Mouse movement object in a straight line

I have this project where I’m hammering nails into a board and control the hammers location by having it follow the mouse position. It’s currently pivoting in an arc around the camera at a distance of 22. How could I make it so it just move in a straight line across the screen instead of arcing around the camera?

using UnityEngine;
using System.Collections;

public class HammerMovement : MonoBehaviour {

private float distance = 22f;
private Transform hammer;

void Start()
{
    hammer = GetComponent<Transform>();
    Cursor.visible = false;
}

void Update()
{
    MoveHammer();
	
}
void MoveHammer()
{
    Vector3 pos = Input.mousePosition;
    Ray ray = Camera.main.ScreenPointToRay(pos);
    Vector3 point = ray.origin + (ray.direction * distance);

    hammer.position = point;
}

This is headed in the right direction, but is the second Vector3 pos, supposed to be a new variable? I already defined a vector3 named “pos” at the start of the function so I get an error when this code is added. I tried just changing the variable name but that didn’t change anything.

This is headed in the right direction, but is the second Vector3 pos, supposed to be a new variable? I already defined a vector3 named “pos” at the start of the function so I get an error when this code is added. I tried just changing the variable name but that didn’t change anything.