I have been looking at this for a while and its easy enough to do
I need a high accuracy lathe ,A CNC one I have designed the headstock casting and bedways (to take linear guide rails) and also a large bore spindle to take a D1-4
There are a couple of issues that brought this about namely that small chinese cnc machines which are converted are a bit of a compromise and the boxfords with any kind of capacity are like hens teeth
So I designed my own on the basis that most of the stuff is bought
Linear guide rails
SERVO/Steppers (steppers will be fine)
Spindle is machined and ground
on that basis I can get 3 stress relieved castings made but I have to get them cast in 10s to make them cost effective The costs arent that great but it would be a waste to pay for the castings and then do a one off
Is this something that's interesting or would it be a better bet to but the amadeal lathe bed and headstock and modify from there to suit ,I still think the spindle would be too small using this headstock casting.
Maybe theres a market for a high quality machine or do the mini lathe CNC' conversions provide enough for people into this sort of hobby,light production thing
Any chance of some sizes (swing/spindlebore/bed length), and prices?
I've looked at various options, and have come to the same conclusions that converting an existing lathe is far from ideal.
Ideally i could load up some cad models done in Pro E or solidworks
Spindle bore im thinking needs to be about 35 mm
Bed size would be about the size of a mini lathe or sieg s6 size
I just keep looking at the cheap chinese castings and thinking they skimped on the casting mass and the beds are a bit skinny If it was cnc and we used slides (hiwin rails) we could just getthe thing ground and tapped to bolt the lot to the bed
The foundry i have been speaking to does GREY CAST IRON ductile was recomended
Im wondering if it would be wise to use a cartridge for the spindle and just thru bore the casting then the precision part for the preload on the spindle etc would need to be the money part
C6 sizes about the right kind of bed size, but personally I'd want a bigger spindle bore (i'd like to be able to get 2" bar through).
For the spindle, I'd personally machine my own, as that way I'd get what I'd like (big hole and cam lock!)
One thing I'm wondering, why 3 castings?
Surely bed and headstock are the only castings that are really needed?
So roughly 24" bed length which I'm pretty sure is short enough to machine on a bridgeport. Is surface grinding strictly required since it's only to mount the profile rail, it's not a running surface? Just needs to be accurate...
So it can accept the slides for a lathe but it could also do double duty in that I could take the spindle casting dowel and bolt it on and use the same casting for the mill
I havent ruled out epoxy granite for the bed but feel it isnt needed on a hobby size machine its not worth it,Ive done epoxy granite before for a company called zeiss over in germany ,they were damn accurate machines but hey as hobbyist or gor precision engineering it seems we might get a bit hung up on how accurate the machine is
The head casting could take a bored through hole Insert a ground master and moglice it to take a cartridge spindle.
The actual casting cost for the head is 37 quid each and the saddle 17 quid im expecting the bed to be a bit more based on him getting back to me, however the grinder i qot a quote from in sheffield will segmentally grind then line grind the A datum top and B datum foot of the bed casting flat to within 0.05 for 25 quid which seems damn reasonable.
My weak area is electronics I have seen these electronic leadscrews that let you program a pendant to machine instead of using full cnc control I would liketo have some manual control of the lathe without it being connected to a pc using MPG'S TO DRIVE THE STEPPERS does anyone know anything about this?
Ill also cross link this post/ question over on another more electronically oriented part of the forum.
I might be interested
But would like to see a drawing first
I may be able to help. I have a foundry in my garage. I can do the old cope and drag or I can vacuum loss foam castings.
I'm set up for doing development work on my race bikes so one-off isn't an issue. I'm in Grenoside by the way.
Compositepro, did you ever get any further with this?
By justice86 in forum New Member IntroductionsReplies: 0Last Post: 06-11-2013, 12:02 AM