[Herbertkabi]

I really appreciate the discussions here.

Herbert, did you end up using the thin Aluminium foil from your sandwiches to fine tune the preload? What thicknesses did you end up using on your AC bearing pairs on your last couple of spindles?

Looks like I'll order a bunch of shim packs form McMaster Carr and get a friend to bring them over when they do an aircraft delivery.

Last spindles used perfect matched pairs - no needs for any "tunings" between. Earlier I used different materials, the thinnest was 0.1 mm special rolled brass(bronze) and 0.05 mm nickel alloy, dont remember exact name
anymore.
But anyway I need and use thin shims - not between pairs but in several another places where precision trim wil be needed, like back side bearing cup ... and between face flange ...
cheers,
herbert

[RotarySMP]

Throw out a few questions and then follow up the answers with clarifying questions, and this forum is a great place to learn. Thanks guys.

Line boring... I'd need to make a between centers boring bar, then I need to make a micrometer tool setting jig to accurately set the tool bit in the boring bar for each pass. Then I need to make a spindle housing holding jig to mount it to my cross slide during boring.

It is a daunting prospect. I have thought about making the between centers boring bar and setting jig before (I really want to make a decent rigid tailstock for my lathe one day), and will make one sooner or later, but right now I think I'll be putting my time into finishing the mill (getting it CNC'd), finishing the low speed ER-32 spindle, and finishing the bending brake.

I like how Herbert mounts the upper floating bearing in a housing located by an o-ring, allowing a little misalignment there. Sure it makes the entire system softer and less rigid, but the actual cutting forces must be minuscule on a 30K+rpm high speed spindle driving <6mm end mills. Herbert is reporting good experience with his, so I will be copying this design for the first one.

John, I like your method or cutting the shim. Using the tail stock to sandwich the shim must be a real time saver.

How do you cut the ID?

If I understand your preload jig, you torque up the bolt holding the inner races of two bearings together, while moving the outer races with the clamping levers. Once the lever slips, you have your preload setting. Have you any torque measurement to give guidance on what that slippage torque should be? As drawn, your slippage torque could be totally different from mine, if we maching those bore a fraction differently.

Pat, you talk about setting preload using a preloading nut on a thread. I had always read that this is bad practice, as it is difficult to the real preload being applied, verses the torque absorbed by the threads. I do understand your point that this lets you directly "feel" the preload.

[JLSD]

Hi Mark,
Should've said, the clamping pad is exact I/D, allowing a "touch-off" reference for I/D, but O/D CUT FIRST. I've used this for soft metals up to approx .25m.m., and plastics to .8m.m., (this with 35m.m. radial width in the breeze!)
Smallest I've needed were 7X10 for model I/C crank bearings-lost more in the chip tray than used!!
John

[isvflorin]

Ok guys, I'm in the spindle game too, been trying to put together a DIY spindle.
My question is : paired angular contact bearings, laser etched - do they need any spacer for preload ? I bought them from ebay and they even came with a datasheet but unfortunately it is written in Chinese. I wish I could read chinese...

regards,

Florin

[Herbertkabi]

Mark,
Misalignment? Please precise where I have. About what draw you are speaking?
My spindles are as rigid as possible ...with used shank diameter.
Some parts I have made new and new ... turned/grinded 2...3 times until got exact fit - no slacks, no jams. Do you mean this spindle (attached)???
There the only two O-rings are for sealing motor cooling and works as well like motor vibration dampers, +motor bottom seal.
Where "floating bearing" there are not drawed (not shown) set-up screws - three axial screws are for preload - through FIXATOR to "saucer" (no named) to inner ring of bearing ... three radial screws fix FIXATOR (one piece with coupling mother side) to the groove on the shank.
Regards,
Herbert

[Herbertkabi]

Ok guys, I'm in the spindle game too, been trying to put together a DIY spindle.
My question is : paired angular contact bearings, laser etched - do they need any spacer for preload ? I bought them from ebay and they even came with a datasheet but unfortunately it is written in Chinese. I wish I could read chinese...

regards,

Florin

Some are just "matched pairs" , real ones are really matched pairs of super precision AC bearings - there you do not need any additional shims or spacers. Real matched pair of SPAC&#180;s costs a lot ... but somertimes ... if you are happy ...
What we can do when bought "matched pairs"? Like with common pairs of AC bearings and even with two not-paired SPAC bearings - you just need to try and measure and find out exact thicknes you need. This is not a simple work!
Sometimes you can use two precision grinded(!!!) steel shims (spacers) - for example outer 1.00mm and inner 0.95mm ... (depends about type).
Please understand - it was *for example*.

regards,
herbert

[wildwestpat]

Hi Mark

Using a thread to adjust the pre-load works and works well provided you use a very fine thread. Yes the adjustment is a bit hit and miss. I have always had a good listen to the bearings using a contact microphone during set up with the shaft rotated at moderate speeds and again during the first hour at full speed. You hear the bearings making a delightfull singing noise when they are happy and a very sorry noise when not loaded. The noise when they are over loaded is even worse! I guess it would be informative to use a scope to look at the wave form from the contact microphone but the noises are so distinctive headphones are good enough.

