Conect 121 Lathe - The toy collection grows!

[m_c]

Following a chat with somebody last week, I'm now the owner of a Conect 121 lathe.

So far, I've got it home, opened up all the covers, taken some pics, and done a bit googling.

Pics can be found at http://www.flickr.com/photos/mc_mtb/...7625154378941/

From google, I've found out it's based on a ML10, and the original software needed either a BBC or Dos based computer.


I'm now of to clean it up, power it up, and see if anything works.
From the quick look at it I had earlier, it appears that the Stepper drives and control is built into one board, with the spindle speed control in the other, so I'll check that at the same time.

My plans are to retrofit a couple new stepper motor drives, along with the SmoothStepper and CNC4PC board which I bought for the (as yet unfinished) mill conversion, and get it running as it is, before deciding on if I want to upgrade it anymore.

[John S]

Best thing, the original software was a dog on the BBC, the PC version was better but the boards are specif to the computer.
keep the spindle board and ditch the rest.

John S.

[m_c]

After some tinkering this afternoon, I may have an issue with the spindle board/motor/choke.

The manual overide doesn't work, so started of by bridging the start connector on the spindle board (it's a Control Techniques ASP-5 with symbols drawn on for the motor/control connections), which would let me up the speed to maybe 50-60rpm, before it would start grumbling/hesitating a lot before either blowing the 13A fuse in the plug, or tripping the 32A ring main circuit breaker.
So I disconnected the main control board, and wired the spindle switch/speed poteniometer directly onto the spindle board. This worked better, however any increase of speed above about midway on the dial, or any sudden increase in speed would again pop a fuse or trip the circuit breaker. The built in ammeter was showing about 1A at slow speed, and as speed was increased, it would rise to about 4A and gradually drop back to about 3A if the speed dial was left untouched. The fuse would blow/circuit breaker trip if the ammeter peaked above 5A. Also during this, the motor was at times a bit grumbly.

Tried disconnecting the motor from the spindle, and current pretty much dropped to zero, and the motor would spin upto max speed with no noise or hesitation. However, after trying the speed control a few times, it tripped the circuit breaker again.

After disconnecting the belt, I tried spinning the spindle by hand, and although it's not super smooth, it doesn't take much effort to turn it, and I would expect the motor to manage to spin it without much effort.


Does anybody know if this is likely being caused by a fault with the board, motor, or choke (fitted inline between the motor + board)?

[Swarfing]

Are you able to try a different power supply? maybe the transformer windings breaking down not allowing more power to be pulled?

[m_c]

The motor control board is totally independant of the main transformer in the control cabinent. The controller has it's own small 18v transformer on the board, which supplies power for all the motor controls.

[m_c]

I'm quickly starting to think that CNC is more hassle than it's worth!

The conclusion is the Motor Controller is the issue, so that's going to cost me (see thread here).

So now I know where I am with the spindle woes, the current plan, with regards the drives/controller, is to keep the existing power supplies (36V + 18V) and steppers, drop in the smoothstepper and C23 board, fix up a 5V supply for the SS & C23, and add in a couple stepper drivers.

I had planned on using the smaller drives from ArcEuroTrade, as I was going to order a quick change tool post at the same time, but they're out of stock with no planned date for delivery. I'm now very much regretting selling those two Gecko G251's last year :-/
Had a quick search for other options, but for similar drives, they're all a bit more expensive than Arc.

While on the subject of tool posts, would the model 200 from Arc be too big?
Having measured it up, and laid a holder on the cross slide (I already have a model 200 on my Clarke lathe, along with 10 assorted holders), it could fit, but look totally out of place size wise. I'd say the lever will hit the cover, but I'd soon modify/remove the lever.
Depending on how I get on with this lathe, I may build a tool changer for it, so the other short term option is to try and match the existing quick change tool post that is already fitted, and get a couple holders for now, depending on price.

I've also been looking at adding flood coolant, and it would mean sealing up the enclosure. The enclosure is just bolted together, with numerous seems for fluid to leak out, so I'm not sure on the feasability. I'm thinking some PU adhesive along the seems would do, but coolant could still leak past the headstock, so would need to add a bit extra protection in that area.

[m_c]

We have a working spindle!

The KBIC controller arrived from Axis Controls today, so I quickly wired it in to test it, and the spindle goes from nothing to full speed with little noise.
Stepper drivers have also been ordered, and will hopefully be here this week.

I now just need to work out all the extra bits I need (fuses, holders, regulators, mountings, wire...), so I can start getting everything wired up.

[m_c]

I now have most of the bits needed to get this thing working, but need to finish another job first.

Big box of bits turned up from RS yesterday, and I've now got a little red gecko to keep my green gecko company :-)

[m_c]

Progress has been pretty slow, as I've had an ear infection meaning I've spent most of the week hiding inside keeping warm and trying to avoid falling over.

However, been out tonight, got the heatsink drilled/tapped for the geckos. Got everything laid out in the control box, and just need to get the control box drilled for all the mounting screws, then wiring can begin.

[m_c]

Just a quick update on progress.

The control box is almost wired up, and ready to be attached back onto the lathe.
All the 240V wiring is done, the BOB has power, the Smoothstepper is connecting to Mach, and activating the BOB.

Just got to wire up the Gecko's and connect the KBIC to the BOB, then the next stage can begin.