Yes, you can't disengage the half nut from the lead screw on metric threads. And you also have to change gears but you know that. You use the reversing lever to move the carriage back to the right.
Posts: 17442 | Location: USA | Registered: 02 August 2009
Thanks for the reply. Now would any one know what the tap drill size is for a 10x.7 metric thread is. I'm making the pc that holds the firing pin on a old Spanish shot gun.
Take a cut. Back out real fast while reversing feed. Feed compound in. Reverse feed again. Take a cut. Back out real fast again. Repeat repeat repeat REAL FAST.
Doug Humbarger NRA Life member Tonkin Gulf Yacht Club 72'73. Yankee Station
Try to look unimportant. Your enemy might be low on ammo.
Posts: 8351 | Location: Jennings Louisiana, Arkansas by way of Alabama by way of South Carloina by way of County Antrim Irland by way of Lanarkshire Scotland. | Registered: 02 November 2001
Not the way I do it; if you reverse the direction while the carriage is moving, it won't reverse; it will continue on, and that will be bad. This lathe is electric; not a clutch type. Just stop the lathe when it is almost at the end of your cut. Then back out the tool, and reverse the carriage. Trying to do it "real fast" will not be good. I've done this, on this lathe, many times.
Posts: 17442 | Location: USA | Registered: 02 August 2009
http://www.conradhoffman.com/metricthreading.htm About 1/2 way down the page. Been using this technique for over 30yrs. Works every time as long as you keep your head out for your ***. Hoffman explains it better than I can/could.
Posts: 719 | Location: fly over America, also known as Oklahoma | Registered: 02 June 2013
I don't know how many phases an Enco lathe has but for sure, if you move the switch to reverse while it is in forward, it does nothing. I know nothing about phases. Maybe the moon phases. And those directions in the link, do not apply to an Enco lathe; you will end up with a mess of crossed "threads".
Posts: 17442 | Location: USA | Registered: 02 August 2009
There is actually a way to cut metric threads on a lathe with imperial lead screw and disengage the half nuts. Have done it several times in the past with excellent results, but still so seldom I have to watch the video each time I cut some! I'll try to find it and post a link.
Doug Humbarger NRA Life member Tonkin Gulf Yacht Club 72'73. Yankee Station
Try to look unimportant. Your enemy might be low on ammo.
Posts: 8351 | Location: Jennings Louisiana, Arkansas by way of Alabama by way of South Carloina by way of County Antrim Irland by way of Lanarkshire Scotland. | Registered: 02 November 2001
Originally posted by kendog: There is actually a way to cut metric threads on a lathe with imperial lead screw and disengage the half nuts. Have done it several times in the past with excellent results, but still so seldom I have to watch the video each time I cut some! I'll try to find it and post a link.
Wow; confusing. I know how to cut metric threads and will just leave the half nut engaged. I do it all the time on ZKK actions; why they changed from 12 TPI make zero sense. Yes, I stop the lathe just before the cut is at the shoulder, then reverse. Come on over and I'll teach you. (And by using the word, You, I am not referring to anyone.) So no more hate PMs. Not rocket surgery.
Posts: 17442 | Location: USA | Registered: 02 August 2009
I think a few here may have learned how to thread metric, with an inch lead screw, to a shoulder without having to keep the half nut engaged all of the time. All it takes is putting the proper gears on, set the QC leavers in their proper position for the desired pitch, and a little practice. Do it however you want. It's just another way of accomplishing the same task.SFM matters.
Posts: 719 | Location: fly over America, also known as Oklahoma | Registered: 02 June 2013
I’ve been threading metric by that method, too easy to disengage thread nut, back out with the cross slide and stop the lathe. Reverse spindle and re-engage threading on the same number on the dial as it comes back the other way. Works very well as long as you’re not one revolution out on that thread dial. The biggest problem I’ve had was forgetting to change out the gears after a metric thread before threading in inches again! Solved that by putting a placard on the face of the lathe that says ‘METRIC’ when I have the gears switched over.
Shoot straight, shoot often. Matt
Posts: 1190 | Location: Wisconsin | Registered: 19 July 2001
I think the foot brake is a blessing when threading metric I don't disengage the half nut. On an older lathe without one then the halfnut way would help getting close to the shoulder. I always set an indicator up to my saddle so when the oil and chips make the stopping point hard to see, the needle on the dial leaves no doubt.
gunmaker ------------------ James Anderson Metalsmith & Stockmaker WEB SITE
Originally posted by matt salm: I’ve been threading metric by that method, too easy to disengage thread nut, back out with the cross slide and stop the lathe. Reverse spindle and re-engage threading on the same number on the dial as it comes back the other way. Works very well as long as you’re not one revolution out on that thread dial. The biggest problem I’ve had was forgetting to change out the gears after a metric thread before threading in inches again! Solved that by putting a placard on the face of the lathe that says ‘METRIC’ when I have the gears switched over.
Been there, done that!
Jim Kobe 10841 Oxborough Ave So Bloomington MN 55437 952.884.6031 Professional member American Custom Gunmakers Guild
Posts: 5534 | Location: Minnesota | Registered: 10 July 2002
On my craftsman 12x36 with a QCGB I swapped the 48 tooth idler gears for a 52/44 combo gear. I can now cut the most common metric threads by moving the sliding gear to the inner position. I lost being able to cut threads 7tpi and coarser.
I leave the half nuts engaged when cutting metric threads. Works for me.
makes life easier.
