[G59]

Ok, just had a peek at your drawing and first thing that popped out at me is how close to end the AC bearings are.
Good for rigidity as you said.
In my opinion, and also the reason why SKF and NSK mount their spindle bearings away from the mounting flange, is to eliminate the possibility of warping the bearing seat/head bore during final assembly into the mill head.
But, provided you have clean and flat mating surfaces between the flange and head, you should be OK.
Their are ways around that but that would be giving away my company's intellectual property...LOL.
Either way, looks fine.

[Azalin]

@G59

I've done that. It was almost perfect inside and outside. Before the cut I tried to cut another piece that has almost same dimensions. When the first cut is complete there was nothing left from the cutting blade. It was Proxxon steel cutting blade. 50mm outer dimension and 1mm thickness. Maybe it was rotating too fast for steel or the steel was too hard for the blade. I don't know. So I decided to use square bars just not to bother. The other reason is to not having gaps between the fingers because it wont be easy for me (I'm just a software engineer who has a garage with limited tools) to fill the gaps for better balance.

I'd like to see yours tough.

Best,
Suat

[Azalin]

BTW, I made a new one because I messed up the previous one on welding. It got melted on one spot due to long arc. The new one is much better.

[G59]

Gaps between the petals you mean?
I think you are over engineering things.
The small gaps are not a problem. After all, the petals incur no torque, only a static extension load from the Belleville washers. The tool's taper, handles all the torque.

Wish I was home, I'd even get you a drawing.

[Azalin]

Am I missing something?
Say you split it up to 4 petals with a 1mm cutting blade. There will be 4mm gap in total. If one petal slips and gets closer to another the balance will be affected because the gaps between fingers are not equal anymore. So you need 1mm small pieces between petals to keep them in place.

Just my .2 cents opinion but sure you know better. Please enlighten me.

[RotarySMP]

Nice work Suat. What steel did you use?. Will you harden it with a flame, or do you have access to a heat Treatment oven?

(ThreadJack) Thanks for the comment G59, that is an aspect which I didn't consider. I think I'll redesign the front labrynthe seal, as it will be a ***** to machine like I drew it. I'll make one side flat like the back one.

Mark

[RotarySMP]

I forgot to ask, did you decide on 45° or 60° pull studs? What are the Advantages/disadvantages?
Mark

[Azalin]

Mark

I will harden the fingers but not sure about tempering. Actually I was going to ask you if it's needed.

I'll use 45 degree studs. It's very common around here.

[RotarySMP]

Hardened and quenched but not tempered would be too brittle.

[Azalin]

Got it. Thanks.

[Azalin]

Mark its C45 (aka 1045) steel.

[mactec54]

My original plan, sometime back, was two duplex 15º AC bearings in a back to back configuration with no spacers between them. So they would be purchased in a matched set. Spindle presses tight to the bottom AC bearing and the two AC bearings are pressed into my housing tight to a shoulder in the lower end of the housing. Then the screw in retainer is installed to hold them in a fixed location. At the top of the spindle, 8" up, there will be a deep groove ball bearing with the inner race sitting on top of a spacer that sits on the inner race of the top AC bearing. On top of that single bearing I have a tabbed lock washer and a spindle nut The outer race of the top bearing is free to float in the housing.

That is a pretty much standard Design, like a BridgePort Spindle and any machine like it

But as I mentioned, I read a couple days ago that a double row AC bearing could replace both the single AC bearings and give me results similar to the two singles. About the best I've found is ABEC-3 bearings in a double row, where as the singles in matched sets are ABEC-7's. Hence the large price difference. That's what got me to thinking and reading a bit more on the double row bearing. But like I said, that was a couple days ago that my thinking started on that choice and why I mentioned it. But to be honest, I couldn't recite the difference between the two classes of bearings, only knowing the -7 is a higher precision than the -3. And so far I've not found much info on comparing the two choices, single row vs double row, other than it could be considered. So not much to go on. On the other side of that is choosing the outer diameter of the AC bearings, with my choices being 72mm, 62mm and 55mm. So there's lots of things to study on and come up with answers for. I'm leaning to the 72mm in a matched set if the double row isn't up to the job.

