Check out this ATC adapter for regular ER11 Chinese spindles...

[Goemon]

I came across this while searching for an entirely unrelated part. I thought I'd share it as I know that diy ATC mods are of interest to some people here.

This is apparently a screw-on ATC adapter to turn a regular ER11 MTC China spindle into an SK15 ATC spindle:

USOVO.de

I knew they had these for Kress routers but I haven't seen them for other spindles before. The adapter and tool cart look affordable - espiecially if you already have the gear for the pneumatics.

I wonder how well they work...

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[1stPrototype]

I bought one and mounted it on 1.5kw Chinese spindle. It's not plug and play, and the documentation is sparse. The unit feels very well constructed and precise, but it has some critical gotchas.

First off, you have to get your spindle taken apart at the top, just to access the pin spanner holes at the top of the shaft. Without that, there is no way to immobilize the spindle to thread the changer on -- and nobody tells you this before you buy it. The Chinese spindles have no spindle lock built-in like the Kress routers that the ATC was originally designed for so they require surgery. With water-cooled spindles, extra care needs to be taken when reassembling the top portion, as that is where the water/electrical barrier is crucial. There are two tiny o-rings counterbored into one side of the mating faces, and they are covered with a slopass dollop of some kind of sealant. In my case, one remained glued to each of the separated faces, and I didn't even notice them the first time I took it apart and reassembled it -- I got lucky, because on subsequent teardowns, one o-ring popped out and rolled across the bench.

The second gotcha - a probable design flaw in the ATC unit. There is a cylindrical collar that screws over the tapered shaft that mates to the Chinese spindle. That collar is about 30 mm in diameter, and is held in place (at 24000 rpm) by about 3 threads, engaging the bearing preloader beneath it only about 2mm. During my first attempted cut, the collar separated from the preloader and that caused the top and bottom air seals to self-destruct. The manufacturer seems to not believe this, and tried to convince me it was my fault for ejecting the tool while spinning...but that did not happen. My theory is that aggressive spindle braking worked the collar loose and exposed its insufficient thread engagement flaw.


The replacement seal kit is about $10 and the shipping is 20 -- for a 40mm x 1mm and a 30mm x 1mm silicone washer. I sourced some 1mm silicone sheet and machined a set of punch dies to cut my own seals -- since I don't believe these seals can last very long as designed. The top seal, in particular, is subject to constant friction, as its inner diameter rides in a groove machined into the spinning collar while its outer diameter is held down by a pinch plate and o-ring. The collar is now held in place with a fair application of Loctite, and we'll see how it holds up. So far, so good in dry runs...not cutting.

I've actually made some modifications to the Chinese spindle to mimic a spindle lock, so now I can install and remove the ATC without giving the spindle another lobotomy. I'll make some test cuts later this week and share anything that is interesting.

[jkkmobile]

This one should be better:
https://www.sorotec.de/shop/Spindles...ange-adapters/

[1stPrototype]

That design immediately solves a problem with Usovo model -- it doesn't use the collet lock threads to engage the changer. If my guess is right, that diagram is depicting a hex profile shaft being held in the Chinese spindle, and that in turn engages with a hex mating hole in the changer. Far more elegant on every level. That would also erase the limitation of only running in CW direction. All that goodness adds about $500 more to the total price, but if you plan to use your system beyond hobby level, that is trivial. A better designed critical component like an ATC should not be fragile or limited to one direction.

[Goemon]

To be fair, if you buy a real ATC spindle, they aren't exactly "plug in and play" but, any product that requires users to mod their spindle themselves would be a no go for me. The fact that they don't warn you about that before you buy doesn't give me a lot of trust in the vendor....

I'd like to see an affordable aftermarket ATC design that focuses on opening and closing the existing collet nut without any internal mods. I noticed that Datron offers (or at least supports) direct ATC designs where only end mills are switched out instead of tool holders. That would make more sense for a low cost product as toolholders are expensive.

To open the collet nut, you would just need something to hold the shaft still and something similar to the power drawbars you see on eBay with a hex driver that is large enough for an ER20 or ER25 collet nut. Or.... a couple of motors with the right size gears....

