Amadeal CJ18A Mini Lathe CNC Conversion

My first CNC conversion was an Amadeal 8 x 20.

Space is, indeed, pretty tight in the cross slide, but it can be done, I think.

You might as well get rid of the top slide / swivel slide / compound slide. It just reduces rigidity on a CNC lathe.

I have lost the photos of that conversion (they were on Picasa) but there are some later ones here. photos.app.goo.gl/nwM9Ze59j3zi5TB77
The machine was a lathe/mill combo, and wasn't a good mill at all, but was an OK lathe.

My cross slide was converted using an 8mm ball screw. The problem is not the screw, but the nut. I ended up having to cut away some of the cross-slide dovetail to make space for the nut, but that was largely because I wanted to copy a feature of my dad's Smart and Brown where the screw is protected by a steel shim cover that passes through a "tunnel" over the ballscrew. The album above shows the same arrangement being set up for the Z slide of the mill attachment.

One thing that did help my conversion was moving the thrust control ourboard into the handwheel area. Cunningly none of the photos really show this, but there was a pair of angular contact bearings mounted in the handwheel area, then a needle roller bearing where the belt drives the ballscrew pulley. This pulley (T2.5 belt) was just small enough to fit under the cross slide as it came back.

The Z axis is very easy.

You probably can get away with using the original screw, as software backlash comp can cope better on a lathe than a mill. You would just have to write the G-code such that tapers are always cut large-to-small so that only one side of the backlash is used

My subsequent conversions spent a lot more money, and look a lot better. If you have a 3D printer then I would suggest printing foundry patterns and making parts that actually look like they belong on a lathe. Reckon on paying £10/kg for castings from AJD and you will find that it starts to look tempting.

(Much bigger than your lathe, but this is the set of castings I made for my second lathe conversion, a whole new gearbox, saddle apron, toolpost riser and covr for the X axis drive chain: photos.app.goo.gl/F5CtJY9Fed1Cruk2A )

arvidb wrote:

It's just loosely fitted for measuring in the image: some steel rings/sleeves will be needed to preload the spindle bearings through the bushing.

I didn't bother, I just preloaded the spindle before final tightening of the taperlock and it worked fine for years.
As long as contact on both sides is only with the taperlock and not with the pulley you can treat the taperlock bush as a solid sleeve.

It's been a while, but probably. I have a vague memory that perhaps I replaced a bit of plastic pipe (Mine was _not_ a quality lathe from the factory)