Author Topic: Bought a CNC lathe  (Read 45888 times)

Offline Brass_Machine

  • Administrator
  • Hero Member
  • *****
  • Posts: 5504
  • Country: us
Re: Bought a CNC lathe
« Reply #75 on: February 19, 2013, 11:04:15 PM »
... I realized that my parallel port cord didn't have the right end on it!  :hammer:  After trying seven different stores I came to the conclusion that no one stocks this cord any more and had to order one on line.  Hopefully the cord will come by Friday so I can finally try out the lathe.
...

I feel your pain Dale. Had the same problem and had to order an adapter...
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #76 on: February 20, 2013, 07:03:04 AM »
What I was able to find out is that the new stepper drives and motors have TOO much torque and will have to get turned down.
That's a very, very wise statement Dale.

Unless you're perfect in your programming, there's some crashes coming very soon that your machine will be grateful for you turning down it's torque & speed!  Lots of "Why the ^&#^#%$$# did it do that!" moments coming.
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #77 on: February 20, 2013, 07:05:24 PM »
Here is a question for you guys about programing a lathe with Mach.  Do I set up the tools to be at "0" when the tip of the tool reaches the middle of the chuck or do I have to touch off the part I'm turing and then set up Mach to take off a certain amount to reach my desired size?  I have played around with Mach 3 Mill quite a bit, but never used Mach 3 for the lathe so I have a lot to learn.

Dale P.


Offline John Stevenson

  • In Memoriam
  • Hero Member
  • *****
  • Posts: 1643
  • Nottingham, England.
Re: Bought a CNC lathe
« Reply #78 on: February 20, 2013, 07:19:42 PM »
Take a test cut, measure and set the display to that.
John Stevenson

Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #79 on: February 21, 2013, 09:56:04 AM »
Take a test cut, measure and set the display to that.
...or half of that if you're working in the radius mode.

I keep telling myself I'm going to change over to diameter mode but I won't listen.

You know what they say: It's OK to talk to yourself and even answer yourself but if you say "Huh?" to yourself you should get professional help.:loco:
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #80 on: February 22, 2013, 05:52:41 PM »
Ok I'm getting closer to making some chips, but still need to work some bugs out.

I installed a C-3 index pulse board as most of you guys have and it's reading around 3x the correct RPM.  There is a single slot in my disk on the spindle and I have the pulse board wired to a spare input (A Limit)  I'm using the timing input in Mach 3 and de bounce settings are at 1. No matter what I try the RPM gauge on the Mach screen is reading high.

Dale P.


Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #81 on: February 23, 2013, 06:22:21 PM »
The good news is I figured out the RPM problem.  There are two different belt settings on the lathe and if you put the belt in the low speed position the tach in Mach 3 is spot on with the tach on the lathe.  The bad news is I think the spindle bearings need replacing as it howls a bit at full speed.  The bearings seem fine when I turn it by hand, but the howling noise makes me wonder if they are OK. 

So how hard do you think it will be to replace them?  There are two and I'm guessing they are pressed in place?  I pulled the spindle out which wasn't too hard, but I may have to make up a tool to pull the bearings, and then I worry about trying to get the new ones in place.

Dale P.

Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #82 on: February 24, 2013, 08:56:39 AM »
Wow, seems odd the bearings would be bad already.  Isn't that a low time machine?

I'd clean them up real good and look at them closely before committing to replace.  I assume they're tapered roller bearings?
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #83 on: February 24, 2013, 09:33:56 AM »
The machine has low hours, but it sat for years not running so it wouldn't have surprised me if the bearings got moisture and went bad.   I took the spindle apart and inspected everything.  The bearings are sealed so I can't see them, but they both feel fine and everything looks good.  When I put it back together I loaded the bearings a bit more and the noise went away.

I ran the spindle for 30 min and nothing got warm so I'm going to move on and call it good. 

Hope to finish dialing in the steppers today and cut some metal!

Dale P.

Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #84 on: February 24, 2013, 11:47:56 AM »
Great, that's good news! Glad to hear you're getting close.  Make sure & post some video!

Actually from what I read on bearing preload, the spindle should heat up after running at high speed for a while.  That's assuming the proper amount of grease was used.  Too much grease= excessive heat.

My ORAC's spindle gets very warm after 5 minutes or so at 1500 rpm and then stabilizes.

I went backwards on mine.  I decided I wanted spindle reversing and got off into relays & circuits that were over my head.  I got it working OK but got worried about screwing up and commanding a reversal before the spindle was fully stopped which would blow up my KB speed controller instantly.

After much hand-wringing, I stole a brand-new KBCC-125R controller on ebay.  It has a built-in relay module that allows switching between forward & reverse at full speed without a whimper.  It has a big ol' braking resistor that puts the whoa on the motor until it stops, then the circuitry smoothly switches direction and the motor spins back up to speed....all from one SPDT switch.  Should be easy-peasy to switch it from Mach via the C-11 B.O.B. which has 2 on-board relays.  I'm really stoked about it since reversing the spindle will make the front & back toolholders much easier to use.

