[Zeppelin1007]

Hey guys.

Ive got some people asking me about doing baseball bats, hollow candle sticks, etched drinking glasses, etc.

I have a machine based off of FLA-100

My questions are simple i guess. Did anyone find a good chinese 4th axis that was actually worth getting? Ive read alot of reviews on the Sunwins that they needed machining after receiving.

I am without machine shop access sadly.

Or, would i be better off just building one? Where i get lost on building one is, how does one physically attach a 4 jaw lathe chuck to a shaft?

I suppose if i built one i'd have the option of changing the motors from a stepper to a full blown AC motor and building a toolpost, and doing lathe work that way.

Input? Thanks in advance guys

[victorofga]

this is a good stuff, and need a tailstock for too..
please note it has harmonic drive, what actually used for at 5 axis machines for B and C axis..

relative high gear ratio 1:50 or 1:100 makes possible small stepper sufficient..

CNC Router Rotational Axis The 4th Axis A Axis for The Engraving Machine 1650 | eBay

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another option beltdriven, faster, also has very little or neglectible backlash, but require larger stepper..

CNC Router Rotational Axis The 4th Axis A Axis Claw Set for Engraving Machine | eBay


you also can lloking for a combined type..
where 2 motor applied onto one rotary attachment..

a stepper for controlled movement, and a regular electric motor for turning task.. where you use lathe cutters instead endmill

[awerby]

Does it have to be Chinese? Why not get a Sherline rotary table that's made in the USA and actually works? CNC-ready Rotary Table The chucks screw on, using the adapter supplied with it.

[Zeppelin1007]

VictorofGa, ive looked at those. I guess does anyone know of a specific seller that has one that actually works as it supposed to. Ive seen mixed reviews. Some work great, some need to be turned on a lathe and fixed.

awerby,I've toyed with the idea of one of those. Especially since i could mount it not only as an A axis, but as a C axis as well. My concern is whats the backlash like? Obviously i wouldnt be doing my full blown AC motor on this thing, but thats ok

[victorofga]

well....

if you have ability to milling aluminum, you can try to build an own..

using timing belt, and using 1:5 ratio you can make a decent dividing head, for wood , plastic and very light aluminum cuts..

but.. counting on the invested time, material cost and also you need a lathe and a mill to make a rotary, I think for 250 you cant loose really..
you can see of links you get a rotary for 250 approx. with a tailstock..

it will not be equal with a 4th axis that use a machineshop.. but, for this money you get one and you can start to use from the day it comes to you..

if you have a lot order then after some money realized you, then you can go for a professional made..what actually starts with thoushands of dollars.. not a few couple hundreds ..


a chuck, a 3 or 4 inches chuck will cost you at least 70 dollar.. a motor wired and 2 timing pulley with belt another 70

that's already 140... buy some little aluminum, another 30-40 dollar..thats 170...
so the question, what you can make of 80 dollar?
can you work several days for 80 dollar?
don't answer me... just make these questions to yourself..

generally a harmonic drive start with 300 at least...

so ypou can see anything you want make, or buy everything will cost at least 500 or more...


for rotary table I would go with harborfreight or grizzly...

http://www.amazon.com/Grizzly-H5685-...SYNT46CYQN29MK

this one you can set vertical or horizontal position.. you also get clamps and steps for clamps for 160...
if you have ability to turn parts, and mill even with router, then go with this..

[awerby]

I doubt you'd save any money trying to build your own rotary table, even if you don't value your time. But if you do decide to go that route, please let us know how it went.

The Sherline rotary table does have a few arc-seconds of backlash, but it's not like the thing wiggles around when you're cutting; it's got a 72:1 planetary gear which keeps it stable. I'm not sure you could say that about those tables you link to that seem to depend on a rubber belt for reduction and stability. If you don't want to compensate for backlash in software, just keep cutting in the same direction. For really critical jobs, you can use indexing and lock it down at the index positions.