Hello people,

Its been a while since I wrote anything here in cnczone but, there were reasons for this, mostly personal, financial and such that are mostly gone. Since then I have moved to Europe from the States and have started working as a teacher, at a university, teaching industrial design.

For people who remember and for who do not, I had this thread going with a lot of input about a automatic tool changer and a spindle to allow this:

New Spindle Design, feedback plz! (http://www.cnczone.com/forums/showthread.php?t=3001)

I have received many messages and email during the last year about how I was doing with the design and why I was not posting and such, so I would like to thank all who have shown interest. I was not able to answer each and every email and message that came through, so I am sorry if I have broken any hearts:)

The news is, I have once again started my CNC project and my spindle project. The difference this time is I have the time, the machines to make it (by professionals who have big CNC machine that can reach the tolarences that I need) and the money to make it happen.

As I said, during the last year I had people contact me about the spindle and about the design, the design has changed somewhat, but I will post the old images up here, as that was requested quite a bit.

You can find more imformation about this whole process in the above thread, but here are listtle explanations above each image:

1st Image: This was the original idea that started it all, a spindle for a chinese mini mill

2nd Image: The progress on the idea using a spring for the toll changing mechanism

3rd Image: The design as it was left of that day when I left the forums, a block-type spindle that can do over 10k rpm ABEC-5 bearings and such in the works, which has somewhat changed since that day:)

4th Image: The actuator from a lay-z-boy chair, working quite good as a puscher rod for the BT-30 collets (ISO30 or CAT30 depending on what you would like in your machine)

5th Image: The setup to test if the actuator had enough power to sequeze ~100 spring washers

6th Image: The test went pretty good

This is just a new beginning for me, almost like I started a new life, in a new place, with no shop (good people with shops around me though) and with less financial problems.

Hopefully, this time it will be alright. Oh and the new design I have which I will post soon hopefully will be made on a CNC lathe quite soon:)

Thanks.

H3ndriX

I'd be inclined to take the lower bearing in design 3 and replace the duplexed A/C plus regular ball brg with a properly matched and triplex'd A/C bearing. The configuration of which and preload (probably 15 deg + 15 DT + 20 in reverse with MED preload) would ultimately depend on the machining loads you're trying to absorb.

If you axially contain the lower bearing, I'd let the top bearing "float" axially at the OD if you fix it to the spindle with the nut as it appears you are doing.

This will prevent any thermal growth of the spindle or housing from applying an undue axial thrust to the upper ball bearing.

Hey! Nice to have you back! :)

Were are you located nowadays?

Cheers,
Sven

h3ndrix,

I for one am thrilled to see you back. I sent you two or three emails and never heard back. I really was concerned because just before you went missing you mentioned problems you were having to deal with. Sure am glad those are working out as well. Do me a favor. Post these pics somewhere permanent! :D

I will be excited to see the progress of this new design.

Good to have you back.

Mike

Hello H3ndriX
tis is a mi spindle
beest regard Tanks, Dario
http://www.cnczone.com/gallery/showgallery.php/cat/500/ppuser/8522

Welcome back!

To be honest I didn't know you where gone as my attendance here is sporadic.

In any event your drawings are fantastic! Not ever having had a tool changing spindle apart I always wondered just how simple they where. I think you have elminated that wonder.

To be honest I have thought about such a spindle for some time. Most of the thinking due to lack of $$$$$ to do anything real. There is one thing that bothers me about your spindle and that is the use of large tapers that frankly are not really suited for many of the maller machines used here. What the hoddie end needs, form my perspective, is a new small taper that can work well within the bearing capability that these smaller mills have. Lets face it even an R8 taper is a bit of over kill for many of the machines used here, why not come up with something new like a 1/2 or 1/3rd scale CAT taper. Put the "standard" out in the wild and I think we could see a wide scale adoption. We might even be able to get a Chinese manufacture to implement it.

Lets face it Some of the tapers (for manual machines) are over 100 years old, new technology wouldn't hurt. So I'd suggest that the thing to do is to go with a design that fits into existing infarstructure on the micro/mini/maxi miling machines currently in use. After all expand the project to far and one might as well buy a real CNC machine. The other issue is that the smaller the bearings the easier it is to hit higher RPM's with modest bearing technology.

As to implementation, would it not be easier to use an air cycliner to push the draw bar down. It wouldn't event need to touch the spindle in normal operation.

All in all very interesting. Which ever way you go I do hope that it works out well. Like everyone else I do hope that you keep us informed.

Thanks
dave

Dave welcome,
sure I will follow your council and as soon as I will have realized of the new designs using smaller bearings, I will put them on the tread of this forum and naturally on my situated one of which bringing back the address under my company sorri of mi bad English that use but I take advantage myself of a translator online.
I not having it to school and to my age is more difficult to learn new things.
Tanks, Dario

Hello people,

3rd Image: The design as it was left of that day when I left the forums, a block-type spindle that can do over 10k rpm ABEC-5 bearings and such in the works, which has somewhat changed since that day:)

H3ndriX

Nice design, but may be difficult to machine.
Here is my spindle. Some details has changed after this design but main construction is the same.
It has ISO30 (DIN 69871) cone, matched pair of 7207 bearings on the bottom and single 6207 on the top.
More about my project (in finnish), http://www.qnet.fi/teamcalibra/cnc/

Sauli

Thx for all the replies:)

Nice to see some people from before;) Anyway, I am really glad for all the feedback, but the design has changed pretty much from being a 30 taper to a much smaller collet design (wizard hit the nail on the head basically) and the reason for this is my devoted design understanding towards this community. I asked myself why the hell I was designing a 30 Taper (btw, except for the bearing designation, like everyone is pointing out, this design is completely ready to be produced). After this question and some realization about the community that we are in, whcih is mostly home based CNC machines, I decided to go for a much smaller collet type that can do in excess of 20,000 rpm, if need be, and keep the cost under $1000. This kind of thinking led to some designs and from there to some other stuff etc., until I cam to a, lets say, beta level of design (referencing the software industry). I am making some smaller adjustments so I dont give the community a design that is, lets say, half-assed.

