Also there is a calibration scew on the thermostat, most of them...
RULE ONE: Turn no scew more than 1/4 turn...period
Now that is covered heres some pointers.
On some models 1970s ish...
Using the mercury clue comment
If the knob is pulled off you will see the stem can be actually a little hollow down the center, dead center at the bottom of the stem is an itsy bitsy scew..."the size of a jewlers straight slotted driver"...to calibrate for 85% of the models of this era you put an accurate thermometer in the oven and turn the oven off...I set to 300 degrees...if the burner goes low before 275 then adjust untill the flame comes up to high flame and just goes to low flame at 295 so as to not overshoot target temp. These are not on/off flames, they are high/low flame control...if temps over shoot adjusting the high flow setting is needed, if targets are never achieved then low flame limits are adjusted and I have not covered that...The point the flame throtles back from High flame setting to the low flame setting is the termostat setting...sooo...this adjustment has two more approaches to its control of input btus (heat) and it can be confusing. I have covered one. High/Low flame setting we can cover later...I am approaching this from the tsat point of view only.
On some of the Mercury temp controls, the two small scews in the front usually one marked H on the right of the valve body and the other L on the oposite side...These are another way to set the temp settings in the oven by controling input heat/gas to the burner.
Now variations exsist, one style has two screws under the knob and has an itsy bity scale...its shaped like a half moon if you got that one I can send instructions.
The rarest is not a high/low
flame control but an on /off
main burner on call of heat with a standing pilot as an ignition source...in this era they are rare.
The new modern ones use generic ignition modules as well and are both the above.
There is hope even if you live in nowhereville. Just keep talking, asking and learning.
I assure you its not rocket science and the parts (controls) are 90% available...if it blew up only did they get rid of it...better for it...if it worked then it was used on a whole bunch of related appliances.