[Mecanix]

thats 7 in 24.....

why cant kids math these days?

Dunno, guess we aren't working in a spindle factory like you
Good to know though, not that I ever plan on making my own holders and spindle, but good info none the less.
ps: That so called machinery handbook needs a serious revision lol

[ihavenofish]

its
a
TRIANGLE!

:P

[michael_lu]

This angle seems to be a bit problematic

[Mecanix]

Where is this "ISO" spec ref, just looked and can't seem to find it... you/anyone got the ref. no. ISOXXXXXX. (just out of curiosity).
Mind you, ISO could be an acronym for anything at this stage... who knows now lol

[ihavenofish]

the ISO spec defines the flange. the taper is defined by the NMTB standard, from the year 1911. EVERY steep taper tool is the same. the only thing that changes is the guage size (10, 20, 30, 40) and the pull stuff / flange.

[Azalin]

Hi again,

Another question on the belt and pulley system. My max RPM will be 16k RPM. So what type of belt and pulley can I use?

[Mecanix]

I hate to advise on this thread, last time I did I made OP cut a tapper for an Alienwave Spindle type.

For the drive belt/pulley you are looking into V shape, if for some reason you can't accommodate a Direct Drive (suggested). At that kind of RPM you don't want any teeth or grooves unless you fancy loud noise, excessive vibrations and heat. That's as far as my knowledge goes for drive belts really. I know there are pitch & profiles that you can/can't use at high'er speed but that all depends on the belt & pulley kit specs from the manufacturer you go with.

Let us know what you find. All up for learning how to make holders, and belt drive-a-fast anything

[ihavenofish]

gates has charts for this.

you would need a poly-v pulley with a diameter of about 30mm which wont fit on your spindle.... and will still wear out real fast and make too much noise and probably slip under load.

so congrats, you are designing a direct drive spindle

[Azalin]

I hate to advise on this thread, last time I did I made OP cut a tapper for an Alienwave Spindle type.

Everything I made in this thread was just fun so don't worry.

So the recommended pulley diameter is max 30mm? Top side of the spindle is 30mm so the pulley will be 45mm or larger.

Thanks Mecanix and ihavenofish.

[ihavenofish]

6500 feet per minute is the max belt speed recommended by gates. and in reality you want to drop that by at least 25%.

direct drive is better anyway

[Azalin]

Direct drive you mean the motor is connected to the spindle with a coupling? I forgot to mention, I'll be having a power drawbar on the top.

[ihavenofish]

don't have the power drawbar on top.

or have a 12000rpm spindle.

[Azalin]

12000RPM is fine too. Not just what I wanted but its OK. I never used my 24k spindle over 10k.

[Mecanix]

16000+ are pretty picky rotating assemblies. Again, not an expert in this domain but I do have a 20k (DD, Siemens Servo, bt30) and anything unbalanced placed in there (e.g. unbalanced holder, off-center tool?) and spun at +15000 kinda make the frequency (and the worlds) around the machine feels weird lol. Feeling it in my teeth. Never really exceeding 8~10k for milling metals anyway... more than that its just bloody terrifying.

That to say, if you don't have the means to dynamically and accurately balance the spindle assembly, don't bother above 10k I'd say (8k safer). 12k is 'pushing' it and just won't work with a belt & pulley imho (that vibration will take out the assembly critical tolerance in <200hrs). As ihavenofish recommends, go DD if you are forced to go high speed.

ps. oh and did I forgot to add you need an oil coolant for that kind of speed. My bad, that's right... I have this ugly oil chiller sitting right next my machine just for that spindle. Can't get rid of it because I occasionally machine with 1mm end mills and that needs the whole 16k-18k in most cases. So... think about that too

done. my uneducated experience with fast spindle rant over lol

[ihavenofish]

I'm going on a limb and guessing hes got no equipment to balance the spindle. Whether he needs precision balancing at a given speed will depend on the shape and size of the spindle.

