Model disappears when motor6d is attached

Hey, my Motor6D on my model keeps disappearing after 5 seconds or so.
Here’s the code:

local model = game.Workspace.Pickaxe
local character = game.Players.LocalPlayer.Character or game.Players.LocalPlayer.CharacterAdded:Wait()
local attachPart = character:WaitForChild("RightHand")

local primaryPart = model.PrimaryPart

model.Parent = character

local motor6D = Instance.new("Motor6D")
motor6D.Part0 = attachPart
motor6D.Part1 = primaryPart
motor6D.C0 = CFrame.new(-0.042, 0, -1) * CFrame.Angles(math.rad(0), math.rad(91), math.rad(-90))
motor6D.Parent = attachPart

which instance is disappearing is it the model or the motor6d ?