[Shop] Lathe semi-broken, use carefully!

[Igor Yeremin]

Update: Lathe is now fixed! (actually several weeks ago, but I forgot to
send the update, oops)

Apparently Busy Bee doesn't sell replacement parts anymore, so I ended
up buying a piece of 4140 and machining a new end cap. The lead screw
was straightened by chucking it in the lathe on one end and pulling
really hard on the other. It now runs out less than 0.005", compared to
over 0.040" after the crash. The old nut appears to be working just fine.

To prevent the same sort of crash from happening again, I drew a mark
with a silver sharpie to indicate where you should stop feeding the
cross slide before it collides with the rear wall. The mark is on the
saddle, left of the cross slide, "END STOP" is written next to it. I'll
put photo of it on the wiki next time I'm at the lab.


On 2017-12-06 8:23 PM, Igor Yeremin wrote:
> Hi Hacklab!
> 
> TL;DR: The lathe cross slide is damaged, but functional. If you're going
> to use the lathe, please be very careful with the cross slide until the
> broken parts are replaced!
> 
> Last night while finishing up a project, I was using the cross power
> feed to face a part. The cross slide reached the end of travel without
> me realizing it and the lathe happily continued pushing it further.
> 
> This forced the Acme nut into the back wall of the cross slide, bending
> the nut at the adjustment joint and compressing the M4 screws used to
> tension it about 1mm. The lead screw bent a little just before the start
> of the thread, and one of the mounting flanges broke on the end cap with
> the thrust bearing.
> 
> With Will's help we managed to disassemble the cross slide, bend the nut
> back into shape, and re-assemble everything. The handle now turns
> unevenly because of the bend in the lead screw, but it seems to be
> usable. We had some trouble engaging the cross slide power feed right
> away, but after moving the cross slide back and forth, power feed
> started engaging correctly again. Next time I'm at the lab I will take
> the power feed gearbox apart to make sure nothing is broken in there.
> 
> For now, the lathe seems to be functional, but please use it carefully
> and stop if you see or hear something wrong. Since the end cap is only
> attached on one side, also avoid applying too much force with the cross
> slide.
> 
> I'll contact Busy Bee Tools to order a replacement end cap, lead screw,
> and nut.
> 
> 
> Igor
>