View Full Version : Conect 121 Lathe - The toy collection grows!

31-10-2010, 01:14 PM
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/sets/72157625154378941/

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
31-10-2010, 01:27 PM
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.

31-10-2010, 05:09 PM
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)?

31-10-2010, 06:30 PM
Are you able to try a different power supply? maybe the transformer windings breaking down not allowing more power to be pulled?

31-10-2010, 09:32 PM
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.

01-11-2010, 08:40 PM
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 (http://www.mycncuk.com/forums/showthread.php/2626-New-SCR-driver-board-or-new-motor-VFD)).

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.

08-11-2010, 02:19 PM
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.

11-11-2010, 12:24 PM
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 :-)

19-11-2010, 08:52 PM
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.

25-11-2010, 12:48 AM
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.

09-03-2011, 08:12 PM
Time for another update.

After a bit of a mishap while wiring up the KBIC to the BOB (note - read the manual, then read it again to ensure you understand the bit about isolated power supplies!), that led to the BOB doing strange things, then delays with post/parcels due to the snow to find out a new set of optos didn't cure the problem, and finally sending the BOB to Lester Caine (www.medw.co.uk (http://www.medw.co.uk)), who discovered a fault that meant the board should never of worked in the first place, I am now finally back to where I was several months ago.
I currently have an E-stop system that works, and steppers that move via pushing some buttons on a keyboard.

Next job is to get the KBIC wired up to the BOB with it's own isolated 12V power supply, connect the spindle sensor to the Smoothstepper, tidy up the wiring, configure Mach for that lot, and then think about what else I need to do so I can make some chips.

12-03-2011, 07:48 PM
Spindle now spins via computer control.
Hopefully be able to start making some chips with it soon :-)

Here's a pic from the other night, prior to the KBIC being connected back up.

Pics now at http://www.flickr.com/photos/mc_mtb/sets/72157625154378941/

14-03-2011, 01:09 PM
Spindle index sensor has now been connected, which has allowed me to adjust the spindle settings so the requested speed is more akin to the actual speed.

Prior to connecting the KBIC to the C23, I adjusted the spindle settings so that the C23 was giving 7V at full speed, as per the KBIC manual for voltage following mode. However, upon setting up the spindle sensor, I was only getting about 1500RPM at full speed, so gradually increased settings until the C23 was outputting 10V, which at the commanded speed of 2100rpm, was giving a true speed of 2069rpm.

I've also got the coolant misting solenoid wired in, but need to get a couple swivel elbows and some new air pipe to get rid of kinks in the pipe work.

Next I need to think about homing/limit switches, and what buttons I want on the front panel.

Ideally I think I'd like to add a Pokeys system and design a completely new control panel, but for now until I get some use out the lathe and figure out what will be good to have, I'm thinking I'll just wire up the existing jog buttons, and the solitary 'feed rate' button as a feed hold. The spindle control stuff I'll just ignore, as that's all controlled via Mach.

19-03-2011, 09:19 PM
Wired up the existing jog buttons during the week, so I can now job the lathe without being near the computer, and got the new quick change toolpost fitted.

Spent some time yesterday cleaning the bed up, and lubricating everything, and it looks quite shiny and clean in the pic!

<pic removed>

Spent this evening tuning the motors, and managed to reliably get 5m/min from the Z-axis, and 4m/min from the X, with acceleration around 120 on the Z and 150 on the X.

Still got the coolant piping to sort out (need to sort the air supply, and get some new locline), fit a X-axis homnig switxh, finish the grounding wires, cable tie up all the wiring, get the control panel screwed shut, and spin the lathe around so I can see while sitting at the computer.

My main thing now though, is to figure out how to use Mach to do useful things!

21-03-2011, 04:31 PM
its looking very smart.

02-04-2011, 10:31 PM
Now that I've got it turned around a bit so I can see the front better, I'm actually surprised by just how well it's cleaned up!

