[Billhill]

I have a DC motor that I will try out as a spindle motor. It comes from a treadmill, about 1HP.

Getting from a threaded shaft to a ball mill- I have no idea what I need next.

For drills, a Jacob chuck seems to make sense.

I see a lot of collet types, 5C and ER20 having made an impression.

I have never watched a machinist change a milling tool, so don't know what happens.

I am attracted to the Tormach TTS system, because of the "Consistent and accurate Z axis tool holding", so OK fine.

For hours, I looked through MSC for collet chucks, and found nothing with a "drawbar", and any reasonably priced pneumatic chuck for auto tool changing, though that's the direction I'm leaning.

I'd like to reduce the weight of the Z-axis. as much as possible, so I don't want a spindle flywheel, or chuck adapter plates, or 18" drawbars and handles, and yet which way should I go?

Should I treat this like a vertical lathe, and get the 5C collet from The Little Machine Shop?

Your opinions are invited and will be considered.

Thanks for the help.

[Cartierusm]

Wow, what you've asked is a lot for one conversation. Let's start off with what are you going to be using for a spindle, you can't use a motor for a spindle, it turns the spindle providing power but is not a spindle itself?

[acondit]

Wow, what you've asked is a lot for one conversation. Let's start off with what are you going to be using for a spindle, you can't use a motor for a spindle, it turns the spindle providing power but is not a spindle itself?

Strictly speaking this is not true. If the motor spindle is large enough diameter, it can be machined to use as a spindle. However, it requires something with adequate precision and freedom from runout. A few people have successfully created spindles from servo motors.

Alan

[Cartierusm]

Duh..brain freeze I was thinking regular motor. But still it's quite a lot of precision work.

[Billhill]

I need someone knowledgeable to help me by pointing out what is missing between the motor and the milling bit. I plan to use electronics or belt pulleys to regulate the spindle speed.

It is the OTHER STUFF that I am unfamiliar with. For example. I know that the milling bit goes in the right sized collet, and that for a quick change to another bit, it is standard practice to take out the last bit/collet and put in the next bit, already mounted in the right sized collet.

What I don't know is, how is the collet held firmly, with little tir? With a collet chuck, I've guessed, which probably extends to open when you yank the drawbar or press a switch. Right there, I am lost. I see lots of bit holders, usually R8, but I am going for a low weight setup, so I want opinions on ER20 and so on.

Also if anyone has direct experience with building a spindle from scratch, then they probably know what to buy and from where. So that is the kind of info I am looking for.

I don't want to just buy a whole spindle setup, I can't afford it. So I have to try to build my own, and THERE'S where I need good experienced advice.

[jsheerin]

Bill,
Do some reading first:
http://www.cnczone.com/forums/showthread.php?t=10695
http://www.cnczone.com/forums/showthread.php?t=41200
http://www.cnczone.com/forums/showthread.php?t=32609
http://www.5bears.com/cnc.htm

This should answer some of your questions. That said, if you're not a machinist and don't have machine tools available to you, I would not try to build a spindle. I'd buy one.

[Billhill]

Thanks for the reading list! That was a generous and helpful thing to do.

I did read each one. The new spindle design and the 5Bears links were useful, while a link in the middle sent me to YouTube, where I happily watched chips flying from DIY machines. Thanks! I'm re-infected with CNC zeal now...

I still haven't been convinced to use huge and chunky R8 gear to rotate a cutter. I noticed the 5 Bear.com builder was upgrading a Sherline, so I'll have to study his approach more.

Thanks again!
Aloha
Bill