I changed arrows and need a much heavier point weight -- I have some Woodsman 150 gr screw in's and was wondering if I can easily get the inserts out of them to install much heavier steel inserts?  

These are factory "screw-in" heads.  Anyone know what kind of glue they use, so I'll know if simply heat will work?  I don't want to have to heat to the point of risking damaging the head.

Any thoughts?...experiences?...horror stories?

A couple thoughts.  

First.  We tend to use torches.  They may not be the best thing as their temperature is high and they can raise the temperature of small metal pieces very quickly.
An alcohol lamp, like was used long ago may be slower and better.

Second,  I have had good luck heating the insert itself, the stem, and not the broadhead.  Heat will transfer and soften the glue.  You may need to twist it out with pliers, but I have had this work well.

ChuckC

I am sorry to say that all the factory screw in woodsmans are mounted with some kind of non heat reversible epoxy. I have tried to remove on before and actually got the head so hot when I grabbed it with pliers I bent it and the insert still wouldn't come out Your best bet is to buy glue on heads and mount them yourself as I don't know of any screw on broadhead that uses an adapter that doesn't come from the factory with an epoxy type glue.

James, don't heat the head, heat the insert.
CHuckC

If the adapter is aluminum you will more than likely ruin the temper in your broadhead before you get it out. Steel adapters hold the heat better and will usually release after some careful heat application. What Chuck mentioned above (second method) has worked well for me with steel adapters, but not with Aluminum.

There getting a bit harder to find, but the glue-ons can still be had. I've made the original Woodsman into about every weight you can think of up to 250g with the right adapter.

Thanks guys -- looks like I may just pack the screw in 150's away this year and buy some glue on's to get the weight I need.  Looking to get about 270 / 275 grains anyhow, so probably need something different than the Woodsmans.

I'd say - try to heat it and see if it works.  I've seen many cases where epoxy is softened with heat.  What's the worst that can happen?