Spindle Idea

[SpindleGuy]

I can help out with any spindle questions anyone has, that is what I do. (Repair Spindles.)

[spoiledbrat]

Attached is a spindle I am getting ready to build. I currently use a PC 892 to cut wood and some aluminum, but I would like to be able to achieve 100 to 4000 rpm, so I am building a spindle. Because I am using a screw-on chuck from porter-cable, all of my tooling is ready to use with it. I am going to redneck this a little bit, and just use the radial bearings that are used in my porter cable. Hey, they have lasted 3 years, with minimal runout @ 24000 rpm. The lower bearing on the PC router I have is a slide-fit onto the spidle, and it is "sprung" into position with a Beveled internal snap ring. There is a complementary bevel on the casing, and it will self adjust a small amount as the bearings wear. I intend to use that in my new spindle.
The servo I am going to use is the Torquemaster 3505 with C winding from Cleveland Motion Controls. The technical assistance guy told me that with my power supply (24V @ 31.5A) and the Gecko drive, I will have 5100 RPM max, with about 2.7 in-lbs of torque (at only 7 amps, about 3.9 @ 10 amps). Is that enough to make heavy cuts in aluminum, at a reasonable speed?
Without the encoder, it is $340 US, an additional $210 for the encoder. I will install my own to the spindle top.
Does anyone have any advice or recomendations before I embark on this 700 dollar project? My CNC is mainly 1/2" plate aluminum, and is more rigid than I expected. I think the mechanicals can handle it. I might have to get silly and try to cut some steel when it is finished...
Please help let my know any recomendations

[miljnor]

Your bearings might work, but its a big might.

NC cams might chime in here but using bearings for a router that are designed for 24k rpm on something that spins 100 to 4k rpm at a higher load(more than likely) is probably a mismatch in application.

there are A lot of bearings on the market that are fairly cheap for that RPM range. I would go with them.

as far as the design is. It looks o.k. as long as the working part of the spindle is held as rigid as possible and not the motor part.

[MikeAber]

Attached is a spindle I am getting ready to build. I currently use a PC 892 to cut wood and some aluminum, but I would like to be able to achieve 100 to 4000 rpm, so I am building a spindle. Because I am using a screw-on chuck from porter-cable, all of my tooling is ready to use with it. I am going to redneck this a little bit, and just use the radial bearings that are used in my porter cable. Hey, they have lasted 3 years, with minimal runout @ 24000 rpm. The lower bearing on the PC router I have is a slide-fit onto the spidle, and it is "sprung" into position with a Beveled internal snap ring. There is a complementary bevel on the casing, and it will self adjust a small amount as the bearings wear. I intend to use that in my new spindle.
The servo I am going to use is the Torquemaster 3505 with C winding from Cleveland Motion Controls. The technical assistance guy told me that with my power supply (24V @ 31.5A) and the Gecko drive, I will have 5100 RPM max, with about 2.7 in-lbs of torque (at only 7 amps, about 3.9 @ 10 amps). Is that enough to make heavy cuts in aluminum, at a reasonable speed?
Without the encoder, it is $340 US, an additional $210 for the encoder. I will install my own to the spindle top.
Does anyone have any advice or recomendations before I embark on this 700 dollar project? My CNC is mainly 1/2" plate aluminum, and is more rigid than I expected. I think the mechanicals can handle it. I might have to get silly and try to cut some steel when it is finished...
Please help let my know any recomendations

I would be looking for foot pounds of torque not inch pounds. This doesn't look practical to me, especially at $700. The standard motor for the mini mill is .45 horsepower, the smallest spindle I run is 1 horsepower.

If you mounted a minimill spindle with a belt drive kit on your machine and remoted the motor controller you would be better off. Mount your screw-on chuck on a standard size rod and use it in a collet mounted in the spindle. No heavy cuts in aluminum with this class machine. Your going to need 2 or more horsepower and a rigid machine for anything serious. Cutting steel in a gantry machine isn't practical.

Most of the time I use the 1 horse Grizzly router in my machine. I just replaced the bearings in it after about 100 hours of run time. 10 sets of bearings for it cost less than $25.00.

The biggest problem for all these machines is finding a light weight motor with lots of horsepower.

I wonder if a variable speed porter cable router could be fitted with a 4:1 reduction belt drive to run a mini mill spindle. That would multiply the torque by 4 and reduce your 24,000 rpm to 6,000 rpm maximum. A 3 horse power router motor would have plenty of torque to work aluminum.