I got the x-axis home switch added today.
< pic removed>
Just need to make a cover for it to stop swarf/coolant falling onto it, and decide how I'm going to secure the wiring. To try it, I just pushed the sensor cable through the same grommit as the x-axis stepper wires, which from a potential electrical noise/interference point I know is not good. However, it seems to work ok, but I'm not sure how the sensor cable will withstand oil/coolant. I had planned on putting a small junction box on the cross slide, then using shielded cable along side the stepper wiring, but there's really not enough room to mount a junction box. I'm now thinking about mounting a junction box on the enclosure, and then use sheilded cable from there to the control box. It still won't be ideal from a noise point of view, but will be far better than the existing set-up.

06-04-2011, 11:38 PM
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.

Does Emerson still manufacture ASP-5? My understanding was that they have been obsolete.

Here's a list of current Control Techniques DC drives. I believe even some of them on that list are obsolete.


07-04-2011, 05:41 PM
The drive turned out to be a Cheetah-II, as the label was facing into the side of the cabinet so I never seen it until I removed it.
I ended up replacing it with a KBIC, as that was the easiest option. I still have the Cheetah-II sitting on the shelf, as I suspect it is repairable, but I've never had the time or tools to do it.

18-04-2011, 09:18 PM
It lives!
Or it did for a minute or so until the spindle fuse blew!
Used the OD taper wizard in Mach to test it on a bit steel, and the cut depth was obviously a little bit too much for the spindle to handle.

Put a new fuse in, reduced the cut depth, and it managed to finish this -
<pic removed>
So now I just need to get the wiring tidied up (mostly solder ground wires onto sheilding, and put a few more cable ties in), get a couple elbows to plumb in the coolant, drill a big hole for the spindle fuse holder, and it will of reached a useable state. I won't use the term finished, as I already have ideas for bits I still want to change/add, but they'll be done when time/funds permit.

19-04-2011, 08:18 AM
that looks great, makes me want to do mine but I dont think I would have enough work for it , just one question where did you get the qiuck change tool post ?



19-04-2011, 10:04 PM
The QCTP is a model 200 from Arc Euro Trade (www.arceurotrade.co.uk (http://www.arceurotrade.co.uk)).
It's very much overkill for a ML10, but my plan was so I can swap tools with my bigger lathe which already has a model 200 and a good few holders. However I'm now thinking it'll be better having seperate tools, as the faff involved with changing tool heights between the lathes kinda kills the benefit of using a QCTP, plus the QC handle means I can't close the cover.

22-04-2011, 08:00 PM
Thought I'd do the right thing, and connect up all the sheilding wires to ground, but it meant the spindle sensor started giving some very erratic readings (3 million rpm is just slightly high...)
So cut the sheilding wire, and things went back to being stable.
I'm just going to leave the ground wires of for now, as everything appears to work how it should with them off. I think the real issue is that with the current control box layout, the ground wires are having to run past the transformer, bridge rectifiers, and capacitors, and they're picking up interference from them. I could redo the control box, but I'm wanting to make parts, so I'll leave that for a future upgrade, as I'm not entirely happy with the current break out board (even though it's repaired, I'm not 100% convinced by it's reliability).

Just need to get a couple airline connectors now, and get the control cabinet screwed shut, so I can get the lathe turned around and the workshop rearranged for the other new toy.

19-09-2011, 09:24 PM
With little else to do tonight, I thought I'd get the new backplate on, and machine it up for the ER collet chuck I've had lying around for a while.
Expecting the 3jaw to be seized on, I was surprised that it came of with gentle use of some mole grips (because Conect removed the original pulley block, there's no spanner flats on the headstock) and a lever, it slackened with no need to resort to expletives.

Spun the new backplate on, nipped it up, then hit the first problem.
The carriage wouldn't move near enough to the headstock for the tool to reach the backplate. After much umming and r'ing, going through the tool collection, thinking it was the ball screw cover at the headstock end bottoming out, which would involve a lot of dismantling to remove, it finally dawned on me the problem was the ballscrew cover at the tailstock end, so with one screw removed, I had the required travel.

So onto getting some G-code to face the backplate. Loaded the wizards in Mach, and first attempt cutting air done the wrong thing, so while putting some more figures into the wizard, I'm aware of a crackling sound, the lights briefly dim, then a pop, followed by the dreaded smell.

