Need Help!- Mini Mill X2 Spindle Head + VFD + Chinese Spindle= custom!

[diyengineer]

LittleMachineShop.com - Mini Mill Spindle Box Assembly R8

What size of bearings does this use?? What is the highest speed you could run this spindle without extra balancing? assuming the bearing RPM was not the limiting factor because you swapped them out for angular contact bearings?

10,000 rpm? Less? More?

If i knew the size of the bearings i could search for some bearings!

Thank you.

[diyengineer]

Stock Bearings from little machine shop.

Lower Bearing:
6007 RS deep groove ball bearing.
The bearing is 35 mm ID, 62 mm OD, and 14 mm wide.
This bearing is used on mini mills with R8 spindles.
These are Nachi or NTN brand, permanently lubricated and sealed bearings.
LittleMachineShop.com - Bearing, Spindle Bottom

Upper:
6206 2RS deep groove ball bearing.
The bearing is 30 mm ID, 62 mm OD, and 16 mm wide.
This bearing is used on the spindle of all mini lathes and mini mills. Two are used on all machines except the mini mill with R8 spindle which uses one.
These are NTN or Nachi brand, permanently lubricated and sealed bearings.
LittleMachineShop.com - Bearing, Spindle

[diyengineer]

These would be good for 11,000-14,000 RPM

Lower Bearing Replacement: $9.51

Item: 6007 Nachi Ball Bearings
Dimensions: 35*62*14 mm/Metric
Dynamic load rating Cr: 16,000 N
Static load rating Cor: 10,300 N
Limiting Speed:
Grease Lubrication: 12,000 RPM
Oil Lubrication: 14,000 RPM
ID (inner diameter)/Bore=35mm
OD (outer diameter D1)=62mm
Width/Height/thickness=14mm
Radial Clearance: C3
6007 Type: Nachi Deep groove Ball Bearings
Size: 35mm x 62mm x 14mm
Made in Japan
Quantity: One Bearing 6007
6007 Nachi Bearing 35x62x14:Open:C3:Japan:Ball Bearings

Upper Bearing: $6.88
Item: 6206 Nachi Ball Bearings
Dimensions: 30*62*16 mm/Metric
Dynamic load rating Cr: 19,500 N
Static load rating Cor: 11,300 N
Limiting Speed:
Grease Lubrication: 11,000 RPM
Oil Lubrication: 13,000 RPM
ID (inner diameter)/Bore=30mm
OD (outer diameter D1)=62mm
Width/Height/thickness=16mm
Radial Clearance: C3
6206 Type: Nachi Deep groove Ball Bearings
Size: 30mm x 62mm x 16mm
Made in Japan
Quantity: One Bearing 6206
6206 Nachi Bearing 30x62x16:Open:C3:Japan:Ball Bearings

Less than $20 dollars would get you 13,000 RPM max if you had oil lubrication, 11,000RPM if you stuck with grease.

[diyengineer]

If i change out the bearings on the head it will allow me to run upwards of 13,000 rpm with oil cooling, or 11,000 with grease. (Assuming the spindle didn't need to be balanced for those speeds).

I then could convert the spindle to pneumatic tool change and belt drive.

I would then use a VFD and a Chinese spindle with a gear attached to drive the X2 spindle. I could use a step down gear ratio of 2:1 and belt. The Chinese spindle could then run at its max of 24,000 rpm and the x2 spindle would be at its max of say 12,000 rpm. OR I could also use a 1:1 ratio and keep the Chinese spindle at a lower RPM. I'm thinking of how i could get a gear that would be balanced enough to actually rotate @ that RPM and be balanced.

I Could also place a encoder onto the spindle for spindle orientation!

This all sounds mighty doable based off a small $119 dollar X2 head. Would be a sweet project that could be easily attached to a gantry.

[LeeWay]

I just installed new bearings in my spindle the other day. I have to do that about once a year. Easy enough to do though.
Nice prices on those bearings. I get mine from VXB.

