We've removed the bobbin case in the last entry, revealing the bare hook assembly beneath. As you can see in the photo, the area underneath the hook assembly is filthy. We've got the bobbin case off, so we might as well remove the hook assembly to clean down there. We only need to remove one screw, that big one in the center.
This screw is a rare case where a B-Square bit (#10 3/8) fits perfectly, and a Brownells bit (#360-4) is workable but not a perfect fit. If you have the Chapman screwdriver set, the bit labeled "98" is likewise just a passable fit, not perfect. (UPDATE: On one of my 201s, I found the Chapman "97" bit fit better than the "98," although both machines have screws with slots that seem identical to the naked eye. Test both bits first--stick them in the slot by themselves and wiggle them loosely--to see which is a better fit before you start to remove the screw.)
Click here to read an earlier post about these screwdriver sets, and click here if you need to order the Brownells bit.
Please note that the Chapman bit numbers are read with the blade pointing to the left. In other words, this is a "98," not an "86:"
|Try the Chapman "98" bit as well as the "97" to see which fits better.|
If you use the Brownells or Chapman bits for this screw, be sure the blade is perfectly centered in the screw. With these two, the blades are not quite wide enough to take up the entire screw slot, so if the blade is not centered, it is possible you will strip the screw.
For new wrenchers, removing this screw can be a little tricky for two reasons:
1) The machine's arm will be slightly in the way, forcing the screwdriver into an angle, which increases chances of strippage. If you're clumsy or not yet confident with your screwdriver skills, I'd recommend using a screwdriver ratchet (you can learn about them in this post).
2) The balance wheel needs to be held in place while you loosen the screw, or the hook assembly will just turn with the screwdriver. If you need both hands on the screwdriver, have someone hold the balance wheel for you.
Remember this piece of screwdriver advice: Once you've got the bit going straight into the screw--not an an angle--press down quite hard, as if trying to push the bit right through the screw. Only then should you start turning the driver, so that it doesn't slip out. (If you're clumsy, have someone else hold the balance wheel, then use two hands on the screwdriver--one up top on the handle, pressing down, and the other hand holding the bit so that it doesn't slip out of the screw.)
It's not a long screw and comes out pretty quick.
|Nice thing about magnetic bits: They pull the screw up with them.|
It will probably be slightly stuck and will not come right off. Wiggle it gently back and forth--like a see-saw, not a steering wheel--and it will loosen itself enough for you to easily pull it off.
Now you can clean out all this nasty crud.
I like to use Q-tips dipped in rubbing alcohol. Be careful not to drip onto the bed of the machine, the alcohol is not good for the paint job.
The reason I use alcohol here is because it breaks up old oil and grease, and it evaporates completely, leaving no residue. I wouldn't use sewing machine oil to clean here because it leaves a sticky residue, which will quickly attract more lint and dust.
Once you've got it nice and clean, just pop the hook assembly back on. There's a little positioning pin on top of the mounting shaft, so there's only one way to put this back on. Replace the screw, tighten it up, and you're done.
Ready to move on? Click over to How to put the bobbin case and retaining ring back on, easily.