Setting the Timing of the Hook
This is only scary for the first time (or two) you do it. Lori would be one of the few experienced longarm quilters to escape this job. She has one magic word, though, that seems to get the job done ... "Mi-ike!!"
"The Hook" may refer to either the rotating assembly as a whole or to the business end of it - the wedge-shaped pointy bit that does the job of plucking loops of thread off the back of the needle. In this picture the pointed bit hidden under the hopping foot is part of "the shield" and the pointed bit that is visible is the tip of the hook itself.
Note that the hook assembly is secured to the shaft coming out of the gearbox by three largish screws - the screwdriver is on one of them. The inside bit of the hook assembly rotates while the outside is held stationary by a retaining finger seated part-way into the notch just visible at the front of the hook assembly.
Inspecting the hook is easy. If you have a problem with missed stitches or there is a clicking or clanking or crunching noise coming from that end of the machine you really HAVE to do this. The most common cause of throwing the timing out is hitting a pin.
The shaft into which you screw the needle is called, appropriately, the needlebar. Wind the needlebar right down using the forward thumbwheel. Where the needlebar emerges from the machine through a bronze bushing you will see circular marks scored around it: these are the Timing Marks. There are five of them on most machines.
So you need to know the theory of what it is you’re looking for. Here it is:
- In turning the mechanism by hand in a clockwise direction as you look at it from the front, the needle will descend to its lowest point as in the picture.
- At this stage you need to make a couple of observations: how much of the needle’s eye can you see when looking straight-on through the front of the hook (allowing for parallax ’cos it’s difficult to get your head in the right position) and, how many timing marks can you see at the top of the needlebar where it vanishes into the bronze bushing? If the answers are: "nearly the whole of the eye" and, "I can just see the 5th or top-most timing mark peeping out of the bushing" then you can carry on. If one of these things isn’t happening we will deal with it below. If you didn’t understand the question then read on. We’re only trying for an overview here.
- Continue winding slowly in a forward direction until the needle has risen 5/64". By happy coincidence this is exactly the gap between the 5th and 4th timing marks which are scribed on the needlebar. In other words you just need to wind on until the 4th timing mark occupies the same position that the 5th timing mark did when the needle was at its lowest point.
- THIS is the critical point when THREE things must come together: [1] the 4th timing mark is as described above, [2] looking from the front, the tip of the hook is precisely behind the needle in the scarf (the flat area just above the eye of the needle), [3] looking from the side across the face of the scarf, there is only the tiniest weeniest bit of daylight showing between the tip of the hook and the scarf. If and when all this checks out then your timing is set up correctly. If not, read on.
Other things that can happen: not directly related to hook timing:
- The collar on the shaft where it emerges from the gearbox is allowing the hook to move in and out - loosen the 1/8" grubscrew and re-seat the collar closer in towards the gearbox
- Retaining finger not firmly in the slot at the top of the outer (stationary) part of the hook. NOTE - this finger should be set NO MORE than half way into the slot because the thread needs to get around the end of it.
- Excessive play in the entire mechanism when working the forward thumbwheel with one hand against the hook gripped firmly in the other hand - on three occasions in eight years I have known the rubberised union between the motor and the lower shaft to have worked loose.
- Can’t get the throat plate off once screws are out - position point of screwdriver underneath plate and thump handle of screwdriver.
Undoing the throatplate
I find a 10X jewellers loupe an extremely useful tool. Many may think it is overkill but this is high speed precision machinery we’re dealing with here.
Re-Setting the Timing
You should make sure the power to the machine is turned off before you start this.
If you loosen off the three big screws that hold the hook assembly onto the shaft coming out of the gearbox then the hook should be movable both around and along the shaft. It is therefore just a matter of positioning it in the correct place before re-tightening the three big screws. Easy!! Some tips:
In the first picture of this article the screwdriver is resting on the one screw that you can see when things are lined up: we might call this the principal screw. Once you have all three screws loosened it may help if the principal screw wasn’t quite loose so that you have something to work against. It’s really annoying to get things well positioned only to have them flop around as soon as you let them go or start to tighten the screws.
