Reply with QuoteParlec collet chucks http://www.parlec.com/pages/straight...et_chucks.html are ground up to a shoulder.Originally Posted by nlancaster
At least that is the brand I am looking at for making a small lathe spindle.
Best regards,
Randy
Solidworks is the program used to do the model. Yes I know what you mean about the extrusion possibly not being stiff enough but that is one big extrusion and you could alwas replace the extrusion with a lathed steel shape later on without that much work.
On those er shafts posted earlier from MSC, enco and so on. I don't see anyway to fix the lower bearing to the shaft. It just looks like the shaft is one smooth shaft from threaded nut on the collet to the end of the shaft. How could you mount the lower bearing so that it would not move?
Last edited by nlancaster; 10-09-2007 at 02:07 PM.
Parlec collet chucks http://www.parlec.com/pages/straight...et_chucks.html are ground up to a shoulder.
At least that is the brand I am looking at for making a small lathe spindle.
Best regards,
Randy
Hi JR,
Good to see you lurking around.
The best way to find a workable solution is to find a set of good bearings that will handle at least twice the rpm and workload you expect to use.
While I like the collet extender concept, I couldn't find a suitable bearing to fit a 3/4" shaft size. The bottom support bearing ('s) should be a pair of angular bearings in a back to back configuration to control the load; the top bearing only needs to support the pulley and provide rotational support. Read the article from Barden Bearings in this post about the application of various bearing configurations:http://www.cnczone.com/forums/showpo...5&postcount=76
The attached thumbnail shows a suitable spindle bearing configuration.
IMO the only two collet sizes to consider are the ER-16 and ER-32; ER-16 for high speed light work and ER-32 for general purpose use. ER collets inherently provide better accuracy and a wider usable range than R8 collets.
Carbide tooling should be capable of turning the end of the extender shaft and threading it to hold a clamping nut. Otherwise you could anneal the end of the shaft and machine it. If your machining resourced were limited you could use a belleville washer stack and a 3/4" quicklock pulley (split sleeve) to hold the assembly together. The quicklock is mounted on the motor shaft in the picture in this post: http://www.cnczone.com/forums/showpo...&postcount=104
MikeAber
Last edited by MikeAber; 10-10-2007 at 07:30 PM.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
The one problem with using any of those collet chucks is you are precluded from using any quick change tooling in the future. I found this spindle shaft at Littlemachineshop.com and I think it could be integrated into a custom spindle just fine. At first you could keep using the 3MT collets and then eventually switch to a Tormach or similer tooling system in the future. This spindle would integerate with my design just fine other then the shorter length of the entire spindle housing.
I would double nut the spindle shaft to lock things in place, I'd hate to see it come loose.
If it's not nailed down, it's mine.
If I can pry it loose, it's not nailed down.
Well, I used the R8 spindle box but the MT3 spindle box is actually a better choice as it uses 2 - 6206 2RS deep groove ball bearings and high speed bearings are easier to obtain in that size. I use the Tormach tool system that supports MT3 spindles as well. I don't think you could make a spindle cheaper than the $100 spindle box assembly.
MikeAber
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Mike you are right you could not build it for less then the $100 spindle box assembly. But you could build it lighter. That spindle box assembly weighs a heafty 13lbs and you still have to add a motor and drive assembly. I am pretty sure building a design like mine out of aluminum you could get the spindle assembly itself down to less then half the weight, making it much more practical for most peoples CNC routers.
By the way if someone wants to have a go at building a design like mine let me know I will get you some drawings and parts lists. I am making a new design based on the 3MT taper spindle shaft I linked to above also.
Last edited by nlancaster; 10-11-2007 at 01:45 PM.
[QUOTE=nlancaster;353164]Mike you are right you could not build it for less then the $100 spindle box assembly. But you could build it lighter. That spindle box assembly weighs a heafty 13lbs and you still have to add a motor and drive assembly. I am pretty sure building a design like mine out of aluminum you could get the spindle assembly itself down to less then half the weight, making it much more practical for most peoples CNC routers.[QUOTE]
By the time you make the bearing endcaps from steel you will have a very short section of 80/20 between the endcaps using the MT3 spindle shaft. IMO the savings in weight will not be significant and the loss of rigidity will be substantial. You need the cast iron mass for stability and to dampen harmonics. You would be better off cutting down the spindle box and removing excess material to reduce weight.
The cut down cast iron box assembly with a 2.5HP treadmill motor, pulleys, belt, and mount for my Mini Gantry Mill weighs 20 pounds. You're right, this is alot of weight for a gantry machine. 2.5HP is too much power for my machine and I'm considering purchasing a complete head assembly for $250 to replace my heavy spindle. The price is reasonable as it includes the spindle box, motor, motor controller, and controls. I think adding the belt drive kit would offer the versatility I want. The motor mount could be relocated to the side as you see in my 2.5HP spindle and I think the .47HP motor would provide ample power. The motor weighs less than 5 pounds, the cut down spindle box could weigh less than 10 pounds with the motor mount and belt drive. The controls and motor controller relocated to the CNC controller location.
I offer these comments only as food for thought... not to discourage you from making something different. I've changed direction on virtually every project as I continue to learn more about what doesn't work than what does work.
Mike
Last edited by MikeAber; 10-11-2007 at 05:51 PM.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Mike that is one big ass motor on that spindle.
