21. Swage, a machine with both good and bad sides, but first a harassed customer

A couple of weeks ago an obvious upset customer came into the workshop with a problem. He had tried, without success, to fit a rubber seal to the boot lid of his Volvo 140. On this car the seal is fitted into a sheet channel or profile, Image 1.

Image 1. Rubber seal hold by a channel welded, screwed or riveted to the detail. 1. Rubber seal 2. Channel

This kind of fitment is used on huge number of cars and works well as long as the seal is untouched. But refitting of a new seal in the profile is almost always troublesome, see the book. Smaller pieces of seals can be put into place with help of a flat screwdriver but with a risk of damages of the seal and the surrounding painting. And, the work with a screwdriver is slow.

A tool, not available in the trade, is described in the book, Image 2. On the request of the customer the tool was made in a small batch. The tool helped him to fit the seal very quickly and without effort, Image 3. There are a few tools left which I offer you with insight in the problem to buy. The price is 300 SEK or 33 $ or 27 £ or 31.3 € including shipping. Please order the tool via a message at info@bladsforlag.com, not at the bookshop which is special designed only for the book.

Image 2. The tools for easy fitment of the rubber seal.
Image 3. Fitment of a rubber seal.

The swage is a machine with two rotating rolls, Image 4, forced to rotate with the axles by Woodruff keys. The rolls and their axles can be pressed together by the crank on the top. The device is usually used for shaping bent edges, Image 5, and depressions, Image 6, in a panel. The process is good for bending of edges but can be troublesome when making depressions which begins and stops at a distance from the edge of the panel. The sheet will often be effected or uneven over a large area.

Image 4. The swage, note the stop used and the flat stop on top to the right.
Image 5. Bending of a slightly curved front edge of a door skin.

The edge of the sheet can be hold against a stop of different kinds during the operation, see Image 4.

If we look at a conventional pressing process the forming of the sheet is made by help of a tool with a male and a female part and a space for the sheet between them. The part fits exactly to each other, the better fitment the better result in the end.

During the press work the press force must be higher than the yield limit of the material; this is a condition for the changes of the shape. Above this limit the material is said to be floating. The phenomena is called plasticizing, see chapter 10 in the book. Without plasticizing no changes of the shape will occur.

When shaping a depression shorter than the panel in a swage, like the one in Image 6, it is not possible to keep the sheet tight during the process resulting in a complete floating of the material. The extra material needed for creating the depression is partly “stolen” from the surroundings and that results in unintended changes of the shape.

Image 6. Creating a profile across the panel.

When shaping a depression shorter than the panel in a swage, like the one in Image 6, it is not possible to keep the sheet tight during the process resulting in a complete floating of the material. The extra material needed for creating the depression is partly “stolen” from the surroundings and that results in unintended changes of the shape.

But, it is possible to pre-stretch the sheet before the work in the swage, for example in the English wheel, reducing the establishment of unintended shapes, see chapter 10 in the book.

With time the numbers of rolls used often are increased. Image 7 shows the table with rolls at the back of the machine. All rolls are made in rather mild steel; it is not necessary or desirable to harden them, it is only a waste of money. See the book for information about shapes, dimensions and so on.

Image 7. Rolls and distances arranged at a table at the back of the machine. Note that the machine is on wheels.

More important than questions about hardening and so on is the possibility to make a keyway in the rolls. Either in a well equipped workshop in the neighborhood or self. How to make such is detailed described in the book.

As a bonus, it is possible to make rolls for bending board mills for glove boxes and similar and for creating flanges to cooling tubes, see the book.

Finally a detail worth a short thought is the working depth of the machine. Today many small and inexperienced makers are keen to offer swages made of square tubes with considerable depths thinking that the size is the most important factor. But, usually the deeper machine the more flex in the frame. Personally I prefer a not so deep but stable, casted and old machine bought used before a deep but welded and more flexible modern one!

Another detail worth attention is the possibility to convert the machine with an electric motor and a pedal for forth and back rotations! See the book for information about rotation speed and more.

Panel Beating Doctor Bengt Blad

At this point in my life when I was about three quarters through the medical schooI I discovered the English wheel and the Eckold machine, and, one thing leading to another - no more time for med school.

More about the book

This book, with around 1,500 pages of reader-friendly text and about as many illustrations, is a summary of 40 years of working with vintage, collectors' and racing cars.

visaStripePixneypaypalmenumenu_2mastercardFlagSvFlagEndiscoveramex