Solid Bench Top Mill Build (warning large photos)

[louieatienza]

When it comes to machining steel/stainless, you don't think you would start missing steps? you can't just set feeds and speeds as low as you want ( as you said )

maybe it would be ok. never really considered steppers for my build. maybe i should.

Tormach, Novakon, Syil, FlashCut, Smithy, Sherline, Taig, MicroKinetics.... All sell mills with steppers. If they're sized right and run within their parameters you won't miss steps.

[handlewanker]

The one item you picked offers just one.

But quite alot have minium order quantities.

Don't ask a question about something then disregard the answer.

Google the website and you'll get your answer.

Only buy from trusted sellers on alibaba as well, quite a few dodgy goings on to be found with minium research.

Hi.......I "googled" Alibaba.com for brushless motors and after 25 pages of all kinds of motors, the only one that showed promise was the same one that I looked at in that first link....the Hishine mob.

They have a 2.2KW model, 400rpm min to 6,000 rpm max, 300 volt DC, 7.3Amp, 7NM peak, weight 9KG and complete with controller....... model no.HSBL-123F-22060 .....sizes are... body length 214mm long X 123mm square with a shaft diam of 19mm....keyed.

That appears to be what I'm after, and their quoted price of $100 is for a minimum order qty of just 1.......if that's for real the quest for the Grail is over......shipping cost on top of that of course.....even if the shipping cost was as much as the motor for one item it's still a good buy........all providing I haven't missed something in the small print etc.

I don't think I need to have a bigger motor for this build........heck, there's bigger CNC routers with smaller motors out there all doing good work........having a separate motor belt driving the spindle allows a PWD to be employed, which is highly desirable.

If this works out I'll have the spindle in the centre of the Z axis with the motor to the right belt driving it........that will enable the X axis saddle to move over to the far left for a possible ATC solution.

A separate motor and spindle with a PDB means a lot of weigh on the X axis carriage, so maybe a Nema 34 stepper might be necessary here in case the Nema 23 @ 425 OZ/in struggles to keep up......the Z axis will be weight compensated so I don't see a problem there.

I might dangle my line in the water with that mob and see what bites.....they have a large brushless range in their site, and most of them are for a min order qty of one.
Ian.

[Feist92]

Fiest, have you tried many of the plasma/laser cutting shops around auckland? some of them may have that size in an offcut bin.

yea ive tried as many as I could find but no luck. they all quoted me for cutting out of a fresh bit of plate

Try fletcher steel, i got a price of $155 for 300x400x40 (grade300) which is around $4.20/KG vs $7.60/KG (300x300x30 @ $160)

Thats the same as easysteel yes? I got a quote from them wich didnt look too bad but it was still more that i was hoping for

Tormach, Novakon, Syil, FlashCut, Smithy, Sherline, Taig, MicroKinetics.... All sell mills with steppers. If they're sized right and run within their parameters you won't miss steps.

Thats what I figured. People can tke a prettry hefty cut on a tormach and the spindle power is usually the limiting factor

Hi.......I "googled" Alibaba.com for brushless motors and after 25 pages of all kinds of motors, the only one that showed promise was the same one that I looked at in that first link....the Hishine mob.

They have a 2.2KW model, 400rpm min to 6,000 rpm max, 300 volt DC, 7.3Amp, 7NM peak, weight 9KG and complete with controller....... model no.HSBL-123F-22060 .....sizes are... body length 214mm long X 123mm square with a shaft diam of 19mm....keyed.

That appears to be what I'm after, and their quoted price of $100 is for a minimum order qty of just 1.......if that's for real the quest for the Grail is over......shipping cost on top of that of course.....even if the shipping cost was as much as the motor for one item it's still a good buy........all providing I haven't missed something in the small print etc.

I don't think I need to have a bigger motor for this build........heck, there's bigger CNC routers with smaller motors out there all doing good work........having a separate motor belt driving the spindle allows a PWD to be employed, which is highly desirable.

If this works out I'll have the spindle in the centre of the Z axis with the motor to the right belt driving it........that will enable the X axis saddle to move over to the far left for a possible ATC solution.

A separate motor and spindle with a PDB means a lot of weigh on the X axis carriage, so maybe a Nema 34 stepper might be necessary here in case the Nema 23 @ 425 OZ/in struggles to keep up......the Z axis will be weight compensated so I don't see a problem there.

