4th axis opinion - Ebay

Originally saw these units from LMS:
4th Axis Rotary Table for CNC - LittleMachineShop.com

Then i searched ebay, and found similar units:
CNC Router Rotational Rotary Axis A Axis 4th Axis 3 Jaw and Tailstock | eBay

Anyone have one? Not looking at using this for production. Would like to use it for more small one off jobs in aluminum and plastic, and honestly just to learn and get comfortable with programming for a 4th axis. The belt drive should be adequate for what i have planned. I see it has a ratio of 1:8. With a little bit of re-engineering an additional pulley system could be added easily to multiply the ratio.

Looks like a 3" or 4" chuck. Kinda small to me, but a larger diameter faceplate can be added when needed.

Looks exactly like the one that just showed up here via DHL last week! :D
(just clicked your link... yup! Same seller)

So far so good. Motor driver is almost exactly the same as my Wantai ones. Microstepping goes down to 800, and up to... ummm.. 25600?
Very nice castings, everything looks and feels tight.
Reduction is 8:1 (save YOU having to count it out like I did!). <-- edit: just noticed you mention that above!
Belt cover is pretty cheap looking (maybe because... it is?!), but other than that everything else looks good.

Thank you for the review. Did you purchase the one with the tail stock? Is the tail stock only good for longer items? If you have any youtube videos of it running or a review feel free to post them or add me on youtube, my user name is diyengineer

Yes - got the one with the tail stock.
I wasn't going to bother at first, but then figured, for the small extra bucks now vs extra shipping later....
Of course, your needs may differ.

I don't have any videos of it actually in operation - but I guess that wouldn't be a huge deal to do.
I'll think up something amusing to mill into something then shoot it.
I'm user "DrFiero" on youtube (same as here, just no ".")

How true does the headstock run in this kit?

Honestly, at this point I have no idea. I only got it a short while ago, and have been busy building up the rest of the mill at the same time!

I'm at the point I'd like to start actually making something (other than more parts for itself). If I get a chance, while I'm shooting a test video, I'll grab my mag base and dial indicator and include a few random shots with that too.

That would be great! Thanks.

those things are expensive! I bought extra motor to be able to add a 4th axis down the road, so I just need to figure out how to get the headstock put together. Harbor Freight has a small 2" Mini Lathe Chuck and a 6" Wood Lathe Chuck pretty reasonable. I'm thinking the 6" would be too large. Too bad they don't have a 4".

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Originally Posted by mcphill

How true does the headstock run in this kit?

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Here ya go - this what you wanted to know?
http://www.youtube.com/watch?v=muPamjGNBn4

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Originally Posted by diyengineer

If you have any youtube videos of it running or a review feel free to post them

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Didn't. Now I do! :D
Here you go... http://www.youtube.com/watch?v=VgJ3rlv2Hyo

Update on the runout video (I updated the video to reflect BTW).

I grabbed various rods (mostly tooling bits) and chucked them up. I got very consistent readings across all of them, and saw up to 12 thou of runout!
Same readings on all of the different bits, and all at the same point of rotation (so I doubt they're all bent at the same spot).

What I shot yesterday was really only checking the backing plate, bearings etc. My bad.
I should have checked the chuck as well.

I'll just have to keep this in mind when doing 'stuff' that it better not be that tight of tolerance!
I was mostly going to use it for artistic things anyhow, except for the odd gear.

Is the chuck a loose fit on the backing plate? Or have you taken it off yet to see? It shouldn't be too hard to dial it in, I ran across a HF 9X20 lathe with that much or more runout, just had to clean up the backing plate and locating ring to get something useful out of it.

I would take the chuck off and check runout on the face and step of the backing plate.

Sent from tapatalk

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Originally Posted by Dr.Fiero

Didn't. Now I do! :D
Here you go... http://www.youtube.com/watch?v=VgJ3rlv2Hyo

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is that a blower you have on there?

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Originally Posted by Marti

is that a blower you have on there?

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Yeah! 6:71 Roots. Was going to go with the 8:71, but didn't want to seem pretentious. ;)

(of course, it could be the one that BD Tools aka Billy sells)

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Originally Posted by Dylwad

Is the chuck a loose fit on the backing plate? Or have you taken it off yet to see? It shouldn't be too hard to dial it in, I ran across a HF 9X20 lathe with that much or more runout, just had to clean up the backing plate and locating ring to get something useful out of it.

I would take the chuck off and check runout on the face and step of the backing plate.

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Good plan.

So, took the chuck off the backing plate (bolted on with 3 8mm bolts, that are just a hair too long to be able to be removed without removing the backing plate). Runout across the face is fine. Runout around the inner locating ring is fine.

Was in the process of checking the ID of the chuck where it meets the locating ring... when my calipers croaked. Sigh. It was looking good just before then.

Anyhow, looks like I *might* be able to lightly ream the holes in the backing plate to give me some wiggle room. Then I can center it, and tighten it down (which of course will throw it off whack, then I can repeat forever! Heh).

So the fix is to clean, loosen up bolts and ream them to allow adjustment? If you do make a how to video haha. Ill be buying in the near future!! :)

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Originally Posted by diyengineer

Ill be buying in the near future!! :)

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Guess mine was a monday morning, or friday afternoon production run.
Hopefully yours was/will be made on a Wednesday. :D

But yeah, if I get motivated enough to fix it, I'll try to film it.

Thanks! Dr. Fiero, i checked all over Youtube and you seem to be the only one with that style off ebay. I'm sure you will generate some traffic on your video from others like myself searching for info about it. I'm sure with a little cleaning and realigning it will be well worth the money!

Any luck on fixing it?

CNC Router Rotational Axis 4th Axis A Axis 3 Jaw 100mm Chuck Gear Box 1700 | eBay

Also see they have a gearbox 50:1 and 100:1 unit now. No clue what the backlash is but assuming you always program one direction.. haha

Haven't actually tried! Had too many house issues, finding a new career/job, etc etc....

Just milled out a few things here and there for small jobs. Nothing round needed doing yet. :)

Hello, Any updates? :)

Looking at getting the plug and play one for my Little machine shop 3503 (KX3).

https://littlemachineshop.com/produc...3519&category=

The price is $822 with no 3 or 4 jaw chuck. Much more than the ebay ones, but i know it will plug and play, plus I know it should work, and if it doesnt i have someone to call. Thoughts?

Yo how is it going peoples! Looks like this discussion needs some dusting off. I just purchased this same unit off ebay. I have yet to even hook power to it. As of writing this I am still in the process of machining 3-axis parts on my G0704 -> CNC. I have 2 parts I need the 4th axis for. You guys have any luck?