With any aftermarket ATC design, I think there is a hard price limit above which the product becomes pointless. Once you get above $1,000 or $1500 for the whole package (spindle, ATC adapter and tool rack), most people would probably just invest in a real ATC spindle.

[ger21]

I noticed that Datron offers (or at least supports) direct ATC designs where only end mills are switched out instead of tool holders. That would make more sense for a low cost product as toolholders are expensive.

I bet that spindle costs at least $10K-$15K. And it's only available in small spindles (600w-2Kw), which makes sense as it probably can't clamp tight enough to handle higher power. I've never seen one of those before.

[Goemon]

I bet that spindle costs at least $10K-$15K. And it's only available in small spindles (600w-2Kw), which makes sense as it probably can't clamp tight enough to handle higher power. I've never seen one of those before.

I bet you are right. They don't list spindle prices on their site but I have seen those Jager and GMN spindles sell for upwards of $30,000 on ebay so god knows what Datron charge....

The ATC adapter I posted a link to is limited to 2.2kw spindles for the reasons you suggested but I think that covers most of the hobby market it is aimed at so I don't see it as a barrier for most people (although it was for me).

With that said, they make regular MTC spindles with far larger motors than that. If an ATC adapter used a regular collet nut with direct connect end mills, I can't see why one couldn't be made to work with more powerful spindles. It would just be a case of ensuring that enough torque was used for the size.

My spindle's manual has a table listing the torque requirement for each size of spindle and collet nut. It would be part of the design spec for the ATC device. Whether any of us would trust a Chinese made ATC adapter with a 10hp spindle or not is a different matter....

For now, I think the most cost effective route to ATC for hobby use is still buying one of those Tormach spindle cartridges and one of the many cheap (but functional) power drawbars.

[ger21]

If an ATC adapter used a regular collet nut with direct connect end mills, I can't see why one couldn't be made to work with more powerful spindles. It would just be a case of ensuring that enough torque was used for the size.

You'll never see something like that, as there's just no market for it.

For now, I think the most cost effective route to ATC for hobby use is still buying one of those Tormach spindle cartridges and one of the many cheap (but functional) power drawbars.

That's not really an option for router users.

[Goemon]

You'll never see something like that, as there's just no market for it.




That's not really an option for router users.

do you mean because the speed is limited to 10,000 rpm? I was thinking that could be somewhat fixed with a bearing upgrade. It's not ideal but it seems like all of the low cost ATC options have limitations. For me, it would be the most appealing option if I wanted to go the ATC route for hobby use. I use my router at 12,000 and 15,000 rpm fairly regularly.

I am going to respectfully disagree on the point about there being no market. I think there is as much of a potential market as there is for any hobby CNC products and, just like other hobby CNC products, I think it entirely depends on the price point. I don't think there is any market for a hobby-level ATC adapter at the price point some of these companies are charging now. However, If there was a product that was as affordable as the Chinese spindles and it worked properly.... and.... it was easy and intuitive to set up, it's an obvious upgrade. I'd buy one.

It's logical that an ATC adapter that is plug in and play will be more appealing to hobby users than any requiring internal spindle mods. One that doesn't require expensive toolholders is also more appealing (again, assuming it works).

I guess we will see.

[1stPrototype]

do you mean because the speed is limited to 10,000 rpm? I was thinking that could be somewhat fixed with a bearing upgrade. It's not ideal but it seems like all of the low cost ATC options have limitations. For me, it would be the most appealing option if I wanted to go the ATC route for hobby use. I use my router at 12,000 and 15,000 rpm fairly regularly.

I am going to respectfully disagree on the point about there being no market. I think there is as much of a potential market as there is for any hobby CNC products and, just like other hobby CNC products, I think it entirely depends on the price point. I don't think there is any market for a hobby-level ATC adapter at the price point some of these companies are charging now. However, If there was a product that was as affordable as the Chinese spindles and it worked properly.... and.... it was easy and intuitive to set up, it's an obvious upgrade. I'd buy one.

It's logical that an ATC adapter that is plug in and play will be more appealing to hobby users than any requiring internal spindle mods. One that doesn't require expensive toolholders is also more appealing (again, assuming it works).

I guess we will see.

Yeah...the SK15 tool holders are a cool $65 per copy. Total cost for a 5-tool setup is pushing a grand as is...