Start by winding the needlebar in a forward direction until it gets to bottom then rises that 5/64" - ie the 4th timing mark is now where the 5th mark was when the needlebar was lowest. Call this the critical point. If you can hold the needlebar steady (use the thumbwheel perhaps) while you rotate the hook assembly on the shaft so that the tip of the hook comes round to the scarf of the needle then you’re halfway there. If it is a little stiff to rotate, just back off the principal screw a tad. We only need a little backpressure, not to have to struggle against it.
Once you have the tip of the hook behind the scarf of the needle with the timing marks still in the critical position it only remains to adjust the gap between scarf and tip by sliding the hook along the shaft so that there is the merest sliver of daylight showing. Any closer and they would touch. In technical parlance - half a gnat’s whisker away.
To this point I would have used my jewellers loupe to
- Examine the precise amount of the 5th timing mark showing when the needlebar was at its lowest
- Ensure that the 4th timing mark was in that exact same position. I can eyeball the alignment of hook behind needle from the front of the machine (the eyes aren’t that far gone just yet)
- Check from the side that the gap between the tip of the hook and the scarf of the needle is minimal.
Nip up the principal screw when you think everything is set up properly. The other two big screws could be nipped up too but I like to check that the process of tightening the screws is not distorting the set-up as I go. I will check a couple of times while I’m tightening screws that things are still lined up right. Do the three screws up as tight as you can.
Wind the mechanism over by hand watching closely (a loupe is good here) to seem the set-up working dynamically. If it seems good then turn your machine on a try a single stitch. OK? Now let the machine run slowly and listen for any "tick-tick-tick" noise as in hook-touching-needle type of noise. You can check this more carefully by holding the blade of a large screwdriver to the body of the machine with the handle of the screwdriver held to your ear. Any mechanical knocking sound will be quite audible like this.
Congratulations. You survived!!
Contingencies
What if: Your needle seems too low or too high?
Check first of all that the needle is properly inserted as high up as it will go. Check to see if there is a build-up of lint at the top of the hole the needle goes into (there is a cross-ways hole above the needlebar thread guide that you can clean out). If you need to raise or lower the needle there is a hole in the front plate that mounts the handlebars. When the needlebar is right down a slot-headed screw appears behind this hole. The screw tightens a clamp which holds the top of the needlebar at this height. CAUTION - always keep a grip on the needlebar when loosening this screw. If the needlebar slips out of its clamp you will have to remove the side cover or even the handlebars to get it back in. It is not necessary or desirable to loosen off the screw any more than you need in order to gently twirl the needlebar between your fingertips. In this twirling motion you can work the needlebar up or down to the position you need. Be careful that the needle finishes facing the same way it did when you started - straight on, hopefully. This will avoid a problem that arises where the needlebar threadguide hits the elbow of the hopping foot. How high should the needle eye be? This is fundamental to perfect timing. Fractions of a millimeter make all the difference. For many years I have been setting hooks as recommended by the factory ie - you start by being able to see half the eye of the needle through the front of the hook. However, I often found the clearances worked out better if the timing was slightly advanced (tip of the hook gone beyond the scarf at the critical point). Then I read an article that said you should start off by being able to see the whole eye of the needle and have since been finding that I don’t need to do advanced any more. Everything seems to fall into place. You try whichever way seems best to you.
What if: you can’t see the 5th timing mark at all?
If you can see the requisite amount of needle’s eye (somewhere between a half and a whole of the eye) when looking through the front of the hook then it may just be a question of the bush being set too low. The height of the needle is the really important thing to get right here.
You may just like to check the condition of the throatplate before you replace it. In even the best-regulated circles throatplates often get jagged longitudinal grooves scraped down the inside of the hole. These can be a major cause of top thread breakage and random loopies on the back of your quilts. Here - I’ve saved you a picture of a particularly bad one. The pockmarks on the top are ugly but probably have no effect on performance (apart from creating a blunt needle at the time). It’s the condition of the inside of the hole you need to examine. Here’s what to do if you decide it needs cleaning up:
Start with a 1/8" (3mm) drill bit to cream off the biggest bits of burr. Just work the bit by hand as a sort of file. We don’t really want to enlarge the hole itself.
Rip a strip of the side of some fine emery paper, and fold it lengthways so you can get it into the hole. Work it floss-style to smooth any remaining sharpnesses off.