Member postings for Leonard Newton 1

Hi all a carry on email from my last one almost a year ago, I have both axis operational and have carried out some machining of parts but still had problems with the spindle motor and the Gemini drive. So decided to remove this and fit a 240v ac motor and a VFD drive this gives me soft start variable speeds in forward and reverse and the options for jog etc in fact I find this a better control unit.

I carried out this conversion back in the summer and had to move the motor further towards the rear this was carried out by cutting the side casing welds and opening the motor mount cut out to enable a larger diameter one to fit and be fully adjustable, re weld the side casing back on, the motor I had spare one was brand new from a wood lathe the variable frequency drive was from memory about £80.00 a new drive belt, a fairly cheap conversion that works well.

Len.

Hi everyone just a question for you, I have my Boxford TCL125 up and running the only problem is this Gemini spindle controller board seems to be playing up now.

I switched the machine on a few days ago and it clunked as normal a few times but then the spindle went to full speed so had to shut down, now when I start the spindle it just goes up to max revs which is not normal.

I removed the 0-10v wire from my breakout board to pin 2 on the Gemini and still the motor runs away I’ve checked the voltage on pin2 and it’s 10v to 10.8v it’s almost as if pin 2 is being fed from somewhere in the board, has anyone come across this before?

Is there a company that repair these boards or is there a motor and controller I could fit, I’ve seen 3phase motors with a vfd does anyone know of the size and power required.

Len.

Edited By Leonard Newton 1 on 18/01/2021 12:25:21

Just a question to all Mach3 users, how do you set up the actual spindle speed to match the speed you enter, I have on my Boxford an optical sensor and has an index pulse and a 100 pulse per rev, and have set up the Bob with pin 12 for index and pin 13 for timing.

Is there an easy set up for this.

Len.

Hi everyone just another update, this morning I carried out tests on my as I thought damaged Gemini board, removed the variable resistor from the front panel and connected it to the board as per Graham’s diagram and guess what the motor started with full power as before, but on this occasion I was at the rear of the machine and could see was happening, there was a growling noise and I could see arcing from the rear of the spindle motor so I turned the resistor down and the motor slowed down so the board is ok.

I turned the max speed adjustment pot on the right of the board now the motor works up and down through its full range, now all I need to do is to get my breakout board to vary the voltage I presume this can be done using a voltmeter in dc voltage between pins 0-10 and ground?

Len.

Hi Michael, yes I have the X and Y working ok inc the steps per revolution in Mach3 it’s so easy and seems very accurate, the spindle drive is a bit of a problem Graham has been a great help on my first ever go at CNC machines.

I have the forward and reverse controller to operate but the speed is a problem, the Gemini speed controller is tripping out within 5 or 6 seconds after it receives the 0-10v signal from the breakout board, I have disconnected the motor then the spindle controller but the problem is still there.The motor did run in the beginning but at full speed and there seemed to be a clunking as if it was being switched on and off very quickly, so more investigation required.

Len.

Martin I toggled when on Mach turn and yes up came soft limits, many thanks again.

Len.

Thanks for that, I’m hopefully using a parallel port to switch the motor from forward to reverse and variable dc voltage to the spindle controller and use the on board speed sensor to send a signal to Mach3.

Well that’s the theory I just hope it works in practice, that remote keyboard is very interesting but I’m not very keen on wireless controls, I think I’m over cautious with these machines.

Len.

Just a quick update to my last post, I have at last got the soft limits to work the problem was that when I pressed the page up and down arrows it moved my z axis which is ok for a milling machine but on a lathe it moves the carriage to the left and right, so I went into config and system hotkeys and set up my keyboard accordingly now it works on the up and down, left and right arrow keys it now makes sense.

Len.

Hi Martin the answers to your questions are the Boxford has a z switch fitted as standard Which I have wired to my breakout board, there are switches everywhere on this machine two on the Perspex cover and hinges the rear and side covers etc, I think because it was designed as an educational machine they went over board to stop little fingers fiddling.

