Thoughts on buy a used Colombo spindle of unknown history?

[Goemon]

What do you guys think about the idea of buying an old Colombo spindle over a new Chinese one?

I have been offered a good price for a Colombo that meets my needs in terms of power, voltage input and collet size but the seller has no idea how old it is or how much use it has seen. He says I can return it if it doesn't work but I don't really know how to check what sort of condition it is in.

Everyone is always saying how much better Colombo spindles are than the Chinese ones. Specifically how much better the bearings are and how much longer they last etc. Is it worth taking a chance on an old one? Do Colombo spindles last indefinitely or do they have a short shelf life like the Chinese ones?

Is there a way of checking if a spindle is worn out or on it's last legs without any special equiptment?

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[awerby]

What generally wears out on a spindle like that are the bearings. Replacing them is expensive - both for the labor and the bearings themselves, which are usually the ceramic type. But once you've done that, it should last quite a while. You might call Colombo Electric Spindle Repair Services | Colombo USA and ask them what it would cost to rebuild yours, in a worst-case scenario.

If you're inspecting a spindle, try rotating the shaft by hand. If it feels "crunchy", that's not good. If it rotates smoothly, try rocking it - if there's any movement relative to the spindle body, that's a bad sign. If all seems good, you can try measuring the runout with a test dial indicator; anything over about .001" indicates worn bearings.

[warrenb]

In my experience router spindles are consumables, like an endmill. I would only buy new or from a reputable rebuilder. I have worked with machines using a Chinese spindle with no problems.

[Goemon]

That's useful to know. Sometimes when something looks like a bargain, it pays to stop and ask why nobody else tried to buy it already.

It has been a hard topic to research because everyone involved in the CNC industry sucks at marketing. Every product looks the same with no decernable difference in the specs between $200 and $3000 spindles. They all claim the same power, the same run out etc. If I was selling a similar looking product for 20x the price, I would expect to be able to articulate why mine is better.... By better I mean the differences I would notice in the end product and not this generic comments about "better bearings".

I have seen a handful of posts with people saying they got a faulty Chinese spindle and had to return it but for the most part, those that actually own them seem to be happy.

I'll mainly be making aluminum molds. If there is nothing to gain from taking a chance on a used Colombo then I might as well buy a cheaper new Chinese one.

Would you expect to see any difference in the finish quality of machined parts from using a Colombo spindle instead of a cheap eBay one?

[ger21]

What size spindle is the Columbo, and how much is it? That has a LOT to do with whether or not it's a good deal.

Every product looks the same with no decernable difference in the specs between $200 and $3000 spindles. They all claim the same power, the same run out etc. If I was selling a similar looking product for 20x the price, I would expect to be able to articulate why mine is better...

I think you're looking at this backwards. The question, is, how can a $200 spindle be as good as a $3000 spindle? Or more like a $1200-$1500 spindle. Chinese published specs, and reality are probably two very different things.
Sure, some spindles will have the low runout that the specs say. But the low cost and poor quality control dictate that not all of them will. And the cheap collets and nuts that they come with don't help the cause at all.
10 years ago, there were no chinese spindles, so high quality (and expensive) spindles were the only option.


There are a lot of reasons why spindles cost so much.
Labor cost is probably the biggest factor.
And surprisingly, better bearings is also a big factor. Bearings in a high quality spindle can easily cost upwards of $500-$1000. The bearings in a chines spindle probably cost about $20.
If you were to hold a Columbo or HSD spindle, and compare it to a $200 chinese spindle, the build quality would be instantly apparent. My chinese spindle looks like it had rust on the bottom bearing housing, that was painted over. The screws that hold the fan cover on go into holes that look hand tapped, and partially stripped. The taper is ground very rough when compared to a high end spindle, or even a decent router for that matter. Basically, almost everything about a chinese spindle is vastly inferior to a more expensive, name brand spindle.

But, at the end of the day, a spindle is just a motor, with the shaft machined to accept a collet. If the bearings are tight, and the taper is ground properly, a cheap chines spindle can be very good.

Would you expect to see any difference in the finish quality of machined parts from using a Colombo spindle instead of a cheap eBay one?

