Juki Maintenance Notes
The Juki 5550-6 has a stationary knife, a moving knife, and a thread guide. If they get dull, you will find that the thread does not cut and a rat's nest can build up in the needle plate. The stationary knife may be resharpened once, but I don't think we have a sharpening stone. Its easiest to replace all three at once. I found our thread guide was broken too. If sewing heavy thread, the knife will only last 3 months. It takes under an hour to replace these parts. Keep the knife area clean by removing the needle plate and blowing compressed air on the knives. This helps a lot.
Page 7, Section 20 of the manual has a lame description of this part of the machine. Manual: Media:Juki-ddl-5550-6.pdf
I bought a pack of all three parts for $18 on eBay. They are Strong H brand and may not be as good as Juki brand parts, but so far (after one day) they are better than the dull knives we had. I searched ebay for Juki 5550-6. Its listed as an 'Undertrimmer Knife Set'. Original Juki parts would cost $38+tax and a trip to Apparel City (I couldn't find Juki brand parts online).
Caution! Unplug the machine!
You need a #3 allen wrench and this wrench with a 4.5 flathead bit. and a can of compressed air. The small flathead screwdriver used for needle changes (in the grey drawer beneath the Juki) is useful too.
Remove needle plate.
Clean the area with compressed air (use air compressor in the dirty shop if there is no canned air).
Note current adjustment position of the stationary knife... This is how we probably want the new one installed.
Remove stationary knife first, then remove the tiny thread guide screw and remove the thread guide, then loosen the allen screw and slide the moving knife toward you.
The wrench pictured above makes it possible to loosen and tighten these small screws at the tough angle. I found the tools in the dirty shop in the top right drawer. The small wrench was in with the ratchets.
Dab a drop of sewing machine oil on the moving knife with a cotton swab. (I'm not sure if this is needed. It may just attract dirt. Considering the abuse it takes, it's probably a good idea).
Replace all three parts in the reverse order that you removed them. A dab of something sticky (I used solder rosin) on the needle replacement flathead screwdriver can keep the tiny screw captive as you replace it into it's hole.
- Last Replaced (log replacement date here)
May 1, 2011 - Chris Murphy