Tormach PCNC440 Fogbuster and Manual Oiler Service

Back from after a few weeks in France and back in the workshop.

Every now and then there is a project that is on the go and you can’t sit down and focus on it.  It is a sort of mechanical procrastination.   A reluctance to put the first pencil mark on the paper.   You then suddenly find all sorts of other things that you kid yourself are more important / higher priority and you get distracted.   You know that job will still be there but maybe tomorrow, not   today.   You suddenly develop a clear conscience about doing something else while you do some background thinking ….

This particular day started off by cleaning down the accumulated swarf (chips) in the 440 tray.  Really important job.  This led to a check behind the various 440 slideway bellows to see that all was well with the oiling mechanism on the slideways and the ballscrews.   X and Y were fine but Z was dry.  Not good news.   

The 440 is supplied with a manual oiler as standard.   This is a reservoir of oil and a pump/plunger which you pull out and release to initiate a slow pressure to the oil distribution pipes. 

Tormach manual oiler reservoir
View of the manual oiler mounted on the Tormach 440

 I checked the plunger and it didn’t feel like it was applying much pressure.   This is not the first time I have experienced this problem.   If I pumped a few times it felt better so something should have been happening at the oiling points on the Z.   I disconnected each of these where I could  and sure enough if I pumped hard enough some oil dribbled out but not with much pressure.   Something probably not right with the plunger ?

Squeezing round the back of the mill I removed the top of the reservoir (4 retaining screws), disconnected the oil pipe union and lifted the plunger clear.  The reservoir can be left in place sitting on the mounting bracket. 

There is a large end cap at the union end of the plunger cylinder which I removed and sure enough I could see a mangled O ring.   To get the plunger out you have to be a bit brutal.   You pull the T handle plunger back out of its housing against its spring using the handle as shown above and then grip the shaft with pliers so you can then twist the handle off.   What you don’t do then is suddenly release the pliers grip or the plunger will go into low Earth orbit under the pressure of its spring …

Having disassembled the plunger it was obvious that the O ring had failed quite badly.   Tormach support do not offer spares as the oiler is a third party item.  They do not know what size the O ring should be.   Checking in my box of miscellaneous O rings it looked like a 9mm ID, 3mm thickness part would do the trick.   Smearing the O ring with DC4 silicon grease allowed easy re-assembly into the piston bore and then back onto the 440.  I now had lots of pressure and oil was apparent trickling down the Z slideways and ball screws.  Job done.   No pumping needed, just one pull out of the piston handle was generating a slow release of oil to the key areas.

The job I should have been doing was still sat on the bench glaring at me but psychologically I was doing something more important.

Next problem was the Fogbuster air activation valve.  Under CNC control this reliably switched on but sometimes would not switch off when commanded to.  There are various forum discussions on this problem and many contributors just replace the solenoid valve with a different version.   Forum chat also recommended that electrical transient snubbers are fitted across various inductive loads in the Tormach control unit.   I had some of these in my stock box (Tormach offer a kit for this).   They are simply a series resistor and capacitor in an epoxy block.   They are fitted across any inductive device to suppress switching transients.   I dived into the control box and fitted one across the controller relay coil that switches the Fogbuster ON and OFF and another one across the outlet from the control box feeding the Fogbuster solenoid coil.   See picture below.

snubber inside tormach cabinet
Snubber across Fogbuster activation relay coil.  There is a second snubber fitted to the lower LHS contact which activates the air solenoid.   The other end of this snubber goes to the any ‘100’ connection which is mains neutral.

The problem seemed to be improved but still occasionally the solenoid did not switch OFF.

The Fogbuster solenoid has a clear housing over the activation coil connections and there is a LED inside this that comes on when the Fogbuster is switched on.   

Fogbuster activation solenoid
Fogbuster solenoid assembly showing the connection clear housing which plugs into the solenoid coil which in turn sits over the activating plunger assembly.  There is a screw in the LHS to release the electrical connection and the nut on the top releases the coil to reveal the plunger housing.

This connection housing plugs into the coil and the mechanics of the solenoid body and is released with a screw in the end.   Toggling the coolant ON and OFF via the PathPilot user interface I could see the LED responding correctly to the ON and OFF commands but occasionally the solenoid was not closing.   It was therefore not an electrical problem but mechanical.

