Time to say Hi

[JAZZCNC]

Hi Graeme,

Few things to mention.
First regards the frame then it's 99% ok except It needs bracing at the sides where uprights meets the base.? Because the uprights only connect with small amount of lower frame then you could get resonance thru the uprights. I would brace the ends more or have them extend down lower than bed creating feet and brace between them kind of thing.

Second regards a 4th axis and removing the bed I wouldn't do that on a small machine.? Leveling and skimming the bed parallel to spindle is a time consuming and messy affair and you would have to do this every time you replace the bed which is pain.
Much better to have on the end or have gantry extend past the sides and run down side of machine if longer lengths required.
Having the Rails extend past the end of the bed is an easy way to incoprarate 4th axis and have it fasten to the legs just below the rails so keeping distance to Z axis short.
The other upside to extending rails past end is that you can machine the edges of long boards or oversize material. Or fasten material to the ends enabling dove tailing etc. Extending past the end is very useful at times and add's very little extra cost to machine.
If you extend both ends you can recover the lost bed and use all the bed area.!

Why so tall if your not having adjustable bed and only thinking to cut wood.? The distance the Z axis extends greatly affects the quality of finish you'll get so if your only planning on cutting boards then keep the Gantry/bed distance to a minimum for maximum strength.
It's nice having extra clearence for the odd 10% of times you'll cut deeper material or jobs but it does come with a cost on quality for the 90% of time you won't.!! . . . Unless you raise the material to the cutter.? In which case your better having an adjustable bed.!

EDIT: On looking again and seeing 155mm Z dimension it's not exactly over tall and think the perspective makes it look worse but still some of what I say above still applies if your mostly cutting boards or material less than 50-75mm thickness.!!

Good luck and nice to see someone who's taken the time to do some research for a change.!