Handy Tips – Page 4 – Woody's Workshop

June 25, 2021

Tormach PCNC440 Z axis oil manifold access

Turning a Dribble into a Flow

The right hand side oiler for the Z axis on my 440 has always had a poor oil feed to the slideway. I had tried to clear all the pipework that is easily accessible but with no improvement. I was conscious that deeply embedded in the spindle assembly was an oil manifold that fed the left and right slideways and the ball screw. Could this be the source of the problem and how was I going to get at it without a major strip down of the Z axis spindle assembly ?

Looking down from the top of the spindle assembly I could just see the manifold in a hole in the casting. If I could get to this I might just be able to work on it without a major strip down.

First of all an apology that I do not have any photographs of what follows as I was so engrossed and so grubby that I left my phone secure and out of the way. The process will become obvious as you progress and is not overtly difficult.

The stripping process was to remove the two screws holding the door interlock switch, remove the four screws holding the wrap round cover, remove the holding pin on the power drawbar and remove the two bolts holding the spindle motor. With all these fixings and parts freed off it is possible to lift the outer cover up and over out of the way and to lay the spindle motor inside it. It is tight to shimmy the cover around the power drawbar body flange but it is possible without removing the drawbar piston assembly.

With all this removed it fully reveals and gives access to the cavity containing the manifold. It is a short term joy because it is pretty much impossible to undo the right hand side oil feed as this is from the end of the manifold.

Light bulb moment – if I drilled two 6mm holes in the assembly casting opposite the two hex head screws that are holding the manifold in place, I could get a hex driver T bar to remove these screws and free the manifold from the casting wall. This would allow the manifold to be moved to work on it.

Here is a drawing to help locate the two holes giving the distance from the back and bottom of the casting. (The lower black and blue assembly is my fogbuster mounting).

Once the manifold is free to be moved around it is possible to remove the right hand feed pipe and remove the associated length of pipework to clean it. I found the manifold end of the pipe had not been cleanly cut and was restricting oil flow.

A word of warning – the oil feed to the ball screw is a semi rigid pipe and this terminates in the side of the ball screw. Do not overstress this length of pipework or there will be tears.

Assembly is the reverse process. Apologies once again for the lack of supporting pictures.

I can report my right hand side Z axis slideway oil flow is much improved.

Similar or related subjects : –

February 3, 2021February 3, 2021

Having it and not needing it or Needing it and not having it ?

Changing the Drive Belt on a Cowells ME90 Lathe

One of the posters that Jimmy Diresta sells says “I’d rather have it and not need it than need it and not have it”. The saying is apt and often strikes home. This is not just in terms of larger workshop assets but also in the small scheme of things like workshop tooling. You know the time you spent making a jig for a job and thought ‘all that extra time and effort to just make that and what do I do with the tooling now ?’

I think it is a saying that is close to the heart of many hobbyist no matter what the medium you are working in. It does explain why our workshops are full of ‘stuff’ that we accumulate on the ‘just in case’ basis. How many screwdrivers do we really need ? The answer of course is ‘one more’.

I believe there should be a sub clause to Jimmy’s poster – “Needing it and Having it yet not being able to Use It”.

I have a Cowells ME90 mini lathe which is a beautiful piece of engineering and I seem to remember it was my first real mechanical engineering purchase. For 364 days of the year it sits looking forlorn at the back of the bench asking to be valued, loved and used. When it is called into use it is indispensable. Usually. On a recent once in a blue moon 365th day when it and only it could perform a task for me I found the drive belt to the headstock had perished. You could almost see the grin on the ME90s face. Gottcha mate, serves you right for not looking after me.

Thankfully the drive belts are standard sewing machine belts (#MB410) and are readily available both direct from Cowells or numerous sources on the Internet including Amazon. A replacement was ordered and it arrived quite quickly.

Now to the nub of the problem – how to fit the belt ? Looking at the headstock it suggested that maybe the whole assembly had to be lifted off and split but the cap head screws for this which went down into the baseplate did not want to budge. I looked at the spindle and it seemed to have differing diameters that at first glance would not allow it to be removed out of the bearing mounts.

Cowells ME90 headstock assembly for reference while following the belt replacement instructions working left to right

Rather than risk a regretful step I emailed Cowells and very quickly got a support reply from Colin. For all future intrepid belt changers here are his instructions : –

The only way to fit the belt between the 3 step pulleys is to dismantle the headstock assembly.

Its quite simple really:-

Start at the left hand side of the headstock.

1, Unscrew the knurled gear retaining nut.

2, Pull off the 20 tooth gear ( be careful not to lose the tiny Woodruffe key beneath it).

3, Unscrew the round adjuster nut that butts against the large (64t) gear. -You can use a pair of pliers/grips if you put some emery cloth in their jaws.

4, Slacken the M5 grub screw ( or take it out) in the 64t gear.

5, Pull this gear off. (If it is reluctant to budge then, its probably due to a burr underneath- see below for advice).

6, Slacken the M4 grub screw( or remove) in the little collar that abuts the headstock pulley inside the headstock channel.

