Right you are, manicmike, it's a 27, my mistake. I also need to know what to use to release a set screw. It's holding the needle plate on and I have tried a number of things to loosen it, but it still won't budge. It's broken so I need to get it out to replace it. Please HELP.

Has the head broken off it? Upload a picture and I'll be able to help you. My dad and I (he's a retired mechanic from the Isle of rust - Ireland) have removed many stubborn fixtures.

Is it the screw or needle plate that's broken? If the head of the screw is ok you can try a couple gentle taps on the end of a well fitted screw driver. Sometimes that will be enough to break the bond loose so you can back the screw out. Go gentle. You don't want to break the cast iron machine it's in.
Rodney

manicmike; no the head is not broken off. it may be rusted fast.
rodney; the needle plate is broken. i have tried tapping with a hammer and used liquid wrench several times a day for over a week and it won't budge. sorry no camera so no pictures. I have ordered a new needle plate but have to get the old one off first.

lolthom have you tried heat yet? either a blow dryer or I'v had success just setting the machine out in the noon time sun for an hour or so and it worked like magic with the liquid wrench, a tap with a rubber hammer on the screwdriver.

Some times those screws can be really hard to get out. Before my house was broken into, I had a real long skinny screwdriver that had been ground to a slight angle. That thing would get anything out. Now days I use a T shaped screwdriver I got at Harbor Freight. You may still have to grind those tips a little to fit the slots. I have also used a little screwdriver tip in a little wrench. If you can hold it in place it has a bit more leverage than the little screwdrivers you usually see.

Well if I'd done all that it would be time to get serious :o. It wouldn't be hard to get the head off (with a grinder, if it's already broken) so you can get the old plate off. With the plate removed you'll be able to get at a little of it with pliers or vise grips. If it doesn't move, grind it flat and drill it. Be very careful not to touch the threads with the drill bit or the new screw won't fit very well.
If you do, don't panic: You could tap a new hole and use a slightly bigger screw (but this is a real pain, so be careful instead).

I think we have ever only done that one time.

He has his voice back.

windblown; not much sunshine here in pa. in march. how long should i heat it with a hairdryer? linda