As a point of reference. You can buy a rather nice ISO25 belt drive milling spindle rated for up to 12k (ceramic bearings) for about $1000. You can buy a 30000rpm ISO20 "light duty" motor spindle for $1380 shipped. You can buy a 60000rpm ISO10 spindle for under $2000 shipped.

You need to figure out WHY you are making your spindle. If its for learning and fun, try everything and see first hand what happens. (you could balance the assembled unit with an accelerometer from adafruit and an ams encoder). If this is to be a product, you need to study what everyone else before you has made very closely. Then choose your battles carefully as well on what you intend to do differently.

[mactec54]

Everything I made in this thread was just fun so don't worry.

So the recommended pulley diameter is max 30mm? Top side of the spindle is 30mm so the pulley will be 45mm or larger.

Thanks Mecanix and ihavenofish.

You can make a Poly-V-Belt pulley any size you want, I have used them for years at around 100mm I use the J series belts 7 to 10 rib I never ran over 14,000 RPM though so don't know what 16,000 RPM would do, probably not much as the loading would not change much from 12,000 to 16,000 RPM

[Azalin]

@mactech54
I will use the spindle in my router so there will be almost no load.

ps. oh and did I forgot to add you need an oil coolant for that kind of speed. My bad, that's right... I have this ugly oil chiller sitting right next my machine just for that spindle. Can't get rid of it because I occasionally machine with 1mm end mills and that needs the whole 16k-18k in most cases. So... think about that too

Is the oil coolant just for cooling down the housing or does it flow right trough the bearings so cooling and lubrication is achieved together? Sorry I'm lost at that point.

oh, and yes, I don't have a dynamic balancing equipment. I wanted to build one but I never get into it.

[Mecanix]

@mactech54
Is the oil coolant just for cooling down the housing or does it flow right trough the bearings so cooling and lubrication is achieved together? Sorry I'm lost at that point.

I'll be very honest with you, I have absolutely no idea. All I know is there are two tubes connecting to the main spindle assy; an intake at the front (circled in red) and outlet on the back.
My assumption would be housing cooling as I just can't figure out how the oil would be delivered to and from the bearing themselves.
Other pic is the oil chiller (white boxxy thing). Its big man... that 20k rpm spinner really gets hot passed 15k when machining with a 0.5kg BT30s holder/tool. More or less 20~30min in the operation and the chiller kicks in...
Not at the shop currently, best pics I could quickly find on hdd to illustrate.

Keep us updated, g'luck with the project

[mactec54]

@mactech54
I will use the spindle in my router so there will be almost no load.



Is the oil coolant just for cooling down the housing or does it flow right trough the bearings so cooling and lubrication is achieved together? Sorry I'm lost at that point.

oh, and yes, I don't have a dynamic balancing equipment. I wanted to build one but I never get into it.

All the Chinese Spindles are using Grease on there high speed spindles, and they last quite well

The oil is for the Bearings lube, and is normally in a mist with air, which helps to clear dust etc. from out the front through the labyrinth seal but high quality grease can be used at those speeds, oil lube you can run at higher RPM and if your air is dry, the Bearing can last longer

But without any balancing you won't be running at those speeds anyway 12,000 RPM will most likely where you will be at, any part that you machine that is concentric inside and out will be in balance any cutout screws nuts Etc. will throw it out of balance, so for a smooth running spindle balancing is a requirement, including tool holders, although ISO 20 tool holder can be machined machined as one piece, shrink fit to hold the cutter can eliminate any need for balancing of the tool holder

[Mecanix]

Those are the holders "type" I'm literally forced to use with for HSM with above 12k revs. Some ideas... in case you plan on making some for high speed rev...
Apart from the facemill (i.e. 3000RPM max), all the rest are dyn balanced. Notice the no hex-nuts and concentric assy (SK collets)
Any other types of holder and trust me it feels really weird around the machine at above +12k speed lol

Fast is good man, bloody terrifying (andhot), but good