I might dangle my line in the water with that mob and see what bites.....they have a large brushless range in their site, and most of them are for a min order qty of one.
Ian.

Please do Id be interested to see what you find out. Btw Ill post an update on progress some time this weekend

[Furbi]

yea, easysteel is fletcher easysteel


what size steppers you going with?

[Feist92]

yea, easysteel is fletcher easysteel


what size steppers you going with?

Probably nema 34 but i havent really looked into them yet

I just got a quote for the 6000rpm 2.2kw motor and they want $660 USD including shipping to NZ

[Feist92]

This is how she sits atm. I have the parts for the zaxis almost finished, just have to drill and tap a few holes.

[handlewanker]

Hi Feisty.....to say you've been busy would be an understatement......it's almost ready to fly......love the colour scheme......gunmetal grey/blue?

That motor price would slay me.........I'll have to try Alibaba as they are emailing me now with offers since I browsed their site.........the company name with the most suitable brushless motors is Hishine.

If you're thinking of a separate belt drive motor design, what design are you intending for the spindle itself?

My opinion is that the conventional layout with two angular contacts at the bottom and a pair of sealed floating radials at the top is simple and hard to beat......but tool retention will tax your ingenuity to the hilt.

The tool holding/mounting requirement will dictate the spindle shaft itself and then the bearings and housing. dimensions, but with any R 8 - ISO 30 PDB spindle design the housing will get to at least 100mm diam.

To have a small spindle design the only option is to have a 2 or 3 Morse taper in the spindle end with a restricter coller on the tools shanks.....that makes tooling extremely cheap to source......there are dozens of other tool shank designs but sourcing tooling with any of them is virtually impossible.

I have a Deckel D bit grinder and the collets are like R8 but smaller in diam......quite ideal but not suitable as tooling with that shank is unavailable anywhere.

The PDB for Morse retention does not require to exert tremendous force to hold the tools in as the shank taper is self retaining once seated and only needs a small force to hold it in and unseat it......coupled with the fact that you don't need drive lugs like ISO30 so tool changing without the need for spindle rotation positioning is possible..............that is a whole different ball game with R8 or ISO 30 where 800 lbs draw bar pressure is the norm just for a holding force and a lot more to unseat the tooling, and spindle rotational position is a must for ISO 30.

I contemplated having the motor as a stand alone unit with an ER chuck "attached" to the end of the shaft, but that cuts out having any PDB which for me is paramount to the whole design......changing tools with just an ER chuck is not an option.

Have you any preferences as to tool shank design and/or having a PDB?
Ian.

[Feist92]

Thanks the colour is just grey por15 but it came out pretty well.
The quote was from hishine through alibaba so it looks like were out of luck. I wonder if it would be much cheaper for a group buy? In saying that I looked up the dimensions and the motor is rather huge.

As promised progress will be almost non existant from now on. I got a new job that works very long hours but it should be rather interesting work.
The spindle will probably be the last thing i look into as id like to get everything else completed first at least mechanically. I had initially planned to use a seig r8 spindle and make a housing for it. Their spindle housings are around 80mm across so im sure you could make a smaller one

[handlewanker]

Oh gee.......that's a bummer......$5 or $6 hundred is steep......I thought the min qty and price that the Alibaba site showed was a bit of a wonder......can't understand how the indicated pricing works......it's possible they have a sliding scale for qty and pricing........that would make group buying sensible..

As you say, it's quite a big motor, but it does have the grunt......7NM and.all 9 KG's of it.......at this rate with that pricing it's going to go no where.

I even considered........in my wildest dreams.......of building one from scratch.

Compared to a 3 phase synchronous motor they are pretty basic simple.

Hand winding the stator with the rotor as an out runner would be a chore.......they sell NDM magnets in many forms on Ali B, and that's the heart of the motor.

I read a write up of a guy that constructed a BLDC inrunner motor from the very beginning, making the steel stator too and then hand winding it.......it was an exercise for a uni project to get marks for his degree......it worked but only just......the copper windings and iron combination of the stator are critical to performance.

With that weight factor, I'm thinking that a stripped down double stacked stator 3 phase 1/3rd HP motor at 3,500 rpm could be a contender, as the motors are only $59 on EBAY......just a thought.

You can speed up a 3 phase motor with a VFD to get quite a speed range, up in the 7,000 rpm mark.

With the motor weight and size problem (and cost) it bears out my contention that small cuts and many of them are the way to go for router CNC'ing as it brings into view smaller motors with less HP.

