BABYLOCK SERGER SLOWS DOWN REPAIR links

January 01, 2020

BABYLOCK SERGER SLOWS DOWN REPAIR links

BabyLock sergers are fantastic, especially the vintage BabyLock Pro Series, all metal (except plastic face plate, covers, and tension knobs), but like all mechanical items, they can slow down, mostly from dry oil, or, this stitch length eccentric CAM, seizes up, inside the feed dog BUSHING.

Router bushing has the stitch length eccentric cam, under the router bit, which needs the outer rim polished, with a drop or two of oil, and the finest dremel bit, or sandpaper. Above it, to the left, in photo, is the feed dog bushing, which the cam must rotate within.

I have polished the inner rim of the bushing, and am finishing polishing the inner rim, with jeweler's rouge, a denim impregnated with diamond dust. (Black rolled up strip of jeweler's rouge.)

1. Remove plastic cap with red arrow, then remove large black screw to left of red dot, set it, and the stitch length numbered part aside, then you will be able to see the stitch length eccentric cam. If it hasn't seized up, fully, it may be easily removed, but if seized, you will need to loosen a set screw, and remove a couple other parts, a pin/bearing - held in by set screw, to get the frozen seized up parts out, so you can tap out the eccentric cam and bushing, for easier polishing, with a dremel, or fine sandpaper.

(Models with differental feed DF have a few more parts than models without differential feed, but the removal of the main feed dog bushing is the same. Loosen the set screw holding the pin/bearing, no need to remove C clips, pin/bearing slides out, allowing bushing removal. DF has a spacer on pin/bearing.

DF also has a nut, spacer and screw, for the DF extra arm which activates the front feed dog section of DF.)

If the motor runs fine, without the belt attached to the handwheel, these vintage BabyLock sergers have one area that just needs a little extra care, to get it back in good running shape!

1. Remove plastic cap with red arrow, to access screw under it.

2. Remove screw to the left of red dot, holding stitch length setting in.

3. Loosen set screw (do not remove it, only loosen it until you can slide pin/bearing out - you do not need to remove C clip.) This model does not have differential feed.

4. This is the entire FEED DOG BUSHING with the pin/bearing that slides out, after you loosen the set screw that held it in place. Notice the blocks on the stitch length cam were on the inside. This cam was completely seized, so did not fall out.

There is a metal STITCH LENGTH ECCENTRIC CAM, inside the FEED DOG BUSHING, of different types of metal, so over time, they have differing rates of expansion and contraction, when exposed to heat and cold, so the stitch length eccentric cam "grows", and/or the feed dog bushing responds enough differently, that they build up metal burrs, and/orget so stuck to each other, which make it so they slow the serger down, or even seize up, as soon as it warms up!

After polishing with dremel, I finish polishing smooth, with jeweler's rouge, inside the bushing, as shown here, then outside of cam.

5. Using superfine flat sided dremel bit, and a drop or 2 of oil, polish the inside of the bushing, and the outside of the stitch length cam. They need to be super smooth, and slip easily together, with grease (Super Lube) and if necessary, a drop or two of oil, cam MUST spin easily inside bushing, and slip in and out of each other, before reassembling.

If stitch length cam is seized (green arrow shows cam after I tapped it out), inside the bushing (yellow arrow), oil (or WD40) between them, then try tapping it out of the bushing, by setting it on a set of pipe wrench pliers (blue arrow), opened enough to support the bushing, but not under the cam. Use a rubber mallet to tap the cam down, into the open area.

If the cam doesn't come completely out, set a 5/16" socket (purple arrow) on the cam, and tap it again, with rubber mallet, until cam is free.

Models without differential feed, look like this. I am holding the pin/bearing that easily slides out, once set screw is loosened. Notice the blocks on inner part of stitch length cam,does not gall out, when seized.

