Help changing size of meshpart but it brakes the welding its also welded to another meshpart?

--// Edited for code block. In the future, please enclose all code within your question in a code block by inserting it within two sets of tildes (~).
local saberHight = 0.2

while wait() do
    if saberLight == true then
        if saberHight < 3.616 then
            saberHight = saberHight + 0.1
        elseif saberHight > 3.616 then
            saberHight = 3.616
        end
    else
        if saberHight > 0 then
            saberHight = saberHight - 0.1
        elseif saberHight < 0 then
            saberHight = 0
        end
    end
    saber.Size = Vector3.new(0.2, saberHight, 0.2)
end