A not so long time ago we came across a low lying railroad bridge.
We hit it with the top of our mast.
With damage to the anemometer transducer we felt it was in our best interest to invest some $$ to make it easier to get my old gut up the mast without having Vicky being shaking in her boots while tending me up the mast, relying on her sole ability to keep me from plummeting to the deck.
So we bought some steps.
Of course the old machinist in me felt they were not up to my standards of being de-burred/no sharp edges, so I grabbed a mill file and hit them proper where it counted, just in case I ventured up there barefoot. I will!
After checking with many others who had and used and installed mast steps, that 18" would be fine. I bought enough steps for that distance but at the last minute (thanks Tor) I went with 16" which lets me very comfortably climb and always have at least three limbs secure on the mast. At 5' 8" and shrinking fast this distance is PERFECT for me.
Here's how I installed them while hanging from a chair....
First, using a self centering bit (designed for centering hinge screws quickly in door installations) I would start a first hole. Great device with a spring loaded collar that centers the drill in a countersunk hole.
I'd then drill out the started hole with the proper drill dia. for a 1/4- 20 tapped hole. Tap the hole and then attach the mast step base to the mast with one screw. I was using some old diesel fuel as tapping fluid. A little dip of the tap in an old prescription pill container filled with diesel oil did the job of keeping the tap lubricated while easy to get to from a bucket while hanging there.
I'd then fasten the base onto the mast with one screw tight and take the self centering drill to start the other three holes while it was securely in place.
Then drill the three remaining holes out to the proper dia. for the tap, remove the base and carefully tap all the remaining holes. Then I'd take a countersink and clean the sharp edges off the tapped holes.
A generous douche of Lanocote in the threaded holes...
Another generous coating on the countersunk holes and on each screw threads as final assembly.
A very easy climb...