Is 1N4001 Diode Safe for 0.6A Load in Battery Circuit? Heat Concerns at 0.42W

I'm working on a battery powered circuit that is using a 1N4001 diode to bring the 6V from 4xAA closer to 5V as well as for protection in case the batteries are put in backwards.

The total circuit draws around 0.6A when driving some LEDs and, when doing so, the diode gets pretty toasty. Definitely uncomfortable for prolonged contact. Probably in the high 100's (F).
I have also see the article about How does 1N4001 diode work : http://www.hqew.net/news/news-33817 ,it's useful but it didn't give me a certain answer.
I'm really more of a software guy so a lot of this is new to me. I tried looking at the diode datasheet but it was mostly a bunch of stuff I didn't quite understand. Since it's dropping 0.7V @ 0.6A I realize that it's dissipating 0.42W of power, but it doesn't seem that that would be all that much.

Should I be worried about it being too hot or is this sound like it would be in normal operating conditions.

Diodes - especially the 1N400x series -  are pretty rugged and getting warm is not too much cause for concern. If it is almost instantly too hot to touch then that's probably too hot, but if you can keep you finger on it for a few seconds it's not way out of its comfort zone. 0.6A is well within its 1A maximum rating.But if you are worried about it you could try a 1N5401 which is rated at 3A, it's a much bigger case so should run a bit cooler.You could also try putting 3 or 4 1N5819 diodes in series.  These are 1A Schottky diodes and only have 0.2-0.3 V drop.  That might also get you closer to your 5V target.Finally, you could use a low dropout 5V regulator.  The good old 7805 needs a bigger differential - about 2V I think, so your supply would have to be 7V+.  but something like the LM2940T5.0only needs 5.5V input to regulate to 5.0V, and they are not too pricey.

First of all let me refer you to Elizabeth Simon's excellent blog "How to Read Data Sheets: Rectifier Diodes" where she discusses this problem. For further reading, you may want to look at my blog "Power Dissipation: My Arch-Nemesis".As Elizabeth says, the more current you draw the higher the volt drop across the diode will be- as you approach 1A, the drop will be closer to 1V than 0.7V. And even 0.3W can get stinking hot on a small part. You will find that the power dissipation rating on axial components like resistors and diodes often a given base an Nmm of lead still attached, so the longer the leads the greater to dissipation capability. Alternative diodes as David suggests are a good and cheap possibility, but remember that as the battery voltage drops, so does your nominal 5V output- can your circuitry handle the variation? The voltage regulator is a better option in that the voltage output is constant (until the battery hits the dropout voltage) and that it is easier to create additional heatsinking on the PCB. The part suggested by David also has reverse battery protection. But keep in mind 1V*0.6A is 600mW and still stinking hot without sufficient heatsinking.In my experience in electronics, 0.6A is pretty high unless you are driving some load. And the loads (like relays) can be quite tolerant of power supplies- you may not even need a regulator. What exactly is drawing your current?

Further to Aubrey's answer -- take a look at my The Hidden Horrors Lurking in Data Sheets column -- this lists a bunch of Elizabeth's "How to Read Data Sheet" columns (including the Linear Rectifiers column) which are incredibly useful for beginners, professionals, and even software dweebs (LOL)

And further again to Aubrey's answer: "You will find that the power dissipation rating on axial components like resistors and diodes often a given base an Nmm of lead still attached, so the longer the leads the greater to dissipation capability." I have occasionally seen the leads bent into zigzags or coils so that the lead can act as an extra heat dissipator.  Might be a useful trick for you to try if you are running the part close to its limits, and if you have space for it.

use schottky diodes the drop is only .2v and fast switching .go to the net and get your required current rating .