Re: More paddles and keys ...


Hello Jim, W0EB,

The 'engineering drawings' are not so much engineering as just rough design drawings. The finished key is closer to this, than the first one I posted (my first drawing):

The thing about a drawing is that is easy to change.
Change is the only constant.
My main concern was to not have to drill and tap holes in the 1/2 inch thick steel base.
So this is kind of what the drill holes looked like when I was done:

I used 8-32 brass screws throughout the key.
A #20 drilled hole just allows an 8-32 screw to fit through.
I used heat-shrink for screw insulation on the DIT/DAH binding posts and contact posts.
So therefore, a #11 drilled hole was used to allow the insulated screw to fit.
I used plastic mayonnaise jar lids, cut to size for DIT/DAH post insulation.
The whole key is ground except for the DIT/DAH binding and contact point posts.

You can see that the dimensions are not exact. I held a ruler up to my monitor and got dimensions as close as possible. But they are not exact. I used a raster graphics program called Kolourpaint4 to make my drawings. If you want to be exact, use your favorite CAD program, or dust off your drafting table, T-square, and sharpen a pencil. ;-D

The 3/16" hole is for the rear post for the levers. Use a 1/8" post for paddles closer together.
I couldn't find any 1/8" brass rod in the shop, but had a 3 foot length of 3/16" brass rod, so I used it.

I used #11 holes for the posts so I would have a tiny bit of wiggle room for adjustment.
As you can see, I used two screws on each brass post to fasten them to the brass lintel.
But I only used one brass screw to fasten each post to the steel base. Less drilling through steel.

(Not to Scale)

I broke one end of a 3/16" center drill when drilling the pivot holes in the steel base.
As a result, I ended up moving the pivot holes in the steel base, back 1/4".
I had two plans for getting the pivots lined up.
Plan "A" was for pivot holes in the steel base.
Plan "B" was the alternate plan in case Plan "A" didn't work.
Plan "A" worked out to be close enough, so I went with it.

My main inspiration for my brass and steel DIY Dual Lever Paddle was a Vibroplex Iambic-S.
I looked at a lot of pictures on the Internet while I was designing my paddle.

Some things were designed because of the materials available to me.
For example, the 1/2 inch thick 4x5 inch steel base was cut from a 4" wide piece of steel.
I did not feel like cutting it smaller, so 4" wide was what I went with. I cut 5 inches off of 12 inches.

I used 8-32 brass screws because there were not enough 10-32 knurled nuts at the hardware store.
I bought ten 8-32 brass screws 1 1/2 inches long, with a hex nut and a knurled nut for each one.
I ended up buying ten more screws. I cut them to length with a jeweler's saw frame with a 2/0 saw blade.

I guess the main thing is to be flexible. Drawings are not chiseled in stone.
I think you will have much better results with your milling machine.
I look forward to seeing what you do.

Ken, KM4NFQ "Not Fully Qualified"

Ken, KM4NFQ "Not Fully Qualified"

On Mon, Nov 11, 2019 at 12:08 PM Jim Sheldon <w0eb@...> wrote:
Wow!  Thanks for posting your "Engineering" drawings.  I have a bunch of brass stock left over from refurbishing an old home made bug (had to replace the base because the guy that made it originally back in the 1940's made the base out of ASBESTOS of all things!).  I also have a Harbor Freight table top milling machine that also doubles as a drill press and lots of different end mill bits.

Having your precise dimensions will make it a heck of a lot easier to duplicate, and I also have a couple of 3D printers that I can use to make the paddles.  I have gotten reasonably proficient with Autodesk's Fusion 360 3D CAD program so colored plastic paddles won't be a problem either.  

I have a Begali "Stradivarius" paddle that I use every day, and that will be hard to get away from, but having a decent set like your design will be nice for the "portable" station (Elecraft KX3 at the moment, still waiting for Hans' QSX). 

This will be a long-term Winter project for me and having made a couple of hand keys, this should be pretty easy with the milling machine/drill press.

Jim - W0EB

------ Original Message ------
From: "Ken KM4NFQ" <km4nfq@...>
Sent: 11/11/2019 5:47:34 AM
Subject: Re: [QRPLabs] More paddles and keys ...

Thanks for you kind words David, K8WPE.
I started work on the DIY Dual Lever Paddle by drawing a couple of diagrams.

These were used as a guide to get started.
This is a snapshot of a piece of scrap brass used to make some parts.


I used a reciprocating cut saw to cut out the block, and a micro-lathe to machine it in a 4-jaw chuck.
The micro-lathe has a three inch swing.
The 8-32 brass screws, nuts, and knurled nuts were bought at the local Ace hardware store.

Ken, KM4NFQ "Not Fully Qualified"

Ken, KM4NFQ "Not Fully Qualified"

On Mon, Nov 11, 2019 at 5:33 AM David Wilcox via Groups.Io <> wrote:
Beautiful.  Not “pretty” yet but made with your own hands.  I am sure your CW will be a joy to hear.  It has heart and soul...... 

David J. Wilcox K8WPE’s iPad

On Nov 10, 2019, at 5:27 PM, Ken KM4NFQ <km4nfq@...> wrote:


I have been working on a DIY Dual Lever Paddle made from brass & steel.
Here are a couple of work-in-progress snapshots:


I still need to bevel the sharp corners, and clean it up.
I had the steel and the brass in the shop, as well as the sterling silver for the contact points.
The springs are from the battery compartment of an old toy.
The main expenses were for brass screws, nuts, knurled nuts, and taps/drills.
I estimate that I have about $40.00 + time & labor invested in this paddle.
I have had fun making it.

Ken, KM4NFQ "Not Fully Qualified"

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