If you are within 20lbs of bodyweight, maybe you can switch to chinup negatives now (aka jumping chinups).
I've been using the lat pull machine for chins rather than real chinups. I can't do any real chinups. I weigh about 135-140 or so and I'm up to 115 on the lat pull machine. The problem is that the weight on the stack is pulling my body up and I find that it's becoming more of a leg exercise as I use my legs more to keep myself in place. This seems like it will defeat the purpose. Should I try to put a dumbbell in my lap or something? (And how would I do that?)
If you are within 20lbs of bodyweight, maybe you can switch to chinup negatives now (aka jumping chinups).
Chins with bands supporting the feet are popular in my gym with people who cannot do them unassisted.
Look for Gillians band assisted chinup article.
Bands are awesome for training up to chinups.
What rep range are you working in for lat pulls?
If you can't keep yourself down, they're probably too heavy.
That's just it. Keeping myself down with my legs seems to be cheating.
I cannot reach most of the chinup bars in the gym. So far jumping to them results in no ability to get to the top for a negative. It's just too far to jump. I'd like to get closer to my body weight on the lat pulls before I do any real chins.
Once I can do 8-10 reps for several sets I go up in weight. At 115 I was only able to do 5-6 reps.
Seated lat pulls open up several options, if the machine configuration allows for it.
I've no idea if unilateral one-armed lat pulls are a thing, but they might be fun to try in any case.
I really haven't found negatives to be the panacea they are made out to be. So now I want to try getting myself strong enough on the positives with the lat pull machine. I also don't want to do embarrassing things like drag some big box jumping thing over so the whole world can watch some short fat woman get to the bar and then do nothing but flail there and be in everyone's way. So right now, I will stick to the lat pull machine until I can pull at least my own weight, maybe more.