My assessment of their safety space goes like this. The read head must he able to travel back and forth between the two end limits plus a wee little bit for installation errors. In machining terms, that means that the sum of the scale on both sides of the read head equals the full travel. In other words, the scale length isn't just the travel, it's the travel PLUS the length of the read head and its wipers. This extra length is what I came to believe Ditron called their safety space. Obviously, it varies with the read head dimensions.
In practice, you need a little more than that to avoid installation problems. I just added another centimeter on both ends because I knew that would fit. In hind sight I might have added 5cm if I had the room because I did end up close to the end in one case. Besides, magnetic scales are easy to trim.
Just to re-state how I handled it, the scale length I gave them is the machine travel plus my fudge factor. What they produce for scale travel is that number (LO) PLUS their own Safety Space. The physical (overall) length of the scale can be calculated from their drawings using the "LO+XX" dimension.
I remembered what you said as month end after they mentioned they wanted to close the deal by month end so they probably have month end and quarterly etc. goals or so they say. They may use it as a tactic to close the deal!Although my memory might be failing me, I never had the sense that they had month end numbers to hit. But I did get the sense that they had quarter end targets. If they volunteered that to Tecnico, I'd be thrilled - and maybe pissed that I didnt already order my lathe system at the end of January. I've been aiming at March 31st. But such is the way these things go.
I did the math and the price turned out better to buy the tape/head from Ditron. They gave me the smallest of their 1um heads for that and the quill mag scale. I'm thinking of reducing the bulk by using the tape on the quill too. Oh, I couldn't find the tape on the Ditron web site, I tripped over it on AliEx. It's also 10mm wide so it should install like the Aikron tapeAnother little piece of info. I got a small strip of Aikron magnetic scale from @Xyphota a while back. I plan to install it on the inside of my cross slide so I don't need to worry about damaging the scale with flying swarf or the tailstock or about any lost travel of the carriage. Ditron wanted too much coin for their scale and wouldn't sell it without the aluminium carrier. My system is the slim scales. The Aikron is smaller still by quite a bit. It does work with my Ditron system, but I had to set the resolution to 1/2 micron to get the right output. Something is funny there but it does work and does repeat.
D