Where do I lubricate my machine and with what?

There is two distinct parts, the treadle part you operate with your feet and the sewing machine itself. They are joined by the belt. Both parts need lubrication with light machine oil. Remove the belt and lubricate the treadle, then test it runs smoothly. Then clean and lubricate the sewing machine making sure that runs smoothly using the handwheel. Then put the belt back on.

The problem is that there is oil in between the Acetal (Delrin) shoe and radial slide of the stitch width.
This can be repaired by adding a solvent to the radial slide while turning the stitch width knob back and forth. Blow out the solvent with compressed air and let the machine sit for a while until all of the solvent has evaporated. ( I can provide a short list of cleaning agents by way of request)
The removal of lubricant on this slide will solve the problem. This problem is common to all Bernina 1000 series machines up to the 1008 and 1030. These machines generally need little or no lubrication as they are fitted with pre-lubricated sintered bearings.

"Too much oil is more harmful than not enough oil".

Additionally, use only a a class 68 machine oil. Avoid using coagulating lubricants like WD-40 and other oils found in hardware stores for use on bicycles (chains) and oils contain teflon particulate. Do not use any oil that will not disclose the basic lubricant.
Keep in mind that most all general lubricants purchased in stores are for the neophyte person... "uneducated and zero technical mentality" where one assumes that oil is just oil. Not so... Nearly all machine problems today where failure of mechanical functions are due to sticky oil and grease varnishing. (more on that subject upon request on this site).
The machine were designed for class 68 machine oils (hydraulic oils) with oxidation, corrosion inhibitors, etc. (Mobil DTE Heavy medium) and other cross referenced lubricants.

https://www.manualslib.com/download/780643/White-979.html
pg 41

Make sure the needle is not bent and fully inserted per machine instructions. Clean shuttle area and feed dogs. Look for fabric debris and/or needle fragments. Oil the two locations shown in illustration (4) with 1 drop each of high quality gun (firearm) or sewing machine oil.

Your manual should have directions on how to oil and lubricate your machine. If you do not have a manual a make and model number is needed to help you further.

Lubricating...
Some sewing Machines w/computer is equipped with a
LM (low mass) hook system which requires no
lubrication. But...
HINT*** If however you do lubricate any parts, always
run the sewing computer immediately afterwards
on scrap material to avoid soiling your work!!!

Each machine has different lubrication requirements look to your user manual for lubrication points and how often to lubricate.

Cheers,
Kelly

Use only sewing machine oil on the sewing machine..

The 7442 is permanently lubricated, and has a self lubricating design, you shouldn't have to oil it yourself at any time.

Are you having another problem that perhaps makes you think it's a lubrication issue?

lubrication depends on the make and model of machine. most newer machines require very little if any oil by the user, however should be serviced by a technician every year or 2.

generally speaking lubricate all moving linkages or sliding or rotating shafts at the point where metal to metal contact is made. use good quality thin lubricant which will not 'gum up' after a few months.

scott.

The grease has hardened and that is what makes it not work. You need to remove the spring and clean all the old grease off it. You can put new grease on if you want but it isn't necessary. The machine should be lubricated with a good quality sewing machine oil(not 3 in 1). You need to oil any place that moves and rubs, This includes the ends of each shaft, the needle bar and the cinnecting links that drive the needle bar. Nothing is permanently lubricated.. you'll find this machine will run much smoother and quieter with fresh lubrication.As a matter of fact, if you use the machine a lot, it should be lubricated once a year and never less thanonce every 5 years.
One more thing. If it is on the main shaft that it has hardened you can spray it with a mixture of fantastic, water and some ammonia. Free it up and give it a light shot of oil.
sewman7