Enclosure finally added to my Tormach PCNC440

Reduction in Sparkly Bits around the House

When I bought my Tormach PCNC440 in 2016 I included the enclosure kit in my order.   On receipt I thought that fitting the enclosure would dominate the size of the workshop so I never got round to fitting it.   It has sat in its shipping box since then.  I have consequently shared quite a bit of my swarf (chips) with long suffering family.

After a recent (particularly heavy) CNC run I had a serious covering of swarf in the machine tray and because I had no enclosure round the mill, I had quite a lot distributed further afield (i.e. into the house).   Domestic peace was becoming an issue. Time to do something about it. 

Out came the enclosure kit, cobwebs dusted off and around three hours later I had the enclosure fitted.  I have to say it looks good and does not overpower the workshop as I thought it would.   My wife is impressed and says it looks a more professional machine and ‘if you had it why didn’t you fit it before now’ ? 

My Tormach PCNC440 with its enclosure fitted
The picture above shows the enclosure mounted on my PCNC440 with the monitor in the original position before fitting the extension arm to the ISO bracket. The keyboard tray uses a domestic drawer rail mounted on the top of the standard Tormach cabinet. My recently fitted dual fogbuster system and my Hall Effect based tool height setter (yellow top) are visible.

The fitting did however create some follow up problems.   

My control monitor had up to now been mounted on the side of the 440 on a standard ISO TV mount.  With the enclosure fitted this meant it was ’round the side’ and difficult to get to.   I debated a new long reach ISO but they are expensive.  Plan B was to make something. I rummaged around in my aluminium stock and with the help of Fusion 360 came up with a seriously overengineered extension arm to add to the existing ISO mount. This would allow the monitor to move forward to be in reach at the front of the mill. 

ISO bracket extension on Tormach PCNC440
My seriously over engineered extension bracket to move the ISO mounting of the monitor more to the front of the 440

This bracket became the first CNC job to run after fitting the enclosure.   I am pleased to say it was the cleanest my workshop floor had ever been after running a job.

Having fitted the new bracket and mounted the monitor, all the cables needed extending.  Fortunately I had had the foresight on my original order to include the extension cable kit.   As a result I only had to extend the power supply lead from the monitor 12V ‘brick’ supply.

The second issue was where to mount my ITTP probe as this had formerly mounted on the side of the 440.   With help of some more Fusion design I modelled a corner mount that picked up on the enclosure fastenings.

After that first heavy machining run I noticed for the first time the slight smell of the mist coolant when opening the enclosure doors.   Before the enclosure was fitted the smell must have dispersed into the general workshop air.   With the enclosure fitted the air was concentrated inside the mill and I only got the smell when sticking my head inside.  While it had never been a problem (as far as I can tell …) I thought I should do something about it.

Sometime ago I installed a ceiling extract duct in the workshop.   This vents to the outside world via a custom roof tile. Normally the system sits with a flared cowling (made from a cut down flower pot) on the ceiling entry duct.  The system normally acts as a background trickle extract.   The cunning plan in the design was to use various pipe components to provide bayonet style connection pins (Nylon screws) to allow extension trunking to be used.   A bit like a BNC RF connector if this is familiar to you.   This would allow me to use an add-on length of expanding flexi trunking to bring the extract nearer to any heavy fumy activity such as welding or oil bath hardening.

With the use of further scrap odds and ends of aluminium, I mounted a pair of support bars across the top of the new 440 enclosure. These would fix the ducting over the enclosure during heaving CNC sessions.   Not a total solution but certainly one that will reduce the general smell of XtremeCut 250C when I stick my head in the enclosure.

Workshop extract system
Extract system showing ceiling mounting intake, trunking adapter and mounting on my Tormach PCNC440.  Note the two Nylon screw protrusions are for a bench mounting clamp when used for welding extraction etc and now used on this new use of the system on the mill.

A good day’s activity with all the issues addressed and domestic bliss hopefully restored.

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Fogbuster update prompted by Clough42 and other projects

Fogbusters Everywhere

Apart from working on the Thwaites clock parts, I have also done an upgrade to the mounting of my Fogbuster coolant nozzle installation on my Tormach 440.  This was triggered after viewing and being impressed by Clough42’s idea.   The Fogbuster is a great way to clear swarf and apply coolant.  The Fogbuster is normally supplied with a magnetic mounting arm but James’ modification uses LocLine gooseneck components to provide a much more flexible ‘aiming’ capability.

Something to be aware of – James recommends a download from GrabCAD for the 3D files of the two halves of the nozzle holder.   These had been uploaded by contributor Br BRB.  These were apparently publicly available via GrabCAD.  James slightly modified these and was offering them as a free download from his Thingiverse folder.  He has since had to remove them for download due to commercial issues.   BrBRB has also removed the original files from GrabCAD and is seeking to sell these as finished items.  I was lucky to have downloaded the files before the politics cropped up.  I  still have the downloads.

