A question for those who have done the conversion - manual machining?

Hi Everyone,

I haven't even gotten my lathe yet but I wanted to put this question out there as it's hard to "find" this information on the web. I nearly bought a Taig CNC lathe but it just didn't have the flexibility that i needed - i need tailstock support for what i do, and generally needed more space than the taig would provide.

Primarily my question is this - once you've done a conversion, how easy/hard is it to do manual operations? Is it as simple as getting a pendant and just getting used to using it, or do you find that you will just write quick programs in conversational g-code?

I've seen Wade'O Designs' incredibly CNC conversion where he retained manual control with his handwheels, but for me the lathe is a means to an end (I make pens), not the project/hobby in itself. I do small production runs and need to be operational most days of the week. He's also done a substantial amount of mill work and that's not something I'm capable of - i'm strictly looking at a conversion kit from BD tools or the like.

Generally speaking I would use the CNC for tenons and threading triple-start threads at various sizes, in addition to shaping pen bodies and caps. But i'd also be using the lathe in manual mode for some of the stranger materials that i use, putting a dremel on the tool post, making inlay rings, accent rings, the odd bit of hardware for cabinets i make around the house, etc. I'm just hoping to understand what post-conversion use of the lathe looks like, so any insight you can provide would be much appreciated!
 

gerritv

Gerrit
I implemented an electronic leadscrew on my 1022 lathe earlier this year. When the motors are not enabled the cross slide is easy to turn. Yes you do notice the 'steps' but there is no real resistance. IMO for most turning you don't need ball screws, most controllers deal with backlash quite well.
Direct drive via belt on the cross slide (using original lead screw) and belt drive on the carriage leadscrew, effect only when half-nuts engaged. Using this I have cut lots of BA and metric threads so far, turned down to diameter and created a MT3 die holder for my tail stock. Even took a stab at making WW collets but that is on hold for the moment.

WadeO's implementation replaced everything with fly-by-wire and included ball screws and a custom controller software. A rather full blown effort. I used his design for the cross slide motor mount, milled on my shop made gantry mill/router.

I am almost done rewiring my control box to add a DB25, this will let me eventually hook with a 7i92 to my Pathpilot controller.
Summary, if you don't switch to ball screws then using the machine in manual mode (as in hand wheels) even with steppers installed is very feasible.

Re: BD Tools, I think it is a good implementation but you will have difficulty with manual mode since there is no provision at all for hand wheels. Personally I can't imagine lathe work with MPG's.


Gerrit
 
I implemented an electronic leadscrew on my 1022 lathe earlier this year. When the motors are not enabled the cross slide is easy to turn. Yes you do notice the 'steps' but there is no real resistance. IMO for most turning you don't need ball screws, most controllers deal with backlash quite well.
Direct drive via belt on the cross slide (using original lead screw) and belt drive on the carriage leadscrew, effect only when half-nuts engaged. Using this I have cut lots of BA and metric threads so far, turned down to diameter and created a MT3 die holder for my tail stock. Even took a stab at making WW collets but that is on hold for the moment.

WadeO's implementation replaced everything with fly-by-wire and included ball screws and a custom controller software. A rather full blown effort. I used his design for the cross slide motor mount, milled on my shop made gantry mill/router.

I am almost done rewiring my control box to add a DB25, this will let me eventually hook with a 7i92 to my Pathpilot controller.
Summary, if you don't switch to ball screws then using the machine in manual mode (as in hand wheels) even with steppers installed is very feasible.

Re: BD Tools, I think it is a good implementation but you will have difficulty with manual mode since there is no provision at all for hand wheels. Personally I can't imagine lathe work with MPG's.


Gerrit
would it work the same way will a full CNC though? Many of the implementations i've seen seem to replace the handwheels with motors, so I'll lose the ability to even turn them. I considered the ELS approach as well, but to make my shaping/finishing process more efficient it was clear that I'll need full CNC control.

edit: just saw your edit, haha! yeah that's the main thrust of my question... if, when giving up the handwheels, it's "OK" to use pendant control for the lathe or if i'll need to write a program for everything (and in that case - how easy is it to do so)
 

David_R8

Scrapper of metal
Moderator
Premium Member
would it work the same way will a full CNC though? Many of the implementations i've seen seem to replace the handwheels with motors, so I'll lose the ability to even turn them. I considered the ELS approach as well, but to make my shaping/finishing process more efficient it was clear that I'll need full CNC control.

edit: just saw your edit, haha! yeah that's the main thrust of my question... if, when giving up the handwheels, it's "OK" to use pendant control for the lathe or if i'll need to write a program for everything (and in that case - how easy is it to do so)
I know it's not the same as a lathe but I use a pendant to jog my CNC router. I can start and stop programs, home and jog all three axes. It has controls to set the jog distance per step of the encoder wheel and jog velocity as a percentage of maximum speed. My machine maxes out at 10,000mm/min and I can move it as little as .01mm/step and as slow as .5% of maximum velocity.
Even with this fine grained control I think it would be very challenging to use the pendant to actually machine anything beyond simple linear moves.
 
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This is a video of my ELS in action:
You can't see the handwheels turn as the steppers do their thing but they do. When not using the ELS I just turn the handwheels as before.
ahh, ok so i just learned about Dual-Shaft motors, which for some reason nobody on youtube has ever used for a conversion! Is that what you did - and is that what makes it possible to use handwheels? that would be soooo much simpler than Wade'O, even though i do love the way his motor mounts basically "hide" the motors and from the outside make it look like a fully manual machine. I've also strongly considered getting an import weiss-style 8x16 simply for CNC conversion and keeping the 10x22 as fully manual - but i'm gonna need to sell a LOT more products before I go down that rabbit hole haha!
 

gerritv

Gerrit
Some photos of my 'conversion', it really is more an addition though. The leadscrew bearing mount is 3D printed (2 bearings inside), the encoder pulleys are GT3, 3D printed. Everything bolts on (or off)
The cross slide motor mount is a lsightly modified version of WadeO's. If I were to make another I would make more changes to the design for machineability but outside would look the same.
I need slightly better cross slide motor but with a few param changes in the ELS code it works wel enough.
 

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Some photos of my 'conversion', it really is more an addition though. The leadscrew bearing mount is 3D printed (2 bearings inside), the encoder pulleys are GT3, 3D printed. Everything bolts on (or off)
The cross slide motor mount is a lsightly modified version of WadeO's. If I were to make another I would make more changes to the design for machineability but outside would look the same.
I need slightly better cross slide motor but with a few param changes in the ELS code it works wel enough.
Awesome! I think I understand it a bit better now - I love the idea of the "addition" as it would certainly take less time and machining than a conversion. That's what attracted me to the Pro-Cut CNC kits but after doing a bit of research on the company I'll be avoiding them entirely. I like that things are 3D printed, as I haven't got a mill but i do have 3D printer access. Any idea if they would slowly degrade or lose accuracy over time? And regarding the addition of DB25 - did you find this was necessary for some reason or just a nice-to-have?
 

gerritv

Gerrit
the db25 may or may not happen, it was only for convenience/compatability with other boxes. Presently I use a Mesa 7i92 on a PC with Tormach's Pathpilot for my gantry mill/router. I could use that for the lathe as well (Tormach 8L lathe) but might be too much fiddling.
Plan B, or is it D, is to eventually use https://github.com/terjeio/grblHAL or https://github.com/bdring/FluidNC and generate CAM/gcode from Fusion360. Lots of other projects first though.

The cross slide motor mount is aluminum: some of the maching here:

Gerrit
 
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