How would I 'service 'them? Take out blade and wet dry paper to remove rust then 3 in1 oil?
It's often referred to as "fettling" a plane. I actually have a Record #060-1/2 block plane here, bought for one of the apprentices, so I'll start going through that tomorrow so you have the steps.
Yeah what is purpose of adjustable mouth?
The adjustable mouth isn't strictly necessary when a block plane is used for its' original function of "blocking in", or trimming end grain, such as flush trimming the exposed end of protruding tenons (such as when making up a traditional mortised door, for example) and and trimming end grain on mouldings (e.g. a piece of beading that is fractionally too long or where the angle needs to be altered slightly, or for that matter adjusting a mitre joint on a skirting), etc. For those purposes the grain will tend to break up easily and generally won't clog the mouth of the plane.
When you start to use a block plane along the grain for tasks such as rounding over a door edge putting a small chamfer on a piece, etc (another words, as a sort of bench plane) the big open mouth of a non-adjustable mouth block plane can be at a serious disadvantage especially when working rowed timber (such as sapele where the grain changes direction all over the place), awkward timbers (such as pippy oak, quilted sycamore, etc) or where there is a need to work against the direction of the grain. Even knotty pine can tear out with a wide mouths plane.The adjustable mouth gives you the ability to reduce the mouth opening so that there is a limit on how thick a shaving the tool can take and so makes it possible to handle awkward materials with minimal tear out.
Above: An old Stanley #60-1/2 adjustable mouth low angle block plane (black), a modern Irwin-Record #60-1/2 block plane (blue) and a Wood River #65 knuckle lever cap adjustable mouth low angle block plane
Below: Relative sizes - #7 jointer #4 smoother and Irwin-Record #60-1/2 block plane
Block planes are typically small enough (3 to 7in long) to be used in one hand. In site trimming and installation this is a major advantage over a smoothing plane which requires a 2 -handed grip meaning that block planes are absolutely essential for any type of joinery installation where the work is not clamped in position
Is the big plane a smoothing plane not jack plane? Or are they the same
No. Smoothing planes (sizes #2, #3, #4 and #4-1/2 - you will probably only ever see sizes #3 or #4) are all designed to do adjustment and cleaning up tasks on the bench when making up wooden items. They are all progressively larger than each other, a #2 being about 7in long with a 1-5/8in cutter whilst a #4-1/2 is a large 10in long x 2-3/8in wide cutter. The #2s were sort of "dolls house joinery" planes and are too small for most people to hold, #3 is more of a cabinetmaking size (think of it as almost a block plane with a 2 hand grip), #4 (which was once by far the most widely sold metal plane) is a good size for general bench work and its' smaller size and lower weight than the #4-1/2 makes it better suited to highly mobile site work (e.g adjusting sash frames), and finally there's the #4-1/2, which is a hulking brute of a plane, but where the weight and heft can give advantages when working on larger joinery items, especially in the shop. The #4 and #4-1/2 can be used as general planes, doing much of the work of jack planes, but the shorter sole length does make them less accurate when longer straight edges need to be produced (the longer the sole of the plane the longer straight piece you can make - think about how straight a door stile needs to be). In general you set a smoothing plane up with a straight ground blade where the corners of the blade are given a slight radius to reduce the tendency to leave "tramlines" on the finished surface
Above (l to r): #4-1/2, #4 and #3 smoothing planes
Below: Showing the difference in size between a #4-1/2 (bottom) and a #4 smoother
Jack planes are bigger and heavier than smoothers. They are "Jack's of all trades" and can work as short jointer planes (on shorter stock), as big, albeit heavy, smoothers and as scrub planes.The two numbers you'll see associated with the name "jack plane" are #5 and #5-1/2. #5 planes are 14in long with a 2in cutter whilst the heavier #5-1/2 is 15in long x 2-3/8in. The #5 is probably handier on site where weight is an issue, but both are good for tasks such as trimming doors (straight cutter), small on-site jointing jobs, rough planing or scrub work (where a chambered, or round edged, cutter is used instead of the standard cutter and the material is worked on alternative diagonals to reduce the thickness quickly before the surface is smoothed flat - this is hard work and a power plane is much preferable).
Above: #5 (front) and #5-1/2 jack planes
Below: Showing the relative sizes
Below: Showing the relative sizes of a #5-1/2 (top) #5 (middle) and #4 (bottom) planes. It should be obvious that the jack planes will be able to produce straighter edges than the smoother
Given a choice I carry a block plane and a #5 for general carpentry
Does that help?
Above and below: Endpiece - a #7 jointer plane (back above, right below), the #5-1/2 jack and the #4 smoother (front above, left below). Whilst you can do shorter jointing jobs with a jack plane, the jointer is obviously better suited to the task. The jointer is pretty much a one trick pony and the size and weight make it too heavy for prolonged use. They are also a bit fragile for site use
Note: Before anyone picks me up on it, the plane sizes quoted are the original Stanley plane sizes and have been used for clarity. Leonard Bailey and Stanley were the originators of all these designs.
As a matter of record the bench planes used were (in order of increasing size):
- an early Record #03-SS smoother (#3 size)
- a WWII finish Record #04-SS smoother (#4 size)
- an early 1930s Marples M.4-1/2 smoother (#4-1/2 size)
- a late 1950s period Record #05-SS jack plane (#5 size)
- a WWII period Millers-Falls #15 jack plane (#5-1/2 size)
- an early WWII finish USA Stanley #7 jointer plane
All these tools are unrenovated (at present), hence the odd bit of rust here and there, but whilst none of these tools is available on the market any longer, the newest bench plane being at least 55 years old, modern equivalents of reasonable quality of all of these planes are still available
The block planes are (largest to smallest):
- a Wood River #65 (Wood River is made by Quangsheng), my site block plane
- a modern Irwin-Record #060-1/2 (wider than the original Stanley)
- an older (probably 1960s) Stanley #60-1/2
Both the I-R and the Wood River planes are currently (2021) in production whilst Stanley now makes an updated version of the #60-1/2 called the 5-12-060
Apologies for the quality of the pictures. I am a better joiner than I am a photographer, honestly!
Jobandknock is doing all the hard work! 
