Reproduction Sheet Metal Demystified
There are many opinions regarding the current state of quality of aftermarket sheet metal for restoration purposes and while some of those opinions are fact-based, many misconceptions exist which can cloud the issue. So here are some facts which may help people better understand
To begin with, metal stamping is a process that has a large number of variables that must be controlled to make dimensionally correct parts on a repeatable basis. Contrary to popular belief, parts as complex as body panels are not stamped with a die of fixed geometry so that the part will be the same all the time. Today, as in the 60’s and 70’s, dies are complex machines themselves - with moving parts and those parts that must be maintained. Steel used to make parts can differ coil to coil in the gauge, camber, cross bow, buckles, etc. Settings and control of the stamping machines as well as the skill of the die setup crew also contribute greatly to part quality. Frankly it was back in the day and is today a miracle that part dimensions can be repeatable at all. Said another way, it is very possible to take a die and make parts one day and the next day using the same die have parts that differ as much as ¼” on a large part like a body panel. Finally, dies do wear with time, so details like body lines tend to become obscured over time naturally. With all that said, sheet metal of the 60’s and 70’s had as much – and likely more variability than that of metal stamped today because the quality systems today are much further advanced.
Couple this with how bodies were assembled in the 60’s and 70’s – many were man-handled to fit in the fixtures when welded up, so the bodies themselves had variability when assembled (much more so than today). Subject the assembled car to 45+ years of wear and tear and even putting pristine NOS sheet metal on it today can pose challenges.
A remaining question is who made / owns the tooling that makes the sheet metal parts for the aftermarket? It is probable that it is a combination; some of the marketers like AMD, Dynacorn, Goodmark, etc. own some of their own tools as well as buy parts from tools owned by the metal stamper. In today’s world of stamped metal parts most of the time the buyer of the part specifies the geometry and the stamper has the tool built for the customer and charges him for it (either in total, or amortizes the cost over “X” number of parts sold to the customer). It’s possible, but not typical for a customer to supply a tool especially to an overseas stamper.
Now many people are concerned about the current aftermarket sheet metal source, feeling that “cheap Asian” sheet metal is the problem. This really isn’t true - certainly any company can (and does) make bad product from time to time, but it isn’t rational for a business to consistently make and sell sub-par quality as a basis for a business model. Today there are a handful of companies serving the aftermarket sheet metal for restorers. In the US the well known ones are Auto Metal Direct (AMD) Dynacorn (DII), Goodmark and Sherman & Associates. There is a perception that some or all make their own parts to sell. This isn’t the case; none of these companies currently stamp their own sheet metal in the US. They all source their parts to Taiwanese companies who mostly stamp in Taiwan, but may also then sub-contract to facilities in China.
Those companies in Taiwan that produce aftermarket sheet metal parts are CHL Autoparts, TriPlus, He Qing Industry Co., LTD, Golden Legion Automotive Corp. and Shyi Tan Enterprises Co, LTD. These companies sell to most of the marketers of sheet metal in the US and many marketers sell the same part as their own. It is not uncommon to find stickers on parts that carry many different part numbers on them that represent Goodmark and Sherman as an example. While some of these marketers may own the tool that produced the part, it is more than likely that the metal stamper had to the tool built and is amortizing the tool cost in each piece they produce. The larger number of parts made on a tool, the more cost effective the tool becomes.
Each marketer may have their own quality control process which may be a point of differentiation, so it is possible that parts from say Goodmark show better than say Sherman because Goodmark inspected the parts that were imported more thoroughly than Sherman and therefore culled out any off-spec parts before retailing them in the US market. NOTE – THIS IS FOR EXAMPLE ONLY, WE MAKE NO JUDGEMENT ON THE QUALITY OF ANY MARKETER’S PARTS.
In the end, when you buy an AMD, Dynacorn, Goodmark or Sherman for the most part you are buying a part made by one of the following metal stampers: CHL Automotive, TriPlus, Golden Legion Automotive Corp, Shyi Tan Enterprises CO LTD or He Qing Industry CO, LTD. They are all good companies, based in Taiwan and sell to most all of the marketers of aftermarket sheet metal in the US on a non-exclusive basis.