Workshop assets – Page 6 – Woody's Workshop

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 ?

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February 3, 2021February 14, 2022

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 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’ …

UPDATE 2 : – The 3D printed ball joint kept working lose on both the milling machine fogbuster mouunts. The more I tightened the screws to grip it tighter, the more the 3D components began to crack and give way. The solution was to fit brass inserts into the 3D prints. Problem solved. Incidentally there is a good review of such inserts on CNC Kitchen.

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November 9, 2020February 16, 2021

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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October 30, 2020April 16, 2021

BK3 Replacement Drive Wheel

Final Push on the BK3 Bandsaw Upgrade

Having solved the BK3 motor drive pulley replacement my attention turned to the large drive wheel replacement.

My initial tack was to create a 3D printed version. As I wanted to include the high speed option this needed a 24 tooth 5mm pitch pulley included. This did not print well.

Plan B was to buy a standard Bearing Boys 24 tooth pulley and incorporate this into the large diameter wheel. I modelled this in Fusion and concluded that perhaps a CNC aluminium part would be better. This would allow undercutting of the underside face of the pulley. This would not be possible using 3D printing as this would not be a supported area.

The stub axle that the pulley would revolve on protrudes 25.5mm from the BK3 side wall. The blade wheel groove needed to be 10.25 wide to accommodate the belt width. The retaining side walls needed to be 1.5mm wide. This totals 13.5mm width for the large pulley leaving only 12mm for the small pulley that would be needed for the highspeed set up.

This now became complicated in that the large wheel needed to sit around 5mm from the side wall to keep the belt in line with the motor drive pulley. A spacer washer was made for this. This left only 7mm width for the high speed belt and I needed at least 9.25mm just for the belt without retaining side flanges.

The light bulb moment was to realise that the high speed pulley could protrude beyond the stub axle without fouling the outer case cover. I could use the full depth of the pulley and counter bore the front face sufficiently to allow the axial retaining screw to hold the pulley assembly in place and allow free movement.

Here is a very much simplified sketch of the final assembly showing the counterbore for the retaining screw and the counterbore for the pulley boss into the large wheel. The small pulley and large wheel are locked together with 3 off radially spaced M3 x 10mm countersink head screws.

Simplfied sketch of final wheel assembly — Simplified sketch of the final assembly of the large wheel on the BK3. Profiling of the wheel internal area is not shown but see Fusion image below for these aspects.

Here is a Fusion 360 graphic of the final pairing of the 24 tooth commercial pulley and the CNC machined large wheel. With hindsight the large pulley could be 3D printed by leaving the rear face completely flat rather than having a profile like the front face.

Parts needed to be bought in were obtained from Bearing Boys as follows : –

14-5M-25 (14 tooth, 5mm pitch,25mm tooth width) for the motor drive pulley.

24-5m-09 (24 tooth, 5mm pitch, 9mm tooth width) for the high speed pulley.

300-5M-09 (300mm, 5mm pitch, 9mm wide) 60 tooth belt for high speed operation

525-5M-09 (525mm, 5mm pitch, 9mm wide) 105 tooth belt for low speed operation

Note that all pulley and belt parts are to the HTD standard profile.

Here is the wheel in place with the belt set to run in high speed mode.

Replacement blade drive pulley with high speed pulley option — Replacement blade drive pulley with high speed option selected using the small 24 teeth pulley driven from the 14 tooth motor drive pulley.

Note that I had one additional issue to address.

The aluminium wheel tended to not hold the blade centrally in the blade groove with the result that the teeth of the blade would rub against the wheel front flange. This did not happen in low speed mode when the blade runs on top of the drive belt. My solution was to fit a 160mm x 10mm wide elastic band in the wheel groove only when in high speed mode. The particular elastic bands are a standard size from Amazon and others. This solved the problem. There is no abrasive impact on the elastic band so life expectancy should be high and replacements are very low cost.

The above drive modifications in addition to the modified blade guide that I have detailed elsewhere, have given my BK3 not just a new lease of life but also a more accurate cutting capability. The effort has been more than rewarded and is to be recommended.

I have created a summary compendium of all the BK3 mods and additions that can be downloaded as a ZIP file on the link below.

ZIP file download link for BK3 Modifications v2

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October 30, 2020October 30, 2020

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

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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