The Shop > Tools
Boley 4LV
Rob.Wilson:
good solid machine , and you got the steady s :dremel:
Rob
BillTodd:
There's a chap (Harold Mulder) on the PM forum looking for a Boley 4L changewheel plate (or diagram & list ). Does this machine have such a thing ?
Nice machine BTW
When you said "cnc it" I trust you meant only the threading operation ?
Bill (lathe protection squad hit-men on standby)
PekkaNF:
--- Quote from: RotarySMP on November 24, 2012, 03:39:31 PM ---Depends if you consider this a lathe... many don't!
--- End quote ---
Looks like a lathe to me. And it looks greatly improved to the original.
I have pretty similar, least when it comes to top slide and toolpost! Mine does not have steppers and invertter - yet.
I'm not considering CNC without ballscrews, ballslides and central lube, but electronic feed would be very high on my list. l am not yet very conviced on ELS, I'm having hard time "getting it" how it actually could make an accurate thread with one pulse per spindle revolution and without servo.
Pekka
RotarySMP:
Thanks for your comments guys. I am in contact with Harald.
If I CNC the 4L, it will be a reversable change (as it is on the 7x12). I am not sure if that is the path I take with the 4L though. I just talked to my dad and he has a spare set of change gears he was given a few years ago. No idea what machine they are off, but if the size is near enough, and bores are small enough to be bored out, then I might end up adapting that set (if he brings them over from NZ in summer).
The 4L is a very simple machine. This makes it ideal for CNC, as all the wonderful mechanically tricky features which make something like a 5LZ or 1EE so cool, becomme redundant once a computor spins the wheels.
Remove the 4L lead screw, and install a ball screw mounted on bearing blocks and a nut carrier which pick up the existing mount holes.
Same for the the cross slide.
Top slide is replaced by a tool riser block.
Two inductive sensor, one the spindle cog for rpm, and another on a 1/rev feature for indexing.
The T-Slot for sliding stops on the bed will be excellent for mounting limit and home switches.
The motor is a standard, industrial, flanged motor. It is only .75/.9k. I am not sure if the place I bought has 3ph in the cellar. If not I will probably need a 240 3PH motor, and will run it off a 1PH -> 3PH VFD like I have my current lathe.
Pekka, 1/rev indexing worked fine under T-CNC. Since I swapped to LinuxCNC (EMC2) I only have the index signal set up to provide RPM indication and havent done any threading.
On a CNC lathe, you can cut the thread with dozens of light cuts, and at much higher spindle speeds than you would comfortably do manually, so the spindle doesn't really load up or slow down enough to make a significant effect on thread accuracy (obvious it depends on the desired accuracy). I have cut two M40x1.5 (er32 collet nut) threads on 7x12. It was just on the wrong side of the machines capacity, and turned out ugly on one, and worked on the other.
I think you only need a Px oiling system if you use the mchine for hours each day. I just squirt oil on the ways and screws regularly (like every time I use it). Given the cost of 7x replacement parts, it is probably easier just to replacing things if they start getting worn.
PekkaNF:
--- Quote from: RotarySMP on November 25, 2012, 05:37:30 AM ---.....
Pekka, 1/rev indexing worked fine under T-CNC. Since I swapped to LinuxCNC (EMC2) I only have the index signal set up to provide RPM indication and havent done any threading.
On a CNC lathe, you can cut the thread with dozens of light cuts, and at much higher spindle speeds than you would comfortably do manually, so the spindle doesn't really load up or slow down enough to make a significant effect on thread accuracy (obvious it depends on the desired accuracy). I have cut two M40x1.5 (er32 collet nut) threads on 7x12. It was just on the wrong side of the machines capacity, and turned out ugly on one, and worked on the other.
I think you only need a Px oiling system if you use the mchine for hours each day. I just squirt oil on the ways and screws regularly (like every time I use it). Given the cost of 7x replacement parts, it is probably easier just to replacing things if they start getting worn.
--- End quote ---
Looks like you have sorted it out :clap:
I was considering this method for semiautomatic machining (sort of ELS) with a bunch of other guys who were whole lot more electronically versed, but when we "clocked" the spindle, leacrews etc, we noticed that:
* normal capacitor run AC motor is absolutely out of questions if only one pulse per spindle revolution is used. 3phase AC, more "flywheel" and stiff belt drive was an improvement.
* Takes some time to stabilize the speed, ELS needs delays to wait until spindle is "at speed" and some preset distance to "build speed for leadscrew".
* Cutting does not generate constant force, forces seem to be cyclic
Therefore threading seem to be heading to direction of servodrive for a spindle and/or greater pulse count on spindle and more processing power. We did regognized that with tweaking it could be doable, but not as predictable as mechanical solution.
Would love to get some info on your workking system:
* AC-motor/inverter rating, spindle speed used for threading
* Threading dimenssions tested succesfully and failed ones (they are best to find linmits!)
* Inertia masses are hard, but rought chuck/belt wheel dimessions would help
* Lead screw pitch/ratio/stepper motor and current you run it would give great insight
PekkaNF
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