Creating a snapping UISlider in Swift - ios

Question

I am trying to create a snapping UISlider in Swift with a simple line at each snap, and the issue isn't the actual snapping part it is the subviews added. The subviews added look like garbage but I do not know how to make so that the subviews are equally spread out at the point where it would snap? If you look they are slightly off
protocol SnappingSliderDelegate {
func sliderChanged(_ value: Int)
}
class SnappingSlider: UISlider {
let step:CGFloat = 5
let start:CGFloat = 15
let end:CGFloat = 70
var delegate:SnappingSliderDelegate?
override init(frame: CGRect) {
super.init(frame: frame)
setupView()
}
override func awakeFromNib() {
setupView()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
func setupView(){
//self.setThumbImage(UIImage(named: "Play_black"), for: .normal)
self.minimumValue = Float(self.start)
self.maximumValue = Float(self.end)
for i in Int(start)...Int(end) where i % 5 == 0 {
let view = UIView(frame: CGRect(x: (Int(self.frame.width) / 11) * ((i - 15) / 5), y: 0, width: 1, height: 29))
view.backgroundColor = .lightGray
self.insertSubview(view, at: 0)
}
let view = UIView(frame: CGRect(x: self.frame.width, y: 0, width: 1, height: 29))
self.insertSubview(view, at: 0)
self.addTarget(self, action: #selector(valueChanged), for: .valueChanged)
}
#objc func valueChanged(_ sender: UISlider){
let step: Float = 5
let roundedValue = round(sender.value / step) * step
self.value = roundedValue
delegate?.sliderChanged(Int(roundedValue))
}
}