Buying belts

source/docs/common-mechanisms/power-transmission/belt.rst

@@ -39,6 +39,8 @@ The actual calculations to determine which belt to use to get close to a given c
    .. raw:: html
       :file: belt-calculator.html
 
+.. warning:: This calculator will suggest belt lengths even if they are difficult to get from vendors. Make sure the C2C distance you design around is for a belt length that you can purchase.
+
 SDP-SI has a `more advanced calculator <https://sdp-si.com/tools/center-distance-designer.php>`_, as does `ReCalc <https://www.reca.lc/belts>`_. The equations for calculating these values by hand can be found in `SDP-SI's Designing a Miniature Belt and Pulley Drive System Design Guide <https://www.sdp-si.com/Belt-Drive/Designing-a-miniature-belt-drive.pdf>`_.
 
 Belt Wrap
@@ -83,3 +85,33 @@ Disadvantages:
    :alt: A drivetrain by 8417 using belt
 
    8417 Lectric Legends, Rover Ruckus
+
+Purchasing Belts
+----------------
+
+Once you know what pitch and length belt you want, purchasing a belt requires navigating the vendor's website. Almost every COTS belt vendor will identify belts by 3 values: pitch, pitch length, and width. Pitch is the pitch of the belt, pitch length is the length of the belt (belt teeth times pitch), and width is the width of the belt. From there, its a matter of searching the vendor's page for the right belt.
+
+SDP-SI
+^^^^^^
+
+SDP-SI is an established mechanical parts vendor that sells a large assortment of COTS belts. To navigate the site, go to the `main belts page <https://www.sdp-si.com/products/details/timing-belt-detail.php>`_, navigate to the correct belt type, then select the option for the correct pitch.
+
+.. important::
+    Make sure to select the Single Sided belt type, and not the Timing Belt Stock type. Timing Belt Stock is a long stretch of belt that is not in a loop, whereas Single Sided belts are a loop.
+
+For example, to purchase an HTD-5 belt, first navigate to GATES HTD Timing Belts, navigate to 5mm pitch, and select buy now under the single sided belt option.
+
+V-Belt Guys
+^^^^^^^^^^^
+
+V-Belt Guys stocks a large number of options for belts. They are known for stocking almost every width of belt, since they cut belts to size for the order. Searching the site uses belt codes with the format "Pitch Length-Pitch Code-Width". For example, a 200 pitch length HTD5 belt with a 5mm side to side width would be the code 200-5m-5. A list of common pitch codes is below.
+
+=======    ==========
+Name       Pitch Code
+=======    ==========
+HTD-5      5m
+HTD-3      3m
+GT3-2mm    2mgt
+GT3-3mm    3mgt
+GT3-5mm    5mgt
+=======    ==========