I have not run it at full speed but at 15k you can barely hear it running. For high speeds you should air cool the spindle. I have not used it enough to tell you feeds and speeds but I typically use .001, .003 or .005 pyramid cutters on wax and .012 to .016 straight end mills on sterling silver. From what I am told I can run these fairly high without cutter breakage.
Dan
Nice!I use my current Taig spindle with .01" endmills at 11k and it sounds like the bearings are going to explode. My question: how do they cut the flutes in a .01" endmill???? Love to see that machine at work!
Is the little air tube at the top of the spindle for air cooling, or is that for something else? (like air bearings?) My compressor is so dirty I'm almost afraid to use it with an NSK without like 5 filters inline..
Good luck with your cutting!
Last edited by Riceburner98; 09-13-2009 at 06:40 PM.
I have no idea what machine cuts a .01 endmill but this is where I buy them:
http://www.bitsbits.net/index.php?ma...roducts_id=332
Yes there is an air line for cooling and a power line into the top of the spindle. You can buy a special filter for the NSK it does have to be oil and moisture free air. Currently running a .03 ball nose end mill at 15k and 10 ipm. I could most likely go faster but I don't want to push it.
Dan
short video.
http://www.pencraftsman.com/spindle.wmv
Wow, that's pretty silent! Thanks much for the video!
I'm still of the theory that the German water cooled spindles on eBay would be a great idea. They're the same ones Keling is selling, just a WC version from the same mfg. Actually, if you need a filtered, dried, compressed air source, WC is less complicated that that. Just add a cheap PC water cooling pump and radiator and the spindle should run extremely cool and quiet. According to my calcs, the dissipation required is well within the capabilities of a PC water-cooling radiator.
Last edited by MechanoMan; 09-23-2009 at 07:31 PM.
Perhaps you can get some ideas and parts from http://www.usovo.de/shop/
Cheers,
Herbert
Hello Herbertkabi
Hi there Herbertkabi, I was looking over your posts, again, and wondered if you can give some dimensions to the homemade high speed spindle featured in this thread. I know it may be an old post, and you may not have this in your possesion but I'm having trouble determining the dimensions to the above high speed spindle you made.
"Are you gonna eat that?"
Hi Herbertkabi,
This is one of the best threads we have had here on CNCZ. It really helps that you post so many pictures, when explaniing your work. Thansk.
Your method of preloading the lower bearings through the upper bearing inner race is excellent. Thanks for explaining it.
I have a set of ER-16 collets (Sherline mill spindle cartridge), so I am looking at an ER-16 collet chuck with a 20 DIA shaft. For the stuff I need, 3-6mm milling in aluminium and steel will be most common.
I have a few questions:
1/ In post #72 you talk of remachining the collet chuck all over, but in #82 I think you are saying that this is not necessay. In your experience, are these chinese collet chuck shafts normaly dimensionally accurate enough to mount P2 Angular contact bearings without regrinding the OD? (There are some nice P2's on Ebay Germany).
2/What type of bearing do you now use for the upper bearing? I see you make a floating mount centered with O-rings.
3/ You preload the upper bearing with a home made wavy washer. You mention in post #85 that you might post a "how to" thread describing how you make these. I would really appreciate if you could. You have stated that the wavy washer is made of 0.05 -0.1mm Brass sheet. I would have thought this this brass stock would have little spring back, and would flattern and provide little or no spring force? Am I confusing the shim to preload the two lower angular contact bearings with the spring for preloading the upper spindle bearing? What force in N are you aiming for on the upper spindle bearing?
4/ In #75 you said you could give us some links of where to get chinese motors. In #78 you pointed us to Hobbycity.com, thanks. I checked their website and it would seem that their KD36-74-15XL would be most appropriate to what would like to do. Do you have any experience with this motor? If you have any other good links to chinese or hong kong web shops please post them.
5/ All I know about speed controllers, I have learnt in this thread
6/ What else do I need to get this motor running with this speed controller? As PSU, I would make a simple unregulated 28V 500W PSU with a big cap. I see programming cards available for most other brands of speed controller but not for Hobbykings house brand. Do I need one? Having governor mode activated sounds practical.
The Speedcontroller has the same interface with the Rx as a servo. Looking at http://www.epanorama.net/documents/motor/rcservos.html, it looks like this is a PWM interface, but only runs between 0-4% duty cylce on the signal pin. Mach 3 can directly output a PWM signal, but I don't think it allows control of the pulse width between 1ms (off) and 2ms(full), rather it controls the line between 0 and 100%. I'm sure it would not be differcult for someone with more electronic knowledge than me to make a widget to convert this Mach 3 0-100% PWM signal to a 0-4% for the RC Speed controler . I'd probably just use a Homann spindle speed control board to convert 0-100% to 0-10V, and build the widget in the above link to interface that with the speed cotroller.
