Black Friday Deal got me :)

yep, already had that thought with the 4-jaw chuck route. the pneumatic idea will require different jaws for different material size but those could be made as well. that's the easy part. figuring out how to put it all together and not break the bank in the process is the hard part any kind of hollow body design for something fancy gets expensive quick the bigger you get.

That manual self-centering 4 jaw chuck came yesterday, and that brand seems pretty well made and works really well.

i have some material ordered and coming for a attempt at a rotary union, the seals should be here today, i hope this material is not under sized or i will have issues. for whatever reason thick-walled tube in this size range is expensive and i only had one supplier that i have used that was fair on price, but sizes were limited. i checked on bar stock prices and that was even more expensive yet it's amazing how you get screwed so bad on prices for small orders.

these unions are hard to make on the cheap. i did see one import that had 120 mm bore but was around $400 each. what i am trying is 140 mm bore. not big enough for a 4" square tube so it is what it is i guess. if i can make these i can make 2 of them for around half the price of one of the smaller imports.

i hope i can make it work would be a neat build and if nothing else i am eager to try it at least. nothing ventured nothing gained

the deeper i get into this the more i realize how ambitious this project really is one thing i did notice was i need to add some travel to my z axis to do everything i want it to do. these self-centering pneumatic chucks are turning out to be pretty big once you cover them with some sort of guard. the rotary end is going to be much more involved if this works out for me. as far as the moving parts go things seem to work really well so far. the thing that could break this is the rotary union if it does not seal well.

this build is like building 3 machines if everything works out as planned these end up being almost 21" tall and a little over 19" in diameter and 6 1/4 "wide i added a 5" round tube which will be the max on round tube. the guards should be a treat to make the plan is to laser cut some flat sheet and either weld them together or use a special solder rod made for aluminum. welding aluminum is not something i enjoy or am very good at

but anyways here is a screen grab of my model to give you and idea of what this will look like if it works    

 

Travis MItchell has an excellent series on buidling a rotary tube cutter for a laser head for circular, square and rectangular tube.


You should review his chuck design befor going to far into this. The material is held between 2 seperate self centring roller assemblies so it can move in and out while driven by a powered chuck at the other end on a tailstock on the Y axis. I don't get why he powers two chucks. I think only one powered chuck is required.

I think converting this to a table addon, I would extend th x axis past the table edge and suspend the chuck below it and just have a lazy unpowered chuck at the end of the table aligned to the roller chuck. It would be the roller chuck moving then.

i seen his video it's a pretty nice build but it is a manual self-centering if i remember right. the idea is to have the overhang so you can have both the flat table for larger stuff and the rotary off to one side.
what would be different about what i want to do is have the automated clamping and a second liner axis as a bar feeder and drive the rotary from a second in the rear in line with the fixed end. the fixed end is basically a steady rest with automated clamping system to hold the place while the other can be released to move back and grab another bite on the material and keep feeding material if you want to cut something long,

you basically have infinite travel on a small footprint machine.