On top of the solenoid housing is a single large nut which when released allows the solenoid coil to be lifted off.   This leaves two countersink screws which hold the mechanical plunger housing in place and if these are removed the plunger can be gently removed.   Inside the valve is very simple.   A central hole allows the air to pass through and when the solenoid is de-energised a spring forces the solenoid plunger to seal this hole.   I gave everything a thorough blast with compressed air and re-assembled it.   Care is needed re-assembling as there is a tiny O ring seal on the plunger cover.   The solenoid now responds correctly to the PathPilot commands.

Another tick.  Job done.  Warm glow.

That other job is still sat on the bench glaring at me ….

Similar or related subjects : –

Editing the PathPilot Tool Table with Conversational machining codes

Introduction

Tormach’s PathPilot CNC control software offers a Tool Table facility that will accept up to 1000 different tool entries.   This is more than enough tools for the small machine shop and if fully populated would represent a small fortune in tools and collet investment.

In PathPilot when you go to the Offsets tab to edit a tool, the following dialogue box comes up (sorry about the quality of the image ..) suggesting that you can be quite clever with the descriptions of your tools. 

tormach tool table intelligent codes for conversational milling

How you describe the tool helps local machining settings such as Conversational routines.  It has no impact if you are loading an externally created GCode from CAD/CAM packages such as Fusion 360.

When I first started using PathPilot I had never bothered to add this intelligence when I described the tool. I simply wrote something that meant something to me.  As time has passed and I have added more and more tools, the prospect of going back into the Tool Table and making edits to conform to these intelligent descriptions did not seem like a glamorous prospect, even for a rainy day job.

Tormach Changes

What has changed is that in the latest versions of PathPilot, Tormach has added a search routine for the tool table.  This depends for its success in finding what you are searching for on the consistency of entries in each line description.   

There is now an incentive to have a ‘rainy day’ session and clean up the table entries.

See Mill-tool-table-editor  to download a folder containing the description of how to do this and also the Excel file used to manipulate the data.

Similar or related subjects : –

Wildhorse Innovations Passive Probe

I bought one of the Wildhorse Innovations Passive Probes some time ago and it gets used occasionally (usually when I have dispatched another Haimer tip to happier hunting grounds).

wildhorse innovations passive probe
The Passive Probe as supplied by Wildhorse Innovations

The Wildhorse design is nice and simple and it can be bought with a ‘Tormach Option’ which is a cable with a ready fitted 5 pin DIN that is pre-wired to plug straight into the Tormach 440 accessories socket.   I have to say it did not talk to the Tormach PathPilot interface immediately.  I had to snipped the pull up resistor inside the unit to solve this.  When in use on the Tormach you have to designate the probe as Tool 99 in the tool table so as to be able to utilise the PathPilot probing routines (which are very good).

So where is all this going ?  Well it is a A to B to C progression …

I dusted the probe off to use the other day and as I had not used it for some time, I did a centring calibration of the probe ball point while mounted  in the Tormach spindle.   This is a real pain to do as the three centralising adjustment screws are on the bottom face of the body.  As a result you can’t see what you are doing and there is a danger of knocking your dial gauge in the process and having to start again.

This got me thinking about whether I could do this adjustment off line in the lathe.  This way the adjustment screws on the bottom face are readily accessible.   This seemed like a good idea except the umbilical cable is permanently wired into the unit so it needed to be protected from a disastrous wrap round the chuck.  Initially I wrapped the cable around the body of the probe and held it there with masking tape but it wasn’t ideal.

Watching the probe spin in the lathe chuck made me also realise that because I had mounted the probe in a Tormach TTS collet this was a waste of a collet. It might also be adding to eccentricity through using such a combination. So you see that one thing leads to another and to another.   A workshop wormhole.

A plan was made.  Fit a connector on the probe body to allow the cable to be disconnected and replace the existing mounting rod with a TTS equivalent.

Finding a suitable connector was a bit more tricky than expected in that there is not a lot of room inside the probe body and a connector that protruded too far would foul the spring loaded mechanics.   My search for a suitable connector combination Iead me to a 2 pin Binder rear mounted socket (Part Number 09 0074 00 02).  Being pedantic it should be a fixed plug as the connecting cable connector (Part Number 99-0071-100-02) would now have two exposed pins carrying a voltage.   The supplier only had the fixed socket version in stock so I conveniently looked the other way on that argument – the cable would rarely be unplugged so not likely to be a problem …

The circular body of the Wildhorse Probe is quite substantial.  When the connector arrived and I was ready to proceed, I took a picture of the existing wiring and then snipped the cable clear.  I enlarged the hole in the body wall to 9mm but then discovered that the mounting thread on the connector was not long enough protrude through the probe body wall far enough to pick up on the retaining nut.   To overcome this I milled a flat area on the shell outer surface.  The two connecting wires where then soldered in place on the fixed connector and then on the mating male connector on the free end of the cable.