Regards,
Mark
1.) I have not met bad made China chuck, are as described.
The only thing I do is hot pressed cone (after that remachined), and perhaps some gooves ...
2.) my first spindle where floating upper bearing I used deep groove bearing, later changed to angular - was much better. I use only super precision angular contact bearings, only once bought from factory, most of from ebay, brand new but much cheaper. Sometimes I do replace steel balls -> ceramics ... grease I use Kluber - again from eBay.
3.) First wave washer was selfmade, yes, now I have some factory made as well. But instead of mentioned - also I do use small spiral springs with plugs and circlewise bored small holes on the "piston" and on the inner edge of housing.
When waved washer then its made from ca 0.3mm steel, waving is hot-wormed and adequate threated.
Yeah - pressed-packed 10...20 layers of 0.05 -0.1mm Brass sheet - there I do machine (milling machine) set-up washers ;-)
4.) I just rebuilt this Chinese motor ... to be honest I do rebuild even Lehner or what ever motors :-) I do build myself as well - from A to Z - not because to save the money ... its just my beloved area ... when used the best possible materials and custom balancing service then cost of selfmade ones will surelly exceed any seen price.
Chinese or not chinese - the right size, Power, Voltage, kV, max rpm and VIBRATION(!!!) are what you need to check . And bearings must to be replaced to the best of ones. When slotless motor like mentioned chinese - then water cooling surelly necessary.
5.) LiPo (3-6 cells);NIHM (8-18 cells) - up to 24V,
ESC you need you must to look from "high voltage" section, at least LiPo (2-10 cells);NIHM (6-30 cells) Max Voltage : 42Vdc
Although the Amp-meter shows 3...5...9A when milling - I use at least 25A ESCs ... even 100A ... I have a lot of controllers because years of RC activity ... but anyway I have bought and used newest Asia made ESCs with success.
6.) Just connect motor, connect Servo-Tester to motor (when ESC has no BEC, then you will need external bec to feed servo tester ...) -> power supply. Or go to any rc-forum and ask - my Englisg is too wooden (DIY ;-)
EBAY offers a lot of RC bl speed controllers and motors, new and used - I have never despised used stuff - risk is near nonexistent but saved money notable - saved 50%, sometimes you can get 200$ stuff for $20
I have bought different stuff total more than 1600 times from ebay ;-)
http://modellbau.shop.ebay.de/RC-Mod...=p3286.c0.m282
http://toys.shop.ebay.com/?_from=R40...ess&_sacat=220
cheers,
herbert
Thanks for you response Herbert.
So you use a pair of AC bearings preloaded back to back at the bottom, and then another AC bearing lightly spring loaded at the top. Wouldn't a needle roller bearing be better for the top end? What did you not like about the performance of the spindle with the deep groove ball bearing at the top?
Thanks for clearing up that you are using the brass for shims to preload the bottom AC bearing pair, and are using thin steel wavy washers to preload to top one. Where do you buy the spring wavy washers?
Have you ever made a low speed spindle? My current milling spindle is a Sherline ER-16 and it is only good for 2500 RPM (with standard preload) or 10K if you back off the preload a bit. It doesn't have a pair for preloaded AC bearings at the spindle end.
I have ordered a pair of 7204 P2 bearings and a C20 ER16 150L coller chuck. Once the chuck arrives I can measure it up and start designing my spindle.
Regards,
Mark
hi RotarySMP,Originally Posted by RotarySMP
Needle bearings are not for even 2500 rpm, at least not for me.
At that you need axial preload for bottom bearing or pair of bearings,
And at the same time this upper one must to keep spindle shaft rigid and very stabil. When "normal" deep groove bearing then it did work well just month maximum for me ... you can hear it and you can see on the sample you are milling ... and then it will come more worse and worse up till you can not use it anymore. At that it will ruin your nice and expensive bottom bearins
Perhaps you have some kind of mil.spec ... ceramic ... its possible, but for
me was simplest to use AC bearing. I have seen interior of several better-known and similar size spindles - all they use only AC bearings on the bottom and upper side as well.
