Diy Brushless Spindle

[njhussey]

The second piece is for the cap, I've rough (rough bring the operative word!!) turned the first piece but should really have bought a longer piece of Ali...so I'm going to turn a shoulder in the end of the first piece to more accurately hold it in the jaws (so I can then finish machine out the jaw marks) then finish machine, bore it for the bearings and part off ( couldn't get the parting off tool near enough without hitting the jaws before)...

Well that's the cunning plan anyway ;-)

What's the easiest way to accurately drill the holes for mounting the motor without any sort of indexing head/table anyone?

[blackburn mark]

What's the easiest way to accurately drill the holes for mounting the motor without any sort of indexing head/table anyone?

errrr? i did a bit of a hatchet job on my first one (not having cnc at that point)
scribed a line with a centre finder square... dot punched my first two holes then used my vernier calipers (one tip in the dot) and scribed a circumfrence from both dots trail and error style :)

it got me there (just)

make sure you mark and drill the face that is going to sit on your motor just in case your drill wanders.... i find it really easy to forget stuff like that

[njhussey]

Well I was thinking of either buying one of these http://www.rdgtools.co.uk/acatalog/PROTRACTORS_ETC.html or drawing the bit in CAD, printing it out and sticking it on and centre punching the holes before drilling on the pillar drill, think I'll go the first way as the second seems a bit crude!!

[Jonathan]

Well I was thinking of either buying one of these http://www.rdgtools.co.uk/acatalog/PROTRACTORS_ETC.html or drawing the bit in CAD, printing it out and sticking it on and centre punching the holes before drilling on the pillar drill, think I'll go the first way as the second seems a bit crude!!

No need to buy those... as Mark said all you need is dividers. Scribe a circle, or lightly touch the lathe tool to it whilst in the lathe to make a circle then use dividers to divide that circle equally - centre punch then a quick swing on the pillar drill. Equally nothing wrong with printing out a template and sticking it on - printers are pretty accurate.

If you've got access to a milling machine then just put it in the vice, center drill (or spot drill) in mill and mark out the holes with that. Zero the X/Y dials in the center, noting in what direction you zeroed them so you can compensate for the backlash by always turning to that point in the same direction. Move it the correct distance using CAD program or simple trig to find the distances.

There's many more ways to do it sufficiently accurately without buying anything.

[njhussey]

No need to buy those... as Mark said all you need is dividers.

Hmmm... Dont have any but do have vernier calipers so might try that

Scribe a circle, or lightly touch the lathe tool to it whilst in the lathe to make a circle then use dividers to divide that circle equally - centre punch then a quick swing on the pillar drill. Equally nothing wrong with printing out a template and sticking it on - printers are pretty accurate.

Might have a go at one of those ways on some scrap bar..,

If you've got access to a milling machine then just put it in the vice, center drill (or spot drill) in mill and mark out the holes with that. Zero the X/Y dials in the center, noting in what direction you zeroed them so you can compensate for the backlash by always turning to that point in the same direction. Move it the correct distance using CAD program or simple trig to find the distances.

We have an old Bridgeport milling machine at work, not sure if it works though, will ask the guys tomorrow.

Cheers chaps, given me plenty to think about...

[njhussey]

Well I've ordered the ER16 collet from fleabay http://www.ebay.co.uk/itm/ws/eBayISA...EOIBSA:GB:1123 and have had a go a boring the bearing housing. However my boring tool (went for the 10mm brazed tip boring bar http://www.rdgtools.co.uk/acatalog/B...ring_Bars.html) needs alot of grinding to get it to not rub...might see if I can grind one from scratch as we have a few lengths of tool steel lying around...still got probably 3 weeks to do it in before my ER16 collet arrives on these shores Thinking of which my bearings should be here from the US within the next week

[njhussey]

Collet arrived today :-) ...but still waiting for my bearings :-( Going into work early tomorrow to do a bit more (been doing 12 hr days at work recently so not had a chance to get more done tut) on the spindle and maybe even my machine!!

[Villacherman]

Neil,

Great work so far on the spindle, I'm anxiously watching how it turns out. I'm building a similar spindle, however, I'm thinking of incorporating a v-belt pulley drive so if I want to change the speed/torque I can have that option. Does complicate things a little more.

My intent is primarily to machine aluminum and hard plastics. I'm designing for 500-4000 RPM with hefty torque to use with 3-12mm end mills.

Anybody have an idea if these type motors will deliver decent torque at 500 RPM?

Adam

[Jonathan]

Anybody have an idea if these type motors will deliver decent torque at 500 RPM?

Not unless you either rewind the motor to get a lower kv, or use belts, which you are doing. Still 500rpm is pushing it with one belt reduction. I think you'd need two. My brushless motor spindle is a big 12 pole motor, so it's quite slow - but still 6000rpm on the full 50V. Eleven to one reduction isn't happening with one belt, but 3:1 to get max 2000rpm would probably be fine with that motor. You would only get about a quarter of the power out of that motor, but a quarter of 6kW or so is still plenty!

[njhussey]

Well bought the motor today, got a 320kV one http://www.giantcod.co.uk/xyh5065-32...-p-404606.html so hope to have that early next week! Still waiting for my bearings from the US, been over a month now :-(

Still will give me a chance to finish off the bearing housing!