High Speed Spindle for SIEG X2 - I found it

[whelen]

I wrote up a post "High Speed Spindle for SIEG X2 - Getting Technical", well I found the spindle.

Looking for an affordable high speed spindle for your SIEG X1, X2, or X3 - or for any bench milling machine? I've been looking for one for over a year, and finally found one at KDN Tool.

I first looked at the NSK Astro-E 250, which sells for over $2,000. I can buy 18 of the KDN Tool high speed spindles for the price of one NSK Astro-E 250. The solutions I found on ebay, the internet, and in the discussions on Yahoo CAD-CAM-EDM-DRO group, DIY-CNC group, hf47158toCNC group, Irk-torquemax group, X-Series-Mills group, and CNCzone came close, but not quite close enough in price, power, number of collet sizes, reliable collet chuck design for small end mill shanks, air cooling, variable spindle speed, commercial designed spindle nose bearings, low spindle run out, quiet running, and a fairly good duty cycle for long jobs.

I've got it on order - 5,000 to 20,000 rpm with six collets 1/32" to 1/8" - for $170, which includes the mounting bracket for the SIEG X2. You will find it on www.kdntool.com

Finding the KDN Tool spindle has been quite an adventure. When I first got into CNC, I determined that I would not be primarily making conventional machine parts, but would be engraving, and sculpting plastic, aluminum, and brass. I was surprised to learn that I would need a high speed spindle, for the same reason that PWB drilling, and engraving applications demand. The very small diameter end mills require the high speed. My stock SIEG X2 at 2,500 rpm needed to be stretched up to 20,000 rpm. No way. I looked at high speed routers (collet limited to one size), air driven spindle motors (too noisy), hand pieces for manual grinding, engraving, sculpting (not enough power or too expensive), and die grinders (one speed).

The breakthrough for me was when I found an article by Paul Frederickson and David Grimes of The Precise Corporation, “Increasing Torque For A High Speed Spindle”, in MMS Online. They published a formula to determine the cutting torque required, and a Power equation. The cutting torque equation is:
Torque (N-m)= Depth of cut (mm) x Width of cut (mm) x Feed rate ( mm per tooth ) x Number of teeth per revolution x Machinability Torque Factor

Machinability Torque Factor – aluminum (0.145), brass (0.29), and steel (0.435).
I wrote Paul Frederickson and he graciously told me the process for determining the Feed rate ( mm per tooth ), and told me the factor for brass. He said that, “a good rule of thumb to start with is 1% of tool diameter per tooth”.

So a 1/32” ( 0.794 mm ) dia end mill, 0.4 mm deep cut, 0.008 mm feed rate per tooth, and 2 teeth results in Torque ( N-m ) of 0.0007 aluminum, 0.0015 brass, and 0.0022 steel. The power in watts for the KDN Tool spindle at 20,000 rpm is 1.5 aluminum, 3.0 brass, and 4.6 steel. The KDN Tool spindle has a 100 watt capability. So it will cut through these speed and feeds like butter. If you've never seen such high rpms before, it's because it involves the breakthroughs from High Speed Machining technology. Engraving machines have been running at those rpms for decades, and so have PWB drills. Small end mills / drills, small chip loads, and high rpm.

For a 1/8” ( 3.175 mm ) dia end mill, 1.6 mm deep cut, 0.032 mm feed rate per tooth, and 2 teeth results in Torque (N-m) of 0.046 aluminum, 0.093 brass, and 0.139 steel. The power in watts for the KDN Tool spindle at 20,000 rpm is 97.2 aluminum, 194.4 brass, and 291.6 steel. So for brass and steel either the depth of cut needs to be reduced, or the speed needs to be decreased to 10,289 rpm for brass, and 6,859 rpm for steel.
Power ( kw ) = ( Torque (N-m) x rpm ) / 9,550

When I tried to adapt some of the other solutions to my SIEG X2 I was stunned to find out that it is a major production to remove the “Spindle box” casting part # 49 from the “Spindle box seat” casting part # 63, which rides the column Z axis vee way. Part #49 is bolted through the back of part # 63, and you can’t see the bolt heads, because the are covered by the Z axis column vee way. Aggghhh!

Wait till you see KDN Tool’s solution. It’s just right for me, I don’t need all of the X axis travel. When you get to the web site scroll down past "It's Alive", and past "Just Born" to "Our Latest Innovations" - "High Speed Spindle Attachment For The X2 Mini Mill", click on CLICK HERE for more information.

