Many ways to skin a cat What i would do if the wood is in good condition is use a chemical stripper to remove the old finish. If it's got scratches or chips i'd just sand it down with 120 grit emery cloth. Depressions in the wood can be lifted if the scratch or gouge is just pressed into the wood rather than wood removed, by using steam from an iron and a wet cloth. Just keep steaming till the dent lifts.
Once the old finish is removed I'd further sand it smooth with 320 grit emery cloth. Sand
with the grain at all times and collect this sanding dust, it will come in handy later. Dont collect the first rough sanding dust though.
Finish it off with a final sanding of 400 grit until all sanding marks are gone. Also at this time any checkering can either be recut with needle files or taped off with masking tape.
Now you can finish with any number of finishes including boiled linseed oil, Tung oil, tru oil... whatever. I'd use tung oil so i'll give tips on that. I find it gives the nicest finish, to my eyes anyway. Though the steps would be the same with BLO.
Mix tung oil (i use circa 1850 brand) and mineral spirits 50/50 and give the stock a heavy soaking in this, after 1/2 hour wipe it down and let it dry for no less than 2 days.
Next step is very important if you want a high quality finish. Lightly sand the stock again with 400 grit. Now, take out your saved sanding dust and add enough tung oil to make it a wet paste. Using a clean cloth you lightly smear the paste all over the stock
perpendicular to the grain to fill in the grain holes. Keep smearing until you have the stock covered but with little apparent residue left on the surface. let dry 2 days.
Next, you sand off the stock again, very lightly with 400 grit again. For best results, you repeat the above process 2-6 times to ensure you have totally filled in all the grain. Once you are happy with the smoothness of the surface you can apply the finishing coat.
I again use tung oil mixed with a couple drops of japan dryer which will help to make a very tough finish and it will dry quicker. Apply the mix with the tips of your fingers, rubbing it the length of the stock with quite a bit of pressure so that it becomes quite warm. Keep looking at it from different angles to make sure you dont have any areas with more or less varnish.
I like to let it dry at least 24 hours per coat for this process, and i apply about 6 coats. Every 2nd coat i use oil soaked 800 grit to smooth out the finish, and i dont sand the last coat.
Once done, i use a coat of johnsons paste wax to seal the finish. It takes me on average about 2-3 weeks to complete a high quality finish, from start to,... finish.
It takes a stock from this (notice how you can see the holes in the grain)
To this (no holes in the grain)