There are a lot of factors that can come into play here. Machine rigidity, and how aggressive the cut is will have more to do with the cut quality than the spindle will. When you watch a $250,000 machine on Youtube blasting through aluminum and leaving a mirror finish, it's not just the spindle that makes the difference.
If you have a good chinese spindle with the same runout as the Columbo, and are taking light cuts, than no, I wouldn't expect to see any difference. Put the two spindles on a $200,000 machine, and push them to their limits, and then you';ll start to see the differences.
The Columbo will have more power, will be more rigid, and should have a much longer lifespan than a chinese spindle.
But unless your work demads a high end spindle, it's hard to justify when you can buy 5 chinese spindles for the price of one "good" spindle.

[Goemon]

What size spindle is the Columbo, and how much is it? That has a LOT to do with whether or not it's a good deal.



I think you're looking at this backwards. The question, is, how can a $200 spindle be as good as a $3000 spindle? Or more like a $1200-$1500 spindle. Chinese published specs, and reality are probably two very different things.
Sure, some spindles will have the low runout that the specs say. But the low cost and poor quality control dictate that not all of them will. And the cheap collets and nuts that they come with don't help the cause at all.
10 years ago, there were no chinese spindles, so high quality (and expensive) spindles were the only option.


There are a lot of reasons why spindles cost so much.
Labor cost is probably the biggest factor.
And surprisingly, better bearings is also a big factor. Bearings in a high quality spindle can easily cost upwards of $500-$1000. The bearings in a chines spindle probably cost about $20.
If you were to hold a Columbo or HSD spindle, and compare it to a $200 chinese spindle, the build quality would be instantly apparent. My chinese spindle looks like it had rust on the bottom bearing housing, that was painted over. The screws that hold the fan cover on go into holes that look hand tapped, and partially stripped. The taper is ground very rough when compared to a high end spindle, or even a decent router for that matter. Basically, almost everything about a chinese spindle is vastly inferior to a more expensive, name brand spindle.

But, at the end of the day, a spindle is just a motor, with the shaft machined to accept a collet. If the bearings are tight, and the taper is ground properly, a cheap chines spindle can be very good.




There are a lot of factors that can come into play here. Machine rigidity, and how aggressive the cut is will have more to do with the cut quality than the spindle will. When you watch a $250,000 machine on Youtube blasting through aluminum and leaving a mirror finish, it's not just the spindle that makes the difference.
If you have a good chinese spindle with the same runout as the Columbo, and are taking light cuts, than no, I wouldn't expect to see any difference. Put the two spindles on a $200,000 machine, and push them to their limits, and then you';ll start to see the differences.
The Columbo will have more power, will be more rigid, and should have a much longer lifespan than a chinese spindle.
But unless your work demads a high end spindle, it's hard to justify when you can buy 5 chinese spindles for the price of one "good" spindle.

These discussion points are clear and logical to me when compairing a $200 Chinese spindle off eBay and a new $3,000 Colombo. Where the water gets muddy is when you can get a used Colombo for the same price as a new Chinese spindle. The question then becomes whether a person would still see some benefits with old well used bearings and whether it would still last longer if it's already 10 years old.

It is also worth noting that there are various grades of Chinese spindle. Those GMT spindles sold at an elevated price point are made in China. They are advertised as "professional CNC spindles" but that term has no actual meaning to me. I have no idea if they are better than other Chinese spindles or if the extra cash is just for an American sellers mark-up.

Is your view that it is worth taking a chance on a used Colombo instead of a new Chinese one?

I am still not even sure if a high speed spindle is right for my needs. For milling 1" deep mold cavities in slabs of aluminum, most of the spindle speed calculators indicate that a lower speed device is more appropriate. The Chinese spindles recommended for metal work at Automation technologies are 6000 rpm units that cost 3x the price for 1/3 the power...

[ger21]

I would maybe spend $500 on a 10 year old Columbo? As long as you can return it.
If it runs with no bearing noises, then it should be fine. If the bearings eventually fail, then expect at least $1000 to have the bearings replaced by a competent shop.

Yes, you'll want a high speed spindle, especially if you'll be using small tools.

