New PM-1228 Joins the Crew

[AlanB]

Today I was doing some boring and decided to try the carriage stop. The carriage just pushed the stop, even with it quite tight. So I found the clutch adjustment pins to reduce the clutch tension. One pin fit fine, the other did not quite fit into the holes on the clutch adjuster. A few moments on the belt sander fixed that. I reduced the tension too far and the heavy spring pushed the threaded end of the adjuster out entirely. I used a piece of wood to push the adjuster's end nut against the strong spring and spun the housing with fingers to re-engage it to a minimum setting, with 2-3 threads engaged. This seems to be working, at least with the present workload which is quite light. The mechanism slips quietly, not with the loud clicks as mentioned and shown in Frank Hoose's videos. This was at low speed, at higher speed it might get noisy. The feed clutch is another nice feature of the PM-1228.

 

[AlanB]

I 3D printed a cradle for the four jaw chuck, here are both the 6" (160mm) and the 8" (200mm) cradles on the PM-1228. The cradles have 3mm clearance so they don't get stuck when the chuck is mounted on the lathe. They are precisely fitted to the lathe ways so the alignment of the chuck is very close. The same design can be used to make way covers which will come in handy. Sharp eyed viewers will notice that the cradle under the smaller chuck is an earlier version and lacks the chamfer on the upper edges that was added. Both designs now have that feature.

 

[AlanB]

I have published the files for the chuck cradles here:

PM-1228 Lathe Chuck Cradles by AlanB | Download free STL model | Printables.com

Chuck Cradles for 6" (160mm) and 8" (200mm) chucks for Precision Matthews 1228 Lathe | Download free 3D printable STL models

www.printables.com

 

[ptrotter]

What program did you use to design these models?

 

[AlanB]

OpenSCAD

 

[AlanB]

I will probably print some way covers next.

 

[AlanB]

I made the first way cover 50mm wide, which fits from the headstock to the chuck cradle when changing chucks. Next I'll make another section 75mm wide which covers under the chuck, together that's about the right amount to use when working near the chuck. I have some ideas about a telescoping addition that will provide ways protection further out.

 

[Badabinski]

Chuck cradles are a brilliant idea. How heavy are your chucks? My 8" 6 jaw is like 60-70 pounds with the backplate and is an absolute bear to mount on a threaded spindle nose, so having a cradle like that would be fantastic.

 

[AlanB]

Your chucks are about twice what these chucks weigh for the 12x28 (I don't have a 6 jaw yet). It pays to use extra care when working with them. I recall one accident investigation involving a 75 pound lathe chuck and some unfortunate fingers. Having a healthy safety perspective is important. Separating the lifting operation from the mounting operation is a useful process improvement. These chucks are in the weight range where it seems easy enough to skip using lifting equipment, but the consequences of a slip can be significant. The cradle is a big help but in order to be able to extract it there must be some clearance to the perfect alignment, unless the cradle had a built in jack or similar feature.

I would like to have a 6 jaw chuck. They have gone quite pricey..

 

[AlanB]

50 and 75mm way covers, fresh off the Prusa MK3 3D Printer: