[bogiestl]

I'm researching stuff for a shop I'd like to do here in a bit... And I've grown used to the manual lathe I usually use where I am now - It's a big ol' Howa... and it has an autostop on the carriage for the compound, so you can set it to stop when you auto feed... Push the lever, debur and inspect the last part, and when you hear the click, pull the cutter out, roll the carriage, pull lever on the collet, swap parts, repeat... Great for simple short runs when we don't want to do the whole CNC route...

Anywho, I've looked at some of the lathes that are out there, and some don't have that feature - Are there any that you guys would recommend? I'm looking for a smaller lathe (i.e., can be moved in the back of a decently stout pickup truck or van).

That, and it's nice to leave the thing set so that I don't cut on the chuck jaws... (grin)

[handlewanker]

Hi, there's an easy way and a hard way, but both are DIY.

First way is to set a trip on the feed shaft that runs through the carriage apron to trip the feed mechanism out.....your lathe design will determine how the trip is fitted, but in essence you will probably need to open up the carriage apron and look at how the feed mechanism is engaged, then just introduce a trip mechanism that is adjustable.

The second way that is a bit more complicated, but is extremely efficient for high speed thread cutting trip out, is the one tooth dog clutch fitted into the gear train that sets your screw cutting/feed gear train on the end of the headstock.

This design for a trip mechanism was described by Martin Cleve in the Model Engineer some time back in 1977.

It allows you to single point screw cut at speed right up to a shoulder and trips the gear train out at the very last moment, much quicker than you could do manually, that is if'n you had the sharp reflexes to trip the gear train using the normal leadscrew unclasping method for screw cutting.

It needs some slight modification to the gear train arrangement, not too drastic, but definately a DIY project.....more details and a sketch if'n your interested.

The actual article appeared in The Model Engineer in March 1977 volume 143 no. 3557 page 334.

This allows one to do screw cutting with any pitch, Imperial or metric, and it's impossible to get crossed threads etc.
Ian.