[wizard]

These discussion points are clear and logical to me when compairing a $200 Chinese spindle off eBay and a new $3,000 Colombo. Where the water gets muddy is when you can get a used Colombo for the same price as a new Chinese spindle. The question then becomes whether a person would still see some benefits with old well used bearings and whether it would still last longer if it's already 10 years old.

Another way to look at this is that you could put high quality bearings in a Chinese spindle to get the extended life and better performance. Guy s do this on low end Chinese lathes and mills because frankly they are shipped with terrible bearings. From what I've seen though Chinese spindles are using a better grade of bearing so maybe not an instant upgrade priority.

As far as a used spindle yo could always do a bearing upgrade yourself if you are up to it. Just realize it isn't a trivial task and likely will require you to buy some tools. My greatest fear isn't the bearings but rather more significant damage to the spindle from crashes or abuse. Unfortunately you need to be "there" to inspect for this possibility and bad bearing could mask a problem.

As others have said the best way to explore your risk is to ask Colombo how much a rebuild of the spindle will cost you. If the tis $1000 then you might have a reasonable purchase.

It is also worth noting that there are various grades of Chinese spindle. Those GMT spindles sold at an elevated price point are made in China. They are advertised as "professional CNC spindles" but that term has no actual meaning to me. I have no idea if they are better than other Chinese spindles or if the extra cash is just for an American sellers mark-up.

Don't kid yourself there is a wide range of companies in China some offering real value in their tools. It doesn't take much to offer a better quality spindle.

Is your view that it is worth taking a chance on a used Colombo instead of a new Chinese one?

I once worked with a plant engineer that had a saying he often repeated: "buy used and buy more". In many cases it makes a lot of sense. The problem with a spindle like we are talking about here is the lack of an inspection and no real history. The gamble is up to you.

I am still not even sure if a high speed spindle is right for my needs.

For Aluminum it makes lots of sense to get above 10,000 RPM. How far above that is an open question. I would want a spindle capable of deliver decent power in the 10,000RPM region.

For milling 1" deep mold cavities in slabs of aluminum, most of the spindle speed calculators indicate that a lower speed device is more appropriate. The Chinese spindles recommended for metal work at Automation technologies are 6000 rpm units that cost 3x the price for 1/3 the power...

Here is the problem with router spindles, machining metals, sometimes you want to get below 10,000 RPM to an RPM range suitable for the tool you are using. You would have to evaluate the tools you expect to use to see if you need performance in the sub 10,000 RPM range.

Also very important the Chinese spindle rate their power at the max RPM for the spindle. Power available at the low end drops off dramatically which is why they are often specced with a minimal RPM of 6000. Don't jump to conclusions as to how much power you will have available at anyone speed check the graphs that should come with each spindle.

[Goemon]

I understand that the power on most spindles is speed dependent. It's one of the things that makes it so hard to choose because, in most cases, sellers of Chinese spindles don't advertise the torque or provide a graph showing how much juice you get at each rpm increment. They only seem to show this info for their more expensive constant torque spindles which start at $600. The ones specifically designed to provide better material removal at lower speeds.

My understanding (which is still very limited on this topic) is that cooling is one of the issues with using cheap spindles at lower speeds too. Perhaps the superior fans in Colombo air cooled spindles allow better performance at lower speeds.

I am usually in favor of buying better used equiptment over cheaper new gear is areas I understand well. I paid $2500 for a 2 year old, hardly used $30,000 projector with an $8,000 lens. I know what I am looking for with home theater gear though. With CNC spindles, there seems to be far less bargains.

There is zero chance of me ever paying $1,000 to fix a spindle I paid $500 for and even less chance of me installing new bearings myself. If I was going to spend $1000, I would probably buy this Tormach spindle:

https://www.tormach.com/store/index....show&ref=31758

It's designed for lower speed milling and gets up to 10,000 rpm. It's kinda heavy for a smaller machine though.

I'll keep a lookout for a deal on a used Colombo and see if I can find one for $500 or less that doesn't look like it's been in a car accident.

At least now I know what to look for (a spindle that turns freely without bearing noise) so I'll know if I should send it back or not.

[skrubol]

Most of the non-ATC colombo spindles I see on Ebay seem overpriced. Once in a while a decently priced ATC spindle pops up though. I picked up a 16HP water cooled HSK-63F Colombo with VFD for about half what I could have gotten a chinese ATC spindle for (even with a lot less power.) It's overkill for my needs, but having one spindle on the mill that can do 24k RPM and still have 7 Ft-lbs of torque at lower speeds was too much to pass.

Colombo's european site has a lot more info than their US site. You may be able to get more info on the spindle from there.
Elettromeccanica Giordano Colombo, produzione elettromandrini - Prodotto

[wizard]

I understand that the power on most spindles is speed dependent. It's one of the things that makes it so hard to choose because, in most cases, sellers of Chinese spindles don't advertise the torque or provide a graph showing how much juice you get at each rpm increment. They only seem to show this info for their more expensive constant torque spindles which start at $600. The ones specifically designed to provide better material removal at lower speeds.

My understanding (which is still very limited on this topic) is that cooling is one of the issues with using cheap spindles at lower speeds too. Perhaps the superior fans in Colombo air cooled spindles allow better performance at lower speeds.

Yep a significant issue. The problem comes from sizing a fan to operate efficiently at the speed you are most likely to run the spindle. Since spindles designed for routers generally assume high speed the fan is often an issue.

This is somewhat related to the problem of running a standard 3 phase induction motor at speeds well below the synchronous speed of the motor. The fan simply can't cool the motor if you are going too slow. In many cases this leads to a second motor being installed to run a large blower to cool the motor.

I am usually in favor of buying better used equiptment over cheaper new gear is areas I understand well. I paid $2500 for a 2 year old, hardly used $30,000 projector with an $8,000 lens. I know what I am looking for with home theater gear though. With CNC spindles, there seems to be far less bargains.

Actually almost any of the Chinese spindles is a bargain. If you go to places like WWW.setco.com, www.ekstromcarlson.com,www.hptprecision.com or even www.gilmanprecision.com you will be paying really big dollars for a spindle many of which won't do high RPM's. By the way there are probably several hundred "spindle" manufactures out there selling spindles for everything from milling to grinding service. Also it never hurts to hit E-Bay for more conventional used spindles.

There is zero chance of me ever paying $1,000 to fix a spindle I paid $500 for and even less chance of me installing new bearings myself. If I was going to spend $1000, I would probably buy this Tormach spindle:

That statement above pretty much settles it, this spindle isn't for you.

https://www.tormach.com/store/index....show&ref=31758

It's designed for lower speed milling and gets up to 10,000 rpm. It's kinda heavy for a smaller machine though.

I'd call that spindle a bargain. It may be worthwhile to inquire as to the bearings and the ability to up the speed a bit. However 10,000 RPM is certainly feasible if your primary interest is machining aluminums though may be wanting for extremely tiny tooling.

I'll keep a lookout for a deal on a used Colombo and see if I can find one for $500 or less that doesn't look like it's been in a car accident.

At least now I know what to look for (a spindle that turns freely without bearing noise) so I'll know if I should send it back or not.

Bearings that turn freely and smoothly are a good sign. The only problem you might run into is if the motor is connected and that motor can introduce cogging or its own bearing issues. This of course assumes a non integrated motor.

[Goemon]

What other brands should I search for on eBay for used spindles?

I have seen deals on Bridgeport type milling heads but they are way too heavy for what I am building and too slow. I have seen some other used high end spindles that make new Colombos look cheap but not much where a used one looks competitive next to a new Chinese one.


I also wanted to ask about the importance of the VFD. Does buying a cheap $130 VFD negate the benefits of investing in a better spindle or do they just need to work?

Some of the Colombo spindles I have seen have a top rpm of 36,000 and state 700hz on the label. Most of the affordable VFDs seem to max out at 400hz with one or two reaching 500hz. Can I run a 700hz spindle with a 400hz VFD and just run it a lower speeds?

[Goemon]

Most of the non-ATC colombo spindles I see on Ebay seem overpriced. Once in a while a decently priced ATC spindle pops up though. I picked up a 16HP water cooled HSK-63F Colombo with VFD for about half what I could have gotten a chinese ATC spindle for (even with a lot less power.) It's overkill for my needs, but having one spindle on the mill that can do 24k RPM and still have 7 Ft-lbs of torque at lower speeds was too much to pass.

Colombo's european site has a lot more info than their US site. You may be able to get more info on the spindle from there.
Elettromeccanica Giordano Colombo, produzione elettromandrini - Prodotto

That's a useful tip. Their American site is very light on info.

I can't think of many occasions where I have regretted buying tools because they were too powerful. I can definitely think of occasions where I regretted buying underpowered tools though.

I have limits on how much power I can draw here and I prefer not to produce more noise than I need but aside from that, I intend to buy a spindle with more power than the minimum. Luckily for me, it doesn't seem to need much power for milling softer metals like aluminum and I don't need it to be super fast as only need it to make molds and not product for resale. I am curious to see what a 16hp spindle could do though.

Is the 16hp spindle super loud? Is it capable of milling harder metals like steel and titanium?

[skrubol]

HSD is another brand I see a lot of on Ebay. One of the more common chinese ATC spindles is a knockoff of a 10HP HSD.
From what I've heard, the chinese VFD's were to be avoided at all cost. At the very least the VFD would burn out, and at worst a bad VFD would contribute to damaging a spindle (or even worse, injuring someone.) At the least, the documentation (or lack thereof) made setting them up difficult. Seems like that may be changing recently, the cheap VFD's of course aren't as good as the brand name ones, but it seems they've gotten a lot better.

As far as running a spindle rated for a higher speed on a 400 Hz VFD, yes you can certainly do that. Problem with a 30kRPM+ spindle is that they tend to have less torque for the same power than a slower spindle.

My Colombo is completely silent, as I haven't wired it up yet
It's not meant for harder metals, but I think I'll be able to get away with using smaller tools and lighter cuts on steel and harder. I'll never be able to use all 16 HP mine has, as I don't have 3 phase power, and a 60A, 240V circuit is the most I can practically run, but hopefully some day I'll build a mill beefy enough to run it at 7-10 HP. 20+CIM of aluminum removal must be quite the site (and noise..)

[awerby]

That's a really powerful spindle, and it might have enough power to spare that it can still perform adequately at half the maximum speed. But spindles like this, where the motor is directly coupled to the collet, aren't what you want for cutting hard metals like steel and titanium with any but the smallest tools, and they are only recommended for light alloys: https://www.cncpd.com/product/colomb...k-63f-spindle/

For metals like steel, stainless, and titanium, you want more torque and lower speeds, which is why most milling machines use pulley reduction to get enough torque from a fixed-speed motor, which is usually running at a much lower speed than that Colombo.

[skrubol]

Many of the HSD and Colombo spindles have full power at half speed or lower. 10+ HP at 12kRPM and under 100 lbs (with power drawbar,) gives you more torque and lower weight than the Tormach 770 head.

[Goemon]

I know that the ideal spindles for milling steel are low speed, high torque, large diameter, seperate motor units etc. I was just curious if a high speed unit with that amount of power allowed you to get away with doing a little steel work. I don't really know how much torque you get from a 16kw 24,000 rpm spindle at any speed. It sounds like you can cut steel better with a 500 watt milling head though.

To be honest, every time I think I finally understand how to choose a spindle, I read something which makes me lose all hope of being able to use the available info to decide.

This guys article makes sense to me and it seems very well explained, it's just that, if he's right (and I think he is), the power rating for spindles is completely useless as a way of determining if it will cut what you need it to:

https://www.mmsonline.com/articles/i...-speed-spindle

It's frustrating that hardly anyone provides info on torque at each rpm but it sounds like that's the important info, at least for my needs.

[wizard]

What other brands should I search for on eBay for used spindles?

Search for used milling machine spindles. Using that phrasing will hopefully filter out all the handheld routers out there. Personally I see going used as a big gamble especially if buying form a third party that knows nothing about the hardware.

I have seen deals on Bridgeport type milling heads but they are way too heavy for what I am building and too slow. I have seen some other used high end spindles that make new Colombos look cheap but not much where a used one looks competitive next to a new Chinese one.

Spindles have historically been expensive. The bearings for such have never really been cheap, even when I was involved in machine tool rebuilding in the mid 1980's bearings were a significant expense. If the spindle itself is manufactured out of tool steel hardened and ground to size, that leads to an elevated expenses also.