Sent from my SM-G900V using Tapatalk

[ger21]

I am going to respectfully disagree on the point about there being no market. I think there is as much of a potential market as there is for any hobby CNC products and, just like other hobby CNC products, I think it entirely depends on the price point.

No market because the price will never be what you want it to be. An ATC spindle requires a level of precision far greater than a $200 chinese spindle, which results in a far greater price. If you are doing production work, where the ATC spindle makes you money, then $2000-$3000 for a chines ATC spindle is cheap. Even if they could make one for $1000, it's still 5x more than a standard chinese spindle, and most hobbyists are not going to pay for it.

So yeah, there would be a market for a $400-$500 adapter, if it worked as well as a real ATC. IMO, that's highly unlikely. And your still looking at $1000 all said and done.
I'd be really surprised if you ever see an ATC spindle any cheaper than what you can find now from China, and I'd bet money that you'll never see an adapter for larger spindles.

do you mean because the speed is limited to 10,000 rpm?

That, and many other reasons. There's a reason, that I've never seen anybody use that type of spindle on a router.

[Goemon]

This is a clip of the Datron direct ATC spindle:

[Goemon]

No market because the price will never be what you want it to be. An ATC spindle requires a level of precision far greater than a $200 chinese spindle, which results in a far greater price. If you are doing production work, where the ATC spindle makes you money, then $2000-$3000 for a chines ATC spindle is cheap. Even if they could make one for $1000, it's still 5x more than a standard chinese spindle, and most hobbyists are not going to pay for it.

So yeah, there would be a market for a $400-$500 adapter, if it worked as well as a real ATC. IMO, that's highly unlikely. And your still looking at $1000 all said and done.
I'd be really surprised if you ever see an ATC spindle any cheaper than what you can find now from China, and I'd bet money that you'll never see an adapter for larger spindles.



That, and many other reasons. There's a reason, that I've never seen anybody use that type of spindle on a router.

Haas uses a 40 taper cartridge spindle on their gantry router. There is no reason why not if an acceptable speed can be achieved. Plus, all the old overhead or pin routers use belt drive spindles. An ATC "router spindle" is just a BT30 cartridge spindle with a direct drive (or pin drive) high speed motor.

I think we agree on the ATC thing except that I am more optimistic that, one day, someone will figure out how to make a lower cost ATC adapter. They need a whole new design because very few will feel that it makes sense to invest $1,000 or even $600 in a $150 Chinese spindle. I can understand your lack of confidence in the manufacturers for ATC adapters though. Previous and current attempts haven't exactly "nailed it".

They need to stop comparing their pricing to the industrial market because hobby users aren't writing off the cost against profit. The value of a hobby ATC product is only in convenience.

They need a design that doesn't use pneumatics at all. It needs to use a (fairly cheap) servo or stepper motor with some gears and a mechanical method of stopping the spindle turning while the change happens.

[ger21]

An ATC "router spindle" is just a BT30 cartridge spindle with a direct drive (or pin drive) high speed motor.

No, it's not really. An ATC router spindle is basically the same as a manual tool change spindle, except with a pneumatic drawbar running through it.

[Goemon]

No, it's not really. An ATC router spindle is basically the same as a manual tool change spindle, except with a pneumatic drawbar running through it.

What do you see as the fundimental differences in design that make them so incompatible?

I've looked over the design of both, part by part, and I can find anything that makes them so different that you couldn't change it's purpose with small mods.

An ATC BT30 router spindle has a cylindrical tube housing bearings, a BT30 taper shaft, a pull claw with a pneumatic draw bar and a small high speed motor. Most that I have seen are 80mm or 100mm in diameter. The Tormach BT30 cartridge is an 80mm tube with all the same parts inside minus the motor and pneumatic drawbar. If you added a pneumatic drawbar and high speed motor and switch out the bearings for high speed ones, why couldn't it perform router type work with ATC functionality?

Exhibit 2 your honor...

Take a look at this Grizzly 20,000 rpm overhead router. It uses a belt drive which is driven by a low speed 3600 rpm 3hp motor. It uses a cartridge type spindle.

Overarm High Speed Router | Grizzly Industrial

To me, the design has a lot in common with small milling machines. If you switched out the cartridge for one of the Tormach ones and added a power drawbar, it would be a good start for a hybrid mill / router.

