[cncuser1]

Does anyone have suggestions for belts and pulleys to achieve high RPM's?
I'm thinking 8K-12K RPM.

I want to use the stock motor and spindle and upgrade the bearings.

If there are specs out there for the belts, pulleys and possibly drawings for mounting the motor, it would be appreciated.

[robertspark]

Did I miss something, you've not given anyone a clue what your current motor, spindle or machine is?

First off.... Your motor... What is it (hp, kw, rated speed, rpm, amperage, is it single or three phase, does it conform to a size standard or flange and mounting arrangement? Motors are normally mass produced so have a frame size). Shaft size, keyway, taper flange?

Similarly with your spindle.... What is on both ends of it, diameter, keyway, taper, thread?

What do you want to machine? Material

With what do you want to machine it, tool, diameter, flutes, material, coating?


Yes a lot of questions.... It's like putting new wheels on your car, you would need some specs to understand what you have and what you want or where you want to end up.

P = 2*pi*N*T

Faster something spins for the same power, the torque drops off.

Belt ratios are the same as gear ratios....

2:1 means input to output speed is half, but torque conveyed is double.

1:2 means input to output speed is double, but torque conveyed is half.... You ain't going to cut the same things you do now....

If it's a 3 phase motor, you can over drive it a bit rpm wise and the torque does not drop off too drastically.

A single phase motor you can do nothing with inverter or speed control wise

[109jb]

I think from his other post he has an X2 which has a 0.4 hp DC motor that looks like it spins 6000 rpm. You will need about 1.4:1 belt drive to achieve 8000 rpm by the time you take into account the friction losses. I wouldn't even think about 12,000 rpm on an X2 stock spindle. If you really want to do this, you will need high quality angular contact bearings. The stock bearings are 80206 deep groove ball bearings with a 30mm ID, 62mm OD and 16mm width. You can get Nachi angular contact bearings in that size (7206), and they are rated for 10,000 rpm when grease lubricated. I'm thinking that the stock bearings are sealed, so you would have to provide some kind of seal for the angular contact bearings. You could also go with tapered roller bearings but will only get about 6000 rpm from those.

[dazp1976]

Came across this:
https://www.blocklayer.com/pulley-belt.aspx
Looks handy for working out pulley sizes needed for required rpm's.

[cncuser1]

robertspark you didn't miss anything, I posted poorly. In my head I was posting to an exclusively Sieg X2 forum, this isn't that.

My Machine is a Sieg X2, I want to use the stock 6000RPM brushed DC, .4HP motor. I also want to use the stock R8 spindle.

I'd like to run it up to 8K-12K RPM.

So I was wondering if anyone has retrofit a stock X2? To save me a bit of trouble of looking for appropriate style ( v-belt, toothed belt), appropriate diamters that give the desired RPMs, but still fit.

And hopefully some drawings on the mounting of nthe above components?

[cncuser1]

109jb : Thanks, I plan on upgrading to a better quality bearing.

So I am looking for belt type, pulley part numbers, etc.

[cncuser1]

dazp1976 : Thanks, that's a time saver.

[mactec54]

dazp1976 : Thanks, that's a time saver.

Your best belt type is a Poly-V-Belt this uses less power and has max grip you would need no more than a J5 Rib for your small motor, you can make these pulleys if you can't find anything to suit your machine

[cncuser1]

Well I found this design that Hoss adapted, it is a good start because it has a lot of the basic dimensions.

Does anyone know if there are commercially available pulleys that can be modified.

I would like to avoid machining pulleys out of a honking big piece of stock.

mactec54: I looked for J5 pulleys and it looks like I'd have to machine what I want.

[mactec54]

Well I found this design that Hoss adapted, it is a good start because it has a lot of the basic dimensions.

Does anyone know if there are commercially available pulleys that can be modified.

I would like to avoid machining pulleys out of a honking big piece of stock.

mactec54: I looked for J5 pulleys and it looks like I'd have to machine what I want.

The Pulleys in the Belt Drive PDF are all custom made to suit your machine, so you would have to make them no matter what profile type of belt you use

Poly -V-Belt pulleys are available but are never the sizes you need so it is best to just draw up what you need and make them they are very easy to make and easier than machining a V pulley of the same sizes

[cncuser1]

mactec54: are the Poly-V pulleys easier to machine because the V angle is the same for all pulleys?

[109jb]

They are easier to machine because the depth of the grooves is shallow and can be done with a form tool easily because the amount of material removed with each groove is small. Machining for a standard V-belt will require removing most of the material with something like a parting tool, and then machining the angled faces. On a lathe that means setting the compoundfor one side and then re-setting it for the other. Not hard but a lot harder than just plunging in a form tool a few times.