[handlewanker]

Because the spindle slides in and out at the tool change and thus has to be loose enough to slide in the bearings or whatever?

I think Mac has once again gone to the extreme with the example, totally out of context.....the poster probably has a simple Chinese 25,000 rpm spindle and that is what the question was about...…...not some exotic ATC spindle like Mac showed.
Ian.

[mactec54]

I think Mac has once again gone to the extreme with the example, totally out of context.....the poster probably has a simple Chinese 25,000 rpm spindle and that is what the question was about...…...not some exotic ATC spindle like Mac showed.
Ian.

Not out of context, it's a very good example of what happens with these HS Spindles, it's how they are Designed

The spindle the OP was looking at was one with a ATC

[handlewanker]

Not out of context, it's a very good example of what happens with these HS Spindles, it's how they are Designed

The spindle the OP was looking at was one with a ATC

I apologise Mac for misinterpreting your explanation as I overlooked the point that the spindle in question was ATC and not just an ordinary plain 24,000 water cooled job...….and I advocated using the said ATC spindle as a motor per se to drive a plain spindle, the ATC model, being a complete entity, would not be practical or at all possible.

I'm astounded that the spindle shaft or bearing can move out of the housing when it ejects the tool......watching the video explains this phenomena totally......surely the spindle has bearings that are opposed to one another and therefore are held in the housing like a normal mill spindle....it must be a design function then.

But I expect it is the design of this particular type of (cheap?) high speed spindle, with the ATC function, that dictates how it is designed and constructed to give the tool ejection function as it has the motor on top and therefore probably no way to have a conventional power draw bar design......unless the motor had a hollow spindle too.....and a big escalation in price.

Perhaps by some cunningly devious design the motor part could be made to raise up and down to act as the draw bar in itself without making the bearings in the milling spindle part prone to movement.....2 separate spindle shafts etc......no doubt a more expensive design "could" work like that.

For those that like to think outside of the box, supposing a conventional mill spindle had a high speed water cooled spindle mounted on top of it and a solenoid thingy....whatever..... between the two to make the motor rise and fall and would be attached to the draw bar so that you have an ATC model on the cheap without the problems of bearing moves...….but for milling steel you wouldn't want to have a high speed motor without the reduction I mentioned, so it would be a none starter for the pure milling of metals.

What it would be useful for is to act as an ATC motor on a gantry router for highspeed milling and carving without the bearing problems.

I imagine that a 6040 gantry router fitted with a cheap ATC spindle to that design would be highly sought after......just thinking......if the Chinese are listening ….go for it......cheap CNC gantry type routers will never be the same again.
Ian.

[mactec54]

I apologise Mac for misinterpreting your explanation as I overlooked the point that the spindle in question was ATC and not just an ordinary plain 24,000 water cooled job...….and I advocated using the said ATC spindle as a motor per se to drive a plain spindle, the ATC model, being a complete entity, would not be practical or at all possible.

I'm astounded that the spindle shaft or bearing can move out of the housing when it ejects the tool......watching the video explains this phenomena totally......surely the spindle has bearings that are opposed to one another and therefore are held in the housing like a normal mill spindle....it must be a design function then.

But I expect it is the design of this particular type of (cheap?) high speed spindle, with the ATC function, that dictates how it is designed and constructed to give the tool ejection function as it has the motor on top and therefore probably no way to have a conventional power draw bar design......unless the motor had a hollow spindle too.....and a big escalation in price.

Perhaps by some cunningly devious design the motor part could be made to raise up and down to act as the draw bar in itself without making the bearings in the milling spindle part prone to movement.....2 separate spindle shafts etc......no doubt a more expensive design "could" work like that.

For those that like to think outside of the box, supposing a conventional mill spindle had a high speed water cooled spindle mounted on top of it and a solenoid thingy....whatever..... between the two to make the motor rise and fall and would be attached to the draw bar so that you have an ATC model on the cheap without the problems of bearing moves...….but for milling steel you wouldn't want to have a high speed motor without the reduction I mentioned, so it would be a none starter for the pure milling of metals.

What it would be useful for is to act as an ATC motor on a gantry router for highspeed milling and carving without the bearing problems.

I imagine that a 6040 gantry router fitted with a cheap ATC spindle to that design would be highly sought after......just thinking......if the Chinese are listening ….go for it......cheap CNC gantry type routers will never be the same again.
Ian.

Your High Speed Spindle is made the same way, is non adjustable, unless you know what you are doing with Bearing Preloading, this is how these spindles have to be made No the Bearings are not apposed the Front Bearings by Design for High Speed are mounted this way with cups facing out, now the rear Bearings at the top of the spindle are the opposite way giving you a Back to Back Bearing arrangement, the difference here is that they are spring loaded to keep a constant preload on the front Bearings, this is the only way to get a high speed spindle like this to last

The spring loading at the top Bearings can be adjusted down to a small number, only on these ATC spindles, the Video is showing the extreme with a spindle that needs adjusting which is easy to do by removing the top cap and adjust the preload

If the tool changer was designed and working correctly it would not be putting any load on the spindle to push it forward like this also


This is why I posted this to show that these HS spindles are not suitable for milling steel with Endmills, there are some of these Spindles that have different Bearing arrangements that can be used for steel, normally don't go up to 24,000 RPM and Bearing life is low