locks it in the up position.
- On the Janome models, the upper knife is the knife driven up and down as the machine turns: the fitting steps have you turn the handwheel until the upper knife comes to its lowest position. SINGER's S0230 manual calls its lower cutter stationary.
- Cleaning Upper Knife Area on the 8002D: unplug, open the looper cover and remove the waste pieces to the front with a lint brush; a vacuum cleaner may be used for the upper knife area.
- The 8002D's knife replacement, knife-area cleaning and cutting width procedures each begin with turning off the power switch and unplugging the machine.
- The 8002D's thread cutter, used to cut the thread chain, becomes blunt as loose threads build up, and the manual says to remove the loose threads collected in it.
- The 8002D troubleshooting table lists skipped stitches as caused by a bent or blunt needle, incorrect threading, or an incorrectly inserted needle.
- The 8002D's standard accessories are listed as screwdrivers, tweezers and a set of needles; no knife is listed.
- The 8002D book prints part numbers only in its optional parts list, for feet and attachments, and none for either knife.
- Which knife a manual gives replacement steps for depends on the machine: the Janome 8002D, 1110DX and MyLock 634D books cover the upper knife only, while the Brother 1034D and SINGER S0230 manuals cover both knives.
- Across the five manuals, none gives a replacement interval; each ties replacement to a dull or blunt knife, and the only durability figure is Janome's for the lower knife, over one year in normal use.
- The alignment figures differ by maker (Janome 0.8 to 1.5 mm overlap, Brother 0.5 to 1.0 mm clearance, SINGER about 0.5 to 1 mm) and each is stated only for the models its manual covers.
- None of the five manuals prints a part number for either knife.
- A listing described only as fitting most sergers does not establish fit for a given model: none of the five manuals gives a cross-model knife specification, so fit has to come from the model's own manual or the maker's dealer or service network.
- Janome's 1110DX book carries the same troubleshooting entry for fabric not cut neatly, with the same two causes, referring to page 86.
- The 1110DX Care of Your Machine chapter lists Replacing the Upper Knife and Cleaning Upper Knife Area (page 86) and no lower-knife replacement section.
- The 1110DX book carries the same lower-knife statement: over one year in normal use, and both knives may need replacing after running over a pin or hard object.
- The 1110DX book gives the same upper-knife setting: overlap of 0.8 to 1.5 mm (3/64 in.) with the lower knife edge at the knife's lowest position.
- The 1110DX cutting width procedure is the same: upper knife set down, dial moves the lower knife right (clockwise) or left (counterclockwise), then upper knife set up.
- The 1110DX's cutting width can be adjusted approximately 3.0 to 5.0 mm from the right needle position.
- The 1110DX's standard accessories include an upper knife, and the book has you insert the accessory box into the waste chip box.
- The 1110DX book prints part numbers only in its optional parts list, for feet and attachments, and none for either knife.
- Janome's MyLock 634D book carries the same troubleshooting entry for fabric not cut neatly, with the same two causes, referring to page 34.
- The MyLock 634D Care of Your Machine chapter has Replacing the Upper Knife and Cleaning Upper Knife Area (page 34) and no lower-knife replacement section.
- The MyLock 634D book carries the same lower-knife statement: over one year in normal use, and both knives may need replacing after running over a pin or hard object.
- The MyLock 634D book gives the same upper-knife setting: overlap of 0.8 to 1.5 mm (3/64 in.) with the lower knife edge at the knife's lowest position.
- The MyLock 634D cutting width procedure is the same: upper knife set down, dial moves the lower knife right (clockwise) or left (counterclockwise), then upper knife set up.
- The MyLock 634D's standard accessories include an upper knife, and the book has you insert the accessory box into the waste chip box.
- The MyLock 634D book's optional parts list names feet and attachments without part numbers, and no knife part number appears in the book.
- Brother's 1034D manual says to unplug the power cord from the wall outlet before removing the knives.
- Brother's 1034D manual says worn or blunt knives will cause the material to pucker or the stitches to be uneven.
- Brother's 1034D manual says that if one strand of thread can be cut off in front of or at the rear of the knife, the knife is sharp enough, and that when the knives are blunt they should be replaced.
- Brother's 1034D manual gives steps for replacing both the upper knife and the lower knife.
- When fitting a new upper knife on the 1034D, turn the pulley until the upper knife is down, check it is in front of the lower knife, and set the clearance to the lower knife's edge at 0.5 to 1.0 mm.