James also advocates fitting a second identical nozzle to the Fogbuster to avoid coolant and air shadowing.   I contacted Fogbuster in California and a very helpful lady called Rachel organised an upgrade kit to provide a second feed from my existing coolant reservoir. 

Dual Fogbuster coolant nozzles on Tormach PCNC440
Dual Fogbuster coolant nozzles on Tormach PCNC440 using Clough 42 flexible nozzle idea

It turned out Rachel was from Bristol UK so it is a small world and we had a good chat.   I have fitted both nozzles to the Tormach.  With a pressure of around 10 to 15 psi, the reservoir feeds both nozzles very well and is a huge improvement in use. 

As I was facing a shipping charge from the US I figured I might as well top up the package so I have also splashed out on a baby version of the Fogbuster to fit to my Myford lathe.  This uses the same idea but with slightly different mounting that fits into the T Slot on the Myford saddle.   I already had the 3D model of the T Slot strip from the ‘bits tray’ installation.

UPDATE : – I went to a Plan B on the lathe mounting – see later post

Baby Fogbuster mounted on Myford Super 7 saddle
Baby Fogbuster mounted on my Myford Super 7 saddle based on the Clough 42 flexi nozzle idea

Another pair of incremental asset improvements successfully installed.  I suppose I had better get on and make something now. 

Back to ‘the clock’ …

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CNC Work Reference Centring using Mushrooms

This is probably not original but worth commenting on.   I have a tooling plate on the bed of my Tormach PCNC440.  This has a matrix of M8 holes on 25mm spacing together with intermediate 3.7mm tooling pin holes.

Quite often I have a need to set up my work CNC coordinate system (WCS) such that it is centred on one of the M8 holes. 

If I want to do a quick and dirty centre on one of these holes then I use the Laser Centring tool as mentioned elsewhere on my blog.

If I need to be a bit more precise then I have a mushroom/top hat shaped disc with shank that is a tight fit in the tapped M8 holes.  PathPilot has a number of probing routines and these include finding the centre of a circular object.    Simply push the top hat into the desired hole and then probe the disc for centre.  You can use an active probe such as the Hallmark ITTP.

If you haven’t got an active probe you can use a Haimer.   Simply align the Haimer tip somewhere close to a maximum point on the disc circumference and advance the axis to show a reading on the Haimer.  Rock the opposite axis back and forth and watch the Haimer reading to find the high point on the circumference.   Zero the axis.   Go to the opposite side of the disc and repeat this process and divide the measured diameter by 2 for the disc centre.   Repeat on the opposite axis.

(You can use this Haimer rocking back and forth method to find the diameter high point when cross drilling a circular item to fit grub screws etc).

Hole centring mushrooms
Two examples from my ‘mushroom farm’

The mushrooms are made with a silver steel shank that is skimmed to be a non wobble (how technical is that ..) fit in M8 (~6.8mm) and an aluminium top hat that is superglued in place on the shank.   Once the glue has set the top hat is squared up while held in a collet in the lathe.  This ensures concentricity with the shank.   The disc will now sit flat to the tooling table when the shank is pressed home and perpendicular in the hole.

Clearly the larger the disc diameter the less centring error there will be.

I now have a ‘mushroom farm’ of discs for all manner of hole sizes.  It’s not rocket science but as you well know, I am all for a simple (aka lazy) approach.  Apologies to all the Grannies out there.

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Tormach PCNC440 Oiler Replacement

I have never been over the moon comfortable with the manual slideway oiler as supplied with my Tormach PCNC440.    It has a hand pump that you pump once or twice and this fills a cylinder with oil.  Inside the cylinder is a piston that empties the cylinder under pressure from a compressed spring.   There are two O rings, one on the piston and one on the cylinder access end cap.

original Tormach manual oiler
Original Tormach manual oiler

In the course of my ownership of the 440 I have had to replace the O ring on the cylinder a number of times.  Once replaced the device works for a limited time and then fails again.   The problem is made worse in that I can never find the right size O rings in the UK and have to resort to replacements from Tormach.   These are not expensive but when added to carriage costs from the US it does become an issue.

In frustration at the latest failure I found and bought in an alternative manual pump on Amazon.   The action is slightly different in that pulling the pump handle action generates the pressure to feed the oil rather than leaving it to the spring return action.  When the handle is released, the cylinder refills itself.

Replacement oiler as found on Amazon
Replacement oiler which is available from a number of suppliers including Amazon

Physically the replacement device is slightly larger and I needed to make an adapter plate to fit it in the same position on the rear of the 440.  The new device also has twin output feeds.   This allowed me to replace the existing T splitter assembly with two separate feeds – one to the X and Y oil distribution manifold and one to the Z manifold.

