# Harness heights and blocking pin **Harness heights and blocking pin** – ANY TIME YOU WANT TO ADJUST SHAFT OR LAM HEIGHTS, STEP 1 IS ALWAYS **“INSERT THE BLOCKING PIN.”** **Any adjustment made without the blocking pin in place will result in incorrect positioning of your shafts or lams.** Your loom will arrive from Louët with the harness heights correctly set. Louët uses a fail-proof method to ensure this. When assembling your shafts, the top frame of the castle—containing the upper pulleys—is placed in a jig. The cords are then installed and tensioned to their exact specifications. Next, the harnesses and lams are connected, also using this jig, by resting them on preset shelves before attaching them to the Texsolv cords. Once in place, a level is used to ensure all shafts and lams are precisely parallel. Finally, the blocking pin and a transport safety pin are inserted to keep everything perfectly aligned during packaging and shipment. Therefore, when your loom arrives, you can be confident that the shaft and lam heights have been set correctly. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://learning.loftyfiber.com/floor-and-table-looms-purchasing-information-and-support/louet-floor-and-table-looms/louet-spring-loom/spring-loom-troubleshooting/harness-heights-and-blocking-pin.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.