Rotary 4th Axis Tailstock

[grossmsj]

How do you remove the live center from the Rotary 4th Axis Tailstock? I'd like to use another live center.

I presume the live center is mounted on a #2 Morse Taper shank that fits into the tailstock quill. I don't want to start whacking at it without knowing how it fits together.

Scott

[aluomala]

I tried to separate the tailstock from the mount (I'm strong like bull, smart like tractor) and only succeeded in having it get jammed at about the halfway position (still moves back and forth, but with less range of motion).

I'd like to replace the stock one with something less of a bit-magnet/destroyer, as well as the ability to use different "attachments" such as this set: link. Having something made of brass or aluminum (with a replaceable tip) would be nice as well. I'll probably never need it, but after destroying a $150 carbide end-mill on my live center, I'm once-bitten, twice-shy. 

I suppose the best thing to do would be to call Chad at Axiom, but please post the results of your query here, please. The lack of info/documentation/resources on the rotary axis is bad enough as it is, so getting the information to the other end-users is helpful. 

Allan

[grossmsj]

I suppose the best thing to do would be to call Chad at Axiom, but please post the results of your query here, please.

I'll try that Monday if I don't hear anything. I sent a request about this through the Axiom 'Contact' link a day or two ago and haven't heard anything from them. 

I want to use a live center that doesn't sink in so much. The force I use to support the expected deflection of a spindle 26 inches from the headstock puts a pretty deep poke into the endgrain. The Robust live center I use on my lathe would be perfect. 

I'd like to replace the stock one with something less of a bit-magnet/destroyer,

LOL! Yep, I had a pretty spectacular event when my 1/2 inch carbide bit went into the tailstock. It was pretty interesting to see how carbide shattered when it went into it with force. The tailstock fared pretty well. One would hope to learn from those sorts of experiences...

[joeblow]

It is an MT2. A good knockout bar, not the one sent with the rotary, and some healthy whacks will get it out.

Regarding long pieces and deflection.....there are some great diy options for fabbing up a steady rest using an old rollerskate or rollerblade. I have not made one myself yet but is on the list.

[grossmsj]

Thank you joeblow ! This worked great. Not even whacks, just some decent taps and it popped loose. My other live center is in there now.

Just for completeness sake, I put the whole tailstock in my vise and took off the handwheel so I could see things better. Then I inserted my knockout bar that came with my lathe. It just barely fits in the hole, but I wiggled it in until it was seated where I expected the 2MT shank would be. Tapped it a couple times and it was out.

Scott

[aluomala]

Jan 29, 2022 5:38:13 GMT -5 joeblow said:

It is an MT2. A good knockout bar, not the one sent with the rotary, and some healthy whacks will get it out.

Regarding long pieces and deflection.....there are some great diy options for fabbing up a steady rest using an old rollerskate or rollerblade. I have not made one myself yet but is on the list.

Perfect! Thanks for the info. I guess I wasn't strong/persuasive enough when I tried (that's what half measures will get ya!). 

I was thinking about either making or buying a steady rest, as I was planning on making canes in the future. I was trying to imagine what the workflow for using something like that would be, so that the machine avoids the rest. Probably break it up into thirds, and do the top and bottom thirds first (separate toolpaths, to avoid the machine crashing into the rest, moving between toolpaths), and then finish the middle third (or vice versa). Having 2 rests might alleviate that problem: start with the center portion (having the rests in the top and bottom portions), and then move one rest to the center, and then do the top and bottoms. Interesting challenge, but I might be over-thinking it. Over-thinking tends to be less expensive than underthinking though, so....

Allan

[joeblow]

Glad to help.  

Somewhere in the last couple years I saw a modified diy steady rest that provided support from underneath.  It didn't interfere with toolpathing from above.  Could very well have been from a Vectric forum member that makes great looking walking sticks.  I don't remember .  Anyways, very similar to this pic but would be mounted on the cnc bed directly under whatever stock is being rotated.  The pic I saw was simply some old kiddies plastic rollerskates and might have even been somehow spring loaded to provide pressure as material is chewed away and rotated.  It stuck with me for when the time arises that I need one.

[grossmsj]

I don't think you'll need a steady rest. You'd need it if you are making something pretty thin. Or you may need it if you are making something a little thicker and putting deep passes on it. In either case that strong lateral deflection a long way from the headstock could push things so far away from axis that you'd get a lot of flex, chatter, or possibly movement at the tailstock.

I was mostly concerned about movement at the tailstock. If I just had a little bit of the live center point in the endgrain that lateral deflection could cause the wood to move away from the point. It could get loose and move around by the tailstock. So I tightened the tailstock harder, but then the point of the live center sinks pretty far into the wood. That would cause problems for me when I move the spindle back to my lathe for sanding. The crater created by Axiom's pointy live center would be sloppy.


