### Ducting

I created a series of fittings for Evergreen Square, Rectangular and Round Tubing. This has got very complicated so this article is an attempt to get a handle on this.

To get started .. we have the range of Evergreen tubing listed below, 3 sizes of Rectangular Tubing, 5 sizes of Square Tubing and 12 sizes of Round Tubing for a total of 20 different tubing sizes.

For all of these I need 45°, 90° elbows – perhaps others .. additional ones for the rectangular tubing, Tee-Fittings, Joiners, Flanges etc.

### Short Code

There are quite a few combinations when an elbow connects two lengths of tubing. With 20 tubes you could create 210 different (unique) configurations. Many of these might be considered ‘silly’ but this gives an idea of how complicated it could be. To simplify it a bit I gave a letter to each tube as shown in the left column of Fig 1 above.

So now we can code the connector for two tubes (keep in mind this page and those following are acting as my notepad – and are subject to change as I “work the problem”:

• AA connects two #257 tubes
• AB connects a #257 and a #258 tube
• ABR connects a #257 and a #258 tube with one tube at 90° to the other
• AC connects a #257 and a #259 tube
• AH connects a #257 and a #256 tube
• FP connects a #254 and a #227 tube

The type of connector with additional info is coded as (again . work in progrss):

• EA = EA Elbow (Rectangular to Rectangular)
• EB = EB Elbows (Round to Round)
• EC = EC Elbows (Round Reducing)
• J = Joiner (Surface mounting)
• CJ = Center Joiner (Same size tube)
• 90 = 90°
• L,M,S .. for different lengths of the ‘legs’ of the fitting
• A 90° elbow that joins a #257 and #258 tube would be coded as EAAB as the prefix. Adding the product ID to narrow down and make unique.
• A 45° elbow that joins a #257 and #259 tube at right angle would be coded as EAAC as the prefix and adding the product ID.
• A #257 and #259 tubes would connect inline with a Converter (C) would be coded as CAC as the prefix and adding the product ID.

### SKU

The SKU – or – “Stock Keeping Unit” is created as mentioned above with a prefix and product ID.

• The prefix consists of two parts:
• a one or two letter code for the type of fitting .. C = Converter, EA = Rectangular Elbow, EB = Round Elbow, EC = Round Reducing Elbow, CJ = Center Joiner and so on,
• followed by a two letter code for the tubes being connected – example: a #259 rectangular (C) tube connecting to a #228 round (Q) tube would be CQ.
• The prefix would be then for a Converter … CCQ-(product ID). The product ID is generated by Woocommerce automatically, so you would have something like CCQ-1234
• This is a Legacy assignment so is a bit weird but I can live with it for now.