One of my favourite additions to the workshop has been a laser centring tool for use on my Tormach PCNC milling machine. The tool consists of a low cost laser diode mounted on a 3D printed disc and with a 19mm steel shaft. The tool is held in the Tormach spindle power drawbar. The laser is angled inwards towards the spindle axis at approximately 20 degrees. The 3D print has facilities for a battery supply and ON/OFF switch such that when the laser disc is pulled into the power tool bar collet it switches on the diode.
In use, as the spindle is raised or lowered, the rotating diode creates a circle of light on the milling table which can be used to locate and centre the spindle on features of the item being machined. This might be to locate the centre of a hole or the centre of a block depending on need.
I recently had the need to use my four jaw centring chuck on my Myford lathe. Usually I duck and dive to avoid having to use the 4 jaw as I find it frustrating to set up. This recent bout of frustration lead me to wonder if I could adapt my laser centring tool for use on the lathe such that it would give me a guide ring of light to show where the material was sitting relative to chuck centre.
On the milling version the laser rotates and the job stays fixed. On a lathe version this would be similar. The chuck would be stationary and the laser would rotate in the tailstock.
My wife has the knack of finding some interesting and diverse places to visit for birthday treats. We have just returned from an overnight stay at No Man’s Fort which sits in the Solent between Portsmouth and the Isle of Wight.
The Fort along with three others were constructed in the late 1800s to protect Portsmouth from the French fleet. Like our modern day government projects they overran their construction target date and budget and by the time they were finished so were the French navy. There is plenty to read about them on the Net.
The reason for this mention is the resulting respect and admiration I now have for the engineers that put these fortifications in place. You arrive by shuttle boat at the landing stage faced with a circular wall of stone blocks that are precisely cut and interfaced together and show no sign of cracking or movement. The whole construction has no deep pile foundations but simply sits on the sea bed. They had no laser positioning equipment, no JCB equivalents, no CAD. Yet here these structures sit after 150 years in the most hostile of environments and look non the worse for wear. Impressive.
If you get the chance to visit any of the Solent Forts either for afternoon tea or an overnight stay you should go and you will not fail to be impressed.
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.
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.
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.
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 ….
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.
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.
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.
I am quite anal in needing to have a tidy workshop with everything having a place where I can find it easily. It is a kind of insurance policy to perhaps give me a bit longer time in the workshop before I lose the plot altogether. (The less palatable advantage is the dealer who comes in to clear my workshop when I am in turn in ‘a box’ can easily see what a treasure trove he has stumbled on. We’ll move swiftly on from that thought).
To this end I have settled on using 5 Litre storage boxes for all my ‘stuff’ (technical term as defined by my long suffering wife). These are readily available in the UK at Dunelm and on the net. They are made from a very durable plastic and supplied with a lid which is rarely useful for my application. I believe they are principally intended for ladies to store their shoes. I suppose we could call them Marcos boxes ?
The boxes have a 6.5″x 12″ footprint and are 4″ deep. It is surprising just how much workshop kit can be stored in these (and of course nicely labelled). The 12″ is just not long enough for 13″ silver steel but a little hang over can be tolerated for such useful material.
I have accumulated a reasonable (by my standard) set of Tormach TTS tooling collets with my preferred tools permanently fitted. These are each numbered to match my tool table entries in PathPilot. The numbering is done using an Edding 750 white paint marker.
My solution to storing the collets was to use Marcos boxes. I used a sheet of Dural (150mm x 290mm) and punched a (3 x 6) matrix of 20mm holes into it to take the collets. The Dural sheet sits on 5 off 10mm diameter x 36mm long spacers.
To give you some idea of the strength of the boxes, you can pick up one of these fully loaded with tools by the front wall and your wrist will break before the box does. (Well you know what I mean).
You will notice in the above photo that after some expensive clumsy breakages I now fit 3D printed caps over the most fragile tools such as carbide PCB drills.
So a bit of a slow news day but thought this might stir an organisational initiative somewhere ……