MikeAber

[miljnor]

I wonder if a variable speed porter cable router could be fitted with a 4:1 reduction belt drive to run a mini mill spindle. That would multiply the torque by 4 and reduce your 24,000 rpm to 6,000 rpm maximum. A 3 horse power router motor would have plenty of torque to work aluminum.

I was wondering this as well, I wonder if anyone on the zone has tried this?

anyone?

[wcarrothers1]

I've just mounted a PC 7518 router to my mill..

The thing is heavy as it is. I'd hate to see how heavy it would get adding the guts to gear it down adding a belt drive and such.

I will say it cuts wood real nice with lots of power though.. For sure an upgrade from my nice 2hp bosh. But made the change more so I would stop feeling like I was beating the snot out of my nice bosh router. Have no love for the porter cable for work other then in the mill.

I've often thought it would be a fine idea to take a mini mill head like from the harbor freight mini mill and hang it on a gantry though.. It's motor over all might be a little low on power for doing faster cuts.. Might be a little heavy depending on gantry design as well.



b.

[MikeAber]

Does anyone have any advice or recomendations before I embark on this 700 dollar project? My CNC is mainly 1/2" plate aluminum, and is more rigid than I expected. I think the mechanicals can handle it. I might have to get silly and try to cut some steel when it is finished...
Please help let my know any recomendations

The small bearings are fine for high speed work as the chip load is small and light shock load on the bearings. At slower speeds you want larger bearing surfaces to handle the increased shock load of a larger chip load. Your porter cable bearings will fail quickly if you subject them to heavy loads at slow speed. I like your concept but you need to investigate the bearing issues. You don't want the bottom bearing to have a slip-fit as the spindles temp increases the shaft will grow downward slightly increasing the depth of cut as temperatures increase and you want zero play at the cutting tool to minimize chatter.

Just my .02 cents.

MikeAber

[MikeAber]

I've often thought it would be a fine idea to take a mini mill head like from the harbor freight mini mill and hang it on a gantry though.. It's motor over all might be a little low on power for doing faster cuts.. Might be a little heavy depending on gantry design as well.

b.

Like this?

Here are the pictures of that project described in the volumes of this thread: http://www.cnczone.com/gallery/showgallery.php?cat=9016

The minimill 2.5HP spindle weighs 20 pounds.

Two spindles are the answer to versatility. I use the high speed spindle 90% of the time.

Enjoy,

MikeAber

[spoiledbrat]

Mike,

Is your spindle setup variable speed? Does it have an encoder, or do you have to control the speed manually?

Thanks

[MikeAber]

The spindle is variable speed.

The KBIC125 90VDC motor controller ($45.00) is adjustable for max and minimum speed. It supports speed control from a 0-9VDC control voltage; however, I use a variable resistor to adjust the speed manually.

The motor is a 90VDC treadmill motor ($25.00) and the motor has a shaft protuding from the back that's suitable for an encoder.

Mach3/4 supports 0-9VDC speed control and an encoder input for feedback.

All the details for this project start on page 5 of this thread.

Mike

[Dave's_Not_Here]

Just a quick note before going to a birthday party, "yes dear, I'm coming..."

I have not had time to read all 18 pages but here is a good option for some...

http://stores.ebay.com/Wolfgang-Engi...Q3amesstQQtZkm

If it was already mentioned earlier, I will go back to my hole...

[atenman1]

just a question

[ZipSnipe]

Hey Mike, I just got done reading all 19 pages of this thread and thankful that I did. I,m pretty much going the same route that you,ve gone by using an mini mill r8 head and changing to high speed bearings. Here,s what I plan to make http://www.cnczone.com/forums/showthread.php?t=28908

I plan to use the machine mostly for wood however I would really like the ability to machine steel and aluminum as well. My question is this, have you cut wood with your R8 head mounted on the mill and whats the quality of your finish? Also do you just switch to the router just for faster milling? Or for better quality of cut when milling wood?

[ZipSnipe]

Anyone ?

[MikeAber]

Hey Mike, I just got done reading all 19 pages of this thread and thankful that I did. I,m pretty much going the same route that you,ve gone by using an mini mill r8 head and changing to high speed bearings. Here,s what I plan to make http://www.cnczone.com/forums/showthread.php?t=28908

I plan to use the machine mostly for wood however I would really like the ability to machine steel and aluminum as well. My question is this, have you cut wood with your R8 head mounted on the mill and whats the quality of your finish? Also do you just switch to the router just for faster milling? Or for better quality of cut when milling wood?

