Milling Spindle Motor

It would be interesting to know hat size of mills you want to use and how deep the cuts will be and what feed rate. By this, the power could be calculated (more or less).

Nick

If you are going to buy a motor. Why not check out the cost of a motor and speed control for a mini mill such as a Clark or similar. I think these are about 350 watt and most will have overload cutout incorperated.

If you don't want anything too big the Sherline unit is quite good. Powered by a 90V DC motor, with built in speed controller. Lots of standard accesories as well -collets, chucks, etc.

Regards

Kevin

I had this quote a while back for a project thats still not made it to the top of the list:

This is for the motor for a Seag C3 lathe. I've not dealt with Adam, so can't provide any references.

Hi Steve Motor £49.99 Drive Board £39.99 P&P £8.50 FOR BOTH Regards Adam

Adam Labudek Total Machine Tool Technology Limited

PS: A helpful gentleman at Seag sent me schematics for various of their controller boards.

Steve, I also have a project that uses the Seig boards. Any chance of a copy of the schematics please... pretty please ?

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Sent them - assume your eMail is good.

Steve

Ta mutchly, now just got to work out which board it is.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Can you explain how to calculate this, please ?

I've got a Westbury-Dore mill fitted with a 1/4 HP single phase motor.

I'd like to change it for a variable speed motor, and have a choice of a 440W DC motor or a 550W 3-phase motor (both with Eurotherm controllers). The 3-phase looks a good option, but is it pointlessly big ?

I use cutters up to about 3/8", but would also expect to use a flycutter. I tend to take very light cuts due to the small size of the mill, but I'd be interested in knowing what is within the motor power range.

-adrian

The serial XMT-xxxxxxx on the schematic matches a sticker on the controller board ;-) . Mind you , at first glance they all look the same design, so maybe there is only component value differences or board layout. Need an expert to check what the significant differences are.

Steve

Me too, please.

Adrian, I modified my Dore Westbury head with a .5hp 3 phase motor via an inverter woks very well adequare power and much smoother see

The conventional wisdom is 1 cubic inch of steel per minute per horsepower. I don't think that I have ever achieved this rate while milling on the lathe with a 550W motor. Maybe when turning 3" bar down to 2" bar with carbide bits though.

Mark Rand RTFM

Others will correct me if this is wrong, but I believe 1 HP is generally equivalent to 3/4 kW (750W).

If it were me, I'd go for three phase every time as the controllers can offer loads of useful features such as soft start, jogging, motor braking, and almost-instant reverse.

I've seen posts recently (admittedly WRT surface grinding) that suggest 3-phase motors are smoother and hence vibrate less. On a light mill such as a D-W, this may be an advantage.

OK, lets see:

Math is in metric. :-) [if I write x//y it means x index y]

given: Cutter diameter = 10mm depth of cut = 10mm number of teeth = 3 I assume rough cutting of MS with reccomended feed per tooth and RPM. That would be: feed / tooth (f//t) = 0.016mm cutting speed (v//c) = 28 m / min

P//c = a//p * f//t * N//c * v//c / 20

with: P//c : Power f. cutting steel (in kW) a//p : depth of cut N//c : number of teeth cutting (with a 3 flute cutter, 1.5 teeth are cutting in average)

P//c = 10 * 0.016 * 28 * 1.5 / 20 = 0.336kW

All that could be calculated more precise. I tried it, but got lost in zillions of tables for specific cutter properties, material, dullness of tool and number of beers.

HTH, Nick

Thanks for taking this trouble !

That's almost twice the power of the existing motor and less than either of my alternatives, and the cut is much deeper than I'd normally use.

Which suggests I'm being much too timid (though the mill is probably not rigid enough for recommended feeds) and any of the motors have adequate power. I'm not sure what feed rate I can do smoothly with the manual feed but I suspect that even the existing motor will do anything I dare attempt.

-adrian

That's an interesting mod !

For those who aren't members of the yahoo group : the photo shows a Dore-Westbury head mounted on a horizontal mill's base, replacing the D-W's vertical shaft. This overcomes the common criticism of the D-W, that it doesn't maintain alignment when you change height. Presumably it's also a lot more rigid, as the tall 4" shaft is no longer there.

-adrian

You're welcome!

Don't forget, that this is the required power, and not the power consumption of the motor.

Nick