I use different spindle bearing schemes, not every time like you described above. For small high speed spindle one AC bearinh on the bottom and second on the upper side works well too, but this floating preload system I like very much, if used good bearings then once precision set-uped you can use it years without needs for fine-tune. On my router similar spindle has been in work bit more than two years, 30.000 rpm, every day several hours minimum. Somewhere in May I detected some strange noisesI took it apart but all was very good, clean and sufficiently greased - cause was about Motor bearings
I have told before - dont save the money with motor bearings, I did it (replaced), but seems not to the really best ones.
My latest spindles where all are in the same shaft there no such kind of problems, but much complicated to build (!) when we are speaking about high speed 20k ... 30k and higher - because balancing :-(
Sherline spindle I have rebuilt to direct drive total three, the last one did for myself. When original deep groove bearings then 6k...8k rpm, someone in cncz spoke it runs OK up till 12k ... Im not sure about ... at least my brand new Sherline spindle I especially bought for experiments did not like much higher than 8k. Now when replaced to adequate AC bearings (1+1) I have tried up to 18k RPM. Perhaps Im not right about ... may be ...
Im not any end most clever dick about - many have different opinions and better understandings, many members surelly know much more about ...
Just my own how-know, my opinions based on my modest experience.
Regards,
Herbert
P.S.
FAG Spindellager Schulterlager B71904C.T.P4S.UL Artikelnummer: 170396466022
you can find more ...
B71904-C-T-P4S 20 id / 37 od / 9 h / 38.000 rpm in grease ;-)
Last edited by Herbertkabi; 10-24-2009 at 05:11 PM.
Hi Herbert.
For a lower speed spindle, one could use a needle roller at the top and still preload the lower AC bearing pair through the upper inner race. I guess I need to decide whether I'm building a low speed or a high speed spindle before I start
I often use a small flycutter or a circular saw blade in my mill, so slow speeds are also attractive. Maybe I need to make two spindles, and make interchanging them easy. I have been thinking about using an RC motor to drive the spindle through a belt drive reduction, as then I could also keep the Collet chuck spindle through hole open for using a retaining bar or even an auto tool changer.
My mill would be lucky to run 12H a month at present. I is at a friends place an hour from home.
Thanks for the Tip on the FAG bearing. It is great for the buyer when people put little information in Ebay. I was looking for a 20mm ID AC bearing, but I missed this.
This is the pair I have bought for the bottom of the spindle:
Zwei Stück Spindellager DKF.: A7204C.TAP.P2.UR
FAG-Bez.: B7204C.TPA.P2.UR
Ebay 330318484908.
Regards,
Mark
hi Mark,
Yes, I know DKF (GDR), have bought few sets from `Tusnelda44` for another projects,
Outer ring of your bearing has full shoulders, inner
ring has one shoulder cut away ... see the photp ... do you know the angle?
I have never used this type of angular bearings for high speed milling Spindle.
Perhaps good, but I prefer AC bearings where inner ring has full shoulders.
I use small fly cutter as well - selfmade - Radius 10mm, 7mm shank, 7075,
ca 20k rpm, even up to 30k, makes perfect surface.
Actually VCGT 130304FN-ALU inserts and have more similar fly-cutter for different inserts.
cheers,
herbert
Does that fly cutter howl at 30K rpm?
I can't find the specific for the A7204C.TAP.P2.UR, or the equivalent FAG, but Fag's replacement is a 15° contact angle.
Regards,
Mark
Yeah, Mark, I dont believe you will find equivalent, what ever they made in DDR, all was concerted with Moscow ;-)
Under the name DKF Wälzlagerwerk Leipzig, the company became world-wide known from 1955 to 1990. In 1990, the company was incorporated in the FAG group. The company Kugel- und Rollenlagerwerk Leipzig GmbH was reestablished in 1993 after execution.
http://www.krwleipzig.de/english/pro...8330e09c033c53
My fly cutter cuts very well, there will come some resonance near 30k and near 25k because I keep rpm below 24k. These inserts need to be as sharp as they are in new condition and sharp they are, bought a lot of via ebay.de ;-) Most of all I machine Aluminium, 7075 in majority, another alloys too and have tried brass as well. I use always Coolant. The only rule with this fly cutter is carefulness with Z axis, it likes to cut thin chip.
No, it does not howl.
cheers,
herbert
I hope those DDR bearings are good. This will be my first high speed spindle, so I see it as a learning exercise. If it turns out crap, hopefully I have learnt enough to make the next one better.
