please, how to improve coaxiality when drilling on a lathe ?

[deadlykitten]

hello guys ( and girls ) if inside each post of a turret is a drill, each post will output a different hole size ( chuck rotates, no live tool, no Y axis )

1) turret radial play shoud be < 0.03
2) holder bore dia is H7
3) holder bore position should be <0.03
4) sleeve used has h7 external dia
5) sleeve used has H7 internal dia
6) sleeve concentricity & coaxiality between OD&ID is ...
7) maybe a collet is used to clamp the drill

drill is manufactured in h7 tolerance, while 1+2+3+4+5+6+7 will sum some errors



let's go to a real example : hole o15 is required; standard tolerance is ±0.1; hole size is o15.07; if i put the holder+tool on another post, i get o15.13

the difference is not big, but please, how would you handle such cases ? what would you do, so to get a hole size as close to drill diameter as possible ? kindly

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[deadlykitten]

a drill inside a floating chuck / you have some sense of humor

[deadlykitten]

ooook please, do you have a video / technical book / something for it ? only by looking at the link, is hard to guess what kind of adjusment it has ...

i found this description : https://www.iscar.com/eCatalog/MoreI...8&item=4500404

[deadlykitten]

it has 1degree angular adjustement; at this value, it can compensate a turret Z missalignment of 1.745mm/100mm

nice, thx okuma i will go for a quote ...


also just found these : https://www.iscar.com/eCatalog/Produ...mapp=IT&app=98

[deadlykitten]

hi, that one seems to have 0.2mm radial adjustment

i was thinking about this one, with 2mm rad adj : https://www.iscar.com/eCatalog/Famil...pp=98&GFSTYP=M

also the L dimension is shorter; do you think that is better do have a shorter L ? i mean is there a compromise, comparing to yours ?

and more questions please :
... how do you align those ? you use a centro inside the chuck ?
... is the radial adjustment 360 degrees ? or is it only among Y ?
... also, is the angular adjustment 360 degrees ? like anywhere on the surface of a cone ? or is it only among X ( so to compensate turret Z missalingment )

thank you

[deadlykitten]

about gyro alignment i found attached pdf page, from here : https://www.tungaloy.com/wp-content/uploads/389.pdf

alignment seems to involve :
... turning something in h5/h7, until the "guide bush" slides smooth
... insert a "pin" into the gyro
... gentle rotate the screws, until the "pin" slides smooth into the "guide bush"

this may be a standard procedure, but is long, complicated and loses precision i wont go into such details right now, but there should be a faster way to do it

however, even so, through the flange, there are M6 or M8 screws ( attached image ), and when the tool will be changed, the torque effort for clamping/unclamping the nut will pass through those tiny screws

this is not stable; such a device should be :
... rigid enough to handle higher torque and shocks, or
... less rigid, while tool change procedure should require less torque

in most cases, forces required to change a tool are greater than the cutting forces
... pro example : integral drills clamped inside a collet
... contra example : drills with inserts

so i find this to be more reliable ( because a hydra holder requires less torque to change a tool, comparing to er chucks ) : https://www.iscar.com/eCatalog/Famil...pp=98&GFSTYP=M

[deadlykitten]

hello all, if you wish, please check also these items :

... Dial-Ables – The Answer for Lathe Turret Misalignment ( it is similar to the gyro solution, shared by okuma85 in this thread; i don't like the setup procedure, seems long to me, and the device is not for high cutting forces )

... attached image + pdf ( setup procedure is shorter then the gyro, but also this device is for low cutting forces; you can find the full document here : http://www.everede.net/documents/201...ct_catalog.pdf , more infos here index.html )


i will share soon infos about achieving coaxiality, faster, for operations with higher cutting forces / kindly