Adding stepper motors to a Myford VMB manual milling machine

Myford VMB Manual Mill Conversion to Stepper Motor control

After many years of winding the Z axis up and down on my Myford VMB I have finally got around to fitting motor control and it is a joy to use.   I am however suffering from muscle wastage as a result.

stepper motor control of a VMB manual milling machine
A general view of the stepper motor control conversion of a VMB manual milling machine. Only the X and Z axis are completed so far. The control box is on the wall behind the mill and has the Shumatech DRO control panel mounted on the front panel.

I have done a write up for those who might want to also enjoy a less taxing movement of X, Y or Z axis on their manual milling machine.  Click on the link below to download as a pdf.

 Fitting XYZ motor feeds to Myford VMB v4

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Clough42 Electronic Leadscrew Project Implementation Notes

I have been avidly watching Clough42 on YouTube.  James comes over as a really nice guy and his presentation of his projects is excellent.

My principle interest is the Electronic Leadscrew modification to lathes.  When installed this removes all the hassle of gearboxes and look up tables to be able to cut both Imperial and Metric screw threads and to set X axis movement feed rates.

The concept is simple but his implementation is second to none.  A rotary encoder is fitted to the spindle to count revolutions of the chuck and a stepper motor (or servo hybrid) controls the rotation of the leadscrew.  The resulting feed speed is derived from look up tables.  The whole installation is controlled by a Texas Instruments LaunchPad C2000 microcontroller development board.

I have documented how I implemented this on my Myford Super 7 Big Bore lathe and the pdf can be downloaded below.   There is also a ZIP file of all the Fusion related models for either CNC or 3D printing.

Electronic Leadscrew on Myford Super 7

Minor edits added to v3 relating to programming the servo controller

Electronic Leadscrew on Myford Super 7 v3

Electronic Leadscrew Fusion 360 Files

Update : –

Painted control panel for Clough42 Electronic Leadscrew
Finally got the Clough42 Electronic Leadscrew control panel box painted and rather pleased with the result.

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3D Printed ESAB Warrior Tech Helmet Hinge Latch Plate

My TIG welding frustration suffered more than usual the other day . 

I have an ESAB Warrior Tech helmet which works really well when welding but it would not stay flipped up when I wanted to see things in daylight.   Every time I leaned forward the helmet would drop down over my eyes and thump me on the chest.  Added to the fact I was trying to TIG some thin wall tubing I was no in no mood for distractions.

Before the helmet joined the happy hunting ground over the neighbours fence I took it apart to see why the latch up action was not working.   Inspection revealed that the backing plate had cracked around the latching cam.

I could have bought a completely new head band assembly but the part in question might just be 3D printable.   The Fusion 360 sketch ended up being very complicated based on eyeball guesses on curves and centres but on the second version I had a printed replacement which did the job …. for the time being anyway.

3D printed ESAB Warrior Tech latch plate replacement
The final version of the replacement plate for the ESAB Warrior Tech welding helmet latch.

If anyone is suffering from a bruised chest let me know and I will forward the Fusion file.

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Probes and Haimer Taster Modification

I have been using a Wildhorse Innovation CNC set up probe for some time now.  It works OK but sometimes the results are not consistent.   After one frustration session I decided to upgrade it to the Hallmark ITTP probe from Threadexpress in New Zealand.  

It arrived today after nearly a month in transit due to the current lock down restrictions.  On opening the package I was impressed with the quality of the engineering.  It is a nice device.  It uses the usual 3 pronged contact mechanism.   Supplied with the probe is a tube of grease that helps protect the contact reliability.  The interface cable has a 5 pin DIN that plugs into the Tormach expansion socket and the shank is a standard TTS compatible size.

hallmark ittp cnc probe mounted on the tormach pcnc440
The Hallmark ITTP probe mounted in the Tormach ready for setup and testing.  You can also see my angel ring light illuminator and Hall Effect tool height setter.

I ran through the initial preparatory procedure and then loaded it into the Tormach 440 spindle.   Pathpilot has a number of excellent set up routines to adjust the probe and make measurements.  One of these, the Effective Tip Diameter is quite critical.  All this went to plan and very quickly.  Some initial probing gave repeatable and accurate results so first impressions are good.  

Some of the Tormach PathPilot CNC probing routines
PathPilot probe setup screen and the two probing routine screens.

I’ll give some updates as the probe gets pressed into service but my first impressions are good with repeatable accurate readings.  

In the course of checking out the ITTP probe I needed a reference cross check on the various setup measurements.   My Haimer Taster seemed a bit erratic and on inspection I discovered the axial shank holding bolt had worked lose.  This meant a re-calibration of the eccentricity of the probe point would be needed.  

The alignment process involves adjustment of four grub screws in the shank body.  These tweak the ’tilt’ of the shank to get a concentric rotation of the probe ball point.   As there are four screws I use two hex Allen keys to make the adjustments to each in line pair.  This is quicker than with a single hex key being swapped from side to side.  It is a bit like the process I use when centring a 4 jaw chuck. The adjustment is done against a dial gauge riding against the probe ball point.   Once you get the knack this process doesn’t usually take too long using the two key method.   

The frustration is that the Allen keys provided with the Haimer are a bit chocolate based and the ends chew up easily.  The result is you tighten a grub screw and the hex key end twists and gets jammed into the hex socket in the grub screw.   While trying to waggle the jammed key you mess up your carefully made adjustment.  Aaaargh !

I ground back the worn end of the Allen keys to clean up the hex profile but they quickly degraded.   In the end I took the grub screws out completely and replaced them with some M4 cap head bolts.   Joyful !

adjusting screw change on Haimer Taster concentricity adjustment
How ugly is this ? Replacement screws on my Haimer Taster

Yes I know it doesn’t look pretty but it is now a real pleasure to make the adjustments with a couple of larger T wrenches.  It is probably a criminal thing to do to such a lovely instrument but life is too short.

Next job will be to modify the arrangement of my tool sharing junction box on the Tormach expansion port so my Hall Effect tool height setter and the ITTP can share the input.

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Micro USB with 5 core cable

Lots of activity to be documented and posted but let’s start off with a short note.  Not earth shattering but might help someone somewhere.

I had the bright idea of using Micro USBs as a connecting medium on a couple of projects.  This was driven by the need for a 5 wire connection.   The design was finished and I dug out the Micro USB to Micro USB cable that had been bought in for the project and connected things together.   All the LEDs went out on my project circuit board.  Gloom.

After buzzing the cable through I found that on a standard Micro USB cable the Sense pin is linked to the Ground pin.   There are not 5 independent and isolated cores as you would expect.  Just four. What to do ?

By chance I had some Micro USB connector ends with solder tabs but no shells.   I did not have any flexible small diameter cable with 5 cores.  After some discussions with my other half she offered to plait 5 independent cables together for me as a cable form.   These were soldered to the Micro USB ends.  Two small end caps were quickly designed in Fusion 360 and took 10 minutes to print on the 3D printer. Job complete and project back up and running.

custom micro usb with 5 core cable
Custom Micro USB 5 core cable components showing solder terminal end connectors, 3D printed shell and plaited 5 core cable courtesy of my wife.

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