Some help with motors?

I want to make a killer arm spin forever on a game of mine. I have the script but it only spins once, not forever. Theres 0 errors.

local base = script.Parent.Base
local part = script.Parent.Part
while true do
local motor = Instance.new("Motor", game.JointsService)
motor.Part0 = base
motor.Part1 = part
motor.C0 = CFrame.new(0,0,1)
motor.C1 = CFrame.new(0,0,-1)

motor.MaxVelocity = math.rad(3)
motor.DesiredAngle = math.rad(360)
wait(.5)
end

It repeats but not after .5 seconds. Not sure why.