DeArmond Tremolo Control model 601
DeArmond model 601, back view
The speed control slides the rubber-edged wheel along the tapered pin. At the far, narrow end of the pin, the wheel rotates more slowly.
This is, roughly, the assembly of the canister. (Some do not have the window opening in the brass.) On some units a second rubber washer may have been used instead of the rubber gasket shown at top.
Filling the canister halfway means adding 1.5 ml of Windex.
Filling the canister may require bending the needle on the syringe. If bending is necessary, insert a guitar string into the needle first, to prevent it from kinking. (This photo shows a plastic bottle with a needle tip, not a syringe. A syringe is preferred because it allows fluid to be added and removed accurately.)
DeArmond model 601 schematic.
DeArmond model 800 schematic.