Automatic Threading Stop on SB Heavy 10

[MrWhoopee]

I finally got motivated to try to work this out.

It's still in the "proof of concept" phase, but I think it's going to work. I need a stronger spring for the disengagement. It works okay without any load but can't overcome the pressure of the lead-screw on the half-nut when actually cutting. First tests give a repeatability of about .005 in. or better.

 

[mattthemuppet2]

that is super neat. I'd love to see how the mechanism works.

 

[silence dogood]

MrWhoopee, that is grand.

 

[DavidR8]

That's fantastic work. Looks much simpler than the retracting tool holder thingy that I recall seeing.

 

[MrWhoopee]

Pivot point for the release lever is retained under the threading dial.



The trip rod was originally attached at the top of the release lever. It required too much travel to achieve release.



So I moved the point of attachment to the middle of the lever.






I had to D&T 3x 10-24 holes in the apron , one for the trip spring anchor and two for the trip rod support at the headstock end.

Hoping to find the right spring. I plan to detail the parts (radius the corners etc.) then black oxide.

 

[MrWhoopee]

That's fantastic work. Looks much simpler than the retracting tool holder thingy that I recall seeing.

This one doesn't retract the tool, just stops the carriage. I can only imagine the complexity of a tool retractor.

 

[Mitch Alsup]

Hey, that's neat. I had been trying to figure out how to do it by pushing not with a sear and spring.

 

[MrWhoopee]

Hey, that's neat. I had been trying to figure out how to do it by pushing not with a sear and spring.

I had too, that's what stumped me. Then I saw someone else's approach. It was much more sophisticated (complicated) than mine, but it gave me the idea.

 

[IamNotImportant]

This one doesn't retract the tool, just stops the carriage. I can only imagine the complexity of a tool retractor.

 

[IamNotImportant]

Hemingway Kits Retracting Tool Holder