Working on a Willcox and Gibbs Automatic Tensioner

Working on a Willcox and Gibbs Automatic Tensioner

Written in late February, 2019

The automatic tensioner can be a little intimidating. Here are some tips for both adjusting, and for disassembly/reassembly. The machine I’m referring to in the text and pictures is from 1914. Willcox and Gibbs machines have a lot of variation in their details, so yours might be slightly different in places.

All photos are clickable for larger versions

(By the way, I’ve written more about my sewing machine collection, including more details about W&G needles, W&G foot controller repair, and more, on my sewing machine collection “blog”.)


Adjusting to eliminate thread loops

Two of my W&G machines were sewing badly, but only for tight stitches.

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For longer stitches they were fine. In the end, all that was necessary was to adjust the tensioner on both machines.

The reason for my thread loops was that the tension was releasing too early as the needle came up, allowing the needle to pull from the spool rather than from the underside of the cloth. With long stitches it wasn’t an issue because the movement of the cloth took up more of the available thread, so there was less for the needle to pull up. With short stitches, the tension was released before the needle had pulled enough.

There’s an adjustment which controls when the tension is released during that up stroke of the needle. It’s just under the tension mechanism, right where my wrench is in this picture:

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There are two flats that can be grabbed with a small 5/16” wrench to do the adjustment. (There probably isn’t room for an adjustable wrench – you’ll need a small open end wrench like I used.)

Warning: if the wrench doesn’t turn relatively easily, then stop!! Don’t force it. The tensioner arm is cast iron, and can be snapped by excessive torque. If the adjuster doesn’t turn easily, then it has either reached the limit of its travel, or it’s stuck. You’ll probably want to remove the tensioner arm to loosen the adjuster.

To fix my problem, I changed the adjustment by just 1/4 turn at a time. Since I wanted the tensioner to release later, I needed to make the control arm shorter, which meant I was turning the adjuster clockwise, as viewed from above the sewing machine. This means that holding a wrench as shown in the picture, the handle would swing from right to left. One of my machines just needed 1/2 a turn of the adjuster, the other needed 3/4 of a turn. Now they both stitch perfectly at all stitch lengths.

(It probably goes without saying, but as a reminder: if you try adjusting, keep careful track of how many turns or 1/4 turns you’ve moved the adjuster, so that you can put it back the way it was if adjusting isn’t the solution.)


Cleaning from the outside

Of course, if there’s a lot of lint or gunk around the outside of the tensioner, that should be cleaned off before doing anything else – enough stuff there can prevent the tensioner from closing properly.

I’ve also been told that the tensioner can sometimes be cleaned adequately without taking anything apart. Amy Adams, from the FB W&G group, says she took folded 800 grit sandpaper (probably emery paper), slipped it between the tensioner plates, and kept at it until a light and a magnifying glass showed nothing but shiny plates. It sounds like her plates had rusted a bit, and had also collected some lint or thread.

But if that doesn’t work, or you just want to be absolutely sure it’s clean everywhere, and not just between the plates, then the tensioner needs to be taken apart and cleaned.


Disassembly

A note about tools: I think I did this with a couple of screwdrivers, a right-angle screwdriver, a pair of needle nose pliers, a hooked dental pick, and some #0000 steel wool.

There’s a good video on youtube, by Ray Elkins which is very helpful, but sometimes still pictures are useful as well. (In that video, Ray happens to have a lot of trouble with the twist-lock clip that lets you get the tensioner apart. If you’re in a hurry, skip the parts between about 3:20 and 7:10.)

In the video, Ray claims that the shaft needs to be removed in order to get to the tensioner. I’ve found that not to be necessary, and it means a lot less disassembly. (The hand wheel does need to come off the shaft, something Ray didn’t have to do.)

If you think there’s any chance you’ll drop your machine while doing any of this, remove the spool pin and spool pin arm and set them aside! There’s a reason they’re often missing on these machines. It’ll make the machine easier to handle in any case.

The first step involves loosening the hand wheel – but don’t try and remove it yet! Getting it loose first is a good idea in case it’s tight – it’s a lot easier to loosen it if you’re not worrying about other loose parts swinging around. So put your long thin screwdriver through the access hole in the hand wheel and loosen the setscrew.

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Once the hand wheel is loose, and looks like it will come off, remove the top of the top bearing collar on the needle lever linkage arm. A right angle screwdriver can be useful here, since otherwise it’s hard to get your screwdriver straight onto those screws.

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You don’t need to remove the bottom bearing collar – the arm will come off with the hand wheel.

Pull the hand wheel off slowly and evenly, taking the needle bar arm along with it, but leaving the tensioner arm behind. If the tensioner arm starts coming along with the hand wheel things will jam up, so go slowly and evenly. When the hand wheel is off, remove the tensioner arm. (This might be a good time to take a wrench to the adjuster, just to be sure it will turn if you need to use it later on. But be sure to leave the adjustment as you found it when you’re finished.)