Some thirty years ago shim material was available in laminated form. Many layers of thin material - alli alloy of some sort - was lightly glued together. This was I think called Rose or Rose's metal. Washers were turned out of this laminated sheet and peeled off as needed. May be some one knows of the existence of this material and where it can be obtained. In the electronics industry use is made of thin heat resistant plastic to insulate transistors for their heat sinks. This plastic film is very thin and robust and resists puncturing well which could indicate that it is stable under pressure.

The use of plug gauges is a good tip and as well as the conventional 'go' - 'no go' it is helpful to make the lead in the form of a slight taper for the first few mm. This gives an early warning as the exact size is approached! Many machinists use the same approach in reverse to check the final approach to size by making a trial run on the start of the bore. I hesitate to mention this as so very basic but it can save a lot of tears but can be overlooked in the excitement of getting a good surface finish.

Regards

Pat

[RotarySMP]

Herbert,

I think I made an wrong assumption based on the grooves you turned in the upper bearing carrier (Steel dish) (see picture).

I thought you machined the main spindle housing bearing OD's in two set ups, and then used O rings in those grooves to provide for posible slight missalignment. I see from your CAD model that my assumption was incorrect, sorry about my error.


Which method did you use for machining the main housing?

1/Bore the OD for the lower AC bearing pair, then remove the housing from the lathe, turn it around, remount it, indicate it in and bore the OD for the steel dish which holds the upper bearing?

or

2/ Mount a boring tool between centers, mount the spindle on the carriage, and bore out both lower AC bearing pair OD, and upper bearing carrier (Steel dish) OD in a single setup?

[RotarySMP]

Hi Pat,

Peelable shim is still available from McMaster Carr. I have only ever used it on one job, shimming the side play while reinstalling a Short skyvan nose landing gear, which had been packed in dry ice. Needless to say, peelable shim does not bring up fond memories.

McMMC is also 0.001" per shim layer.

Thanks for you input on using a microphone ot check on the bearings.

[Herbertkabi]

Yeah, these grooves are for keeping grease.
Housing I drill full lenght (with 24mm) and turn on the lathe, Outer to final size and ONE side of inner, very carefully and up to 0.00 , then I cut off exact lenght +0.5...1.0 mm.
Take out all from lathe.
Then I do turn (from thick-wall alu tube I have) every time a new special precision holder into this exact fit ID. I do (slightly) press this housing - so I can turn ANOTHER side of ID of housing without any errors - and again size exact 0.00. For final ID +0.01 or more I later using simple honing tools. I use only the best cutting/boring tools in the lathe (At least what I think what are the best for me ... Im not any expert or nonpareil machinist - Im autididact and I do all like I think it is the best).
These thick wall aluminium tubes I spending - Im happy - because all these 200mm pieces will be used for my another works I need to do for bred ;-).
The final is honing - I do use the same alu tube (still in Lathe) and ... honing up till bearings fit from one side and sliding cup fits from another side. Then promptly I examine exact fit of upper bearing ("floating") inside this sliding cup.
Oh dear ... my English ...
cheers,
herbert

[Herbertkabi]

Some more illustrations, my acad does not want to work well anymore, not updated, no upgrades ... I dont want to buy a new license. Two tears ago bought SolidEdge - excellent!!! but unfortunately old man with salt and pepper beard cant never learn to use it. But OK, may be I will ...
One picture is the same but air cooled. And one is ATC, I have made three different ATC-s ... thats because now Im busy with dynamic balancer - when integrated motor (in the same shaft) then no way without own balancer.
regards,
herbert

[RotarySMP]

Thanks Herbert. Do you have any photos of using those thick wall aluminium tubes please? I am having trouble picturing how you do this.

[Herbertkabi]

Thanks Herbert. Do you have any photos of using those thick wall aluminium tubes please? I am having trouble picturing how you do this.

No,
And I have no time right no to go to workshop, to cut, to install in to lathe and make pictures ... sorry,
What is there incomprehensible? It is most primitive way to keep all in centre because Lathe Chucks lies always ... and changing 3jaw chuck to 4jaw one and then set-up and playing with indicators ... not for me - I do make this "artificial center" - exact perfect inner center- like collet ... - I do this mach more faster and more precise than Im able with 4haw chuck.
Of course it is simple for me because I have a lot of this L-200, OD-82, ID-40 alu,
And also very understandable is - if you need with starting to find any of this kind materials - then for you this is not a brilliant idea at all.
Cheers,
Herbert

[isvflorin]

ok here it is: I got the parts finally,
NSK 7003ATYP5 bearings (can't find any info on them, don't know if you can tell from the picture but they are laser etched in a pair) they are only P5 precision so I guess they won't hold too much high speed.

Got my UBEC, controller and servo tester, but never used this stuff before, I have no ideea how to wire them, they don't have any precise wiring diagrams.
I'm not sure if the controller has BEC incorporated or not, can't figure it out. Power supply is 23-27V, only 20Amps. Motor is 1200kv.

