Topics

Metric thread dial


Jim_B
 


There are metric thread dials. As noted they are for metric threaded lead screws. Also they are quite complex and have multiple gears depending on the thread pitch.








Sent from my iPhone-8 no
Jim B,

--
Jim B


William Nelson
 

Almost every thread I cut is to a shoulder. How do you go about that if you can't disengage the halfnuts? Do you stop the lathe some distance from the shoulder hoping you stop in time or stop far enough to not crash and then hand turn the spindle to get to the shoulder? Perhaps this would be a good operation for left to right threading? I have had the occasion where I would have loved to metric thread but don't have the gears. Maybe in the future. 

Bill form Socal


m. allan noah
 

You CAN disengage the half-nuts when cutting a thread whose type does
not match the thread dial. But, you must then immediately stop the
lathe, and run it in reverse. Then re-engage the half-nuts on the
original mark, and run the tool back out of the thread. See the bottom
of this page for more info.
http://conradhoffman.com/metricthreading.htm

allan

On Sun, Jan 3, 2021 at 2:37 PM William Nelson <wnnelson@sbcglobal.net> wrote:

Almost every thread I cut is to a shoulder. How do you go about that if you can't disengage the halfnuts? Do you stop the lathe some distance from the shoulder hoping you stop in time or stop far enough to not crash and then hand turn the spindle to get to the shoulder? Perhaps this would be a good operation for left to right threading? I have had the occasion where I would have loved to metric thread but don't have the gears. Maybe in the future.

Bill form Socal
--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


Bill in OKC too
 

You can cut threads to driving the carriage from left to right, i.e, towards the tailstock, too. Eliminates the problem. Saw it mentioned on one of the many groups I belong to just a few days ago, IIRC. Could not tell you exactly how, off hand, but I think you'd use a rear tool post with the cutter upside down. I'll see if I can find it. 

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Sunday, January 3, 2021, 01:37:11 PM CST, William Nelson <wnnelson@...> wrote:


Almost every thread I cut is to a shoulder. How do you go about that if you can't disengage the halfnuts? Do you stop the lathe some distance from the shoulder hoping you stop in time or stop far enough to not crash and then hand turn the spindle to get to the shoulder? Perhaps this would be a good operation for left to right threading? I have had the occasion where I would have loved to metric thread but don't have the gears. Maybe in the future. 

Bill form Socal


ww_big_al
 

Get yourself a left-hand threading tool. Turn it upside down on the tool post. Run the lathe in reverse and cut the thread towards the tail stock. Should not do this with a threaded-on chuck.

 

Here is a video from Joe Pi demonstrating it.

(29) Threading on a manual lathe BEST TECHNIQUE EVER !!!! - YouTube

Al

 

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of William Nelson
Sent: Sunday, January 3, 2021 2:36 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Metric thread dial

 

Almost every thread I cut is to a shoulder. How do you go about that if you can't disengage the halfnuts? Do you stop the lathe some distance from the shoulder hoping you stop in time or stop far enough to not crash and then hand turn the spindle to get to the shoulder? Perhaps this would be a good operation for left to right threading? I have had the occasion where I would have loved to metric thread but don't have the gears. Maybe in the future. 

Bill form Socal


Bill in OKC too
 

That is the video I saw! Two of my three lathes, however, have screw-on chucks. I am looking at drilling & tapping the chucks to use a set-screw and brass shoe to try to lock the threads when I want them locked. Not sure how well that will work, but SB has a patent drawing I've seen for something similar. 

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Sunday, January 3, 2021, 02:29:32 PM CST, ww_big_al <arknack@...> wrote:


Get yourself a left-hand threading tool. Turn it upside down on the tool post. Run the lathe in reverse and cut the thread towards the tail stock. Should not do this with a threaded-on chuck.

 

Here is a video from Joe Pi demonstrating it.

(29) Threading on a manual lathe BEST TECHNIQUE EVER !!!! - YouTube

Al

 

 

From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of William Nelson
Sent: Sunday, January 3, 2021 2:36 PM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Metric thread dial

 

Almost every thread I cut is to a shoulder. How do you go about that if you can't disengage the halfnuts? Do you stop the lathe some distance from the shoulder hoping you stop in time or stop far enough to not crash and then hand turn the spindle to get to the shoulder? Perhaps this would be a good operation for left to right threading? I have had the occasion where I would have loved to metric thread but don't have the gears. Maybe in the future. 

Bill form Socal


Ondrej Krejci
 

Howdy,

In the primordial days of thread cutting on lathes, a hole would be drilled where the cutting bit would stop and it would be timed accordingly.  Early threading lathes were hand cranked so stopping was not a problem.  With powered lathes, one would stop short, disengage the belt, and manually turn over the spindle, via the driven pulley.  Such operations do not work well with TC tooling.

Threading dials are mainly on Imperial lathes, the one advantage of the inch.  I have seen only one metric lathe with a threading dial in thirty years.  If threading away from the headstock were possible, the half nut would still have to remain engaged and one would have to run the tool past the shoulder in forward, then manually crank the lathe in reverse to take up slack and bring the tool to the starting position and feed the tool in for the next pass.  Even with a modern lathe, geared drive and instantaneous stop and reverse, any larger quantity of such threading would become tedious.  My suggestions are die threading, using a chasing head, or building a thread milling set-up, listed in increasing cost.

Good Luck!


OK


John Dammeyer
 

Or just install my ELS kit.  
John  

sent from John's new S10

On Jan. 3, 2021 5:06 p.m., "Ondrej Krejci via groups.io" <okrejci@...> wrote:

Howdy,

In the primordial days of thread cutting on lathes, a hole would be drilled where the cutting bit would stop and it would be timed accordingly.  Early threading lathes were hand cranked so stopping was not a problem.  With powered lathes, one would stop short, disengage the belt, and manually turn over the spindle, via the driven pulley.  Such operations do not work well with TC tooling.

Threading dials are mainly on Imperial lathes, the one advantage of the inch.  I have seen only one metric lathe with a threading dial in thirty years.  If threading away from the headstock were possible, the half nut would still have to remain engaged and one would have to run the tool past the shoulder in forward, then manually crank the lathe in reverse to take up slack and bring the tool to the starting position and feed the tool in for the next pass.  Even with a modern lathe, geared drive and instantaneous stop and reverse, any larger quantity of such threading would become tedious.  My suggestions are die threading, using a chasing head, or building a thread milling set-up, listed in increasing cost.

Good Luck!


OK