Seems like this should be simple, but not so much. I am trying to install a connector to the end of a 1-1/4" liquid tight non-metallic conduit. The connector is not like the smaller ones I have used where the conduit pushes on over the connector and the outer ring tightens on it... this one has an outer right, a tapered slip washer and an inner, screw on fitting that fits inside the conduit and has a single thread on it. Problem is, the screw on fitting only goes on about half way before no amount of strength will get it any further. I even have trouble backing it out now. There is no place to use a wrench without tearing up the plastic fitting. I am wondering if there is some secret in getting the screw on type fitting to screw on all the way with normal hand tightening. May be thread sealant? Wire pulling lube? Something else? I'd appreciate any feedback on what the secret is to getting this to work. Thanks!