I have straight shank collet holder and a housing made for the bearings, but still need to remachine it on a lathe, also make a few more parts.

Does anybody have a good link for how to wire up UBEC- servotester-controller-motor ? Anybody reads chinese ? The bearing datasheet specifies some spacer dimensions I guess.
Herbert do you have any close-up picture of a servo tester-ubec-controller-motor setup ? I never wired these things ever, don't want to fry anything.
Also do I need a programming card ? Or I can run these without it ?

Florin

[Herbertkabi]

Its simple. But you need power supply instead of batteries. What Voltage? *** Motor kV x Voltage = RPM *** Dont use too hight voltage! You dont need more than maximum 30.000 rpm for beginning. Even less.

3-wire connector from ESC goes to Servo tester where written Servo (black->ground)
UBEC connected with ESC +/- power ends - Connector to Servo Tester (see -/+)
Potensiometer - always start from endmost CCW!
Now when power in then ESC makes hes signals ... then carefully turn potensiometer ...
When not right direction, then just change two (of three) wires (motor wires) between (when POWER OUT, OF COURSE).
It will work with factory settings, you can try short time, but surely better if you&#180;ll make clear for yourself all SETTINGS! Do you have instruction mamual?
You need:

Timing Mode Setting -> 1&#186; - For 2-4 Pole Inrunner Motors !!

Pulse Width Modulation(PWM) Setting -> two choices 8 and 16khz (any - later look what is better for you)

Cell Type and Number of Cells -> choice any (dont think about NiCad ir Lipo) just Volage ... cut off is for when airplane batteries will come empthy ...)
6-lipo or 18 Nicd = ca 24v - thats all.

Throttle Setting -> Soft Acc !!!!!!!

Brake Setting -> No Brake !!!!!!!

Direction and Cutoff Type -> any (you can change direction as I spoke before ...)

Try to find some friends who acts with brushless RC stuff ... or read/ask from
http://www.rcgroups.com/forums/showt...=657606&page=4
http://www.daddyhobby.com/forum/showthread.php?t=49280
http://www.wattflyer.com/forums/showthread.php?t=11604

Cheers,
Herbert


Yeah, now I see - 23-27V, only 20Amps. Motor is 1200kv. ...
20A is enough. and your max RPM will come ca 30.000. If you can regulate this Voltage then choice 23 (minimum) - 27.600 RPM is OK - because you are not sure about bearings.

[wam]

Ok guys, I'm in the spindle game too, been trying to put together a DIY spindle.
My question is : paired angular contact bearings, laser etched - do they need any spacer for preload ? I bought them from ebay and they even came with a datasheet but unfortunately it is written in Chinese. I wish I could read chinese...

regards,

Florin

Which dialect of Chinese?

[isvflorin]

Hi there,
I have no ideea about the dialect, might be even Japanese, it's all Chinese to me (pun intended). Here is the datasheet. There are 3 bearings all laser etched in arrow shape, 2 of them are paired and the 3rd seems to be the 4th bearing from another pair (like they initially were 4 bearings all laser etched in matching pairs from start to end bearing - from this configuration of 4 bearings I have numbers 1,2 and 4, judging by the etching on the side)

[BobWarfield]

The laser etchings are orientation marks that tell you which face goes which way and how to rotate them in their pocket to minimize the runout. NSK's will be documented on their web site. At the very least, go check out how to line up the marks.

I suspect you will be able to tell from the site whether you need a spacer, but I'll bet not.

Also, those are inspection sheets. The diagram is telling you pretty clearly how it wants to sit for proper preload. Note the offsets in microns. Take the bearing code, 7008ATYP5, and go look it up on the NSK site.

Best,

BW

[isvflorin]

Bob,
NSK website was the first thing I checked of course. However these apear to be really old stock bearings and they changed numbering since. The new numbering is different and can't see any corelations between.
They are probably old style numbering, who knows from how many years ago.
I'll keep looking, however the datasheet gives some micron numbers that appear to be tolerances and dimensions of inner and outer race.

I would be really nice not to need spacers, I guess there is a simple test I can make, just assemble without spacer and see if there is axial play ?

FLorin

[BobWarfield]

Take a closer look at the diagram on the lower left. Those dimensions are displacements from the resting state of the bearing. Looks like preload to me.

Worst case is you need a spacer the thickness they're calling out. And yes, your penalty for having gotten them cheap is you will need to painfully wade through their online site to figure out their numbering. If you just did a search, forget it. There are multiple bearing catalogs. Go find every one of them that deals with angular contact bearings, print them out, and scan through them by hand. It's a lot of work, but you'll learn quite a lot about bearings doing so.

Your second penalty is you're going to have to do some experimentation. That's ok too. Wait until you see the page in the bearing catalog that tells you what the tolerances for mounting the bearing are supposed to be. It will take you a trial or two at the lathe to hit anything close to those tolerances unless I miss my guess!

Cheers,

BW