Turns out the toiroid has melted itself, but there's no obvious reason why.
The fibre washer on the mounting bolt looks to be where it should of been, so that's not caused it, but it has been heating for a while going by the melted tape and how hot it still was by the time I pulled the lathe out and unscrewed the back cover.
There is a arcing mark on the base, so I wonder if a bit swarf has worked it's way in somewhere causing the problems :confused:
Anyway, here's a couple photos of the culprit

I've already had a search for a direct replacement, but dual voltage toiroids seem to be pretty rare, as this had a 12V and a 24V secondary.
Think this may be a suitable time to up the voltage aswell, as those geckos are good for 50V, and the basic motor calcs say they should handle the voltage....:naughty:

19-09-2011, 11:03 PM
That is just not nice. Good luck on getting either a new one (they be hard to find as you noted) or one that will meet the required need.


19-09-2011, 11:26 PM
Hmm, that must be extremely annoying. I've got two transformers on my machine - 500VA powering X motors and Z, 325VA on Y and 4th axis if in use. I only did it as I had a spare and thought it would be good to seperate the supply for X and Y so that if they both draw a high current at the same time (e.g. G0 X0Y , G0 X500 Y500) the voltage doesn't drop too much. Will also help if one goes bang, but they never even get warm so can't see that hapenning. Really odd that yours did since your drivers have overcurrent protection. What did you fuse did you use?

It'd be interesting to try rewinding/repairing the existing transformer. Depending on how many turns that arcing has destroyed you might be able to remove those turns and connect up the loose ends. Then switch it on with no load from a distance ... if it seems fine after a couple of minutes try measuring the voltage.

19-09-2011, 11:44 PM
I'm not sure what happened, as nothing was moving at the time.
I was trying to figure out how to get the Mach wizard to do an outside to inside facing cut, when I heard something starting to crackle.

The only thing I can think of, was I fixed the coolant earlier, and at one point I rattled the back of the casing quite hard when trying to get the locline back together, so I wonder if I dislodged something, but the only obvious damage is the toiroid. Fuses are 6.3A anti-surge.

20-09-2011, 09:40 AM
Fuses are 6.3A anti-surge.

That is much too high to protect the transformer. For that 160VA transformer 2A slow blow would have been more appropriate. Probably 3A slow blow for the new one, maybe less...

20-09-2011, 10:29 AM
The fuse powers the tx and the spindle drive, as that was the original setup that I never changed.
Think i'll add an extra fuse now though!

20-09-2011, 11:30 PM
New TX and assorted bits now ordered.
Ended up getting the stuff from RS, as they were the cheapest ones who had everything in stock.

Bits should hopefully be here on thursday, but I probably won't get them in place until sunday/monday.

30-09-2011, 12:05 AM
The lathe is finally back up and running.

Machined the new backplate for a ER32 collet chuck this week, which took a few attempts to find a suitable feed rate and depth of cut due to the lack of power at low RPM, but got it done eventually.

I'm already considering a PoKey and MPG, as having to move between the lathe and the computer when setting up/jogging/starting/stopping is a pain.

16-11-2011, 08:32 PM
After being distracted with some other repairs (bloody neighbours who buy tractors for a 'good' price thinking they've bought a bargain!), I've finally been able to spend a bit time this week working towards getting the lathe fully functional. I've set the QCTP square, measured the backlash (I still need to check the SS plugin as I couldn't get the Mach backlash to work), set up a couple tools, and even cut a thread!

The final part of what I need now is a drill mounting method, so I've been working on a gang toolholder which will use ER20 collets.
I still need to make a couple T-nuts, bore some holes for holding collet chucks, and also make some collet chucks, which I might get done over the next week (I've got another queue of repairs building up, which may distract me again :confused: ).

Here's a couple pics of the last couple nights work
<pics removed>

01-03-2012, 09:46 AM
Having followed your thread it struck me that the connect 121 is a good solid machine with a reasonable centre height which would be ideal to convert into up-to-date software, I found one last week which is in virtually new condition and collected it yesterday. Unfortunately my enthusiasm outstrips my knowledge I thought the machine would operate in manual modes and by fitting new stepper motor drivers and interface cards I could operate on Mach3. However there is no visible method of starting and controlling spindle speed so I assume that this machine will only run under computer control which since I know absolutely nothing about servo drives and controls leave me with a very steep learning curve or converting to an inverter variable speed drive.
Your horizontal multi tool holder is a great idea in the absence of a turret and if I get mine working certainly fit one.

