[QuinnSjoblom]

I have what i would call a hobby grade bt30 spindle and cheap toolholders. I would say comparable to tormach stuff. My spindle has probably about 5 tenths runout at 4 inches from nose. My toolholders range from a couple tenths to over a thou runout. Some of my tools ive been able to get down to a few tenths by clocking things around but i would like to do better. Im considering sending out my spindle for a regrind as assembly and maybe invest in at least a few good quality holders for the tools that matter.
If i decide thats too much money, im thinking there might be another option. I can buy some centerless ground stock that is larger than the tool, lets say for example i do this with a 3/8 tool. I will load a chunk of 1/2 inch ground stock into the toolholder with a half inch collet, maybe inch and a half long, sitting about flush with nose of collet. Then fixture an undersized drill and small boring bar in milling vise, spin up the spindle and drill, then bore a 3/8 hole in the chunk of ground stock that is loaded in toolholder. At this point the bored hole should be perfectly concentric to the spindle bearings. Then i will put clocking marks on toolholder, collet, and sleeve. The sleeve can then be removed and have a slot milled into it lengthwise. Reload the sleeve into the holder with a 3/8 tool and align the clocking marks. I should now have a tool loaded with zero runout no matter how much runout there is in the spindle taper, toolholder, and collet.
Is this a known method for getting excellent tool runout with not so great gear? I cant think of any reason why this wouldnt work great. One thing i can say about my spindle and holders is that they seem to have good taper contact. With a gauge pin loaded in in holder, i can load and unload holder from spindle many times and the direction and amount of runout is exactly the same every time down to about half a tenth. Any reason why this may not work out so well?

[handlewanker]

Why don't you just shrink a sleeve on your cutters and then grind the sleeve to a set diam.....all of your cutters will then run true.
Ian.

[deadlykitten]

hey quin, sooner or later, maybe you will decide to refresh the spindle, and whatever else is needed

until then, some quick fix ideas :
... craft some excentric sleeves, that you simply rotate inside the toolholder, so to adjust runout
... if toolholder flange is wide enough, put same thread holes in it, then tighten responsibly some screws, and transform it in dual contact, for roughing tools
... if you have a lathe partner, craft some toolholders are you wish
... use a small sharp tool / pcd to refresh the spindle taper

haha, check this google failed " stretch as much as the ostrich worth " ... i think you go it / kindly