A live center like the Robust has a cup and point design. The point lines you up on axis, but the cup holds the piece in place pretty firmly with some pressure and doesn't sink in very far. At least in my case using the same live center also makes it easy to accurately move from the AR6 back to my lathe.

EDIT: Just saw joeblow's post about the spindle steady rest. I DO have one of those for my lathe, and it is very helpful when I'm turning. When you are turning (at least me...) the bevel is running on the piece and one can push down fairly hard to keep things under control. Plus, the piece is rotating at 2000 RPM, so you get chatter with that flex. It seems to me that the really slow speeds and the ability to dictate pass depths make that sort of deflection less likely. That said, I'm new to this, so these are just suppositions.

[aluomala]

Jan 29, 2022 13:26:12 GMT -5 joeblow said:

Glad to help.  

Somewhere in the last couple years I saw a modified diy steady rest that provided support from underneath.  It didn't interfere with toolpathing from above.  Could very well have been from a Vectric forum member that makes great looking walking sticks.  I don't remember .  Anyways, very similar to this pic but would be mounted on the cnc bed directly under whatever stock is being rotated.  The pic I saw was simply some old kiddies plastic rollerskates and might have even been somehow spring loaded to provide pressure as material is chewed away and rotated.  It stuck with me for when the time arises that I need one.


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OK. The support underneath (in this case) is more critical than support laterally or from the top (ie. it's not spinning at high RPMs). Maybe some type of deal where the wheels are supporting from below in a V-shaped setup, to give some lateral support as well? 

It's got me thinking now..... Probably worth investigating and modifying an existing plan (or existing product) rather than re-inventing the wheel. Probably don't need high-speed bearings, so smaller wheels should be feasible.

Allan 

[joeblow]

I found the pic I was referencing.  This should better clarify providing support from below.



This was taken from the following website link.  If the link doesn't work the website is humblesticks.com.  Some good info done by even better cnc craftsmen.

There will always be some deflection of the material on the rotary.  It really just boils down to how much you're willing to live with in your project.  

[grossmsj]

Thanks for the site joeblow . The link doesn't seem to work, but the website is really information rich. That guy has been doing this at a high level for quite a while.
I'd love to sit down and have a few beers with him. 


    Scott

[aluomala]

Thanks for that link Joe! I LOVE the kids rollerskate that he uses. The genius of that method (as he notes in the tutorial) is that the rollerskate can be adjusted back and forth, which is perfect for different sized materials.

Definitely going to read through all of his posts, since there is a decided lack of content related to rotary axis machining.

Allan

[aluomala]

Here is the link to Humblesticks.com: link

Every time I looked at that page (his tutorial), I learned a new trick (the one for the hollow cane made me go "Man, that's smart!"). 

To be honest, one of my favourite things with CNC (and woodworking in general) is that you have to do a lot of troubleshooting and thinking in general. If I ever get to the point where for the majority of my projects, I am just sliding a piece of wood onto my machine, and hitting "Start", without having to think things through, I'll hang up the tools. It's nice to have a routine after you've learned the ropes, but to be stagnant, and keep doing the same-old, same-old (like working in a factory) is boring. 

I'm looking forward to seeing what people can come up with on their rotary axis.

Allan

[joeblow]

Jan 31, 2022 13:57:36 GMT -5 aluomala said:

Here is the link to Humblesticks.com: link

Every time I looked at that page (his tutorial), I learned a new trick (the one for the hollow cane made me go "Man, that's smart!"). 

To be honest, one of my favourite things with CNC (and woodworking in general) is that you have to do a lot of troubleshooting and thinking in general. If I ever get to the point where for the majority of my projects, I am just sliding a piece of wood onto my machine, and hitting "Start", without having to think things through, I'll hang up the tools. It's nice to have a routine after you've learned the ropes, but to be stagnant, and keep doing the same-old, same-old (like working in a factory) is boring. 

I'm looking forward to seeing what people can come up with on their rotary axis.

Allan

Sure nailed that!  My personal projects on the cnc are definitely more challenge driven.  I really enjoy coming up with difficult projects and then “figuring out” how to get there.   

Glad that site is helpful.  Topnotch people for sure.   

[aluomala]

Yeah, I tend to get excited when someone asks me to do something out of the ordinary, that makes me "leave my comfort zone", and usually waive any design fees (which I rarely apply anyway, since I consider a lot of it like an apprenticeship) to work with them on it. I hate wasting time with tire-kickers, but when someone has a cool idea, it usually lights a fire under my butt, and try to come up with something that exceeds their expectations. Not always my expectations, but people are always their own worst critics.