06-03-2012, 04:39 PM
I wouldn't go as far as saying it's a solid machine, but then I'm used to bigger machines.

If you don't want to do a full retrofit, and your machine uses a Conquerer Design & Engineering (CDE) board, then they still exist and do an upgrade kit so the lathe can be run on more modern software - http://www.eaziform.co.uk/index.php?products,cncupgrade

06-03-2012, 07:56 PM
Thanks for the input, I thought I was in for a real problem, but after examination I found that it was fitted with Conquerer driver boards and contacted Eaziform to see if the driver boards would be ok with parallel port Mach3, Alex Mackinnon asked if it had a Conquerer
input board and if so why not connect it to a serial port and run Eazicnc !
Did that and it works!! and the electronics were updated after 2005 so it's no longer an update job, though I still have to get the mist coolant working, calibrate the spindle speed and make your tool holder.
Don't know if it's capable of screw cutting so I still have a learning curve on g-code and software.
Alex at Eaziform has been amazingly helpful and a pleasure to deal with especially I was not and original purchaser of their gear.
The solidity is relative, my main machine is a 17x36 DSG (2 tons) but the Conect struck me as heavier than some of the 65mm centre height machines.

01-07-2012, 11:34 AM
Why is lathes seem to attract clutter?
The milling machine always remains relatively tidy, however lathes somehow end up being used as workbench extensions...

Anyway, I did get some time last week to use this. To finish the gang tool holder, I needed to make up a 20mm adapter for holding the boring head.
I grabbed a bit silver steel and using my clarke lathe, turned a section to a bit under 20mm to fit the largest ER32 collet, then mounted it on the ER chuck on the 121, and using the various Mach wizards, machined a suitable end for the boring head to screw on to. The thread cutting worked well, and only took a couple tweaks to get the right depth of thread.
<pic removed>

Then for simplicity, put it back in the clarke and machined the thread undercut using the cut-off tool.

Next step is to bore the gang block to final size. I've done the grunt work on the milling machine, as the 121 just doesn't have the power to push a drill into steel, so just need to remove the last couple millimeter using the boring head in the 121.
I also need to figure out CSS, and tuning the spindle speed so the actual speed is nearer the set speed. I've tried the settings in Mach, however I suspect their lack of function may be something to so with the SS.

22-07-2012, 09:47 PM
I've had some more time over the past week while waiting on parts for various other jobs.

The gang tool holder has been bored using the boring head, and a few lines of G-code to semi-automate the process. Took about 40 minutes of repeated adjust, click start, and wander of do something for a few minutes while it cycled through the three holes.

<pic removed>

I've also machined two ER20 inserts for the tool holder, which put the lathe to good use.
I chopped a bit 1inch silver steel long enough to make two holders, drilled a 13mm hole through the center with the bigger lathe and done all the rest in the Conect.

Threading depth/profile is still more miss than hit, but I suspect that could be because the insert I'm using is a partial profile and it's possibly not got the right angled shim under it. It does the job however, and if I need to do more threading I'll invest in the proper inserts, and spend some time tweaking the threading numbers.

<pic removed>

I tried the new toolholder out with a 8mm drill in some alu, and it worked perfectly.
I now need to wait for some collet nuts to arrive, make another collet holder, and hunt down some stub drills in the required sizes so I can (hopefully) start making some money with it!

19-08-2012, 11:05 PM
The gang collet holder is finally finished!
I even made an extra holder.

<pic removed>

I'm surprised how well the Conect managed the threading. You can waste a minute or so of your life watching the threading video here (http://www.flickr.com/photos/mc_mtb/7818370534/in/photostream). For the silver steel, I've got to set a pretty low depth of cut to avoid spindle stall issues, so the collet thread ends up takng about 17 passes. Not ideal, but I don't plan on doing steel very often.

Details of the gang tool holder can now be found at http://www.machsupport.com/forum/index.php/topic,20153.msg154926.html#msg154926

01-04-2014, 12:44 AM
It's now for sale - http://www.mycncuk.com/forums/items-sale/7334-conect-121-cnc-lathe.html