An interesting component of the Hammond that has never quite received enough attention is the impression strip. Turns out you can make your own! See below.
The impression strip of the Hammond typewriter is a (un)neccessary component for the proper usage of the machine. Technically, true. In practice, it depends!
When the Hammond company began selling its machines with shuttles they had a terrible breakage problem. The hammer’s force was such that it would crack the face of the shuttle, which is just hardened rubber.
To resolve this issue, the company came up with a rubber barrier between the hammer and the shuttle to soften the blow. This barrier would be known as the impression strip and it would attach to a series of pegs on either side of the carriage.
The Hammond typewriter does not have a platen, just a pair of rollers. The platen on a modern typewriter allows the hammer to impact the paper but not damage it, or the slug. For the Hammond, it’s platen is the impression strip.
The original impression strip was made of thin natural rubber. Over time attaching it to the machine got better and the strip was made to fit the entire Hammond line. In addition to the everyday workhorse strip made of rubber, the company also produced a “gossamer” strip.
For some, an inelegant impression strip purchased online made from the same material as bicycle inner tubes may be enough. However, you can and should make your own, which will not only be cheaper but can be from nicer materials.
An impression strip may not even be needed in some cases. In 1900, onionskin was widely used in offices, but it had a weight of just 9 pounds. Very similar to modern day tracing paper. Comparatively, modern printer paper has a weight of 20 pounds. The author uses 100% linen fiber paper with a weight of 24 and no impression strip. The added thickness acts as an impression strip of its own, softening the blow of the hammer, but historically and technically it would be more accurate to use a strip.
Something else we have going in our favor of choosing to use a strip: The average Hammond mainspring is at least 100+ years old, and maybe holds half the power it did when it was new. That decreased power means a lighter impact of the hammer, and thus less impact on the shuttle. There are tricks to increase the darkness of the print, but ultimately it would require putting a new mainspring in the machine.
With the full force of a new mainspring it would be necessary to use the impression strip. The fun part until then is you can create your own out of just about any materials. Cloth, fabric, latex, neoprene, felt, etc. You really don’t need to buy one online when there are many more elegant, and equally useful options.
In these videos, Tim Moffitt walks us through making our own gossamer impression strip.