I'm in the process of re-wiring everything to suit it as I've run out of room in the enclosure and it'll have to be mounted in a seperate box on the back of the machine.
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #85 on: February 24, 2013, 01:19:02 PM »
Wow, that sounds like a really nice speed controller. Can you post the auction # as I would like to check that model out for a future CNC mill build. 

What type of mount does your spindle have?  If it's threaded you may have issues with using reverse as the chuck could come right off.  My 9X20 lathe is threaded, but has a small lock to prevent this, but my CNC lathe doesn't have any type of lock so I didn't add a reverse for that reason.

I bumped into this auction and thought you should buy it for the tool changer and toss the rest as it's quite rusty.http://www.ebay.com/itm/281067128474?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

After I get the lathe up and running I plan to make a face plate for it and also up grade the 4" chuck to a 5" so I can hold some larger items.

Dale P.

Offline John Stevenson

  • In Memoriam
  • Hero Member
  • *****
  • Posts: 1643
  • Nottingham, England.
Re: Bought a CNC lathe
« Reply #86 on: February 24, 2013, 01:35:15 PM »
Note the "It needs a power supply "  which roughly translated to "it doesn't work but I'm not telling you that "
4 days left and reserve not hit yet.
Interesting to see what it fetches, over here that's worth about £800 [ $1200 ] with the toolchanger
John Stevenson

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #87 on: February 24, 2013, 02:37:26 PM »
Yeah, I had wondered what "it needs a power supply" meant too.  I'm sure your right and it needs a lot more.  It's a shame there is so much rust on it. 

Dale P.

Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #88 on: February 24, 2013, 06:43:03 PM »
Wow, that sounds like a really nice speed controller. Can you post the auction # as I would like to check that model out for a future CNC mill build.
http://www.ebay.com/itm/KB-Electronics-KBCC-125R-DC-Motor-Speed-Control-/330745553010?pt=LH_DefaultDomain_0&hash=item4d01f8a072  N.I.B. just like this one except I stole mine for $65.00 + shipping.  Blind hog gets an acorn one in a while.  There's an online .pdf manual if you want to learn more about it.

ORAC's are based on Emco Compact 8's which have a DIN 3 bolt flanges.  No reversing worries.  Thanks for the link but I purposely didn't look too close.  I don't need anything else to get side-tracked on until I make a few bucks in the shop!
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #89 on: February 24, 2013, 10:37:55 PM »
$65.00 is a great deal for that speed control.  I changed my X2 mill to a KB (I think it's a KB 120) speed control last year and love it.  I almost doubled the torque and speed verses the stock controller.

I cut my first piece tonight and all went well!  Can't wait for tomorrow night as I will have some more time to play around with it.

Dale P.

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #90 on: February 25, 2013, 12:18:00 AM »
My 15 year old nephew sent over some cad drawings for some speakers that he wants to build.  He drew up full plans in cad for them and needs me to make the "Top Hat" portion out of aluminum.  I originally planed to make them on my 9X20 lathe, but now that the CNC is up and running I might give it a shot.  The only problem is the stock is 5" in diameter and my CNC only has a 4" chuck and is missing the reversible jaws so I need to find a way to hold it.  I'm thinking of making a 6" face plate to mount to the 2 1/4" - 8 tpi spindle and mount the stock to that.  Should be a neat project and I will take pictures as I go along and post on a new thread.

Here are a few pictures of the print he made for the speakers.  The last picture shows the top part that I need to make, and not just one, but I have to make two of them for the right and left speaker.

Dale P.




Offline DICKEYBIRD

  • Full Member
  • ***
  • Posts: 229
  • Country: us
  • Collierville, TN ya'll
Re: Bought a CNC lathe
« Reply #91 on: February 25, 2013, 06:22:51 PM »
Great speakers and CAD work; especially for a 15 yr. old.  I'll bet his Dad's proud of him!

You can get a 2 1/4"-8 semi-finished adaptor plate from CDCO Tools.com for $42.00.  Unless you have a stash of big metal lying around, it'd be hard to beat that.
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline ibuildstuff4u

  • Full Member
  • ***
  • Posts: 190
Re: Bought a CNC lathe
« Reply #92 on: March 01, 2013, 02:00:30 PM »
I was looking at some adapters on E-bay and forgot all about CDCO!  Yes I will probably get one from them as the price is good and they are only a state away from me so shipping is fast.

I contacted Interteck to see how much a replacement chuck wrench would be since I don't have one and also asked about replacement inserts just to see how much they charged for them.  They responded and said the chuck wrench was $116.00 and gave me a link to replacing all of the tooling and said it would cost $2035.00 for the tool holders and inserts! Can you believe that, two grand for a few tool holders and boring bars.  Here is a picture of what you would get.

No thanks, I will make my own wrench and figure out what size the inserts are and order them my self.

Dale P.