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Now we’re ready to really tackle the tensioner.

The first thing to be removed on this particular tensioner was a small washer-like disk. I feel like another tensioner I took apart didn’t have this disk, but I may simply not be remembering correctly.

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It was initially (before the above picture was taken) covered (on the bottom, visible, side) with a layer of felt, which quickly disintegrated as I probed. Once I got it out (it’s a snug fit) by poking at the edges, and pulling with a dental pick, I found that the felt went around the rim of the disk, and it had been wired in place. There was just enough of the felt left to cover the rim.

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So… since I happen to have a spare “parts” machine (1904) with an intact tensioner, I took a look to see if that piece was in better shape. It was. These three pictures show this “better” felt-wrapped washer partially dislodged, and then removed. The felt covering is held in place by a thin wire, This works because the “washer” is actually thick enough to have a groove around its rim, which gives the wire something to tighten into. Anyway, hopefully yours looks more like this one than the one I discovered first!

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But now, moving on....

Under that disk, we find the twist lock that holds the tensioner together.

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Here’s the trick with that twist-lock: The center post (which is slotted on this machine, but not on my other spare parts machine), and the short “bridge” piece that spans the oblong hole in the surrounding disk, are essentially one piece, and are rigidly attached to the top cap of the tensioner. The surrounding disk is spring-loaded. If you push on that disk, it frees the bridge piece from the depressed “slot” its sitting in, and you can rotate the cap. When the cap is rotated 90 degrees, the bridge will now line up with the long dimension of the hole in the disk, and can slip through. So the trick is to push on the disk with a slender set of needle-nose pliers, or similar, while rotating the cap with your other hand.

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Fish out what you can at this point, so nothing falls out unexpectedly. In my case, I was able to easily get out the disk, and the first leather (or rubber?) bushing. A small hooked tool is handy at this point. The other lower parts (the spring, with its fixed caps, and the second bushing) were kind of stuck, so I waited on those until I could push them out from the top.

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With nothing holding it, the cap and shaft come out, showing the locking mechanism. There are two washers still on that shaft: one steel, and the other felt. Don’t lose them.

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Now we get to the parts that touch the thread. They all sit on two relatively small posts. The top tension ring is thicker, and comes off first.

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Then next layer has two parts – a smaller, central, grooved disk, and the outer ring, similar to the upper ring, but thinner.

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The top parts are now all gone, so it was time to poke down through and push out the spring and the remaining bushing.

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For completeness, here are almost all the parts that came from the underside of the tensioner, all lined up on my screwdriver. As far as I can tell, the bushings are identical (except for possible wear differences), and the spring is symmetric end-for-end.

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The only thing missing from that picture is the felt-covered washer, which will go in last, after the twist-lock.

At this point in his video, Ray uses a drift and a small hammer to tap out (from the bottom) the metal disk with the small posts that closes off the top of the tensioner cylinder. I don’t see a need for that, unless perhaps you’re planning on stripping and repainting, or unless it’s been oiled and incredibly gunky. Normally it isn’t all that dirty, and you can clean the cylinder well enough with it still in place.


Cleaning

At this point, I use some #0000 steel wool on the metal parts. There should never have been oil in the tensioner, so it’s usually not hard to clean. If the felts have been oiled, I’d soak/wash them very gently with detergent to clean them, and dry thoroughly. Otherwise I just remove any lint by rubbing them gently on a towel.


Reassembly

The two larger rings are the same top and bottom, so they can go back in either way up, but the smaller disk should be installed with the grooved side up. However, I noticed that there were wear marks made by the passing thread on the two facing surfaces of the disks – you can see them in the picture. So when I reinstalled, I flipped them both, in order to start using the fresh surface of the rings.

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I started from the top. First the felt, then the thinner disk and the inner grooved ring (grooves up), and then the thicker disk.

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The cap with its two washers (felt and steel) go in next.

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I seem to have skipped pictures of the installation of the lower parts, but they simply slip in, in the order they appear on the shaft of my screwdriver in that last picture in the Disassembly section.

Once the parts are all in place, you need to once again do the trick with the needle nose pliers – press on the disk, while rotating the top cap 90 degrees in order to get the little bridge piece to sit in its slot again.

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I also didn’t photograph the reinstallation of the felt-covered washer. It just slipped right in, and I could feel it sort of snap into place, with the felt-covered side facing down and out. The felt acts as a cushion against the steel top of the tensioner arm.

The last step is to carefully reinstall the hand wheel. First, turn the shaft as shown, so that the divot that the set screw will tighten into is pointing to the rear of the machine. That way you’ll know where it is when you go to tighten the set screw.

As you slide the hand wheel onto the shaft, the inner cam surface has to insert into the tensioner arm, the top of the needle lever arm has to tuck under the ball on the end of the needle lever, and the set screw needs to stay fairly closely lined up with where you positioned the divot on the shaft. It’s a little tricky, but not impossible.

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That’s it – hope this has been useful!


The End