ants likely indicate too dry, and they're prolly more attracted to the wood than the compostables .... would help to oil the wood [linseed oil], at least on the outside and around the bottom where it contacts the soil .... and no, they won't affect the worms, ants are really part of the decomposer community too

Bill

I don't know how to keep ants out of anything on/in the ground that won't hurt the worms.

I make a point of building my bin with legs that I could put in containers of water or mineral oil.

I've not heard of ants hurting worms but I suppose it's possible. I do know I wouldn't want ants setting up shop in my worm bin as I know they bite me.

Here is a link that might be useful: My Bins

i too have an inground pit,3x4x16. one combo action i find helps is first to track the line to the beds and feed them bait that kills both the quene and teh workers at the next end.
then take your trowel and clear a small ditch a couple inches wide and several inches deep all the way around the pit. now flood with water so that the worms are forced to the top or drown and seek to leave. the mote filled with water blocks there escape and those trapped die due to not being able to return to the nest. the red ants are said to harm your baby worms and your smallest eggs. other ant types are said to be harmless ?????
lastly take your long term yard bait and spread it all around the general area of the pit or better the whole yard to help stop future nest.
boness

correction: ants are forced to the top of the bed.
also i am fairly new to this and would love to hear some of what you have learned working with the in ground pit. thands boness.

Just a thought,
Be careful with the ant killing chemicals. If it can kill ants it will most likely kill the worms too. If the Ants have set up shop IN the worm bin they will be dragging that poison back into the bin.

There is also a good chance that that poison won't break down very fast.

So if an ant brings the poison back to the worm bin and dies, Those dead ants start to break down they can become poisonous food to the worms.