"Due to the disparate metals of the stitch length eccentric cam and linkage, the clearance between the two parts diminishes. The lighter colored cam has to be extracted and polished with emery until the cam spins freely in the linkage bore." Wayne Pedersen

Here is a link to instructions for repairing it-

BabyLock serger hand wheel hard to turn

Babylock Serger slows down hard to turn handwheel repair info

I am including photos of other instructions I printed out, for repairing sergers, for myself, as well as others!

Serger repair information photos

Andy Ruina Feb. 17, 2020 on Facebook Sewing Machine Collect & Repair Lounge

"Successful Babylock Serger repair. BL4-736D. This is a four thread serger from 1970 or 1980 or so. Made by Juki.

Symptom of Problem: Makes a good stitch, runs well for about 10 seconds and then slowly grinds to a halt. Let it rest and the problem repeats.

I don't know how or where to post this so that people can find it. I am posting that which I wish I could have found before. Over the years, here and there on the internet, others seem to have had this problem. I did find the solution below, I don't remember where, but I didn't understand it until I did it myself.

Short version of the solution. Take off the left side of the cover and the machine bottom. At the left side of the machine is a stitch length regulator. Pry off (with a knife) the plastic cap on the cover(with an arrow marked on it). Unscrew the big screw that is revealed. Pull apart that which you can. There is a round piece, about 1" diameter, that slides in a round hole. That piece was tight in that hole. With fine grit sandpaper and a dremel tool grind the two pieces down until they slide easily in each other. Grease and reassemble. We also had to adjust the feed dog timing by unclamping that same piece from the main shaft, and turning until the feed dogs were moving cloth only when the needles were out.

It stitches neatly, smoothly and fast after this repair.

How did we locate the problem? First we loosened the the rotating parts for the feed dog from the main shaft. The motor then ran tirelessly. So the problem is/was somewhere in the feed dog area. Then we reclamped the rotating feed-dog stuff to the main shaft. Then we set the stitch length to zero, so all the feed-dog stuff wasn't moving. And the problem returned. Thus the problem had to be in the part that connected the main shaft to the feed dog stuff because that was the only thing sliding in that general area of the machine.

Because we are lucky, that part is at the protruding end of the main shaft and all comes apart easily once you take off the plastic cap and unscrew that main screw (the one under the plastic cap).

The cam, that eccentric sliding part, was quite jammed, so taking it apart took some little effort, pushing on one side or another. But then it came apart. And dremmeling and sand paper got it so it could go again together and turn without jamming. And grease made it so it would slide smoothly.

What caused the problem? The consensus seems to be that the machine must have sat for a few decades unused, with lubricant evaporating out. Then it was run too hard and too fast and too long. Then the parts got too hot and either galled (metal melting on metal) or got distorted. We couldn't see any galling.

Besides the covers, this repair only involved removing a single screw. And, to get the feed dog timing, which was messed up in the diagnosing phase, we had to loosen and tighten two set screws to the main shaft.

In the end, if I had to do the identical repair again, and no diagnosing, the whole thing would be about 1/2 hour. No complicated disassembly. And only one simple timing adjustment.

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I realize that everytime anyone fixes anything they have an adventure like this. So there are 10,000 potential tips like this out there for 1000 different machines. But it is nice finding tips on the internet. So I leave this one for someone else to find.

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I am still hoping for ideas about where to get information like this about sergers. Mark Sumpter wrote a great introduction to serger stitches. Now we (I) would like some information about the machine(s)."

Another site for serger repair information is She'saSewingMachineMechanic

Shes a sewing machine mechanic

BabyLock Pro Line 838D

BABY LOCK BABYLOCK 5360E

INFORMATION ON BUSHING REPAIR BLOGS

Baby Lock Babylock BL4-736

BabyLock 5360D BL4-5360D
Remove large black screw to left of red dot, set it, and the stitch length numbered part aside, then you will be able to see the stitch length eccentric cam.

If it hasn't seized up, fully, it may be easily removed, but if seized, you will need to loosen a set screw, and remove a couple other parts,to get the frozen seized up parts out, so you can tap out the eccentric cam and bushing, for easier polishing, with a dremel, or fine sandpaper.