you might try a plywood faceplate made in your own shop and mounted in a 3 or 4 jaw chuck. This plywood faceplate is just a small disk and a larger disk of 3/4" / 19 mm thick plywood sawed out and glued and screwed together. The parts to be machined are screwed directly to the larger plywood disk. If the assembly is mounted in a 4 jaw it can be zeroed where desired and no extreme accuracy line up of part to plywood is needed. If using a three jaw to hold the plywood faceplate some care will be needed to align the part to the disk. I sometimes make a centre pop or small hole where zero needs to be, use the tailstock centre to locate on this mark or hole and hold the work to the disk while screws are driven to secure the work to the larger disk.

Light cuts are a must with this setup.

Cheap as chips and it works. Some pics of a couple of mine are in the August EIM magazine in the letters section FYI.

Have a look at Cringle's thread over on HMEM forum, you can see how he holds it there. The clamps with a jacking screw are a bit less likely to go flying than the stepped packing blocks.

Or if you drill the 4 foot holes you could then screw to a wooden plate like Jeff describes.

I have a normal backplate as in the photos posted by others, but also have a backplate intended for wood-turning. It is a blank disc with an array of small holes in it, a bit like that in a dividing head but symmetrical. It is great for odd shapes that can't be easily attached using the normal slots. The holes are only big enough to take M4 bolts but enough of them can be fitted to make it safe for low speed work.

If you do make some clamps like the ones Cringle shows then either slot them for the stud or make then so that the distance from stud to jacking screw is longer than the distance from work to jacking screw as this ensures you get more clamping force where it is needed. Also put the bolt/screw head against the faceplate having turned off any code numbers first as it's less likely to mark the faceplate. One thing I did do on mine was to drill the mounting stud holes all the way through and tap them, so you het a few extra options for fixings.

Although I have used both this type of clamp and the stepped block type on the lathe the ones with jack screws are safer of things come loose as they will all stay attached to the faceplate unlike the step blocks that could fly off. I also find them a bit easier when setting up on the vertical face of the faceplate as the blocks can drop! always worth having a board on the lathe bed when setting up work on the faceplate.

One of the problems with smaller lathes of the imported variety is that the flange mount that they use means the slots can't extend that far towards the centre so either a separate plate to fix to the faceplate with CSK screws or for a job like this ply or MDF would work as it's only a small cut on a 65mm dia aluminium part.

The part in question from Cringle's thread

I prefer Jasons type of clamp with a jacking screw which cannot fly off.Now if you have not used a face plate before,then there can be problems, Face plates are relatively thin and the work piece may be stiffer than the faceplate so over tightening of the clamps may distort the plate,when the work is mounted ,the work may be off set sowill need balancing,one of the photos shows change gears being used as balance weights,before switching on the lathe motor bring up the saddle and tool to the work and rotate the work by hand to ensure that it does not foul the saddle or tool holder,and where possible bring the tool up to where it will finish the cut and again check to see if the f/plate without fouling anything. then start using a very slow speed to see if the work rotates freely without spindle balance problems and increase the speed until it is just under the point where the lathe shakes, avoiding vibration is far more important than reaching the ideal cutting speed,if say when using HSS which has a cutting speed of around 80 ft per minute on cast iron it does not matter if the speed is below out of balance gives say a cutting speed of 50 fpmin it just takes longer to do the job,out of balance can cause problems such as out of roundness and damage to the lathe. It was lot easier for my generation who did apprentice ships and saw operations such as this carried out by more skilled workers,though I did see someone catch a clamp with the saddle and dump the work and clamps on the shop floor. I do not like like loose blocks under clamps , I prefer to use aluminium or steel blocks which have tapped holes so the block can be attached to the face plate via a bolt from the back. sub plate can be used with lots of tapped holes but they reduce the space available between the face plate and the gap in a gap bed lathe. If I want to skim say a brake disc,I have the table part from an old rotary table which has t slots and lots of tapped holes,this is held in the 4 jaw chuck and if the work has to be really parallel I give the old table a light skim ,have done a lot of brake discs and other parts on this fixture .

When you clamp work to the Faceplate, just be careful not to overtighten the fastenings.

the fastenings only need to be just tight enough to prevent the work moving under cutting loads.

Too tight could cause distortion which destroys the accuracy of centering / locating, and in the worst case scenario, crack the Faceplate.

A small fastener can exert quite a load. I once cracked a Myford ML7 Cross Slide by overtightening a 1/4 BSF nut (M6 for those metricated )

Howard