I have not set x and z yet but it seems that you don’t need limit switches to set up soft limits as long as the machine is not moved manually when the Mach3 program is switched off, I have tried setting the the z axis to - and the x axis to + so the chuck end and up as my zeros and then putting in the travel for each axis as 100.00mm but I keep getting out of limits, there seems to be a difference between Mach3 lathe and Mach3 turn, which is best? as the Mach3 turn doesn’t seem to have a soft limit button and the Mach3 lathe uses the page up and page down keys instead of the up and down arrows, if you set one up the axis go a different way on the other, it’s probably me but do you initially set up the lathe or the turn versions?

And I haven’t got the spindle moving yet.

Len.

I thought I would give you all an update on my Boxford 125TCL I actually looked through loads of specifications on motors, drivers and power supplies and thought I would look on eBay and found an easy option, a bundle with two stepper motors, drivers and a power supply, I already have a Mach3 breakout board.

They were Nema 23 type with a 270oz rating the higher powered ones had a longer body length particularly for the x axis, I removed the old microprocessor and stepper boards inc a large capacitor and the associated wiring, fitted the replacement motors etc and after a lot of fiddling about got it to run on Mach3 demo. I have wired up the z stop micro switch n/c so there is no chance of running the tool into the chuck, I’m using Mach3 Turn but I don’t seem to be able to set up the soft limits, any help would be appreciated.

The motors seem to have plenty of power although I haven’t started to cut anything yet, with the help of Graham with his advice and a wiring diagram I’m hopefully wiring in a double relay to enable the motor to run forward and reverse, I’m still waiting for this item at the moment. This has been an interesting project for me as a novice and great to get the steppers controlled by a computer, I know I haven’t finished yet but thanks to you all for your help and encouragement.

Len.

Hi just an update I’ve just ordered a pair of stepper drivers and motors and a power supply, I see from the circuit diagram that the original steppers are an 8 wire configuration with 4wires from the stepper driver board and the other 4 wires paired and then supplied with a 24v through six resistors three for each phase.

so rather than risk blowing up my drivers I will fit the new ones, they are 4wire bipolar, the only thing that concerns me is that once I remove the stepper driver board and the microprocessor board I see that the spindle indexing and the forward and reverse for the spindle will no longer work, is there an off the shelf controller for this?

Thank you Graham for the board diagram but I’m not as I said an electronic wiz kid and building a board from scratch is beyond me so would like advice from you guys.

Len.

Edited By Leonard Newton 1 on 12/04/2020 18:33:09

Thanks as well as well to Michael and yes my board is identical to the one you have sent in a picture of, it’s tucked under the stepper motor drivers.

I would attach some photos but I can’t seem to transfer them from my album.

Len.

Thanks everyone for your help and yes Graham I’ve had to replace the two capacitors in the Gemini controller several years ago, after a loud bang and smoke I thought that sounds expensive, but thankfully just replacement parts and a bit of soldering.

So perhaps I will work out stepper motor sizes and go from there, and after getting it going again yesterday in manual mode the motor starts and the variable speed works but only one way for some reason, the reversing relay is not working, more to have a look at, so any diagrams would be helpful.

Len.

I have Just looked on line at the 2 axis nema 34 stepper motor kits which includes a pair of motors, drivers, and power supplies a breakout board and a what looks like a 25 pin lead for almost £200.00 ( 24vto 80v kit ) any comments welcome.

Len.

Thanks Neil and Dave for your reply’s, as you say it’s not an easy fix and it may pay me to replace the power supply and controller boards but where do I stop with old stepper motors as well?

Len.

Hi Nick thanks for the prompt reply, it is definitely a 1MHz bus as this is the 34 pin break out board attached I need it’s the connections between this and Mach 3 interface

Len.

Hi all, I’m new to this so I apologise if this has been discussed before, because myself and no doubt many of you are staying at home and keeping safe.

My question is with ref to a Boxford 125 TCL has Which I’ve had for years and thought I would have a go at getting running, the machine does work in manual mode and it is in a standard form with a gray ribbon coming out of the side of the casing.

I have no computer with it but I have an IDC34 breakout board and a Mach3 interface board and an old tower computer with a 25 pin connector on the rear I think you call it an LP25.

I have in the past had a go at trying to get it running with a Mach3 program but nothing seems to be working perhaps someone has figured out the wiring and I would appreciate any help.

many thanks Len.