I also wanted to ask about the importance of the VFD. Does buying a cheap $130 VFD negate the benefits of investing in a better spindle or do they just need to work?

Better Drives have better software and often better protection features often the electronics is very similar. In these smaller drives the final electronics are often one component as compared to say a full size drive that has individual transistor for each phase. The high integration of the electronics has resulted in very serviceable drives that fit in the palm of your hand these days.

I would go with a domestic supplier simply due to better service (hopefully) even if the drive is still made in China. At work we have more than a few Automation direct drives that work beautifully in a high heat and RF environment and have had near zero failures of ten years. Any decent drive should last that long once you get past infant mortality. Infant mortality is a something that happens which is why it is nice to have local support with warranty replacement if needed.

Some of the Colombo spindles I have seen have a top rpm of 36,000 and state 700hz on the label. Most of the affordable VFDs seem to max out at 400hz with one or two reaching 500hz. Can I run a 700hz spindle with a 400hz VFD and just run it a lower speeds?

Here is a page that can help with calculations : https://www.precision-elec.com/faq-v...uction-motors/. If you are like me you likely have forgotten what you learned in college the references like this help. The key here with 3 phase induction motors is knowing the number of poles the motor has. It is pretty common for designers to use four pole motors but it never hurts to double check. That Colombo spindle would imply a 2 pole motor.

[ger21]

Here are a few options that I'd consider, if I was strictly milling aluminum.

CNC AIR COOLED SPINDLE 2.2 KW ER25 | eBay

CNC Router Milling 2.2KW Air Cooled Spindle Motor ER25 & 2.2KW VFD inverter | eBay

2.2KW CNC Air-cooled Square Spindle Motor ER25 300Hz 18000rpm Woodworking | eBay

Professional GMT High Torque Spindle Motor Air Cooled 2.2 kW / 3HP ER25 CNC Mill | eBay

[skrubol]

This guys article makes sense to me and it seems very well explained, it's just that, if he's right (and I think he is), the power rating for spindles is completely useless as a way of determining if it will cut what you need it to:

https://www.mmsonline.com/articles/i...-speed-spindle

It's frustrating that hardly anyone provides info on torque at each rpm but it sounds like that's the important info, at least for my needs.

Be careful about reading too much into that. The main point of that article is comparing a milling spindle (with external motor) to a high-speed spindle of the same diameter. Seeing as you aren't retrofitting an existing mill with a specific spindle bore diameter most of that doesn't apply. HSD and Colombo have torque curves available for most of their spindles. Newer HSD's have the curve right on the name plate.
Power is torque * RPM (* a constant depending upon units,) and generally, with a good VFD, you won't have less torque at a lower RPM than at any higher RPM (within reason. At 10 RPM a 24k spindle might have trouble producing much torque. But at 1200 RPM, given a good, properly programmed VFD it should have full torque.) Of course if it's an air-cooled spindle with a fan on the spindle shaft, it won't be able to produce that torque at low speeds for long, as the slow fan won't provide enough cooling and the motor will overheat. ATC spindles rarely have that issue as they're almost all either water cooled or have a fan with a separate motor. (So maybe I've been spoiled, only looking for ATC spindles.)
The name plate of name brand spindles generally give one or more frequencies, with accompanying RPM and power (and sometimes more than one voltage to confuse things.) For example, this auction shows 2:
Giordano Colombo RV11022 Spindle Motor | eBay
Typically the higher number is the max RPM and the lowest number is the "base speed" The torque should be constant below the base speed down to 1/10 of it at least (again, assuming a good VFD and not a spindle with a fan on the spindle shaft.) So for that spindle, the torque up to 12k RPM is 6.6 HP /12000 RPM * 5252 = 2.9 Ft-lb. That particular spindle is a 380V, but it should run on 240V no problem, will have the same 2.9 Ft-lb of torque, but only up to about 7500k (12000 /380V *240V) and therefore only 4.2 HP. You probably won't be able to run a 380V VFD on 240V though, just the motor.

Oh, and to complicate things a little more, spindles made for woodworking may have lesser bearings than those of a metalworking spindle with equivalent torque, so do try to make sure the spindle is at least rated for aluminum. Cutting wood you can get away with a lot more runout than cutting metal.