This is really a negative review of several Blackburn pumps I have owned. I started out 25 years ago with some sort of Blackburn mini pump which I hated, but maybe my expectations were unreasonable (I had never used a mini pump before).
I eventually upgraded to a Blackburn TrakPumpSport TPS-2, which has a dual head with two holes (Schrader, Presta). It was unacceptable at Presta -- hard to get the valve in and out of the hole, hard to get a good seal, hard to get a good grip. It was even worse at Schrader.
At about the same time, I got a Hurricane HP mini pump. It doesn't seem to be branded? It's a basic two-head pump that fits in my fanny pack. It has two-stage compression so it can get to reasonably high PSI if you're patient enough. It is actually the best pump head I owned until today, because it has never once failed to connect to a Presta or Schrader valve. For difficult Schrader valves, it has become standard practice for me to start with the Hurricane HP and then move to the TPS-2 once there is enough pressure to keep the stem up.
Slightly more recently, I bought a Blackburn Airtower 3. It has a new-fangled magic head that accepts Presta and Schrader in the same hole. It is pretty alright at Presta. Insertion and removal takes somewhat more effort than I'd prefer, but it always works. But it is even worse at Schrader than the TPS-2 was! It rarely opens the valve, it often pops off, and it is physically hard to attach it without pushing the stem in.
So for Presta I just use the Airtower 3, but for Schrader I have to fight with it. I try the TPS-2, which works alright about half the time. Then I fall back to the Airtower 3, which works about a quarter of the time. And for the remaining quarter, I have to start with the Hurricane HP before transitioning to one of the floor pumps. It sucks. My kingdom for a Schrader head that works on the first try.
So I just received a Lezyne ABS-1 PRO HP head. It has threads to assertively attach to the valve. The threaded end of its head is reversible, so you unscrew it and put it on backwards to switch between Presta and Schrader. My intent is to use it only for Schrader. For that purpose, I am willing to part with my TPS-2 factory head.
The trouble is that the TPS-2's existing rubber hose has an approximately correct (or slightly large) inner diameter, but its outer diameter is 10.2mm. The inner diameter of the ABS-1's nut accepts a hose up to about 8.4mm. I read an Amazon review saying you can shave down the hose in this case. So, I did that. I whittled it down like I was sharpening a pencil with an x-acto knife.
With some struggling, I was able to get the cap on, and then tighten it down sufficiently. I have no idea if it's strong enough (but maybe it doesn't matter because my Schrader tires are all 60-65psi). It seems to seal well enough, though. I really cranked the thing down, and it appears to have really pinched the rubber adequately.
Anyways I was then able to use it to pump up my bicycle trailer. It was easy. It wasn't quite as quick as in the youtube videos I saw, but it's about the effort I expected. It takes about 15 seconds to attach it, and about 10 seconds to detach it. And once it grabbed the threads, it was just unambiguously working! It was great!
And in my two tries so far, there was no tendency to cross-thread. It doesn't take any particular strength or angle to hold it aligned with one hand, and to turn the knurled bit with the other.
I'll write more here if I ever have any complaints, but at the moment I'm floating on the illusion that I've decisively solved a long-term annoyance.