Bill of Materials

In a previous company, I was a manager of the packaging and manufacturing department for a small auto parts manufacturing/warehouse operation. A key part of that was managing the work flow through 20 different machines, with all their requisite parts, labor and quality standards. Managing all of that can be very complicated, and while software can assist with the scheduling, you still have to have the human interface to plan, shift work, and understand what the software is telling you to do (and make changes when necessary). I actually went back to school to get training in this with APICS (the American Production and Inventory Control Society).

A key aspect of managing the workflow and the inventory was the BOM (Bill of Materials) and Process Flow Diagram. With these, the operators were able to understand all the parts that went into the finished item (the bill of materials) and how to put it together. For every part produced, you needed to have both of these documents, and as you made improvements in the process (something good companies do to keep ahead), you updated the documents.

As I look at pursuing my side hustle, I’ve listed the items that I think I will start with, but now I have to determine how to build the items, what materials are necessary, and what those items might cost. Its only with this information (and an idea of the time/labor to build) that I can come close to identifying how to price my materials.

Here is an example – the tea box I just built for Mrs. 39 Months for Christmas.

I worked through the materials I was going to need to build the item:

Description L W T
Cherry 48      6      1     
Maple 30      8      1     
Poplar 12      6        1/2
Poplar 60      4        1/2

I then had to work out a “cut list” for the final dimensions for each of the parts:

Description Qty L W T Material
Front & Back Pieces 2 13-1/2″ 4-5/8″ 1/2″ Cherry
Side Pieces 2 6-1/2″ 4-5/8″ 1/2″ Cherry
Top Panel 1 12-1/2″ 6″ 1/2″ Mahogany
Bottom Panel 1 12-1/2″ 6″ 1/2″ Poplar
Bottom tray front & back 4 6-1/8″ 3-1/4″ 1/4″ Poplar
Bottom Tray Sides 4 5-7/16″ 3-1/4″ 1/4″ Poplar
Bottom Tray Center pc 2 5-7/16″ 3″ 1/4″ Poplar
Tray bottoms 2 5-7/8″ 5-3/16″ 1/4″ Poplar

Finally, I had to work out the process to build the item:

  1. Joint/Plane/rip/crosscut side, top & bottom pieces
  2. Cut side & back pieces into large blocks to “wrap” the grain around
  3. Cut grooves for the top & bottom – 1/8” (router or tablesaw?) into front, back & side pieces
  4. Cut groove in top piece
  5. Clean up grooves with 1/8” chisel, so bottoms are flat
  6. Cut rabbet in bottom piece with dado set
  7. Crosscut side, front & back pieces to final length
  8. Cut the 45 degree angles in front & side pieces
    • Start from side for grain match
    • Cut first 45-degree for each
    • Put measure on stop block to cut 2nd 45 degree
  9. Dry fit front, back, sides, top & bottom
  10. Sand all pieces (100/180/220)
  11. Glue up bot with painters tape on all four corners, then clamp up after checking for square.
  12. Use bandsaw to make cut for lid
  13. Sand off machine marks
  14. Layout hinge mortises and cut (see FWW article on this)
  15. Shellac finish
  16. Steel wool
  17. Wax over the top

Armed with this information, I can at least try to price out what the materials will cost to build (wood, hardware, finish, etc.)

From there it will be time to determine the labor needed to build – but since that can be affected by the quantity you are building at one time (and thus being able to do the same step for multiple items, saving time). This will be based on the “Economic Order Quantity,” a manufacturing term which considers proposed inventory levels, expected sales, etc. to identify the optimum amount you want to produce at a time. We will handle that in a future email.

So the planning goes on. I’ve been watching some YouTube videos on pricing and marketing your projects. Continuing in the “research” phase of TKD Woodworking.

Move info later. Thanks for all the suggestions!

Mr. 39 Months

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