I am posting a image that has a summary of my research on automatic draw bar systems and gives a general idea, Its only the tip of the Iceberg as my spindle research has exceeded 1200 pages of documentation:)

NC Cam, absolutely right, so I had changed the design, but never had a chance to post it here before I left:)

Sven, thx for having me back, I am located in Turkey from now on probably, atleast for a while.

Turmite, nice to see that you are still here, I know you sent me messages, I was referencing you and some other in my first message, excuse me for not replying, I am truly sorry.

Dag-50, I looked at your spindle and it seems interesting, but I wasn't able to understand it fully, still trying:)

Wizard, Your wishes have already come true as what I have been working on includes smaller collets:) I have thought about the idea of an air cylinder, as mentioned in my older thread, but the reason I didnt go with air is its potential availability to everyone who owns a DIY CNC. I for one will use my CNC indoors and not in a shop or a garage, etc. thus, I do not want a compressor going while trying to concentrate on something:) The electric actuator works with 24 volts and has enough power to push 5000N for a short period, which is all I really need. This also makes it usable by a simple relay, controlled by most common drivers made, like the rutex, lets say.

Hey saulj, you got a very interesting DIY projecy going there, but unfortunately I couldn't see RL images of your spindle, I am using 7005 bearings on my new spindle which can do 38,000 rpm when used single and can do ~30,000 rpm when used in O formation and ~25,000 rpm in X formation. This kind of speeds require extremely nice (accurate) machining while the spindle is being made and so on. Although I have found people who can make it at tolerance of 0.0002" (0.005mm) TIR, I still have not found a decent motor which can do that kind of a speed and have a smaller size with a nice price ( I might go for a nice servo...maybe, but its not included in the $1000:)

Thanks, keep the ideas rolling...

h3ndrix not to worry about not answering. I was only trying to offer support if you needed it. One of your last posts here sounded like you had a load on your sholders, and since I know what that was like I wanted to help if I could.

Now I am excited to see the new designs as well as the others that have posted their designs here. This is going to be a good thing. When you first started the origianal I was only interested in a larger version for about a 7hp motor. Now I need to build two or three small machine and a small tool changer would be a great asset. I will be following closely.

Thanks for coming back! (group)

Mike

I completely understand your point of view with respect to an air compressor. I think the key here is flexibility, many of us do have air compressors and I would imagine as many of us don't want the bother. Ideally the spindle would be easy to actuate anyway that the user might implement.

It is my interpetation that the spindles in question do not require outside energy to hold the collet/arbor in place. The holding being done by the springs. If so many of us would not be using much air at all.

What I'd like to see is an implementation targetted at a specific mills spindle. Say an X3 or something a bit more substantial. The goal being maxiumum reuse of existing hardware due to the fact that I'm cheap. Or more exactly don't have the $$$ to throw at this. Done right I could see somebody making a nice income with the right conversion kit.

As to Turkey I have a few friends at work that are from there. Of course they try to get me to travel and see the country, which would be nice, but that gets harder every year. It is really a shame that we can not think like 45 year olds when we are in our 20's and healthy.

Thanks
Dave



Thx for all the replies:)

Wizard, Your wishes have already come true as what I have been working on includes smaller collets:) I have thought about the idea of an air cylinder, as mentioned in my older thread, but the reason I didnt go with air is its potential availability to everyone who owns a DIY CNC. I for one will use my CNC indoors and not in a shop or a garage, etc. thus, I do not want a compressor going while trying to concentrate on something:) The electric actuator works with 24 volts and has enough power to push 5000N for a short period, which is all I really need. This also makes it usable by a simple relay, controlled by most common drivers made, like the rutex, lets say.
.

I am posting a image that has a summary of my research on automatic draw bar systems and gives a general idea, Its only the tip of the Iceberg as my spindle research has exceeded 1200 pages of documentation:)

NC Cam, absolutely right, so I had changed the design, but never had a chance to post it here before I left:)


does anyone know a source for drawbars like this ....ISO30, or smaller?

Just a quick question, the washers your are compressing, how much force are you putting on them. Im building a spindle myself and im worried that the bearings cant handle this excessive amount of force axial

Just a quick question, the washers your are compressing, how much force are you putting on them. Im building a spindle myself and im worried that the bearings cant handle this excessive amount of force axial

I'm planning to use 3 000 N. If I remember, bearings can handle about 20 - 30 kN static load.
The maximum force, when gripper is open position, is about 6 000 N, so it is far below bearings max. load.

Sauli
http://www.qnet.fi/teamcalibra/cnc/

The picture of the drawbar look like a product shot, can you tell me who sells them?

Nice spindle projects, all.

Best,

BW

h3ndrix- I am very pleased to see you return, and I eagerly await your spindle design mature into a reality. If I am not mistaken, this is a product that you will be offering for sale? Or is this only a one-off for yourself?

Any case- welcome back!
Colin