johnsmachines

machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most.

Tag: CNC conversion

Boxford 125TCL CNC Upgrade

This small CNC lathe was converted from the original c1985 electronics, to components which are compatible with a PC running Windows XP and Mach3.

Reader Paul M asked about circuit diagrams.  I must confess that I do not have such.  Indeed, I would not understand them.  The electronic connections were made by my expert friend Stuart T.   I believe that Stuart intends to write up the conversion for one of the Australian magazines, and possibly this post might give him a gentle shove~.

In passing, I should give Stuart a thumbs up for his excellent CNC lathe program, which is far superior, in my opinion, than Mach3 for running the CNC lathe.  It is called Ezilathe and is available as a free download.

Anyway Paul, here are the promised photographs of the electronic components of the Boxford, after the conversion.  You should be able to work out many of the connections by zooming in.

 

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The Boxford 125TCL sitting on a bought trolley which could have been made to measure.  The PC is on the bottom shelf, the extra toolholders and tools in the drawers, the wireless MPG on the front, and upgraded stepper motors in black.

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The rear view to show the extra power outlets to supply the screen and PC.  I still operate this lathe in a spare bedroom of my house.  Very handy if I have a sleepless night.  It is so quiet that it does not disturb SWMBO.

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The view with the back open.  The only components from the original setup are the spindle motor, the main switch, and the Gemini controller (RHS with orange cover).

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Power outlets, main switch and power supply.

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Transformer.  Can’t remember what the Fotek is for.

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Gemini with cover removed.

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C11 R9 Breakout board, the optical indexer (top), and Gecko stepper drivers (LHS), parallel cable from the PC,  all mounted on an aluminium plate.

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Spindle motor, original.  But now considering upgrading to a more powerful motor.

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new cable junction box for the stepper cables.

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New cooling fan, top LHS

So, I hope that these shots are some use.  If you do not recognise the components, I suggest that you follow my example and bribe an expert friend to do the connections.

BOXFORD CNC LATHE (3)

Some more photos of the Boxford, after the conversion.  Sounds like the Damascus Road doesn’t it.  Going CNC is almost an epiphany.

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This is the wireless MPG controller.  The lathe can be controlled from across the room, using the MPG and the wireless mouse and keyboard.  The MPG even has an Estop kill button, along with the one on the lathe.

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The new setup.  Normally the keyboard and mouse sit under the screen to avoid swarf.  Note the multitude of LED and halogen lights.  I need those these days.

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The old Dell sits underneath, along with other bits and pieces.  The trolley has been very useful, as the lathe is progressively expelled from different rooms by SWMBO.

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One drawer of tool holders, collets, inserts etc.  The other drawer is not so tidy.

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The Dickson toolpost, and Diamond tangential tool.

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The ER32 collet chuck.  Much more accurate than the Burnerd 3 jaw chuck.  The mounting plate and backing plate were made by me to a design by Stuart Tankard.

If this conversion is of interest to you, look out for a technical description of the process in an article by Stuart Tankard to be published next year in Australian Model Engineer.

BOXFORD CNC LATHE (2)

This is the list of components and prices (AUD 2013) which was required to update the electronics so the Boxford 125 TCL would run on Mach3 and Windows.

Breakout board  C11  $129

Index pulse board  C3  $26

Gecko stepper drivers G251  $68 x2

Relays, relay bases, parallel port cable, Estop button   ~$80

Power supply  $30

Wireless MPG   from China  Ebay  $129

Heat sinks and adhesive   $20

Other cables, connectors, power sockets  ~$100

PC (an old Dell, running XP Pro, perfectly adequate for Mach 3)   free

Flat screen     free,  wireless keyboard and mouse  free.

Support arm for Screen  $60

Trolley  $200

It all adds up to $AUD910.   Plus the original $1500 for the lathe.  That is pretty inexpensive for a quality CNC lathe.  I am told that the Boxford retailed for about $30,000 in 1985!

