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Good'o
(no drama's with the name mix up )

When I flipped open the cover on my little lathe some time ago, it had a cogged drive belt, so I figured to fit a stepper would be real easy to one like that(I mist have another look )
Maybe a 4 jaw chuck would work, seeing as though to undo & re tighten the chuck doesn't need a lot of turns with a chuck key & you only need to turn in one place to get all 4 to move, that could work ?? Is this what you where meaning ??
I can't help but thinking that cheapo lathe/mill I swa might do the job, and even more so when I think about some form of feed. If I could use the chuck and then the mill part to carry the cuting head & just add a couple of extra axis if need be, then the bed of the lathe could almost be used as the feed if I could cut it off and put it on the other side (or shift the Mill part) The feed could travel on the lathe bed and just shift short runs, as the chuck would be holding it most of the time while it'sbeing cut ??

Errrrrrrr place the tube in the machine, it is clamped in the chuck (manual over ride on the machine of course)it's rotated, cut etc, then the chuck releases & it is then fed in the required distance & the chuck clamps again. The feed could also be a clamping devise of some kind, so it only has to travel a short distance while the tube is supported down it's length.
The only othe rproblem I can see is there would be abit of waste at the end (though I spose I could soon weld them together to get value for money)

This is only one of a few machines I'd love to build, but without the knowledge & $$ it is gong to be tough, but we may just nut out the easy bits here

Thanks so far.

(are lasers very costly ?? & what size do you reckon I'd need to cut 1.6mm Stainless.....sorry, my conversion charts are at work, so I'm not sure what thickness that = to in imperial measurement)

Strooth....it's 1.15 am here.......I'd better hit the fart sack.

CHEERS,
Rod.

yea thats what i ment but there is a bit of a problem say you used an old chuck key with some type of profile cut star shaped ­meta­l for your method of opening chuck.i do not think you could say weld that to the chuck you could make some sort of race that would have to go round the entire chuck assem so that it,s supportwd at it,s extremities.even with a rapid opening chuck you would prob have to do do a few cycles of chuck rotation to open and close .that does not matter realy it,s just a g code job realy if you got a toothed drive you are half way there i just had another thought while typing instead of an outer race to support chuck key maybe some sort round clamp on chuck itself balance is not an issue i assume all low speed re laser i have never used one i worked on lot bigger stuff but the principles are same .how you going to feed if you go with lathe set up if u use a physical stop on bed u can make a simple if u are looking at a power feed it,s gona get tricky

G'Day again from Down Under on a Sunday arvo.

I think the feed would be pretty easy, as 2 servos could control that.
one for clamping and one for travel.
I'm not to worried about having extra servos as it should be quite easy to control any number..........just a matter of getting it all to work at once.

I'm starting to think of just using a chuck for the rotational work & not clamping (just run 4 rollers in there) then there wouldn't be any problems with what we have been chatting about, not convinced of that though (what would be holding the work when the feed lets go to shift back ??
Just using the feed to hold and move the stock up after each cycle would make it a bit simpler though.

yes, I think to head for something that already has a toothed drive is the go.
I just fornd a pic of a lathe that has it's head ­frame­ only bolted to the main ­frame­. Not what I would call good, but it may be able to be turned around, so I could use the bed for the travel ??

I'd rather keep the cost down though with just the main investment being in the cutting euqipment itself (a head I can leave on the machine so i can later build a table would be great........

Now....just to find a retired engineer who wants something to do

i just typed a full page and it,s gone so just give a brief de­script­ion of it RE ROLLERS any where use rollers thro away the clamp u can pre tension any roller. example four jaw chuck drill four holes one in each clamp face add a compression spring into each hole and one ball bearing push down and bur edge (just an example)you now have a chuck that u can tweek to any size via chuck key you can then add just one sevo motor for the feed u can pre tension to any degree you wan,t right up to clamping. the stock needs to be held central so may be advisable to get a piece of tube machined to go up the centre of chuck and lathe and maybe give it 20 thou clearance if you know what i mean gona have breakfast and walk the dog

I am getting into this conversation late, b ut I think I understand what you are atempting to do. What about modifying an independent four jaw chuck by making it into a two jaw chuck. Make a pair of v-jaws to hold the square tube, fix one jaw permanante and use the other jaw to clamp. THe screw can be removed and use a cylinder the move it in and out. You will not need a a great deal of clamp force. If you do not need the lathe it would be prety simple to make a face plate to do this clamping and set it up to be drivin by a stepper motor. The advance could be like you mentioned early on with two clamps. The chuck and the advance mechanism. The clamp mechanism would move back the distance of the advance and clamp, release the chuck clamp, advance the movement and then clamp the chuck. There will be a great deal of coding involved in this project. Not an easy first project, but I think it can be done. You could also set up a bar puller like this one. This would save on material. http://cgi.ebay.com/Grippall-CNC-Lathe-Bar-Puller-Haas-Chuck-MADE-IN-USA_W0QQitemZ310112482929QQihZ021QQcategoryZ41946QQssPageNameZWDVWQQrdZ1QQcmdZViewItem it is a Grippall CNC Lathe Bar Puller Haas Chuck. Here is a two jaw power chuck. http://cgi.ebay.com/10-CNC-Power-2-Jaw-Lathe-Chuck-1-5-x-60-HAAS_W0QQitemZ310113399394QQihZ021QQcategoryZ25292QQssPageNameZWDVWQQrdZ1QQcmdZViewItem It is rather large for your needs but gives you an idea. Haas makes all kinds of things that may help you out. Here is a rotary indexer that you may be able to get to work. http://cgi.ebay.com/Haas-7-Rotary-Table-Parts-Repair-w-Servo-Controller_W0QQitemZ120358312466QQihZ002QQcategoryZ41942QQssPageNameZWDVWQQrdZ1QQcmdZViewItem. Basically go to ebay and search HAAS in ­meta­l working. All kinds of goodies.
Hope this helps some.

Never to late mate!!
I'm still collecting ideas & am yet to purchase anything. (though I very nearlly...again!...bought some steppers, but I resisted as I'm not sure what I need.

I think to build the main machine with the add ons, then buy the required motors & then drivers etc would be the way to go, though not much around (in OZ anyway) as far as equipment like you have just mentioned. Even steppers etc are in short supply with the boards that run them (especaially for multi steppers) even harder to find.

I've gotta really get prganised and find out what I need to run it, drivers, boards, computer etc, so I've got lotts to learn.
Your right this is a tough project for a first timer, but I really need it for work, not just as a hobby project.

I'm keen to by matched equipment like boards with steppers etc (as I just don't know what does what.

Thanks again for the input, I will be looking to any odeas that you guys can add, so hope fully by the time I put pen to paper in the planning, purchase & actually build it, I'll be on a winner.

CHEERS,
Rod.