Whoever posted that the double row AC Bearing could replace having 2 AC Bearings does not know what they are talking about, people like yourself get the wrong information, by someone posting/writing this kind of information, there are some double row AC Bearing that could be suitable for spindle use, but not the type that you where looking at, and they are not cheap, anything from ABEC-5 up would be suitable

[mactec54]

Here is a drawing of my spindle plan.The Bore is not finished, as I have not yet decided between petal or ball gripper.

Mark

Pretty much a copy of what I have posted, and others on the Zone before, should be good for your machine Build, one note that if you are looking for more rigidity, you would need to make 2 spacers, to go between the 2 front AC Bearings, the wider you space them, up to around 40mm to 50mm the more rigid your spindle will be,this number can be less, but will also have less effect on the rigidity,20mm to 30mm is about the minimum length, for any advantage

only one Bearing Locknut is needed if you add another spacer between the Front inner Bearings up to the top inner Bearing race

You will also need a Grease Retainer under the top Bearing, made almost like a seal, unless you are using oil mist for lube

Sealed Roller Bearings are available but don't have the ABEC rating for Spindle use

[G59]

Am I missing something?
Say you split it up to 4 petals with a 1mm cutting blade. There will be 4mm gap in total. If one petal slips and gets closer to another the balance will be affected because the gaps between fingers are not equal anymore. So you need 1mm small pieces between petals to keep them in place.

Just my .2 cents opinion but sure you know better. Please enlighten me.

I'm not trying to be smart here, just giving you facts.
Explain to me how a petal will slip???
The only way that can happen is not having enough spring pressure from the Belleville washers,and the tool spins inside the taper which would pretty much make your spindle crap.
Like I said, the petals are not under any torque and don't transfer any rotational force to the tool.
Its a gripper/lock. Not a driving member.
Its your project anyways, do it the way you want. Just trying to "enlighten" you.
PS, when the petals compress back into the hardened sleeve, the gaps are closed just like a collet does on your tool shank..
Have a great day, again I'll just watch this thread as I can see confusion is setting in again.

[Azalin]

I didn't mean to offend you. Just want to understand and make sure I build that thing right. That's due to lack of my English. I think I'm not good on picking the right words. Sorry for that.

Thanks for your help.

[Azalin]

For example, I think they made petals with those little clips to prevent any balancing issue.

[RustedOut]

That is a pretty much standard Design, like a BridgePort Spindle and any machine like it

Yep, like a Bridgeport, that was what I alluded to when I first mentioned bearings.

Whoever posted that the double row AC Bearing could replace having 2 AC Bearings does not know what they are talking about, people like yourself get the wrong information, by someone posting/writing this kind of information, there are some double row AC Bearing that could be suitable for spindle use, but not the type that you where looking at, and they are not cheap, anything from ABEC-5 up would be suitable

As a matter of fact, the info came from a bearing manufacturer and from bearing resellers. It was basically the same info from both and missing finite detail on the use of them. Hence my statement that I was considering that style of bearing. The word considering meaning I was looking for more factual information before decided on going that route. The one I mentioned by part number was the first one I ran into in that fact finding mission. At this point I have found more credible information on their use and it seems that what's available (ABEC-1 and ABEC-3) aren't suitable for my use. That info, again from a bearing manufacturer. And I haven't found any of better precision. Nor have I found matched set single row AC bearings in anything other than ABEC-7. I guess I'm having trouble grasping the need of jumping from tapered roller bearings up to ABEC-7 bearings, but it seems right now, as before, that's the direction this will end up going.

I think we've drifted the subject matter of Azalin's thread too far of course, so I'm done talking of bearings. Anxious to see how his gripper turns out.

Thanks again
Bob

[mactec54]

For example, I think they made petals with those little clips to prevent any balancing issue.

Yes the pieces you see are part of each gripper/petal, it is not a clip, the gripper petals also have a tang on them that fit in a slot in the matting part, this keep them in alignment

This is a different style but will give you an idea of how to do alignment,and the one piece style

[Azalin]

I think we've drifted the subject matter of Azalin's thread too far of course, so I'm done talking of bearings. Anxious to see how his gripper turns out.

Bob

It's OK Bob, but thank you.

I just finished the tools that I'll use for the inside. One for the 45 degree groove and one for the puller slot. It's 23:16 here so I'll take the pics tomorrow morning.

[RustedOut]

Azalin,

I was beginning to think you just stayed up night and day.

Bob