wildhorse innovations passive probe internal view
Internal view of the probe after the Binder socket had been fitted

The next job was to make the new fixing rod.   I always try to have 19mm silver steel available in my stock box.  This matches the TTS collet outside diameter.  I decided I would make a new mounting rod with the silver steel and I would increase the threaded mounting hole on the probe top to M8 from the 1/4″ size as supplied .

wildhorse innovations probe top with new M8 mounting
Top cover of the probe inside view of the M8 inside the spring retaining counterbore

The larger diameter would provide a larger shoulder on the rod to tighten against the probe top. Using M8  would allow the stud mounting hole to still sit within the pocket that retains the pressure spring.   The rod was faced and turned to 8mm for 5mm or so and the M8 thread cut and undercut with a graver.   The other end of the rod was faced and then a 45 degree chamfer turned on it. The finished rod screwed nicely into the top plate and the body now seemed to run solidly square to the central axis.

Wildhorse innovations probe new mounting rod and body top cover
The new 19mm OD silver steel mounting rod and the outside surface of the top cover to which it is fitted.
Modified Wildhorse passive probe
Finished modified probe showing connectors fitted with the flat milled surface and the new mounting rod.

All operations were now complete and I mounted probe with its cable unplugged in the lather chuck with the new 19mm rod.  I mounted my dial gauge on the lathe bed and set about centralising the probe ball.  It was so much easier in the lathe with no cable to get in the way of things. Transferring the modified probe to the Tormach afterwards gave very similar centralising results.

Centralising the modified Wildhorse Innovations passive probe
Modified probe mounted in the lathe to allow easier access to the three centralising screws

So a typical workshop wormhole progression from job to job but as ever it was time well spent.

Similar or related subjects : –

Machining a job that is outside a milling machine’s table travel using Fusion 360

Introduction

This write up is not for the purists with years of experience but is an explanation of how I thought through how to machine something over size that would not fit into my Tormach PCNC440 milling footprint as a single operation.  Hopefully it might help others to grasp the process.

The challenge began when a local turret clock expert came to me and asked if I could machine a new Hour and Minute Hand for a clock he was working on.   The Hour Hand was around 14” long and the Minute Hand some 18” long.   

Here is the Fusion 360 view of the minute Hand.

clock minute hand milled in three steps

Clearly these lengths were way outside the 440 table X movement (10”) so a plan was needed.  There then followed a lot of staring into the distance at mealtimes and also at bedtime accompanied by vocal “hmmm”s as I tried to mentally visualise what was needed.  This idiosyncrasy is something my wife has come to terms with over the years…..

My conclusion from this mental preparation was that I needed to be able to accurately step the stock across the tooling table and then take two or three bites at the profile machining.  

What follows would almost certainly benefit from a video but sadly I am not set up for this. 

Click the link below to download the PDF document.

Milling an oversize object

Similar or related subjects : –

Automated Wheel Cutting GCode for the Tormach with the Sherline CNC Rotary Table

I have been putting this off as I thought it would be hassle and in fact it was very simple.

Here is the code which is the first time I have ever used a sub-routine.

The top section is my standard set up routine for the Tormach.

The middle section has some out of the way locations to try the idea so don’t get too fixated by these.   The important bit is the M98 call for the sub routine, the sub routine name (1001) and the number of repeats (the L5 for five repeats).

The last section is the sub routine indicated by the O1001.   The M64 command is specific to the Tormach USB Expansion board and it makes relay P0 in the box close its contact which in turn activates the Sherline CNC Rotary table to move one step.   The cutter than moves across to cut the tooth and then returns whereupon the relay drops out (M65), waits and then closes once more to increment the table.   Once five repeats have happened the M99 closes the sub routine and the program jumps back to the Z10 line in the middle section before stopping the spindle, homing and ending.

The joy of this method is that it is a simple edit of one line (the M98  instruction) to change the number of tooth cutting increments. I like it a lot.

Some fine tuning is still needed on the back and forth distances needed to clear the cutter through the wheel blank.

The normal test of the cut depth routine will still be needed before this could be run but once this is done it should be a sit and watch job.   Hopefully.

I have yet to run a wheel in anger so I will let you know how it goes. 

A compiled write up of all the related blog entries on this subject can be found on the downloads page.

Similar or related subjects : –