The Hobbyist's Machine Shop – Blog

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Taig 24K RPM Spindle Article Available

The full article on the Taig 24,000 RPM water cooled spindle conversion is now available on The Hobbyist Machine Shop website. Follow this URL: 

https://thehobbyistmachineshop.com/cms/projects/high-speed-spindle-for-the-taig-micro-mill

The new spindle performance exceeds all expectations. It is not a low cost option / addition to an already  adequate micro-machine tool system, but it does provide a very good way to achieve more than double the stock Taig spindle speeds.

Some applications using very small diameter tooling are performed much better when running adequate SFM and cut travel speeds. High speed spindles and especially water cooled ones like this example are a joy to use because of their extremely quite operation.

The Taig spindle is known for its quiet operation and the water cooled spindle here is in my opinion just as quite or perhaps more so, even running at full speed. Tool cutting sound is the same but the spindle motor has none of the sound of a high speed router.

Comments on ER11 Collets

ER11 Collets

ER11 Collets

The new 24K RPM spindle has an ER11 style collet holder. Attempting to measure the TIR (Total Indicated Runout) is not possible with the measuring tools available at THMS. It should be well under 0.0004 inch.

With ER collets, TIR of .0006” (.015MM) is considered Class 1, .0004” (.010MM) – Class 2, and .0002” (0.005MM) is Class AA (5 microns). Of course, the cost increases with accuracy. Class 2 and higher is my recommendation. A holder with excessive TIR negates this accuracy.

The internal surface of the holder looks well finished. I am going to depend on the fact that a spindle of this design and cost should certainly be well machined. First operational tests confirm this hypothesis.

Of most concern after assessing spindle TIR, is the quality of the ER11 collet used. The spindle is shipped with a ¼” ER11 collet in place in the holder. It is good practice to always have a lightly oil-protected collet, finger tight in the spindle holder. This helps prevent contamination and corrosion of the mating surface. Wipe out the spindle protective oil before use.

ER style collets are self-ejecting, so a sticky collet is not an issue. I have read negative “user reports” from clueless owners of ER16 and larger collet retainers (the nut — that has a double meaning) telling of the threads being very poorly machined. The off-center ridge inside the nut is an ER design feature. Not a manufacturing fault. Do some study of the ER collet system.

The ER11 collet has the retaining ridge but it is too small to be made off center. I bought a second nut to be sure. Therefore, the ER11 collet is much harder to insert and remove than the ER16 and larger collets because the retainer ring is centered… Continue reading

24K Spindle Video

The 24,000 RPM water cooled spindle on my Taig Micro-Mill is operational.

The power required to do wax milling with 0.004″ milling bits is extremely low. I use my old settings of 10,000 rpm and 10 IPM travel on the first run. The no load current on the spindle is 0.6 amps. While making the first carving the spindle ran at 0.6 amps. It was as if there was no load on the spindle motor.

The next run as shown in the video was at the recommended limit of the 0.004 inch tapered mill bit. The run shown is 15,000 rpm at 15 IPM travel. The load on the motor increased from 0.6 amps to 0.7 amps. A sign the spindle was doing more work.

The power consumption went from 66 watts to 77 watts. Cooling is almost of no concern. The water must flow, but the spindle operation is producing minimal heat output.

More testing to come. I will be adding a closed loop cooling system with a radiator.

There is absolutely no vibration at any speed, much improved over the original belt drive system. I am extremely pleased with this new spindle and water cooled operation up to 24,000 RPM!

Just Add Water

The water cooling has been added to the high speed spindle through the red tubes in the picture. This is phase one where I will be using a reservoir with a sump pump behind the bench.. This should let me operate for maybe an hour or so. I don’t have any idea how much and how fast the water will warm.

The next step in the water cooling will be to add a closed loop system with a radiator to move the heat out into the ambient air rather than store it in the water tank. But first I need to determine through running and testing how much heat per hour is produced by the spindle in my type of operation.

I will be in the 10K to 24K speed range for many hours of continuous wax milling. I suspect spindle loads will be very low but only through running and testing can I design an adequate cooling radiator system.

Next is the spindle three phase wiring and power connection, followed by programming the VFD. If all goes well the spindle should be operational in a few more days.

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24K Spindle Progress

The parts arrived yesterday. Exactly as shown in the previous post. I placed an order for some four conductor cable for the wiring between the Variable Frequency Drive (VFD) and the spindle motor.

I needed to see the clamping size of the spindle’s electrical plug connector. I didn’t want to select and order a cable that would not fit. The cable is on they way to me, so I created the adapter I needed to mount the new spindle on the Taig Micro-Mill.

The picture shows the results of my work as the spindle is now nicely mounted on the mill.

After I am finished with all the mounting, wiring, and set-up… and I have the new spindle working, I will write a detailed report on the mounting plate and all the work required in making the conversion.

I think the spindle looks like it belongs on the Taig!

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