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.

Category: Boxford 125 TCL.

CNC Lathe Toolpost Mill

Just a quickie to show you a progress photo of my current project.

It is a very small milling motor with a small ER collet, mounted onto the toolpost of my Boxford CNC lathe, which will convert the lathe from 2 to 3 axes.

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At this early stage the toolpost holder and cylindrical motor have been mounted to the water jet cut bracket on the right side.  Pulleys and drive belt yet to be fitted and I will trim the shaft at the left hand end of the motor.  Then the motor wires are connected to a speed and direction and on-off controller.

The usefulness of this tool is apparent in the following video of a completed unit in use.  The main spindle motor of the lathe is now a 750w AC servo motor, which can be controlled from Mach 3, to go to programmed positions and hold the position while a milling procedure takes place.  Of course the milling procedure will be with small cutters or drills, perhaps up to 3-4mm diameter.

The idea, plans, and some of the parts are courtesy of Stuart Tankard, my very clever friend, whose completed machine is the subject of the following video.

Stuart’s video is republished here with permission.  The original, with comments, is visible on YouTube.  If you have technical questions about the setup, I suggest that you contact Stuart via his YouTube post.

Another axis for the Boxford 125TCL

Watch the video of Stuart Tankard making tiny valve handles on his CNC lathe.  Changing the old Boxford spindle motor to a new generation servo motor allows him to use Mach3 to control the spindle to turn very slowly and to a set number of degrees, producing the very attractive handle cut-outs and rim dimples.  i.e. he has added the functionality of an indexing head to his CNC lathe.

It required adding a small milling head and motor to the toolpost.

I can see one of these on my Boxford 125TCL in the near future.

New Spindle Motor for the Boxford 125TCL CNC lathe.

Reader Ben asked about the spindle motor replacement on the Boxford.   This is a small CNC lathe, and was often used for teaching in secondary schools in Australia.  Mine was made in 1985, and I replaced the electronics a few years back because they were obsolete and not functioning.  The mechanicals of the lathe were beautifully made and in excellent condition.  I did replace the ball screws, but in retrospect, that was probably unnecessary.   I also installed new and bigger axis stepper motors.

I was still getting some unreliable results, despite the the upgrades, and wondered whether the spindle motor was lacking power.  I was taking lighter cuts to try and cope but clearly a new spindle motor was required.

The space that the motor occupies is fairly tight, and initial searches for a suitable replacement were fruitless.  The new  ClearPath motors looked promising, but enquiries to the manufacturer indicated that the required power and rpm’s were not available.  Then my expert friend (or should that be “friend who is an expert”?), spotted the Ebay ad below, and bought and succesfully installed the servo motor in his 125TCL, so I did likewise.  I am afraid that the electronic aspects remain a mystery to me, so I cannot help with those.  It is a 0.75kW motor, substantially more powerful than the original, but very compact.

 

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Do an Ebay search on the code on the controller.  I paid $AUD339 but it is now plus postage and GST, so close to $AUD400

 

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The new spindle motor and servo controller

 

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A new motor pulley was required.  There is still a high and low belt ratio available, but with the extra power and torque I never use the low ratio.  RPM range is 300-3200.

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This has been a very successful modification.

Many thanks to Stuart Tankard for his generosity in time, expertise and advice in getting it going.

 

 

 

 

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