Why does this weld script not work?

I am working on a rpg and the weld script I use for the swords works fine in studio, but in playing the game for some reason the weld doesnt work. theres no output V my weld script

handle = script.Parent:WaitForChild("Handle")
tool = script.Parent
function weld(part)
    local w1 = Instance.new("Weld")
    w1.Part0 = handle
    w1.Part1 = part
    w1.C0 = handle.CFrame:inverse()
    w1.C1 = part.CFrame:inverse()
    w1.Parent = tool
end

for _, part in pairs (script.Parent:GetChildren()) do
    if part:IsA("BasePart") and part.Name ~= "Handle"then
        weld(part)
    end
end

the model the script is in is in a folder in lighting if that matters