Hi I'm a newbie and I have read this thread and the other one that was recommended. (Thanks!!) When I got my 401a, the stitch selector knobs would push/pull as described in the manual but wouldn't turn. After oiling and using guidance in these threads, I had the outside knob (a-j) turning freely. I began working on the inner knob. It would pull out and I got some very slight movement. I would occasionally rest that knob and turn the a-j knob. I must not have gotten the a-J knob fully back in place (I've realized by reading here), before I pulled on that inner knob to move right side... Because both knobs are jammed. I can't push/pull either and no movement. Have I hopelessly jammed things? I ordered tri-flow but for now have put oil in all the described places. Any advice is so appreciated or guidance to another thread. Thanks.

I like Tri-flow, but it is only an oil. Hopefully the oil you used is a clear sewing machine oil and not 3 in one household oil. You could try a little kerosene to clean the "stacks" where the movement needs to happen. Cleaning is usually needed to de-gunk the old dried oil first and then after cleaning you want to use new oil.

With my own 401A, I move the first knob to B before I can move the other knob. You might try that and see if it works the same for yours.

Getting those knobs to work correctly is a long term commitment. It took me about a year to get the first one right. You have to get every little bit of dried up oil cleaned off it. 3 in 1 oil will really dry gummy and people do like to use it. Some times kerosene will take it some times something else but you want to keep anything you use off the machine's finish. Even then go back in a few days and you may have to clean it again - just a little bit will dry back and you start over.

Thanks so much for your response Christy! I did use Singer machine oil, and it's good to know not to expect miracles from the Tri-flow :). It looks like mine was set to around D on the left side when I attempted to pull the inner knob to move the k-s settings. I will remember to set it there once I get past this jam. I would give anything if I had let that first knob "settle" into place before I worked with the second. Nothing will turn or push back in now.

I didn't try any kerosene. Do you clean everything with kerosene? I had wondered if I needed a degreaser, but will try kerosene. It sounds like I should have kept cleaning before I applied any new oil. (I'm attaching a picture below - with a related question after a local comment I received yesterday.)

Hi Miriam, thank you for your response! Hearing this and Christy's reply, I definitely rushed the process and didn't clean it well enough before adding new oil. I used the Singer oil, but I wondered if the previous owner only used the Singer lubricant - her daughter gave me all of her supplies, and I didn't find any oil, only the lube. I bought new oil. It is still messy as you can see from below and this is after the bit of cleaning I did.

At any rate, I sent these pictures of what it looks like inside (after I jammed it) to a repair guy I met on Craigslist when I was looking for a 401a (I don't know him personally). He commented that it looked like "I think you have messed up the zig zag arm assembly. This arm goes in stacked design patterns. I don't think you can fix this problem yourself." I'm attaching the picture I sent along with a pullback of the same picture in case that helps. I wondered if others agreed with this assessment. I value having work done well, like most, I'm wanting to make sure I've done all I can, and that I am as informed as I can be. Thank you!!

Your cleaning has a long ways to go. You have to get rid of all the dried up oil. Do not use anything with water in it. Solvent is ok but if you get any on the paint it will be toast. Also solvent should be used well ventilated or outdoors.
It is a lot of work/time to clean one of those and get it to work correctly but doable.

Rock the hand wheel back and forth and see if one or both controls doesn’t pop free.

CD in Oklahoma

Thank you Miriam, this is good advice!

Thanks CD for weighing in! I just turned it back and forth, and didn't get any movement, but I will keep trying. I appreciate it.

I've never had any luck doing that to get the stitch controls to budge. Heat some times works long enough to clean up some of the oil underneath.

I think I made a discovery that potentially explains my troubles. Ok see on this web image http://4.bp.blogspot.com/-BK4-xjK-Ab...0/IMG_7074.JPG I know no technical terms so forgive me, but see the two pillars on either side of the cam stack? I noticed how the little finger is hooked into a slot that makes the pillar move up and down on the post? Both sides look the same on the above web image which was originally from: sewingmachinenut.blogspot.ca/2013/03/singer-401a-cam-stack.html

Ok, on mine, the pillar/post closest to the front, that finger has slipped out of the slot on the pillar and is beside the pillar. I expect this happened when I was trying to get it to move. I've tried a couple different angles to show it. On the other side, the finger is in the slot on the pillar.


I wonder if this is the missing puzzle piece as to why it suddenly stopped moving at all? Thanks in advance for any thoughts -

Good eye! Yes that part pull back *partially when you pull out or push in the knob and that allows it to travel up or down the stack and find the appropriate groove to drop into. I would think you could try and carefully maneuver it back into the slot, continue cleaning, and move forward. (I could be wrong. I am not a professional.) That's what I would try at this point though.