[Swede]

I have done a couple of searches on this already, and I didn't find what I needed. Hopefully, this hasn't been hashed to death already.

Back when I built my bench CNC mill, the spindle choice was easily the most difficult and expensive among many other factors that go into a good build. At the time, the choices were pretty limited.

A good spindle (IMO) for a small bench CNC mill should have the following characteristics:

1) Very high rotational speeds... needed for small cutters. When using 1/8" to 3/8" carbide tooling, or especially engraving, RPM's north of 25,000 RPM is not a bad idea.

2) Accuracy - Anything that spins at 40K or more better have excellent bearings and proper balance. Accuracy needs to be at least very good, if not NASA-grade, as contouring with a 1/8" ball end mill will need it.

2) Variable speed. HF (high frequency 3 phase) or DC does this well

3) A common spindle nose taper. ER is excellent, IMO. Proprietary tapers or collets can be expensive.

4) Mass - the spindle/motor mass cannot be too high, as this makes Z-axis travel difficult.

5) Power - 40K RPM and high-speed motion hardware is useless if the cutter bogs down at 6 IPM. My own choice would be at least 1,000 watts, as these power measurements are usually given at high speeds, and if the spindle is running at 5K, you're not getting a kilowatt at the cutter.

With all that said, I ended up with a German-made HF spindle of 600 watts or so, and paid dearly ($$) for it. It works, but not optimally.

Fast forward a few years. There are air and water-cooled HF spindles all over eBay at ridiculous prices. Some claim "German made bearing!! ISO 9000!!" etc, and I don't know what to think.

I'd like to upgrade my spindle. Not having an ER or similar collet system is killing me. I cannot even buy a 3/16" collet for mine, and I'm limited to 1/8" and 1/4". Has anyone put one of these Chinese HF spindles into use? I would love to hear about them... they seem too good to be true, for the money. I'd like an air-cooled 1,500 watt HF spindle with an ER nose, with maybe a 60mm to 90mm body diameter.

This is the style. Prices range from $200 U.S. to $400 or so.


Also, any comments on small, precision spindles in general is welcomed.

[691175002]

There is a hundred page thread about them:
http://www.cnczone.com/forums/diy-cn...periences.html

In general they are pretty good for the money but you want a name-brand Vfd. There is a company called "German' in china that makes the 'german bearings'.

[Maglin]

Now that is shifty. Just name your company German so you can say they are German bearings and not bearings made in Germany.

[SCzEngrgGroup]

Now that is shifty. Just name your company German so you can say they are German bearings and not bearings made in Germany.

Aw, come one! Next you're going to tell me those Harbor Freight "Chicago Electric" power tools are NOT made in the USA?? :-)

Reminds me of one of my favorite newspaper ads when I was a kid - It was for film processing, and when you sent in your film for processing, you'd get a free roll of "Famous Brand film". You got it - the film came in a box proudly labelled "Famous Brand".

Regards,
Ray L.

[awerby]

But in the early post-war years, the Japanese were supposed to have named a town "Usa" so they could label their products "made in Usa". Of course now the shoe's on the other foot; we might be well-advised to rename one of our rust-belt towns "Japan"...

I think the original poster in this thread was talking about High Frequency, not Harbor Freight spindles. I haven't used the Chinese spindles referred to, but I've had pretty good luck with Perske spindles, which are made in Mannheim, Germany (which I think is in Europe...) used with a Hitachi VFD.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[pete from TN]

But looking at the picture it sure looks like if it was the right size in diameter it could be just stuck up inside my RF45 millhead when I needed a higher speed spindle setup for engraving or whatever. Wish they had some sort of quick change collet system so you could get some repeatability but I guess you could use a table mounted tool length sensor for it and be fine. Man 40k would be incredible if the bearings are any good. I wonder if they have ceramic bearings in them. Peace

Pete

[SCzEngrgGroup]

There was a thread a year or two back where someone bought one of those Chinese spindles, and it was not very impressive. Perhaps OK for the price, but not good overall in terms of runout, and quality of the bearings. If you're going to go over 10K RPM, you better have REALLY good bearings, very carefully fitted. And since these things are really intended for small cutters, very low runout is absolutely critical, or cutter life will be seriously compromised.

And talking about running 25K+ RPM with 3/8" cutters on a benchtop machine? Not likely to give a good result.... You need a VERY rigid machine to be able to take advantage of that kind of speed on a tool that size. Lack of rigidity will destroy carbide tools at the kinds of feedrates you MUST run at those RPMs. And if you don't run those high feedrates, you'll ruin the cutters in no-time through rubbing and heating.

Regards,
Ray L.

[Hans_G]

The 1500W spindles are always ER11 (at least when I bought mine, about 8 months ago), which limits you to 1/4". You have to go to the 2200W spindle to get an ER20. GWizard says 108ipm for a 3/8" carbide EM @ 25krpm. Not too far fetched I suppose, would like to see the video.