New Machine Build- Milling Spindle Question

[joprinz]

I'm building a CNC Mill. This would be my second project...My first project was a Wood Router and is working well within design expectations.

Here is my Machine Design Specs:

* 2' x 2' x 5" CNC Mill
* For working with aluminum and probably some mild steel
* Fixed Gantry Design with Two 25mm Supported Shaft and 4 Linear Bearings per Axis.
* 20mm Diameter 5mm Pitch Ballscrews for all drives
* Steppers are all 425 Oz.In and running in Microstepping mode on 50V 10A PS.
* Basic construction is in Welded steel (Aluminum for moving axis parts to reduce load on steppers)
* Mach3 as Control Software

I am new to Milling Aluminum and Mild Steel. I read many posts over here and found that most users use a Milling Spindle when Milling Metals. This Mill is not intended for Professional purposes. I intend to use it for my hobby projects which involve mostly Aluminum based work and occasionally some mild steel.

Hope someone can help me with the following questions...

1. I have a 1.5Hp and another 2Hp Wood Router with me (both have a Variable Speed Function). If I were to keep my feed rates and cut depth low, can I use either of the routers as a Milling Spindle?
   
2. If not, can someone suggest me a Low cost spindle to be used with my mill?
   
3. I would also like to know if a High Frequency Spindle is required for milling Aluminum and Mild steel?

Please Advice!

Thank You!

Joe

[teamtexas]

Joe, the routers would work to mill aluminum as long as your machine is rigid (no deflection) when complete and you keep the cut depth small. I have milled some with my 1-3/4 hp router as a spindle and it worked ok...but I have deflection issues. Take it from me don't build the gantry with unsupported rails!

Not sure about steel.

Dan

[joprinz]

Dan, Thank you for your reply.

As for the deflection aspect you mentioned, I am using a Fixed Gantry design and all Linear shafts are supported. Hope that helps minimizing deflection.

And about the Aluminum Milling U have done using the router as spindle... What Cut Depths, Feed Rates and End-Mills did U use?

Thank You!

Joe!

[joprinz]

Also... anyone reading this post, If you have experience using a Router as a Milling Spindle, Please post your experience here. It would be very helpful for guys like me who are new to Milling Metals.

Thank You!

Joe!

[LeeWay]

I found that it would work, but has drawbacks. I had to drench it down with WD40. Not so bad on a small aluminum block, but when you do a couple square foot sheet on a small router, the WD makes the chips stick everywhere.

Thats not the bad part. Chips were getting into the router in the top side. Not many, but enough to make me worry. Then there is the heat issue. the router got pretty hot when cutting for about 10 minutes. I would always give it about an hour cooling time between cycles.

Some routers have not only a little bearing runnout, but up and down floating as well. Not so bad on profiles, but troublesome for surface finish.
I did make some brackets using the router and now still use a router to cut the sheet stuff, but it is now mounted on my mill.

The right type of aluminum will also help your efforts. Real soft stuff won't do. Stay away from any 5000 series stuff. I mostly use 6000 stuff like 6061 or 6063.


The router is a PC 690 on my cnc router and I use a little Ridgid trim router along side my mill spindle.

They will work, but not optimally and may really effect the life span of the router.

[teamtexas]

I did some engraving with a 60 degree carbide cutter and moved 10ipm in the plunge and 15 ipm in the cuts. Max depth was .020.

Dan

[joprinz]

Thank You Dan, Lee.

I am inclined to buying a High Frequency Spindle. But I'm on a tight budget at the moment. Explains why I am trying to find alternatives to a High Frequency Spindle. Can someone point me to a reasonably priced motorized Direct Drive or a belt-driven spindle for Light Aluminum and Mild steel?

I have read its possible to design your own spindles too. How Successful can it be? or is it something that can be achieved Only using Ultra precision machinery?

I have a High Speed Grinding Spindle rated 333W and 30000 RPM with a 3/8" collet attachment. Can it be used for Milling Aluminum?

Please Advice!

Thank You!

Joe!

[BobWarfield]

You can buy the spindle head as a replacement part from various light mills.

Grizzly will sell you parts and Little Machine Shop will as well.

Alternatively, pretty nice spindles come up from time to time on eBay from milling machines--everything from Bridgeports to VMC's. It can be a long wait though.

Best,

BW