- The figure accompanying the 1034D knife-replacement steps on page 56 shows a 1.2 to 1.7 mm dimension in addition to the 0.5 to 1.0 mm clearance given in the text.
- When fitting a new lower knife on the 1034D, position it so its edge is flush with the needle plate; the manual says upper and lower knife alignment matters for sharp cutting.
- Chapter 15 of the 1034D manual, Upper Knife and Lower Knife, contains Retracting upper knife (page 55) and Replacing the knives (page 56).
- Under Retracting upper knife, the 1034D manual says to move the knife lever to the left when the upper knife is not used; the top of the retracted upper knife then sticks out above the needle plate as a fabric guide, and the stitch width lever is adjusted to move the upper knife to the desired guide position.
- The 1034D manual's Stitch Width section says the stitch width lever, on the left side toward the front, sets the width between R4.5 mm and 7 mm on two-needle models, and does not mention a knife; on one-needle models the width is factory set to 3.5 mm.
- The 1034D troubleshooting table gives thread tensions not adjusted properly for stitches that are not uniform, and thread tension too tight or improper or tangled threading for puckered fabric.
- The 1034D manual's accessories page gives part numbers for included and optional accessories, none of which is a knife.
- Neither the Brother 1034D manual nor the SINGER S0230 manual says how to tell which of the two knives is the blunt one; Brother says to replace the knives when blunt, and SINGER's remedy for worn or damaged cutters is to replace one or both.
- Brother's Consumables & Options page for the 1034D lists only optional serger/overlock feet.
- Brother's Store Locator finds authorized dealers or service centers by product type (including Home Sewing and Embroidery) and distance, and Brother says its dealers help customers purchase or receive support.
- Brother's 1034D manuals page offers the 1034D User's Guide as a PDF download (8.79 MB).
- Brother's support answer for the 1034D and other listed models says the serial number is on a silver sticker on the back of the machine, beginning with the letter U under the barcode.
- SINGER's manual covers the S14-77, S14-78, S14-79 and S0230.
- SINGER's S0230 troubleshooting under Irregular Trimming lists cutters not in proper position (check alignment of cutters) and cutters damaged or worn out (replace one or both cutters).
- SINGER's S0230 manual says the stationary lower cutter should be changed when it becomes blunt, that the new lower cutter's blade should be flush with the stitch plate, and to consult a service agent if there are difficulties.
- SINGER's S0230 manual says the upper cutter should be changed when it becomes blunt, with the new cutter's front edge about 0.5 to 1 mm lower than the cutting edge of the stationary cutter.
- SINGER's S0230 manual says to turn the handwheel slowly toward you to check that the upper blade moves against the lower blade and, if it does not, to check for fabric or waste thread stuck between the blades.
- SINGER's S0230 manual says to insert pins to the left of the presser foot and warns that sewing over pins will damage and might destroy the cutter edges.
- SINGER's S0230 cutting width lever adjusts width within 3 to 5 mm with only the right needle and 5 to 7 mm with only the left needle.
- SINGER's S0230 manual places Replacing the Lower Cutter and Replacing the Upper Cutter under Machine Maintenance, and its accessories list contains no cutter and no cutter part number.
- SINGER's S0230 manual begins its cleaning instructions and both cutter replacement instructions with turning off the main power switch and unplugging the machine.
- SINGER's S0230 manual refers to a plate under the machine that indicates its voltage.
- SINGER says its Warranty Centers in the US and Canada provide repair services and SINGER parts for its sewing machines.
- SINGER's manuals page lists serger manuals, including the S0230 with a PDF link.
- SINGER's help center says many accessories and spare parts are sold directly on singer.com and that its authorized dealers carry an even wider range of accessories and parts.
- SINGER's online accessory collection lists no serger knife or cutter.
- Janome America says it distributes sewing machines, sergers and accessories through authorized Janome dealers and does not sell directly to the public by mail order or the Internet.
- Janome's support page directs service issues and product purchases to authorized Janome dealers.
- Janome's online Serger Accessories category, 26 products over three pages, lists feet, guides, attachments and a waste chip box, and no knives.
- Janome's Software & Manuals page links instruction books for sergers including the 8002D, 1110DX and MyLock 634D.
- Janome's Software & Manuals page tells visitors whose machine is not listed to check its Retired Machines list, and links to Find a Dealer.
- Janome's retired models page links instruction books for discontinued sergers including the MyLock 134D, 334D, 434D, 534D, 644D, 734D and 744D.
- Janome's Find a Dealer page searches for Janome dealers.