Chinese Spindles

**Edmo117** · 24-05-2012

Hi

For what it is worth I think that drilling a hole down the centre may be a very bad idea. Think about it, the Chinese are very good at making things down to a price so their design is not going to be conservative, that's for sure. Therefore, the diameter of the shaft will have been minimised in diameter and material specification to do the job and no more. Removing some of this material will weaken the structure I am sure.

If you want to do it anyway and can't drill or bore it because the material is hard, you can always get is spark eroded ....maybe.

Still think it is not a good idea though.....sorry

**Ricardoco** · 24-05-2012

Originally Posted by Edmo117

Hi

For what it is worth I think that drilling a hole down the centre may be a very bad idea. Think about it, the Chinese are very good at making things down to a price so their design is not going to be conservative, that's for sure. Therefore, the diameter of the shaft will have been minimised in diameter and material specification to do the job and no more. Removing some of this material will weaken the structure I am sure.

If you want to do it anyway and can't drill or bore it because the material is hard, you can always get is spark eroded ....maybe.

Still think it is not a good idea though.....sorry

The picture below is of an ER11 water cooled spindle with a hollow center and looks as though it is meaty enough, so i would assume that an ER20 model would be larger, the problem is some come with hollow shafts and some dont, it seems you take pot luck. I have sent a few mails to see if i can stipulate hollow shaft ER20 collet. we will see how that pans out, but they are not as fragile as you may imagine as the pic shows.. unfortunatly ER11 is a little limiting for my project.. Spark erroding wow but then im not sure where i would get that done..

Click image for larger version.

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**JAZZCNC** · 24-05-2012

The shaft is very strong on the 2.2KW spindle and would easily bore without weakening too much. Obviously it will but to be honest these spindles don't produce enough torque to get anywhere near being able to snap a shaft of this diameter.

I don't think it would be too hard to design some way to draw the ER collet but it would have to be a single large collet permantly installed.
Then separate tool holders machined to actually hold the cutting tools. Similiar to the Tormach system.
Problem with this approach, with this spindle, is both the relatively small diameter of the largest ER20 collet @ 13mm and the fact they will need to be balanced to handle the high spindle speeds.
The tormach system works by using the largest R8 collet @20mm and the tool holders shank match's . . BUT . . the main difference and the area I think will be hardest to over come is the balancing. Also because of the relatively small 13mm shank the tool holders will also need to be machined from high quality steel and hardened appropriatly.

The tormach systems highest spindle speeds are I believe 10K Max. The jump to higher speeds I think is where all the hard work will be.? Getting it wrong will shake the machine and very quickly wear the spindle bearings away, not to mention the shite cutting it will do.

It's do-able but far from simple.!! . . . . If it was simple and done cheaply our Asian cousins would have surely done it by now don't you think .??

There are several ATC spindles out there but the all cost a few 1000's not 100's.!!

**Ricardoco** · 24-05-2012