Releasing stuck extension from vibrating presser bar

[RWL2]

This is for my Consew 226, but could equally be from a Singer 111w class machine or a Seiko STW 8b.  The spring loaded extension was stuck in the vibrating presser bar.  It had been drenched in Kroil, paint thinner and Ed's Red for a week without noticeable effect.  I tapped the free end with a brass mallet, but I didn't want to whale on it too hard because I didn't know whether the extension was already as deep as it would go and hitting it harder was likely only to bend the extension or bugger up the end of the vibrating presser bar.  There was no simple way to grab it with pliers to twist it without marring the surface of the extension.  I really didn't want to grab the larger diameter part near the end because I could see that it was pinned in place.  Holding that would succeed only in shearing the pin.  I tried grabbing the exposed end between wood blocks in my vise, but it just turned in the wood. 

I decided to make some collet blocks to more forcefully grab the extension.  I selected two pieces of scrap aluminum, each approximately 1/2 x 3/8 in cross section from my junk box because aluminum is "grabby" when it's pressed against steel.  I could have used steel, but aluminum grabs better and drills more easily.  Brass would have worked well, but I don't know if I had any scraps of square section brass around and brass is expensive. I measured the diameter of the extension as 0.144" which is identical to the diameter of a #27 wire drill.  I clamped the two pieces of aluminum in the vise with a piece of thin cardboard between them and drilled the hole.  The cardboard was used so that when they were clamped together on the extension there would be a small gap between the two pieces of aluminum allowing pressure to be applied to the presser foot extension.  I slid the spring back and clamped the extension between the two blocks in my bench vise and wiggled the square part of the vibrating presser bar back and forth until it released.  The oil had made its way to the end of the presser bar, but this was partially rusted in place.  I used a soft wire wheel to remove the rust on the extension.  When I inserted the cleaned extension into the presser bar, there was resistance from residual rust and dried oil.  I started with the #27 drill and twisted that in the bore and then used successively larger drills to clean out the bore.  Photos of the process below.  I hope this helps someone else in the future.

 

 

Two more pictures so that the uninitiated know what the complete assembly looks like.