How to weld tools that won't break? [closed]

Lately I've been trying to weld tools with small parts. When first equip the tool everything is fine and in place but when unequipped small parts are scattered everywhere and most of the welds break(some of them are still in place though).

I'm using this script to do the welding:

function weld()
    local parts,last = {}
    local function scan(parent)
        for _,v in pairs(parent:GetChildren()) do
            if (v:IsA("BasePart")) then
                if (last) then
                    local w = Instance.new("Weld")
                    w.Name = ("%s_Weld"):format(v.Name)
                    w.Part0,w.Part1 = last,v
                    w.C0 = last.CFrame:inverse()
                    w.C1 = v.CFrame:inverse()
                    w.Parent = last
                end
                last = v
                table.insert(parts,v)
            end
            scan(v)
        end
    end
    scan(script.Parent)
    for _,v in pairs(parts) do
        v.Anchored = false
    end
end

weld()