Making a Headbobbber Script Framerate-independent

I have a headbobber script that I found online, and it is working well, but unfortunately it isn’t set up to be framerate independent. I use Time.deltaTime all the time, but am not sure how I would apply it in this context, could anybody help me out? Thanks.

using UnityEngine;
using System.Collections;

public class Headbobber : MonoBehaviour {

  private float timer = 0.0f;
  public float bobbingSpeed = 0.18f;
  public float bobbingAmount = 0.2f;
  public float midpoint = 2.0f;

  void Update () {
    float waveslice = 0.0f;
    float horizontal = Input.GetAxis("Horizontal");
    float vertical = Input.GetAxis("Vertical");
    if (Mathf.Abs(horizontal) == 0 && Mathf.Abs(vertical) == 0) {
      timer = 0.0f;
    } else {
      waveslice = Mathf.Sin(timer);
      timer = timer + bobbingSpeed;
      if (timer > Mathf.PI * 2) {
        timer = timer - (Mathf.PI * 2);
      }
    }

    Vector3 v3T = transform.localPosition;
    if (waveslice != 0) {
      float translateChange = waveslice * bobbingAmount;
      float totalAxes = Mathf.Abs(horizontal) + Mathf.Abs(vertical);
      totalAxes = Mathf.Clamp (totalAxes, 0.0f, 1.0f);
      translateChange = totalAxes * translateChange;
      v3T.y = midpoint + translateChange;
    } else {
      v3T.y = midpoint;
    }
    transform.localPosition = v3T;

  }
}

Maybe multiply bobbingSpeed by Time.deltaTime * 60 (or 30, or 120, or whatever your desired frame-rate is) at Line 19.