ATC spindle pushes toolholder when the drawbar is released

[blim]

I have a Chinese 9kW ISO30 ATC spindle on my router and a linear tool rack with ISO30 forks to place the tools into.

However, when the drawbar is released the tool is pushed about 2.5 mm out of the spindle head. This causes the tool fork to deflect a lot when I put a tool back into the fork. And the same when I'm picking a tool I need to place the spindle 2.5mm above the tool, and the tool fork deflects upwards as the drawbar is closing on the tool. All in all, this puts a lot of stress on the tool forks and the z-axis assembly. So my questions is:

1. Is this design usual for most spindles, or could it be that I'm using the wrong type of pull studs on my tool holders?
2. Are there other forks out there that have built-in play in the vertical direction for the tool to travel up and down in the fork as the tool is being released / held?

[JAZZCNC]

#1 Very likely be you have the wrong pull stud or the wrong holders. BT30 and ISO30 look the same but they are very slightly different.

#2 Yes you can get spring-loaded grippers which give a higher degree of flexibility but they are very expensive and difficult to find. However, if you have everything set up correctly regards locations etc then it shouldn't be needed. Alternatively, you could put the tool rack on springs so the whole rack provides some flex.

[dazp1976]

Could this happen if the drawbar is set too low making it come out too far?.
Is that possible?.
Interested to know.
Screwing it loose a bit and adding more springs to compensate it?.

Am I being dumb again?.

[JAZZCNC]

Could this happen if the drawbar is set too low making it come out too far?.
Is that possible?.
Interested to know.
Screwing it loose a bit and adding more springs to compensate it?.

Am I being dumb again?.

Not a dumb question but not how it works.

The Drawbar clamp which grabs the pull stud is pulled against a taper machined into the spindle shaft which then pushes ball bearings or a split collet system against the pull stud to draw it in and clamp. So "screwing it loose" as you call it won't work, it would actually make it worse and would fall off eventually.

The pneumatic piston could be adjusted so it doesn't push the drawbar down as far but that's not possible with these spindles as it's built into the spindle, plus the adjustment is very fine.

Wrong Pull stud length is the most likely cause here me thinks.?