Bicycle Mechanics - Is it OK to stretch forks to fit wider hub?

I bought new wheels for an old schwinn road bike. The distance between the two tips of the forks where the axle/nuts go is a few mm shorter than the distance from endnut to endnut of the axle.

I looked at the axle and can't remove any kind of nuts acting as spacers, etc.

To get it to work I pulled the forks apart a little and installed the wheel. But I don't want to keep using it like this if it could be dangerous.

What is the recommended fix for this type of situation?

Thanks

How much is a little and what material is the fork made of? If it's like 5mm and steel it should be no problem, more distance or different materials could range from 'pretty safe but you should use a bending jig' to 'you probably shouldn't ride on that'.

I wouldn't fancy forcing anything, even if the process were dignified with the euphemism of "cold setting." Bending is bending. Forks are, IMO, springier than stays, and to bend them leaves them under tension. Tension in a mechanism seeks to resolve itself. Better that everything is relaxed. If the shortfall is literally a few millimetres, could you not replace the existing axle locknuts with a pair which are thinner by the requisite amount? If you have access to a machine shop, or know a high-school kid who takes shop class, how about taking a bit of metal off the existing ones?

With steel it's fine. A steel fork can easily accommodate a few mms. Aluminum or carbon... different story.