- Joined
- Sep 28, 2013
- Messages
- 4,395
that Z-axis mount looks stout! You wouldn't be the first to use the "locating pin" instead of screw excuse 
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CNC conversion BL250G/700 lathe
- Thread starter MrCrankyface
- Start date
- Joined
- Nov 7, 2019
- Messages
- 485
Time flies when you're procrastinating finishing projects 
I've used the machine quite a lot and am starting to get comfortable with it.
Granted my ability to keep it clean are mediocre so figured I'd give it a proper clean before I continue working on it.
I disconnected the failed cable chain attempt and started rerouting both lubrication and some cables.
Next up was fixing some bed protection. I've seen some people use these but so far I'm not very happy with it.
Either way I bent up a little mount for the carriage and then welded on another angle ontop. This will both hold the accordion thing and constrain/protect the lubrication hoses.
As to my experience with this so far, quite often when compressing ie moving towards the chuck, the accordion wants to bulge up rather than compress.
Not entirely sure how to sort that out besides maybe weighing it down somehow.
Another issue is lack of clearance between the carriage and extension spring covering the ballscrew.
Quite easy to fix just had to detach the whole side and mill/file a lot more clearance.
This gets me the extra Z-depth I need for some specific setups.
Before the extension spring would snag/collide with the carriage if I tried to move into the last 5cm or so.
Next up was some more waycovers.
Bent up two pieces of steel and riveted on some rubber.
I would've liked an all steel construction but at both ends there's simply not room.
At one end it would collide with the back wall and the other end it would both collide with the pulley for the X-axis and stick out uncomfortably much, some rubber sheet solves this nicely.
Another small fix is grinding down the heads of the gib screws and shortening them so they stick out as little as possible.
On several occasions I've had these snag on chips, the oil hoses etc etc which should now be much less likely.
Then we have the "final" little issue, for some reason the back is open which means chips and debris will go out the back and cause a horrible mess that's hard to clean.
It's hard to get a picture that shows it clearly but I've extended the backwall with some more steel sheet and added a little "slide" at the chuck end to prevent most crap from dropping right into the cable chain which is now hidden behind/beneath the headstock.
Still some other various things I need to fix ..
-Adding the counterweight to the rear of the carriage to even out the bed pressure
-Replace the red PLA plastic with an aluminium piece
-Redo the spindle encoder mounting(wobbles atm, might decrease life of encoder)
-Improve how the ballscrew nut is attached to the X-axis(I think it's currently causing some backlash)
-Properly investigate how accurate the movements are and what backlash I'm getting
-Replace the plastic backplate holding the Z-axis ballscrew nut on.
-Figure out a way to lube the X-axis ballscrew nut.
-Actually lube the Z-axis ballscrew nut .... etc etc etc
I've used the machine quite a lot and am starting to get comfortable with it.
Granted my ability to keep it clean are mediocre so figured I'd give it a proper clean before I continue working on it.
I disconnected the failed cable chain attempt and started rerouting both lubrication and some cables.
Next up was fixing some bed protection. I've seen some people use these but so far I'm not very happy with it.
Either way I bent up a little mount for the carriage and then welded on another angle ontop. This will both hold the accordion thing and constrain/protect the lubrication hoses.
As to my experience with this so far, quite often when compressing ie moving towards the chuck, the accordion wants to bulge up rather than compress.
Not entirely sure how to sort that out besides maybe weighing it down somehow.
Another issue is lack of clearance between the carriage and extension spring covering the ballscrew.
Quite easy to fix just had to detach the whole side and mill/file a lot more clearance.
This gets me the extra Z-depth I need for some specific setups.
Before the extension spring would snag/collide with the carriage if I tried to move into the last 5cm or so.
Next up was some more waycovers.
Bent up two pieces of steel and riveted on some rubber.
I would've liked an all steel construction but at both ends there's simply not room.
At one end it would collide with the back wall and the other end it would both collide with the pulley for the X-axis and stick out uncomfortably much, some rubber sheet solves this nicely.
Another small fix is grinding down the heads of the gib screws and shortening them so they stick out as little as possible.
On several occasions I've had these snag on chips, the oil hoses etc etc which should now be much less likely.
Then we have the "final" little issue, for some reason the back is open which means chips and debris will go out the back and cause a horrible mess that's hard to clean.
It's hard to get a picture that shows it clearly but I've extended the backwall with some more steel sheet and added a little "slide" at the chuck end to prevent most crap from dropping right into the cable chain which is now hidden behind/beneath the headstock.
Still some other various things I need to fix ..
-Adding the counterweight to the rear of the carriage to even out the bed pressure
-Replace the red PLA plastic with an aluminium piece
-Redo the spindle encoder mounting(wobbles atm, might decrease life of encoder)
-Improve how the ballscrew nut is attached to the X-axis(I think it's currently causing some backlash)
-Properly investigate how accurate the movements are and what backlash I'm getting
-Replace the plastic backplate holding the Z-axis ballscrew nut on.
-Figure out a way to lube the X-axis ballscrew nut.
-Actually lube the Z-axis ballscrew nut .... etc etc etc