Distance from collet to table

[Jonas]

Hi
I am trying to design a fixed column desktop machine. Goal is 400 mm(X) x 300 mm(Y) table to the smallest footprint. It is not about 650 mm(X) x 600 mm(Y).
For these machines the Z is limited so I do not want to design the spindle collet to go too close to the table.

So my question is.
How close to the table does the collet nut have to go? Right now I have 20 mm.
It of course depends on the tool and what is to be cut. But lets say you want to cut 3 mm aluminum plate with 3 mm tool? How long is a normal good stick out? I can see that some tools are 50 mm long and have cutting of ~12 mm. I have no idea how much tool will fit into a 2,2 kW Chinese spindle.

[JAZZCNC]

So my question is.
How close to the table does the collet nut have to go? Right now I have 20 mm.
It of course depends on the tool and what is to be cut. But lets say you want to cut 3 mm aluminum plate with 3 mm tool? How long is a normal good stick out? I can see that some tools are 50 mm long and have cutting of ~12 mm. I have no idea how much tool will fit into a 2,2 kW Chinese spindle.

Well for the very best stiffness you should have the least amount of stick out as possible but this will vary with flute length and coatings so no one but you can answer that question really.?
Why coatings.? Many tools have a coating that usually goes past the flute or cutting length, this then becomes your limiting factor because you don't want the coating in the collet otherwise the tool can slip due to the fact the collet is only gripping the coating portion rather than the whole shank.

The length that will go into the 2.2Kw spindles can vary from supplier to supplier, I've had some with the shafts bored very deep and others where they are only 30mm. The one we fit now will take about 50-60mm I believe.? I will get a spindle off the shelf and measure tomorrow.!

Also, note that if you are using the WC 2.2Kw round type spindle you can always slide it up to down in the holder if required.!

[Jonas]

for the very best stiffness you should have the least amount of stick out as possible

Yes.
And thank you for the heads up with the coating.

If the flute does not have coating and could even saw it off if it does not fit all the way into the spindle then maybe for good stiffness maybe should design it to go down to something like 10 mm. 3 mm for stock and then 7 mm between stock and collet nut.
In the picture it is 22 mm, I have to extend the face plate 12 mm down and move the motor holders 12 mm down. My guess is that face plate (20 mm aluminum) is better to extend than move motor down?