I can understand the principle explained to me by you and others on why some CNC routers are not rigid enough to be used for milling metal. I can't understand why a milling head cartridge being driven at 16,000 or 20,000 rpm can't be used for router work.

[691175002]

To me, the design has a lot in common with small milling machines. If you switched out the cartridge for one of the Tormach ones and added a power drawbar, it would be a good start for a hybrid mill / router

You are right, but the cartridges you are looking at are already $800+ and by the time you throw in new bearings, a motor, and an air cylinder; plus do all the design work and construction you might as well just buy one of the $2000 Chinese ATC spindles. You will probably run into balance problems anyways if you push the RPM too far beyond 10k anyways.

This is probably the cheapest ATC design I've seen but you need a motor with torque: https://www.cnczone.com/forums/bench...ml#post2159278

[Goemon]

You are right, but the cartridges you are looking at are already $800+ and by the time you throw in new bearings, a motor, and an air cylinder; plus do all the design work and construction you might as well just buy one of the $2000 Chinese ATC spindles. You will probably run into balance problems anyways if you push the RPM too far beyond 10k anyways.

This is probably the cheapest ATC design I've seen but you need a motor with torque: https://www.cnczone.com/forums/bench...ml#post2159278

The BT30 cartridges are cheaper but you'd have to do your own balancing I saw a tutorial on YouTube. Doesn't look too hard. You are assuming that the "cheap" Chinese ATC spindles are properly balanced too. From what I have seen and read, that is not a given and they start at $1800 (plus shipping from China) and, an air cooled model with acceptable power starts at $2500 (and you are still left with an entry-level spindle).

The problem of creeping costs is always there with these projects. The ATC adapter for a $150 spindle is close to $800 too. I just think that, if you went the cartridge route, you would end up with a better and more vertatile spindle head in the end. I.e. One that could be used for both router work and metal work because you'd retain the ability to increase low speed torque with gearing. Also, it would be upgradable as you choose your own motor. I like modular and upgradable stuff!

As you'd source your own bearings, you might get lucky and find some super precision ones at an affordable price on eBay, so, over time, you could make something fairly decent.

If the Tormach cartridges are too expensive, LMS sells far cheaper R8 cartridges starting at $200. You could then go the TTS route.

There are no great options (yet) though.... if "affordable" is one of the criteria. Once any spindle project gets above $1,000, you've lost the majority of the hobby market.

[Goemon]

That design immediately solves a problem with Usovo model -- it doesn't use the collet lock threads to engage the changer. If my guess is right, that diagram is depicting a hex profile shaft being held in the Chinese spindle, and that in turn engages with a hex mating hole in the changer. Far more elegant on every level. That would also erase the limitation of only running in CW direction. All that goodness adds about $500 more to the total price, but if you plan to use your system beyond hobby level, that is trivial. A better designed critical component like an ATC should not be fragile or limited to one direction.

One thought.... that store is in Germany - not exactly the cheapest place to import goods from. I wonder if it is something that could be sourced directly from China (where it is probably made). If it was $300-$400, it feels less pointless (again, if it actually works properly). If it isn't made in China, I', sure a Chinese manufacturer will "borrow" that design soon enough.

[ger21]

Balancing a spindle to 24000 rpm is not a DIY job.
With our Hsk tool holders, a small wood chip between the spindle and holder, about. 002" thick, will sound like a helicopter, because of the balance being thrown off.

[skrubol]

One issue with just 'adding' a motor into a spindle cartridge is that the motor would need to have a hollow rotor shaft for the draw bar to run through.
Seems a lot easier just to spend the 2 grand on a Chinese ATC spindle (or wait for a good deal on a used 'real' spindle from HSD, Colombo or other.)

There are plenty of ATC spindles that don't use a toolholder as well. It's just the large majority of them are for the PCB industry and can only grab 1/8" shanks. If that's big enough, there are a ton of those on Ebay (Westwind, Dover, Excellon, etc.) Just make sure they're mill/drill spindles not drill only.
The big issue with a spindle that grabs the shank directly is that you can only use 1 shank size of tools on them without changing the collet, and I don't see too many carbide tools out there (larger than 1/8") that have a larger shank than their cutting diameter.