Axminster RF40 - CNC and other modifications

[BASMOTRONIC]

Thought I might share my journey of modifying my RF40. I bought this machine from Axminster tools and shipped it to the UAE where I am currently working. The machine had to fit into a 20ft shipping container which was converted into a workshop - so I was limited on the size of machine I could use. It soon became apparent that this mill has many limitations - which I have slowly been whittling away at.

The backlash on the leadscrews was so large that using the dials on the axes was no good for anything requiring precision. The first modification was to install linear scales (bought from China on ebay).

It wasn't long after that I decided to fit stepper motors (also bought from China on ebay). I used a kflop CNC controller which helped to reduce the issues with the leadscrew backlash using feedback from the linear scales.

The first photo shows the mill in this configuration (sorry - I'm rubbish and remembering to take photos).



The Z axis drove the drill downfeed via the rack and pinion mechanism built into the mill. This was hopeless under CNC control due to the backlash in the mechanism. More of that later....

In the end I gave up with the ACME leadscrews and poor quality bearing blocks (which contributed to the backlash) and fitted ball screws to X and Y axes (also from China on ebay)



Now I am dealing with the real issue with the RF 40 mill - the round column. As anyone that owns one of these machines knows - every time you move the head you lose your Zero.

So here are a few photos of manufacturing a new boxway column for the mill.



This project is still ongoing - so I'll post updates as it progresses.

All of the modifications outlined above (other than the clever bits) are made from scrap steel from my day job (we build pressure vessels, steel structures and piping for a living). So whilst it has taken a lot of manhours in machining and design - the cost of getting the machine to the state it is now would be a lot less than buying a CNC mill. The machine is now accurate in X and Y to +/-0.005mm and will hopefully be as good in the Z axis by the time I have finished !