And I see where you are coming from on I had not thought about cutting down that big spindle housing. I was thinking of making all of the pieces of my spindle from aluminum as I have seen other spindles created entirely of aluminum on this site that seem to work very well. As far as the rigidity of my design the spindle can be mounted from the lower bearing block to the Z-axis carriage. You would then have the bearing blocks supported in 2 points each, to eachother thru the 3030 extrusion and to the z-axis carriage and whatever it is made of. That being said the spindle form littlemachineshop.com would still be far more rigid if your machine can handle the weight.
If you need a less powerful motor (crazy talk, I say) why not just mount the .47 HP motor to your current setup. That would reduce the overall weight by 5 to 6 lbs. and would be a whole lot cheaper.
On another front, have you seen the high speed spindle setup at Little Machine Shop? It's a different spin on your idea of swapping spindles for different speed applications.
http://www.littlemachineshop.com/pro...2892&category=
Mike
If you can't overbuild it, what's the point?
I plan to use the R8 Spindle and 2.5HP motor on another machine that can handle the horsepower and weight. My point exactly; I thought about getting the motor only but for $100 more I get the controller, another spindle and electronics... seems well worth the cost.
BTW I purchased one of those Proxxon die grinders last month; I'll be making a mount for it soon. The high speed tool on the mount below lasted about 20 hours and I've been through 3 different high speed spindles; I hope the proxxon holds up better. I don't mind swapping the spindles; it might take 2-3 minutes to do so.
Mike
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Will you be doing some new mod on this latest mini mill spindle for your gantry mill or are you going strictly with the Proxon?
I have picked up a great deal of information from this thread and I am interested in eventually building a spindle that I can control in Mach 3. Another reason is to reduce the noise level of my machine. How would you rate the noise level of your setup? I read somewhere that the toothed belt and pulleys can be rather noisy but I don't know what they were comparing it with.
Mike
If you can't overbuild it, what's the point?
Hi Mike,
My intent is to make a light weight MT3 version of my existing R8 box spindle and use the Proxxon die grinder as a different spindle as I have two dovetail spindle mounts for the machine and prefer to minimize spindle weight. I use the Mini Gantry Mill for engraving and plastics and a Tormach PCNC1100 for larger work with the Tormach tool system so all I need is a Tormach TTS MT3 collet to use existing tooling. The Proxxon should do well for high speed work in engraving and plastics but I still would like a 100 - 5K spindle for some small parts work with FORTAL (7075) and 41XX alloys where I don't expect to be using tooling larger than 1/4".
The MT3 spindle has the advantage of high speed bearing availability that the R8 spindle does not. I may consider making a spindle box out of FORTAL with a pair of angular contact bearings running in an oil bath on the bottom and a single deep groove bearing at the top.
The belt drive is much quieter than the original 2 speed gear drive but spindle noise is a mute issue compared to the noises generated during cutting operations. I've heard the 2 speed belt drive kit from Little machineshop is quieter still. Both of my machines run Mach3 Mill. I'm using TurboCadCam for my cad/cam package.
Mike
Last edited by MikeAber; 10-27-2007 at 01:42 PM.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Speedre here. Man when I started this thread I had no idea it would take on a life of its own. Who knew? I have made a similar spindle box as Mike Aber and it work famously. I also purchased a K2 CNC 2514, but it was disappointingly light duty, too much flexing in all axis. But that's another story. I am now using the K2 as seed parts for my new milling machine using Littlemachinshops castings as a base. Well I thought to suggest putting this thread to bed but I think not there's just to much information to be shared. Carry on, carry on.
Hi Speedre,
The R8 MiniMill Box Spindle was a fun project, I learned a lot too.
This is one of the most traveled threads on the board. I'm still receiving Pm's and e-mails about our project... I'm gratified and humbled that so many have taken the time to do so.
I've been hanging out on the Home Shop Machinist and Home Gunsmith Forums but I keep an ear tuned here too.
So many toys, so little time... too many projects,
MikeAber
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Having read all 25 pages of this thread, I have some questions.
Why are all the spindles described enclosed; bearings are inside a tube, and the actual spindle is inside them? Is there some reason I couldn't use a pair of pillow blocks mounted to a plate, and run the spindle through them? Other then a safety reason?
My machining target is aluminum and mild steel, and I want to build an ATC.
Bob Hayes
Hey Bob,
I can think of two quick reasons for using a solid tube or square. The first one is rigidity. A solid mass at that point is critical to absorb the vibration, etc. The second one is that most pillow blocks have low RPM ratings in the order of 1 to 2K and high runout.
If you throw enough plates and hold everything tightly, it might work fine for your
application. Look into mini-mill spindles as an alternative.
Happy new year!
JR
Thanks for the reply JR. I was only planning on a max. of 1500 rpm anyway. Where do I buy mini-mill spindles by themselves without paying for the whole mill?
Bob Hayes
Heavy-duty portable shaft
Bob,
Your post about the pillow-block bearings reminded me of something I saw recently. This looks like it was made to be a spindle.
http://www.grizzly.com/products/h8025
They make them in 3/8, 1/2, 5/8, and 3/4-inch shaft sizes.
Mike
Mike
If you can't overbuild it, what's the point?
Hey Bob. See here: http://www.littlemachineshop.com/pro...1663&category=
JR
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