If you don't own a CNC Mill and want to get one for small hobby work or jewelry making take a look at "Just Born" - full CNC conversion of the Proxxon MF70 micro mill, with stepping motors and full electronics, and it comes with a Proxxon high speed spindle.

If you are looking at the SIEG X2 then you may want to look at "It's Alive" XJ-95 alternative to the SIEG X2 - with Y axis travel of 6.3" vs SIEG X2 3.94". I sometimes wish I had the extra 2.3", oh well it wasn't around when I was looking.

With the KDN Tool, SIEG X2 High Speed Spindle and adapter, I'll be able to finally start me sculpting, and engraving.

God bless you all.

Bill Perun

[dammachines]

Just wanted to mention, that is the same grinder, and a very similar setup to what Tormach offers as a high speed spindle option.

I believe their "Universal Mount" clamps around the spindle housing though...

Dave

[BobWarfield]

That sounds like a pretty cool setup. Would love to see some pix of work done in a CNC with that Proxxon unit.

Best,

BW

[whelen]

Dave (dammachines), thanks for the heads up on the Tormach. Since they are using the Proxxon IB/E as their high speed spindle option - it has to be good. Bob Warfield, I'm still getting my machine setup, and have not machined anything yet, so there is nothing to take a picture of. But KDN Tool has a picture on their web site.

At first it was hard for me to grasp that the Proxxon is a great high speed spindle - for only what KDN Tool is selling it for - $110.00 www.kdntool.com/_sgt/f10000.htm Those things sell for over $500. But once I did the cutting torque calculations I learned that I could do a lot of engraving / sculpting with small dia end mills and 100 watts.

I should mention that Chris Horne posted a heads up on the 2.7" left side mounting offset. He pointed out that if the SIEG X2 table is extended 2.7" or more to the left, then the 2.7" is not lost. Also, it should be mentioned that if more than one Proxxon IB/E were mounted on the spindle casting, each the same distance from the spindle centerline (the same "pitch"), then multiple identical parts could be machined at the same time. Their width would have to be equal to or less than the "pitch". Great idea for PWB fabrication.

God bless both of you.

Bill Perun

[BobWarfield]

Just mount two spindles and two parts?

Aw c'mon! That's too easy! There has to be a better way:



Seriously, I love the idea of two spindles for certain jobs, and this spindle is certainly cheap enough. Heck, I could probably fit 4 of 'em on my IH Mill! They scarcely cost more than the collet fixtures shown in my snapshot either.

Best,

BW

[whelen]

Bob Warfield, from the picture you posted, it would seem that you are actually machining multiple parts. Is that a setup to expidite set up time to make a succession of parts? Yes, each 5C collet station could have a KDN Tool, Proxxon spindle mounted above it, and all the the 5C collet stations could be machining all at once. How's that for productivity.

God bless you.

Bill Perun

[totally_screwed]

Has anybody made a successful mounting bracket for Proxxon IB/E high speed spindle on the Sieg X1 Micro Mill?

Chris

[philbur]

Hi Bill

You may find that the 100 watts is the maximum input power not what you get at the cutting tool. Also I think that reducing the rpm will reduce the available power. I have a Proxxon IB/E fitted to my Tormach, using a home made adaptor. At the lowest speed I can quite easily stop the spindle with two fingers.

To allow you to keep the rpms (and therefore the available power) up you may want to consider using carbide cutting tools.

Regards
Phil

Originally Posted by whelen For a 1/8” ( 3.175 mm ) dia end mill, 1.6 mm deep cut, 0.032 mm feed rate per tooth, and 2 teeth results in Torque (N-m) of 0.046 aluminum, 0.093 brass, and 0.139 steel. The power in watts for the KDN Tool spindle at 20,000 rpm is 97.2 aluminum, 194.4 brass, and 291.6 steel. So for brass and steel either the depth of cut needs to be reduced, or the speed needs to be decreased to 10,289 rpm for brass, and 6,859 rpm for steel. Power ( kw ) = ( Torque (N-m) x rpm ) / 9,550 Bill Perun

[InspirationTool]

I have this same grinder/mounting that I bought from Littlemachineshop.com.

I haven't tried it yet.

Mounting it on the left side of the head requires moving the electronics box. Mounting it on the right side after redrilling the countersinks blocks the spindle lock hole.

I'll let you know when I've tried it.

BTW, I have both the KDN XJ-95 and the Syil X2. My review of the XJ-95 is on my website: http://www.jeffalbro.net/cnc/

I will review the X2 and grinder after a few weeks use.

-Jeff