I'll have a go at contacting Hishine at Ali B to see what qty and price they want, but the motor weight/size is now a big question, and it's possible a different approach should be tried motor wise as to the actual power requirements needed to mill effectively.
Ian.

[RCaffin]

You would not want that to walk off the table by accident - it could hurt your toes!

Spindle Drive:
Frankly, I do not like the idea of having the motor and the main spindle bearings all in one unit. Too many compromises there. Too many Chinese compromises.

I have a 500 W 180 V Baldor industrial DC brush motor for the spindle. Only 500 W you ask?!?!? Yeah, but you should see the size of the motor! It's HUGE! I really mean that! You can run it at 3000 RPM at 500 W all day and it would just purr along. That's an INDUSTRIAL rating. You can NOT do that with most of the much smaller Chinese spindles: they overheat and die.

I also have an ammeter in the spindle drive circuit. To be sure, it can kick up to 4 A when started at 3000 RPM, but it usually drops back to maybe 1 A at 180 V. Forgive me, but all this stuff about 3 kW drive motors seems to be a bit of a waffle in a home shop. I suspect that few of those integrated spindle motors could sustain that power level for very long. My experience is that I just do not need that power level. (OK, I am conservative and I am mainly machining aluminium alloys, but I do machine some steel.)

The only time I had to draw 500 W on the spindle was when I was drilling 8 mm holes in Ti 6Al4V rather faster than was maybe wise. It coped (and so did the Dormer drill bits), but I did cut the RPM and feed down to a less hungry level next time.

My spindle has double 7208 angular contact bearings fitted to zero clearance at the bottom, and a single 6207 DGB at the top to take the pulley. The drive is a 1:1 toothed belt connection. The belt has to be tight or it can flap at resonant speeds, but that's OK. I think these bearings are probably a shade larger than the ones in a Chinese spindle?

Cheers

[louieatienza]

You can buy quality Chinese stuff as well. I wouldn't knock electric spindles, Colombo and Perske make some really good ones. Also Kollmorgen and Parker make frameless motors that can be integrated into your own spindle design...

[handlewanker]

Hmmmmm.....thanks a ton Roger.......that puts the spindle motor requirement into a clearer perspective.

I take it you are referring to a router layout with that motor/spindle you mentioned........any idea of the weight of the actual motor?

It would seem that without actually driving a spindle with known power consumption under load the picture becomes hazy and figures for capacity suddenly become blurred......bigger is better as the saying goes, bit not all that really true.

The BLDC motor I've been watching is quite large and weighs 9 KG.......so I might take a closer look at a 1/3rd HP 3,500 rpm 3 phase motor specs to see if it scales anything like the BLDC one.........the Z axis has to carry it .......the cost is also low at $59 on EBAY from a dealer quite close to me.

I already have a 3 phase motor driving a small lathe and that is .75 HP, 2770 rpm and draws 2.2 amps........size is 150mm long X 130mm diam, but as it has cooling fins cast on the body, machining them off would give me a motor 100mm diam........that is more like it.

At any rate, mounting the motor side by side with a spindle and belt driving it is how I see it, and coupled to a VFD.

Physical size, and less of it, is probably more important than weight in a motor.....my opinion........but it can be accommodated if the right motor is found.

We can throw money at these options, but in the end a DIY hobby use approach is not a money spewing solution......different if you want to earn a crust of bread with your device.....then money talks as it's a ROI situation.

Just waiting on the Hishine website to see what offers they have for motors in quantity regarding the price.......probably have to re-evaluate the requirements now to lower figures as the 3 phase motors are now starting to look very promising.
Ian.

[handlewanker]

Hi, here's a pic of the 3 phase motor being sold on EBAY for $59 that I mentioned.........the fan casing diam is 110mm which makes the body itself about 100mm diam....... overall length to the end of the fan casing is 199mm....that includes 22mm for the shaft length.

I'm toying with the idea of getting one and stripping it down to the bare bones, that is removing the fan casing, fan and cable box, also cutting off the fins to make it more "streamlined" and compact.....$59 is not the end of the World for experimenting.......I could arrange a separate small cooling fan to draw air up from inside on the top if necessary.

The EBAY adv says they can supply a motor (China import) from .18KW to 300KW......so as this one is ,37KW (1/2HP) there's an even smaller one at .18KW (1/4HP).....but it might have the same frame size, so no gain there.

