N3ZN Single-Lever Key Fingerpieces

New Fingerpieces for N3ZN Single-Lever Key

There was the passing thought that I would really like to have a single-lever key. Acting on that thought, a N3ZN Single-Lever Key (ZN-SL) was bought from DX Engineering around the first of December last year (2021). Merry Christmas to me!

The CW Op’s CW Academy Basic Course had just been completed the last week of October (OCT21) along with having already signed-up for their Intermediate Course starting the first week in January (JAN22). My Basic Course advisor, Roy, KK**, had recommended to those of us in the course about the merits of a single level key for CW code speeds around 24 WPM and higher. I figured it was worth a try getting a decent single lever key for transitioning off of the Bencher BY-2 Iambic Key. That Bencher key was bought around early 1986 when working on getting my Extra when still living and working in the Dallas, TX area. The basis for all of this my renewed interest in CW after letting it totally lapse since about 1988, well over thirty (30) years.

Along comes the ZN-SL key. I still tend to be a bit rough at times with my code sending and receiving practice and in the Course’s Zoom sessions. I seem to be good up to around 18-20 WPM although striving and maybe even struggling for better proficiency and speed. After getting the ZN-SL, setting the WinKeyer USB Keyer for Ultimatic mode, the end result is – I seemed to be more rough and just about horrible. I even switched back to the Bencher briefly.

Early into the CW Op’s CW Academy Intermediate Course, classmate Brent, VA***, and I team up one Sunday afternoon for us to have our own virtual Zoom practice session. Once again, I seem to be pretty rough with the ZN-SL key. I mention to Brent some of my frustration adjusting to the key with a main one being my wrist being at weird angle relative to my forearm (which is resting flat on the desk). Brent recommends getting my wrist up a bit. I have no idea why I did not think of that earlier! Some type of pad was needed to get my wrist up some. A short stack of some mouse pads under my wrist seemed to help the ergonomics.

Several days later found me with a newly acquired wrist support for mouse – just a small little bean-bag type cushion found at Best Buy for about $5. That seemed to really help get rid of the stress, the unnatural wrist angle when operating the key.

I also found out about in the middle of the CW Academy’s Intermediate Course that my advisor, Roy, KK**, was using the same ZN-SL key. That made me feel better about what I had. Now, I just needed to really learn and adjust to using it proficiently. I was still struggling with it.

The “lightbulb” moment appeared. What was noticed was the ZN-SL’s fingerpieces were high, quite high really. That was compared to the Bencher and a Kent Iambic Keys. The ZN-SL’s fingerpieces were assessed on the key for their position relative to the operating position. I found the bottom of the fingerpieces just shy of an inch. No wonder my wrist was a bit “achey” after 15-20 minutes of using the key. There did not seem to be any way to comfortably operate the ZN-SL key with such a weird wrist angle with one’s elbow and forearm resting on the desk surface. Somehow, the fingerpieces needed to extend down towards the operating surface more.

An email was sent to Tony, N3ZN, enquiring if there were alternative fingerpieces to the stock ones that came with the key. I was informed there was no alternative to the stock fingerpieces available. Within several minutes of receiving that email response, a quick online search resulted in one person making fingerpieces for the N3ZN keys. I thought they were quite pricey coupled with thinking that a set could be made for what was really desired – keeping my wrist at a natural position when operating.

Several small 12x12-inch sheets of black plexiglass were ordered. There was some preparation work to be done though while waiting for the plexiglass to arrive.

The ZN-SL’s fingerpieces were removed with one being scanned-in. In Visio[1], that fingerpiece image was inserted and sized to 100% of their overall measured size, 26.25 x 38.5 mm[2]. That “template” was then used as the basis for a new fingerpiece outline. The focus was getting the soon-to-be fabricated fingerpieces to extend down towards the operating surface. I elected to get the fingerpieces’ “ear” down to about even with the bottom of the key’s base. The overall size was targeted to be about 43 x 38 mm.

A 45 mm wide strip along the edge of the recently arrived 12 x 12-inch black plexiglass was cut on the band saw with a new 24-TPI blade. That strip was then cut into ~40 mm blocks. That gave me 6 blocks. The blocks were stacked on top of each other using several strips of 2-sided scrapbook tape between each block’s protective surface paper with each block’s uncut and true straight edge being aligned and flat. That flat edge was now the reference for measurements and forming. A cutout of the new shape’s outline drawing was taped to the top block using the 2-sided scrapbook tape

The new fingerpieces rough shape was cutout from the block using the band saw. Between using a combination disc and belt sander for the outside curves, and a small ~1-inch round sanding “tube” inserted in the small drill press for the tight inside curve, the overall shape of the new fingerpieces were made. The two (2) mounting holes were measured, marked, and drilled.

The only regret is failing to get pictures of the cutout and forming of the 6-stack “fingerpiece block” (with it still being winter and the small space heater on, I was only out in the garage for maybe an hour or so each time due to getting cold).

[1] Even though a docked MacBook Pro 15-inch (2019) is used exclusively, Microsoft’s Windows 10 runs within the Parallels application. That allows me to run a few ‘Windows only” ham radio and other applications such as Visio.

[2] I find it much easier to work with metric, and especially with small items. Note: I used to live and work overseas for about half of my career. Personally, I really wish the US would “go metric” as it is just so much easier to work with.

Original fingerpiece (top) used as the foundation for creating the new one's outline drawing (bottom). The block’s uncut and true straight edge was the one perpendicular to the mounting holes at the top.

The block was separated into three (3) pairs of fingerpieces. Each pair was marked on that flat uncut straight edge with either one, two, or three “scratches” with the backside of an Exacto blade – I wanted to make sure each pair was marked in case being separated later.

Each pair was filed and sanded for a left and right fingerpiece. The filing was done to get the each one’s edge “close”. Then, there was a lot of sanding with finer grit starting with about 120 grit down to 800 grit sandpaper strips getting each fingerpiece’s left and right outside rounded and smooth. The inside edges were just “touched” enough with some sandpaper to get the sharp edge off each piece. The filing and especially the sanding took the longest to get done for the 3 pairs. The plexiglass’s protective paper was left on until the very end. The drill press vise’s jaws were covered with masking tape as an added precaution against scratches.

The edges were then finished and polished with a Dremel tool set on the slowest speed using a small axial felt pad. Each fingerpiece pair was polished using some auto compound polish that I had (and about dried-up since not having used it in a long time). That seemed to really worked good in getting the edges polished.

The mounting holes needed to be “touched up” a bit relative to each fingerpiece’s clean or straight edge – there was too much distance between the edge and the first of the two mounting holes. Using the double-sided scrapbook tape once again, the fingerpieces were again formed into a block aligning the previously drilled holes and the straight edge. With some 800-grit sandpaper on the 6-inch disc sander, the block was “trued-up” sanding down a little bit at a time until getting the right distance between the straight edge and the first mounting hole.

The new fingerpieces were installed on the ZN-SL – they look good along with a much better feel.

The end result is the new fingerpieces allowing my wrist to be at a more natural position with my forearm resting comfortably on the desk.

Now, there still needs to be some more work on getting my code better with the ZN-SL!

Fingerpiece pairs - original (top), and newly fabricated (bottom).