Blade not staying on tight

Check to see if the blade is moving when turned on. If the blade isn't moving the clipper blade may need to be thoroughly cleaned. If the blade is clean and well lubricated but still not moving you may have blown the motor.
However, if the blade is moving freely when turned on, and the hair/fur is just not being cut (or is cutting raggedly or pulling at the hair/fur) you will need to get the blade sharpened.

if the blade keeps coming loose replace the hub that holds the blade in place

Use a block of wood to hold blade stationary while tightening bolt. Ensure threads are cleaned with a wire brush before tightening. Is there a spacer or washer missing?

Hello,
Try cleaning the head cutter below the main stem. Remove screws and clean old hairs in there, also lubricate.
Thanks

Sometimes the new blades from Andis are not sharpen enough to get that clean cut. also all trimmers need to be readjusted for power and alignment, plus sharpening the blade, it look like you need a complete sharpen & service on your Andis trimmer. check out Manny's Sharpening they have a Mail Order service, the service they provide is fast and they will sharpen make all the adjustment and give your trimmer more power and the blade will cut clean. They will even adjust the blade at your request on how you want that blade to be set at. Line Ups or Fade Cuts and even shave set. Manny's Sharpening been around for over 20 years and they have a very good rating on the net. Check it out Manny's Sharpening

Generally removing the two screws.. on the blade foot (don't do this over the sink unless the drain is closed!).. and taking the blade apart.. cleaning the trimmers with a small brush.. apply grease in the blade groove.. reassemble

Usually it's best to put those two screws back just get them in lose.. not quite snug..set the blade upside down on a flat surface..so it pushes the blade back away from the cutting end..level..then tighten those screws while you are pushing or holding down on the clippers cutting edge against the flat surface/table. ... oil the blade with the proper oil or a light mineral oil.

This usually will get them back to cutting properly..the blade should be oiled prior to each use...about two to three drops right along the visible part..or a light spray also hair should be clean.. dirty hair does not cut well at all..and the clippers will tug and pull rather than cut cleanly.

Lastly..if they see a lot of use. might be blade replacement time..

Best of luck!

Check your blade latch is working properly. If you took your clipper apart and your blades are not cutting it is one of 2 things. Your blade drive is not assembled properly or your blade latch is not holding the blade on the clipper. If you took your blade apart, check the blade alignment. The cutter blade needs to be slightly behind the comb blade.

They are garbage.....it's a common problem. Call the manufacturer

These kinds of clippers are fussy about oiling and dirt. It is essential that the blades be spotless and well oiled FREQUENTLY. Oil after every haircut always. Also, if there is not enough tension on the blades, the hair will slip between the blade and blade guard, getting caught and damaging the blades. Blades should be screwed on tight. Also, it may be time to replace the blade if nothing else helps. These blades do not last very long in my experience especially if not carefully cleaned and oiled.

OIL THE CLIPPERS AND CLEAN THE HAIR OUT REALLY GOOD.