As the company is just down the road from me, I might pop down there on Monday and see what they have to offer.

BTW, for comparison, I have a small bench drill press and that has a 1/10 HP 1400 RPM single phase motor with a 4 step pulley, but even at that small size it drills steel quite easily......the chuck is 13mm capacity, but I doubt it'll be able to drill 13mm straight into steel even at the lowest belt reduction.....OK for wood and aluminium etc.
Ian.

[RCaffin]

Hi Ian

I take it you are referring to a router layout with that motor/spindle you mentioned

Anything but!

It's a fairly serious machining centre. $30k new, but it cost me ~$13k second hand (but almost unused). Not large, but extremely rugged. I can program moves down to 0.8 um resolution, and I can zero X & Y axes to 10 um and expect them to hold that. Yes, I have tested that. The Z axis is giving me a bit of a problem right now as it seems to hold only 20 - 30 um, but having sorted out the RFI from the spindle drive I think much of the remaining problem is in the XL toothed belt driving the Z axis ball screw. You may remember my comments about how the older series of toothed belts do have backlash? I am replacing that belt and pulleys this week: they are off the machine right now. I just have to fit the GT2 replacements on.

Motor weight? Dunno, but unlikely to be under 10 kg. There's an air spring balancing it. Yes, that loads the Z axis motor, but the mill table sure loads the X-axis motor too!

Converting a 3-phase motor to VFD - interesting thought. I would wonder about the heating losses of course, but ...

cooling fins cast on the body, machining them off would give me a motor 100mm diam

UNWISE imho. Those fins are there for good reason. I suggest keeping them.

You could of course experiment with a splined motor connection, as used on the RF30 mill. You could fit a PDB on top of that. Where to buy the spline ?

There seems to be a HUGE difference between hobby motors rated for light duty and short operations, and industrial motors rated to run 24/7. A huge difference.

Cheers

[Feist92]

What machine is it? Wouldnt mind looking it up. I hadnt heard of a commercial machine with a 500w motor before

[handlewanker]

Hi Rog, I doubt the term serious machining would apply to my world....it's mostly bits and pieces for fun and hobby work..... when and whatever.

You can run a 3 phase motor on a VFD as it's just a frequency variable thing.

The one I have takes single phase from the mains and gives you 3 phases out with variable frequency up to 200%.

As far as cooling is concerned I think the external electric fan will do the trick.......still to be tested........it'll put a lot more air through the motor when it's running slower.

As soon as I can get to the motor people for a looksee I'll know what the score is, but it'll still be light cuts and lots of them.

BTW Feist92....are you going to mount a second slab on the existing one to give you a table?
Ian.

[rocketflier]

Producing a diamond from the rough and landing a job so quickly?!!! All I have to add is "OUTSTANDING"!!!

[RCaffin]

What machine is it? Wouldnt mind looking it up. I hadnt heard of a commercial machine with a 500w motor before

Australian made Adept. Bit of a long story there.

It was designed and built for tech school or college use, and the mfr contracted to the NSW Education Department for a large number. But after a small amount of production the Gov't reneged, leaving the mfr unable to pay for the very big CNC they had bought for the production work. They went bankrupt.

Thing is, it was designed to take repeated abuse by students crashing the machine on a daily basis (as it were). The X axis rails are only ~350 mm long, but they are 40 mm hardened and ground steel rods for instance. The rest is similarly over-engineered. It's built like a tank! (It weighs like a tank too.)

Now, the reason the Dept Ed reneged is probably because they could not get the qualified teachers. You don't let students loose on a CNC without proper supervision after all - for their OWN safety! But what happened then was that a number of these machines sat in the back corner at schools for a decade or so without use. The Adept CIM Centre in Q'lnd buys them from the schools very cheaply, replaces the DOS-based computer and upgrades the electronics, and resells them.

Caution: when you think of a 500 W motor you are probably thinking of a Chinese 500 W motor. This is a Baldor Industrial DC motor. Maybe 120 mm dia and 240 mm long. The rating is 500 W - for 24/7 operation. Reality is I rarely put >200 W through it with a 6 mm cutter.

Cheers
Roger

[Feist92]

BTW Feist92....are you going to mount a second slab on the existing one to give you a table?
Ian.