Replacement oiler in place on the rear of the PCNC440
Replacement oiler in place on the rear of the PCNC440

So far so good and it seems to push the oil out to all oiling points. Clearly this is something that has to be monitored or there is the danger of dry slideways and dry ball screws damaging the mill operation.  I will report how the new style oiler performs longer term.

It has got me thinking that maybe using an Arduino I could create a ‘time to pump’ prompt beep at switch on and say after 4 hours of operation … a rainy day job ?

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Workshop resources all coming together like clockwork

Another JSN Job ?

You know how I keep on going on about how solutions to problems are often solved by coming at them from different and often unconventional directions, by utilising and marrying available resources ? It was a philosophy that I encouraged in my team while running my business and it has carried over into my way of working in retirement.   A recent job brought his home to me.

A client had a very old clock that had had a new barrel wheel made and fitted but the clock would not run for more than a few minutes.   There appeared to be an incompatibility either between the modulus of the new wheel and its mating pinion or the shape of the original pinion did not match the shape of the new wheel. 

If you spun the barrel wheel you could feel the resistance build up as the synchronisation between the two profiles drifted out.   Adding extra weight to the barrel helped but did not solve the problem.

So what to do ?   

The barrel wheel was serious engineering and I did not fancy making a new one.   The existing mating pinion was a seven leaf format and its leaves were what you might call pear drop shaped rather than the expected profile.  The pinion arbor had a 72 tooth wheel driving the next part of the clock train but we did have a spare one of these to hand from the minute dial.

Calculations from the geometry of the barrel wheel resulted in a modulus        figure of 1.86.  A rather large value and not one that conventional cutters are readily available for.  The pinion was perhaps something that could be drawn in Fusion 360 and then made on my Tormach CNC PCNC440 milling machine.   The only snag was that the profile needed on the pinion would likely be weird and the world’s supply of brass could diminish rapidly while getting the profile correct.

Using Gearwheel Designer I created what would be the expected profile for a 7 leaf pinion with a modulus of 1.86.  This was exported as a DXF line drawing into Fusion 360.  This outline was extruded in Fusion into a 3D design and a boss was added to mount the 72 tooth wheel. 

The design was 3D printed on my Sindoh 3DWOX printer and was mounted on a 6mm silver steel arbor.   I added a driving disc that interlocked with the printed pinion and the crossings on the wheel to drive the assembly.  Surprise surprise it didn’t run but it did mirror the regular pattern of stiffness of the original pinion. 

Original arbor , pinion and wheel with the driving disc and a test profile
The original arbor, pinion and wheel together with the driving disc and a 3D printed pinion test profile. The driving disc has screws to lock it to the wheel and two protruding pins to lock into the 3D printed pinion profile under test. The 3D printed profile was a tight pressure fit onto the new 6mm arbor.

I now had the test bed for quickly making and testing different pinion profiles. There followed a number of hours watching the engagement progression of the profile of the pinion into the barrel wheel and then trying to conceive a profile for the pinion that might run. 

3D printed test profiles
Various trial profiles and the temporary driving disc to engage with the 72 tooth wheel

 

Test pinion in place on the new arbor
A test pinion in place showing the 72 tooth wheel and the driving disc

Fusion 360 made this process so easy and round 10 printed test profiles later I had success with a clock that now ran.    The driving weight on the barrel was around 11kg and it looked to be worthwhile wasting some brass making a ‘proper’ one. 

I took the 3D design and produced CAM code in Fusion.   This would cut the profile ‘on end’ using an adaptive first cut with a 4mm end mill followed by rest machining the remaining material with a 2mm end mill. 

Images of the Fusion 360 process of creating the new 7 leaf pinion
The Fusion 3D model of the pinion, the CAM simulation of the leaf cutting, first adaptive cut of the leaves and rest machining final pinion

The resulting brass pinion was mounted on the arbor and the clock ran with a strong beat.   As expected the brass pinion gave less surface to surface resistance than the 3D printed part and the barrel driving weight was now able to be reduced down to 6.25kg.

new pinion mounted in the clock
The finished pinion mounted in the clock on the new arbor

I ran my Microset Timer on the clock overnight and had a first off timing error of 5 minutes per day which was fixable with a pendulum tweak. The movement had an instability of a few seconds per day which was quite astonishing.

The conclusion of the experience is that at first glance this seemed like a conventional pinion cutting exercise …. but M1.86 cutters are not readily available.   If a cutter could have been found at less than a King’s Ransom it is likely that the resulting conventional profile would have been wrong to match the barrel wheel.   

The alternative route that was taken of Gearwheel Designer to Fusion to 3D print to Fusion CAM to CNC machining solved the problem albeit with a final weird profile.    The purists and traditionalists will groan.   There will be a gnashing of teeth and a pulling out of hair. 

Does it really matter if the result is new life for what could have become a heap of scrap metal ?

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