7, Slacken (or remove) the grub screw in the central vee of the headstock pulley.

8, Slacken the tension on the two bearing adjuster journals- these are the large cap head screws you see on the top face of the headstock body.

9, It should now be possible for the headstock spindle to eject toward the tailstock.

Clean all parts thoroughly and re-assemble in reverse.


If you have trouble removing the 64t gear then, make sure all grub screws are removed as above. Screw back on the knurled gear retaining nut and with a hide mallet, gently tap the headstock spindle toward the tailstock.

As I said in my thank you reply to Colin, I felt like a hybrid version of ‘stupid boy Pike’ and ‘Rodney you plonker’. (UK sitcom specific joke).

Enough said ?

Similar or related subjects : –

June 9, 2020

Helping get cable down a duct

A minor post but it might help someone.

I had a need to run an armoured cable down a duct to an outbuilding. The duct had thoughtfully been installed a long time ago with the potential for use in the future.

The future arrived and it was a daunting cable run of over 25m. Armoured cable is pretty rigid which helps on the straight runs but when it comes to bends in the duct it had a mind of its own.

After struggling for some time I had the thought that some form of leader was needed to navigate the bends. After searching the workshop I decided a cable tie (zip tie) might be rigid enough but flexible enough. I snipped the fastener ratchet block from the tie and taped the residual length to the end of the cable as below.

A liberal coating of DC4 silicon grease and the cable shot down the duct and round the bends like a rat up a drainpipe.

Similar or related subjects : –

May 5, 2020

Supply, IC2 and USB connections over CAT5 connection

CAT5 Breakout Board

One of our group of ‘silver experimenters’ is building an Arduino based celestial camera tracker. This will be deployed in the garden and he needed all control to be routed back inside the house. The garden installation consists of a USB webcam mounted on a servo controlled platform all powered by 12V DC.

We pondered long on how we might remotely connect to the garden. The crucial thought was that the Arduino servo board was a two wire interface using the I2C format data exchange. Given that the USB needed four wires and the DC supply two wires we had a need for an eight core cable connection. It seemed like a length of CAT5 cable would do the job and we could elegantly use standard CAT5 sockets.

The PCB was designed in Design Spark and milled on the Tormach PCNC440 using FlatCAM.

There is a problem with running USB over more than 5m but I did some tests at 10m and all seemed fine which should be adequate for the application.

The breakout boards had a male and female USB connector fitted and the connections had to ‘cross over’ on one of the breakout boards to maintain continuity. We also paired the Data + and Data – connections with the +5 and Ground twisted pairs in the CAT5 so the Data + and Data – were not twinned together.

Nothing technically magic but a simple solution to a project need.

CAT5 breakout board for USB, I2C and DC supply — CAT5 breakout boards for USB, I2C and DC supply

Similar or related subjects : –

April 27, 2020April 27, 2020

How to Register Velux radio controlled windows

Velux Window Registration of Window to Controller

An Off Piste rant ….having just had a few hours of my life dribble through my fingers I thought others might want to avoid having the same misery.

We have two Velux centre hinge windows in our ‘Summer Room’. They have been temperamental about behaving to the handheld controller over the years and at the weekend they both went AWOL to the controller while open.

The handbook is a bit disjointed and has a circular path if you have a problem that does not get you anywhere apart from very frustrated.

First thing is that if you end up with the window open and not responding there is a tiny white button on the electronics box inside of the window frame which if you press once will cause the window to close. This assumes that the window has failed fully open and you can get at the button….

Now to the main problem, getting the remote control to ‘see’ and register the window(s). I got the spectrum analyser out and checked what was happening. When you take the batteries out of the controller and give it a hard bounce it takes you into a primary screen asking for the language option you want. This is followed by a Register menu option. When I selected this I could see a polling signal at 868MHz (European short range devices frequency allocation) so the controller looked to be working OK.

To activate the window to listen for a poll from the controller you have to switch off the power to the window and then switch back on. For the next 10 minutes it should be listening for the controller polling request.

Well I followed all this but the controller was not seeing the windows to register them. I could not see the ACK on the analyser coming back from the window so something was wrong.

Digging in the handbook there is mention of a ‘window reset’. The same white button that allows you to close an open window also acts as a reset button for the window. If the window is closed you can manually open it to get at this button. You hold the button down for 10 seconds and this causes the mechanism in the frame to cycle back and forth and make noises.

When all stopped and it went quiet I turned the windows off and on and re-tried the controller and immediately both windows registered.

Magic. I can now get on with something more important or at least more interesting.

In summary : –

Remove the batteries from the remote controller.
Manually open the window and press the white button on the black electrical unit on the frame for ~8 secs. The white T shaped part of the mechanism will go into an ‘in and out’ process for 6 or more times and then stop.
Close the window manually and switch off the power to the window.
Put the batteries back in the controller.
Switch on the window. You now have 10 minutes to register the window.
The controller will ask for the language to be selected and will then give an option to Register. Cross all your fingers, hold your breath and then press Register and wait for registration to happen.

Hope that helps someone lose a little less of their life trying to get this to work.

Similar or related subjects : –