DIY spindle design

[Jeremy]

I've made a start on the spindle today. Spent a couple of hours turning a bit of 1.5" 6082-T6 bar into swarf...............

All told it's turned out OK. I turned a bit of bar up to fit as an end cap to hold the 550 watt motor (yes, I know it doesn't look like a 550 watt motor, but it's very efficient at around 85 to 90%). I turned up a small adapter to fit into the M10 threaded hole in the end of the collet chuck to fit to the lovejoy coupling. I am reasonably happy with the way it turned out, the runout at the coupling is around 3 thou, well within the 15 thou coupling limit.

The big bar has been bored out to take a pair of bearings, one at the end and another just below the cutout (the cutout is to allow the coupling to be assembled).

I just need to make a spacer to fit to the nose bearing and space the chuck out about 10mm from the bearing (to allow spanner access) and make up a clamp ring to fit at the top of the collet chuck 20mm shaft and allow the bearing pre-load to be set.

The thing with the wires poking out is the 40 amp speed controller. It's a bit of an overkill, as my power supply is only rated to 30 amps, but it should do the job. The current plan is to fit it into a small die cast alloy box next to the spindle and build a servo tester to drive it. This will give me a manual speed control, which I may seek to change to auto at a later date.

Hopefully I should end up with something much more robust and accurate than a Dremel, with a fair bit more power. The motor may need a fan fitted to the top for extra cooling, I'll see how it goes.



Jeremy

[Thomasdj]

Hi Jeremy,

The only reasonable priced spindles I've seen are the Kress spindles..
I find your spindle very interesting! ..I am new to motors in generel and search information about building my own spindle.

I am curious about how your spindle perform, what its limitation is and if these (rc)motors will match my needs. I am building a CNC router with a moving gantry and would like to be able to cut wood, aluminium and mild steel sheet.

[bogflap]

Hi Jeremy

My interest in your thread is for a high speed spindle for isolation routing of printed circuit boards. This as far as I can see will only require bearings that will need to cope with very small axial and radial forces. So the question is has anybody tried attaching say an ER16 collet holder straight to the type of motor that you are using i.e. an r/c model outrunner/inrunner. I assume that these motors are intended to attach straight to a aero prop and so the motors will have fairly robust bearings in the first place. I assume they will be thrust bearings (axial loads) mainly because an aero prop 'pulls' itself through the air. However I assume that there must be some radial loading, which is the issue that plays on my mind at the moment. Has anyone tried this or has anyone any knowledge of what kind of bearings these motors contain.

[templecorran]

Forgive me if this question is off topic.

Jeremy, that is a great piece of work.
You mentioned that you used the Shumaker suggested servo tester to get the pulses needed to get the motor going.

My question is: Does anyone have experience of driving this type of motor control from the MACH3 software suite?
I know from reading the MACH3 manual that PWM speed control is covered on page 5-7 & 5-17, but has anyone actually done it with a DC brushless motor?

Here's hoping!!

John

[templecorran]

Sorry, I just thought to ask you if you have had any machine time with this new spindle yet?

Most important to me is: how noisy is it?

cheers
John