You’re wasting your time trying to cut steel with a gantry mill, it can be done, but who wants to make 100 passes to remove 1" of material @ 5 IPM. I purchased a PCNC1100 for that.

I use the router spindle for my work with plastics (90% of what I do.) The award in the picture is a 5.5 hour run @ 8-10K rpm and 30 IPM with a 3/32" tool. I can run the router 100 hours on a set of bearings and 10 sets of bearings cost less than $25.00.

I use the router spindle for work in wood @ 8-15K rpm @ 30-50 IPM with a 1/4" max tool

The minimill spindle is for work with aluminum and I run that @ 3-5K rpm and 10-15 IPM (mostly 3K). Bearings aren't available at a reasonable cost to run the minimill spindle faster than 5k rpm for any prolonged period of time. Most of the things I do seem to take 2-3 hours of run time and 3 hours of runtime @ 5k rpm will fry a set of bearings. 10 sets of bearings for the minimill spindle would cost over $250.00. My mini gantry mill isn't rigid enough to use the minimill spindle at it's capability - it has the power to make heavy cuts in aluminum but the power twists the structure up to .025" with a cut of .100" .250" deep.

It doesn't make any difference in finish quality or time... I can run the high speed spindle at twice the speed of the minimill spindle and make twice the number of passes at twice the feed rate and half the depth of cut.

Best results are accomplished by making moderate depth of cut passes with a finish pass of .005-.010" depending on the material and the size of the tool.

The mini gantry mill weighs less than 100 pounds; the Tormach PCNC1100 weighs 1300 pounds. The Tormach is much more than 13 times more rigid and it's a light weight machine for cutting steel. I think 1300 pounds of iron is the starting point for working with steel, anything lighter is wishful thinking.

I plan to fit a Porter Cable router to my PCNC1100 for high speed work and dedicate the mini gantry mill to making printed circuit boards, nametags and awards with the high speed spindle only.

If I was going to make another gantry machine I would make something similar to these first two pictures, use rectangular steel tubing for the bridge and move the table.

MikeAber

[Anodizer]

For a spindle that runs at VERY high speed, look at the German made Proxxon hand units, they are larger than the Dremel, have a top speed of 30,000 rpm.
I do not know the runout, but it cannot be too bad if the unit runs at such a high speed.

Fred

[nlancaster]

I realize this is an old thread. But while reading it I had Brainstorm so hard it hurt.

I dont know a huge amount about machining this kind of part. And I am in the process of building my first CNC router. I believe this design I have come up with would work quite well and be easy to build for someone that does not have a large lathe to turn a large chunk of aluminum/steel into a spindle housing. I think all the parts I have designed could be built on a Mill except for the spindle shaft itself. Possibly could use a suitible replacement spindle part in this to build it without having to make your own spindle shaft.

So here it is.


The main body is a peice of 3x3inch 8020 extrusion with machined bearing carriers held at each end. Not seen in the pictures are 4 taper pins that insert into the 4 holes already in the 8020 extursion to center everything. The entire assembly is held together with 8 1/4-20 threaded rods and coresponding lock nuts. The yellow bearings are off the shelf 30mmx62mmx16mm angular contact bearings that sell for $30 a pair, I know not top of the line bearings but this is about building the spindle inexpensively with decent performance. The bearings could be upgraded to any quality you like depending on your budget.

The black washer is an appropriate belleville washer to preload the bearing assembly. The blue washer underneath is steel and would allow using a belleville washer that is bigger then the actual inner race of the bearing and also help seal off the bearing from garbage.

I don't know how it would affect the lubrication of the bearings but the extrusion could be tapped for an air fitting and presureize the assembly.

This design could be scaled up and down to any particular budget or application with appropriate choices of bearings extursions and so on.

[MikeAber]

I realize this is an old thread. But while reading it I had Brainstorm so hard it hurt.

Well don't just sit there...

Build it!

The thread is like me... old but still good.

MikeAber

[Salty72]

Ahhh intrest light is on..... and growing brighter by the second

[JRoque]

sniff sniff...hmm it smells like spindle in here.... someone cooking spindle?

BTW, I think the idea is great. Depending on what you intend to cut, the hollow body of the extrusion frame might not be stiff enough, however. For lighter materials this might just work fine.

Check on this same thread for references to premade ER spindles. All you would need to do is to match the thrust bearings to the spindle OD and thread the back end to hold it in place. Threading might be a challenge since those spindles come hardened pretty good.

Nice drawing! What did you use for that?

JR