Then he saw it, on the floor within arm's length.

At last, however, she came to within arm's length of it.

This means stopping what you're doing and going to within arm's length.

But he steps to within an arm's length of where she sits.

The Speaker came within an arm's length of his son.

She had not allowed very many of them to come within arm's length, as it were.

Together they passed almost within arm's length of where we stood.

His son, who wouldn't let him get within an arm's length.

When the woman stood within arm's length of him she stopped.

When he was within arm's length she put out a hand to stop him coming closer.