[deadlykitten]

Have you ever measured to compare actual results to the sellers claims?

my dear goemon ( if i may ), is not needed to measure such things, once you understand how all tolerance start to sum up, for example into live broches: for a long shaft that ends with a tapered chuck, one can grind the od separately, then finish the cone by grinding it into the assamble, so to take away all tir related to mounting

about collets, some guys, in order to achieve tir repetability, drag a line on the collet+nut+chuck, so to always mount it at identical position, because, sometimes, tir increases if you flip the collet 180*

about entire carbide drills, is known that cilindricity ouput is better when the tool rotates (mill), versus when the tool is stationary (lathe)

about inserts, even if it is h7, tool tir for a toolholder + insert is always > tir of a solid carbide drill

just saying, all those above are common things, that others have done, and i suppose you are also familiar to them; and me, yes, i have measured a few things

I'd assume being able to adjust and fine tune to reduce run-out would be essential for precision

i have never bought fine tir adjustment systems for milling, only that i have toolholders and collets that i use only for finishing; also, to increase tool life, i have use the wire edm to cut coolant chanels into the collet, so to achieve peripherical coolant

onestly, sometimes i have thougth about setting tools so to have crazy low tir, like <3um, but this requires to adjust tir after the toolholder is mount inside the spindle (thus time loss), and so far i did not had any reason to do that

i once thought of buying adjustable tir nuts, but on 2nd thought, i realized that it is a fragile system, that won't keep up with the forces asociated with heavy cuts; i allready have pull out problems with normal er collet + bearing nuts; this does not mean that is not good for someone else, or that i try to discourage someone else to try, no ... is only a matter of application scale

adjustable er collet vendors :
... uk : MTDCNC | CNC Machines | Machine Tools for sale | Lathes and Mills
... usa : GlockCNC - GlockCNC.com

however ... about tir, there is a thing, for example : if final doc is 0.15, and i use an edmill with 4 or 6 teeth, and overall tir is 0.015max, then this means that edge excentricity during cutting is 0.015/4 .. 0.015/6, and such values are way lower than the feed/edge; for example, if you feed at 0.1mm/revolution, and tir is 0.1mm, then you expect to get flatness ? no, simply becuase tir value is comparable to feed value, but if tir is << feed, then surface roughness will decrease; so, as long as you don't have vibrations related to high rpms, then, if possible adjust feed to tir also, by using an electronic roughnes tester, it can be seen that real surface rugosity is better than expected for a specific set of doc&feed, thus sometime one may speed up things, and still be in spec with surface quality

if i would need to reduce tool tir on a high rpm spindle, for whatever crazy application, i would eliminate colets, and use a weldon + an excentric bush, designed to rotate in order to decrease any tir; it's more rigid and more consistent than an er colet if you will ask if i have done that, then answer is yes : i have modified live tooling for lathes that were initialy designed for er32 (max tool shank 20), so to mount a 25 tool shank, with low tir

as for checking er chucks, i use something as described in attached image

sorry for the long reply, i hope you found something usefull / kindly