Yep thats the plan. I wanted more versatility than having the table bolted to the linear blocks. This way I can use sacrificial and job specific fixture plates

Producing a diamond from the rough and landing a job so quickly?!!! All I have to add is "OUTSTANDING"!!!

Thanks very much I apreciate that. Its not just any job either, I get to play with rockets all day

Australian made Adept. Bit of a long story there.

It was designed and built for tech school or college use, and the mfr contracted to the NSW Education Department for a large number. But after a small amount of production the Gov't reneged, leaving the mfr unable to pay for the very big CNC they had bought for the production work. They went bankrupt.

Thing is, it was designed to take repeated abuse by students crashing the machine on a daily basis (as it were). The X axis rails are only ~350 mm long, but they are 40 mm hardened and ground steel rods for instance. The rest is similarly over-engineered. It's built like a tank! (It weighs like a tank too.)

Now, the reason the Dept Ed reneged is probably because they could not get the qualified teachers. You don't let students loose on a CNC without proper supervision after all - for their OWN safety! But what happened then was that a number of these machines sat in the back corner at schools for a decade or so without use. The Adept CIM Centre in Q'lnd buys them from the schools very cheaply, replaces the DOS-based computer and upgrades the electronics, and resells them.

Caution: when you think of a 500 W motor you are probably thinking of a Chinese 500 W motor. This is a Baldor Industrial DC motor. Maybe 120 mm dia and 240 mm long. The rating is 500 W - for 24/7 operation. Reality is I rarely put >200 W through it with a 6 mm cutter.

Cheers
Roger

Interesting. Understandably there seems to be very little info on them. I looked at a video of one of them but I couldnt work out how the spindle and z axis is attached to the machine. I couldnt see a column on it

[handlewanker]

Australian made Adept. Bit of a long story there.

It was designed and built for tech school or college use, and the mfr contracted to the NSW Education Department for a large number. But after a small amount of production the Gov't reneged, leaving the mfr unable to pay for the very big CNC they had bought for the production work. They went bankrupt.

Thing is, it was designed to take repeated abuse by students crashing the machine on a daily basis (as it were). The X axis rails are only ~350 mm long, but they are 40 mm hardened and ground steel rods for instance. The rest is similarly over-engineered. It's built like a tank! (It weighs like a tank too.)

Now, the reason the Dept Ed reneged is probably because they could not get the qualified teachers. You don't let students loose on a CNC without proper supervision after all - for their OWN safety! But what happened then was that a number of these machines sat in the back corner at schools for a decade or so without use. The Adept CIM Centre in Q'lnd buys them from the schools very cheaply, replaces the DOS-based computer and upgrades the electronics, and resells them.

Caution: when you think of a 500 W motor you are probably thinking of a Chinese 500 W motor. This is a Baldor Industrial DC motor. Maybe 120 mm dia and 240 mm long. The rating is 500 W - for 24/7 operation. Reality is I rarely put >200 W through it with a 6 mm cutter.

Cheers
Roger

Hi Rog.........so, even if you have 500 watts on the name plate, it might get heated and burn out?

That would mean a Baldor or equivalent make would probably be 500 + 200 watts to be comparable to the Chinese model for continuous use.

The Baldor you mentioned, with the sizes too, is about the same size as the one I saw on EBAY........120mm diam X 199 overall length......end of shaft to end of fan casing......but it cost $59........any idea of the price of a Baldor with 2,800 rpm and 500 watt?.....pic of the EBAY model attached.

It's very probable that if the EBAY model was suitable it would not need to be driven flat out all the time.......down grading it to 300 watts is still a lot of grunt for $59.

At 500 watts the amp draw is shown as 1.6 amps on 240 volt star connected.

I get the impression that the motor is rated for 300 watts continuous and 500 watts peak for a short time only.

If I can wangle it and do a strip down rework of the casing, it might be the solution I need.....at very minimal cost.

The casing is aluminium, not cast iron, so not much weight saving there but it might be OK physically to fit next to a spindle without hogging the X axis saddle real estate.

Feisty, having a secondary table would make sense for specific applications.....almost like a pallet design.....which would probably be an exciting idea to pursue..........you could have an over long table for that once in a while long job without needing to go to a long machine and long rails and screws etc, or have one made from MDF for a wood project etc.

I got a reply from the Ali B Hishine people asking what I wanted 10 motors for........quantity request for cheaper quote possibility......so another wait for a reply......meanwhile I'll buy the 3 phase model and tinker with it.
Ian.