It is very hard to do at first. Even though I have added muscle and can bench and squat more my pull ups haven't increased much as I weight more. I found them easier when I was skinnier. I need to drop some excess weight, I've gotten too big during the winter an spring. Start off doing just the 1 and rest then do another 1 and rest again, then repeat. Eventually you'll build up the number of reps you can do.
You can get an awesome forearm workout with pullups. Use towels or ropes hung over the bar. You can also drill holes in softballs and run rope or small chain through them and do it holding onto the balls.
Why do curls at all if you can do chinups? If you want a very strong grip work up to a 400lbs deadlift.
Yep much better to work out arms as a whole rather than focusing on one muscle group. And you can always add weights to the chin ups and pull ups for that extra resistance.