If you are just wanting a high speed spindle, why bother with the X2 head. Just use the China product instead.

You will surely loose torque at any lower speeds with the setup you mention.

Mine is not bad with a 2HP DC motor. My slow speed is about 1000 and high speed is 6600 rpm. This is without a belt change. When I run really slow like that using an 1.25" face mill, it will stall if I take to deep a pass in steel. I generally run it at 2000 instead. I run my other steel parts at 3000 rpm taking off only .02" DOC. The parts are mounted on a magnetic chuck and much more would loose hold on the chuck.
When I cut steel in a vise, I slow it down and cut deeper per pass. With any aluminum, my speed is always 6600 RPM.

I think this is all a very good range for an X2 head. Pretty versatile really. The entire setup including motor controller and speed control board was less than $300.

Just curious about the reason behind the spindle you are suggesting. Maybe something I am missing?

[diyengineer]

The X2 head would provide a cheap platform for:

R8 tooling
Auto tool change
Belt drive
Speeds of 12,000RPM
Spindle Orientation.

The Chinese spindle only provides the grunt and power along with the high speed capability. The VFD provides the motor with close to 100% TQ regardless of speed. Without a VFD a simple motor loses TQ in relation to its speed.

There would also be no forces ever acting on the Chinese spindles bearings, thus extending the life of the Chinese spindle!


What i am going after is a super cheap simple platform that offers a numerous amount of features and can be modified or bolted to a gantry style CNC machine.

$120 X2 head with R8 spindle.
$20 Bearings
$100 Pneumatic tool change parts
$400 1.5KW chinese spindle w/ VFD
$65 dollars for encoder for spindle orientation
$100 for aluminum to mount the spindle to the x2 head
$50 for pulleys and a belt.
$Free-your time.

That is roughly $855 dollars for a full pneumatic tool change, 3 HP, R8 taper, belt driven, high speed spindle, with spindle orientation and Chinese VFD.

For the price im pretty sure everyone would be jumping on this if it was commercially available. Mostly people bolting them onto gantry style 80/20 machines etc. It would be a glorified replacement for the standard Chinese spindle, except with all the thrills!

Originally Posted by LeeWay I just installed new bearings in my spindle the other day. I have to do that about once a year. Easy enough to do though. Nice prices on those bearings. I get mine from VXB. If you are just wanting a high speed spindle, why bother with the X2 head. Just use the China product instead. You will surely loose torque at any lower speeds with the setup you mention. Mine is not bad with a 2HP DC motor. My slow speed is about 1000 and high speed is 6600 rpm. This is without a belt change. When I run really slow like that using an 1.25" face mill, it will stall if I take to deep a pass in steel. I generally run it at 2000 instead. I run my other steel parts at 3000 rpm taking off only .02" DOC. The parts are mounted on a magnetic chuck and much more would loose hold on the chuck. When I cut steel in a vise, I slow it down and cut deeper per pass. With any aluminum, my speed is always 6600 RPM. I think this is all a very good range for an X2 head. Pretty versatile really. The entire setup including motor controller and speed control board was less than $300. Just curious about the reason behind the spindle you are suggesting. Maybe something I am missing?

[diyengineer]

If a person really wanted to save money, they could use a super pid instead of VFD, and use a Router to drive the spindle

If (more like when) my Chinese spindle dies, i will be exploring different avenues.

[sdougm]

Hi!
I think in do the same thing in my X2 nad like know if you got fibnish your project...
and i really like see some pictures of the final result!
Thanks

Doug

[diyengineer]

Originally Posted by sdougm Hi! I think in do the same thing in my X2 nad like know if you got fibnish your project... and i really like see some pictures of the final result! Thanks Doug

I did not pursue it (YET). I think it would be a really good option for someone who is a do-it-yourself-er. I hope to possibly try it in the future.