The tightness of a safety razor depends on the specific model and design of the razor. Generally, a safety razor should be tightened enough to hold the blade securely in place, but not so tight that it causes the blade to bend or warp.
To ensure that your safety razor is properly tightened, you should refer to the manufacturer's instructions or guidelines for your specific model. In general, most safety razors require the user to unscrew the handle and remove the top cap to insert a new blade. The blade should be placed flat against the top cap and then the handle should be screwed back on tightly, making sure the blade is held securely in place.
It is important to note that over-tightening a safety razor can cause damage to the razor or the blade, and may also increase the risk of injury during shaving. Under-tightening a safety razor can also cause issues, such as the blade becoming loose and causing irritation or injury during shaving.
Therefore, it is important to strike a balance between tightening the razor enough to hold the blade securely, but not so tight that it causes damage or increases the risk of injury. If you are unsure about how tight your safety razor should be, it may be helpful to consult the manufacturer's instructions or seek advice from a shaving expert.