I was doing a bit more work on my ER-32 low speed spindle for the Frankel Deckel today.
http://www.wrathall.com/Interests/CN...nkenDeckel.htm
I picked up an industrial right angle gearbox ages ago, which looks like it will make a really nice massive spindle body.Found a piece of scrap 40mm Bar with a 20mm hole through it which was to be the spindle. I had already machined and polished the OD down to 35mm for a pair of 32007 taper roller bearings. Today I mounted the spindle with a fixed steady and set about cutting the M40x1.5mm thread for the ER 32 nut. I was going to follow this with roughing out the taper on the lathe (I'd grind the taper finished once it is running in it's own bearings).
Unfortunately such a thread is right on the limit of what I can cut with my converted mini-lathe. I was down nearly to depth (takes about 30-40 passes to cut this thread in steel on my lathe), when the work caught up and rotated in the chuck. I'd used aluminum beer can as a shim to stop the four jaw independent from marking the OD, and I guess it compressed and released the chuck jaws tension. I had it dialed in really sweet using my Verdict 1/10000" DTI, and maybe had left a jaw a little too loose when I got it running round.
Since I use a 1/rev spindle encode for TurboCNC, I should have marked the work with relation to the encoder so that it could be lined back up.
I'll leave it today, but maybe another day I'll have a go at trial and error with getting it back in the chuck, dial in round and running slow threading air cuts till get it indexed again.
Damn, I just realised that I forgot to bid on that AC bearing you sent me the link for. The auction has already finished. I'll have to keep an eye out for those.
Regards,
Mark
Yeah, nice and strong spindle, I like to use dusty stuff from my uppermost shelf - have acquired a lot of by style "perhaps in future" - and mostly this day will come surelly.
You need to be patient and try to search ebay by different ways - sometimes seller does not note full type-Nr of bearing or made mistakes ... or does not know at all what he is selling. After Spindellager I try FAG, Barden, SNFA , GMN, Timken ...etg
it takes time but saves money. And once found something I never forget to look at "Andere Artikel aufrufen" - have found wonder stuff !
Cheers,
Herbert
Hello Herbert.
I have received the ER-16 collet chuck which I will be using as a spindle. The shaft seems nicely ground and mic's at between 19.99 to 19.994 depending on feel (I am using a imperial .0001" Mitotoyo micrometer, and converting).
Since I have no information on the bearings, and the manufacturer is gone, I have no engineering data on those bearings.
The inner races of the DKF bearings are also micing at 19.994mm (to the best of my ablity to measure them, as I only have a set of cheap Chinese telescoping gauges, which seem to slightly retract as you tighten the locking screw, so I had to measure them about twenty times before I had a few measurements with consistent feel - Don't by cheap Chinese precision measuring tools every again Mark!!!!).
In any case, I don't have a sliding fit, and will have to press the bearings on. This makes the assembly a has to be right first time thing, as I can't see myself getting them back off again (at least not still P2 precision afterwards).
Were your bearings also a press fit on the spindle? If the nose of the spindle is shrunk or epoxied in place and then turned between centers, and the bearings are also a press fit, then I can not assemble, as I could no longer get to the screws which fasten the bearing retainer (orange in your model).
I would rather not have to put the spindle between centers and polish the diameter down by a 0.01 to provide a sliding fit, but was that what you had to do?
I measured thickness of the inner and outer races of the bearings with a good .0001" DTI on my surface plate, and they are the same within .0001" (~0,002mm).
What thickness shim/spacer would recommend between the outer races? What preload torque would you recommend I then put on the bearings through the inner races?
Regards,
Mark
hi Mark,
My bearings fit exact - means no pressing, no feelable slack.
You right - when pressed then necessary setings and fine-tunings near impossible.
I have polished the diameter down between centres on the lathe used fine sandpaper (with cooland ot thin oil) ... I do it per 20...30mm, when cleaned, tried and when OK, then next 20...30 mm up to the end. Like this you get better results, at that sometimes just this first part of shank is micron oversized.
Mh ... by remote its impossible to tell about spacers you need.
I have somewhere described how I DIY Spacers using mill and rotary table,
Material - calibrated brass(bronze, capton) foil, 0.01...0.1 pessed (bolted) together ca 3...5 mm stack, upper and lowest must to be some kind of stronger material, cfk, alu ... and then cut it ...
Preload torque is matter of feeling for me. At that maximum preload depends about grade of bearings. I dont use hard preload, rather somewhere middle of between smallest SLACK and HANGING (start of jam, never try full jam(hang)).
"measured thickness of the inner and outer races of the bearings ..." - at least for me it near never helped. Even bought from factory two GRW 1/2/001 ... they told me "you never need spacer between" - in fact did need and used 0.01 capton!
Please show the draft of your assembly, perhaps I can carry out some useful thoughts.
cheers,
herbert
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