[gicos]

Sorry if I'm posting in the wrong spot. I've seen a couple of old posts here on the same subject.

I'm no stranger to lathes, just "lost in the sauce" with all that's available. There's lots available, just not much information about the specifics.

It seems as though progress has stagnated on manual lathe motors in favor of CNC. It makes sense, as all the money is in CNC these days. I've spent weeks searching for a motor that, if it exists, I cannot find.

The motor I need has a spindle bore of at least 1.4", at least 3/4 horsepower, the shaft is directly coupled to the chuck (direct drive), variable speed, 0-3500 rpm (approximate), reversible, 110V 60 Hz. A separate controller is fine. Threading and/or modifications to join the motor to the chuck are expected and not a deal killer.

Richard Zastrow wrote in 2007: "Zumba, The hollow servos are available as frameless and within housings. Danaher calls their housed servos "cartridge motors". Yaskawa, Indramat and IMA (among others) also sell them. I have designed a few machines using these and used keyless clamping sleeves to attach hollow shaft servos to shafts and shafts to gears and sprockets. Keyless clamping sleeves are available from Spieth, Ringfeder and Fenner Drive. None of these require taper boring. If you do the research, you will find that when machined within specs, the keyless connectors on keyless shaft/bores is a stronger setup than using keys. Also it is adjustable axialy and finely radialy for runout correction if needed. Also, these make great integral spindle, shaft, motor heads." I'm wondering what's changed since then.

The only hollow bore motors I can find that are close are for CNC machines, they don't exactly fit the desired use (not intended for the heavy stress of continually running a lathe), and they're thousands of dollars. Large spindle bore chucks are available, mainly for pool cue making, but not in direct drive. The NOVA lathe is direct drive, but has no pass through.

ABEC 1-7 bearings are readily available from BOCA that are large enough, motors in this power range are aplenty, chucks are aplenty, but there seems to be a lack of interest from industry in combining them. Any advise or information is greatly appreciated.Do I go for a frameless motor, wrap my own, or is something out there that I'm not catching?

[ger21]

I've never seen a lathe with a motor like that? They typically use a belt driven spindle.

[Galane]

A 2 to 5 HP motor with a hollow shaft that has a large bore would make for a very compact lathe headstock, especially if coupled to at least a 2 stage, shiftable planetary gearbox coaxial with the motor. With modern permanent magnet technology it ought to be possible to fit a 1" or larger bore into the headstock for lathes as small as 9 or 10" swing.

Just think of it, no belts, no chains, no way to get anything caught in gears. Make the housing with a machinable base that can be milled to fit any lathe in each unit's size range, or make the units with a stock base profile and sell various machinable riser blocks.

The same motor could be used for a CNC machine with precision spindle position/speed control or with a basic manual on/off/reverse/speed control.

[victorofga]

my head works better with mm and watt...
what you asking, a 30 mm bore motor, and 500 watt I think that could be some special motor only..

the 500 watt motor as single phase , I don't think possible drive that mass, what can represent a 30 mm bored motor..

indeed 1.2-1.5 kw or 3 phase and 3x500 watt..

other issue is, you need feedback on the motor for tapping or cutting thread..

even for simple reversing need a controlled acceleration, deceleration..

it will be a real cost..
just try to find bearings for this size... possible they using NN series cylinder roller bearings... designed for machinetools..I could imagine they ask for only bearings several hundred dollar...

CDA - PIPEDRIVE - Hollow Shaft Geared Servo Motor range

[gicos]

Yes, Galene, finally someone who sees the advantages. I let go a Simmons 2 HP with copper rotor for a great price because I couldn't seem to get any thoughts from those who know more. I asked in another forum how much I could expect to lose in power by hogging out a rotor for the bigger shaft (without getting into the squirrel cage) but it's near impossible to tell without just doing it. I figured I'd loose at least 1/2 HP or more, so starting with a 2 HP motor seemed about right to bring it down to 1 - 1 1/2 HP after modification. 1 1/2 HP we know is the limit for a VFD on 110V.

In a former life I was a mechanic, but never an electrical engineer. I'm no newbie to electricity but motor eddy, flux paths, and so on is its own discipline. I'm still with the idea, but it's going to have to be over a longer term than I wanted. You're absolutely right. Calculate the cost of headstock, pulleys, belts, mounting hardware, etc. and it becomes obvious that it's not so expensive to have an integrated solution. And mobility just doesn't mesh with the vernacular of a traditional lathe.

Victoro, yes the bearing are expensive, about $150 each. But, consider that many spindle bearings are over $100 each and it doesn't sound so crazy. The setup would definitely require a good VFD. Shrink the VFD down to where it can be bolted onto or integrated with the motor and you've really got portability. Judging from how fast things are progressing these days I don't think we're that far off from seeing integrated VFDs. The push for electric cars, motorcycles, and bicycles is really accelerating things. Other possibilities include DC motors. Look at the Astro motors that happily spin all day at 7500 rpm putting out 6-8 HP (for the affordable 3200 serioes). Yes, an expensive proposition, but it shows what can be done with high rpms and small motors. The case configuration wouldn't work with a hollow shaft, it's just proof of concept.

[victorofga]

to separating motor from actual spindle has more positive advantage..
but its only my opinion..
I just trie dto give my insight for this..

hope you get your solution...

[metalworm]

Yes, Galene, finally someone who sees the advantages. I let go a Simmons 2 HP with copper rotor for a great price because I couldn't seem to get any thoughts from those who know more. I asked in another forum how much I could expect to lose in power by hogging out a rotor for the bigger shaft (without getting into the squirrel cage) but it's near impossible to tell without just doing it. I figured I'd loose at least 1/2 HP or more, so starting with a 2 HP motor seemed about right to bring it down to 1 - 1 1/2 HP after modification. 1 1/2 HP we know is the limit for a VFD on 110V.

In a former life I was a mechanic, but never an electrical engineer. I'm no newbie to electricity but motor eddy, flux paths, and so on is its own discipline. I'm still with the idea, but it's going to have to be over a longer term than I wanted. You're absolutely right. Calculate the cost of headstock, pulleys, belts, mounting hardware, etc. and it becomes obvious that it's not so expensive to have an integrated solution. And mobility just doesn't mesh with the vernacular of a traditional lathe.

Victoro, yes the bearing are expensive, about $150 each. But, consider that many spindle bearings are over $100 each and it doesn't sound so crazy. The setup would definitely require a good VFD. Shrink the VFD down to where it can be bolted onto or integrated with the motor and you've really got portability. Judging from how fast things are progressing these days I don't think we're that far off from seeing integrated VFDs. The push for electric cars, motorcycles, and bicycles is really accelerating things. Other possibilities include DC motors. Look at the Astro motors that happily spin all day at 7500 rpm putting out 6-8 HP (for the affordable 3200 serioes). Yes, an expensive proposition, but it shows what can be done with high rpms and small motors. The case configuration wouldn't work with a hollow shaft, it's just proof of concept.

I wonder if you eventually found "your" motor?

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