Some before and after photos of the conversion…

 

 

 

 

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The back of the lathe opened, showing the old electricals  The spindle motor is top right.

 

The electricals after the conversion.

The electricals after the conversion.  Some of the old components were retained.  The lights are on the breakout board. 

BOXFORD CNC LATHE

About 3 years ago I decided that I wanted to see what CNC was about.  I had read some beginners guides to CNC, and CNC programming, but it was obvious that I would need to buy a CNC machine and actually start machining if I was to make any real progress.

Initially I bought a second hand lathe which had been converted to CNC.  It was a Seig C3, and stepper motors had been installed on the lead screw and cross slide screw.  Some low end electronics connected to a PC, and the setup was controlled with Mach3.

Needless to say, this machine gave poor results.  Poor finish, and poor reproducibility of dimensions.  The lathe was low quality to start with, and the CNC components were low end.  I was inclined to blame the lack of ball screws, but in retrospect, that was only one of the many problems.  It did however give me a taste of the process of CNC programming, and finishing with a CNC turned item.  I also developed some familiarity with Mach 3, and became a licensed user of the excellent software.

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Seig C3 converted to CNC. Not up to scratch.

 

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Then I saw a Boxford CNC lathe, owned by a friend in my engineering club (GSMEE).  It was 30 years old, and had started life as a technical school teaching lathe.  The original electronics and operating system were based on a CPM computer, pre-dating Windows, even pre-dating DOS.  It ran on software which was loaded each session from a 5.25″ floppy disk, with a capacity of 180 kilobytes.

My friend had changed the operating system to  Windows and Mach 3.  That involved changing many of the electronic components in the lathe, and hooking up a PC.

The lathe was an English Boxford TCL 125.  The swing is only 125mm (62.5mm above the bed), and the maximum length which can be machined is also 125mm. The spindle is belt driven, and spindle speeds range up to 3000 rpm.  The tool post is a very nice quick change Dickson.  The spindle bore is 19mm.  The whole machine has a quality appearance and feel.   My friend was producing work with fine finishes, and consistent dimensions.

It was clearly a quality lathe, and I asked him if he was willing to sell.  The answer, not surprisingly, was no.  However, he did know of an identical machine which might be for sale.  To get on with this story, I did buy the second machine.  It had also been a training lathe in a technical school, and was 30 years old.  It was not running, but the owner said that it had been in use until recently.  Since I planned to replace most of the electronics I was not too concerned that it was not working.  My friend, Stuart, had indicated a willingness to manage the upgrade-conversion, which was just as well, because it really did require a level of expertise with electronics which I do not possess.  Stuart had been through the process, knew exactly what was required, and is indeed, an expert.

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Boxford 125 TCL.  The yellow item is the tailstock which swings up into position. 80mm Pratt Burnerd chuck.  The control panel lower right was removed and replaced with a wireless pendant control.

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It cost $AUD1500, which was a bit much, but the seller probably realised that I really wanted it, and priced it accordingly.  I took the lathe, and the computer, and the 5.25″ floppy drive, and 6 tool holders home.  I immediately put the computer and floppy drive on Ebay, and amazingly they sold for $AUD150 (to a  collector of obsolete computers I presume).

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This old CPM computer with a tiny memory originally ran the Boxford CNC lathe.

We collected the various new electronic components over the next few weeks.  I will list the components in the next post for your interest.  Total cost of these was approximately $AUD800.

Under Stuart’s direction I removed the obsolete electronics, then in two half day sessions he installed the new ones. After some adjustments in the electronics, and in Mach 3, it was up and running.

In the subsequent 2-3 years I have replaced the ball screws (probably unnecessarily), and increased the number of tool holders to 30, and installed an ER32 collet chuck, and soft jaws on the 3 jaw Pratt Burnerd.

I have made many items and become increasingly comfortable with Mach3.  I also use a very useful program called Ezilathe, which I will describe in a later post.