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Here a drawing on blind threading I talked about in past thread.? This good drawing. I have not used the 30° angle since 1970's.?? Dave? 
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Good teaching image.
I fiddled with the 30 degree threading technique once.? ?I generally do well straight in.? ? May want to play with it more when time permits (not soon).
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Lone Tree, Colorado? ?USA
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I believe the 29 (or 29.5, should NOT be 30) topic has been discussed before.? You CAN go straight in, but there are cases where that can cause tearing or excess stress to the tool bit tip. This is less likely to be seen in the size work typically done on mini lathes, especially if using aluminum or brass, and the low speeds and light cuts typically taken.
The root issue is chip production control.? When going straight in, the left and right edges both produce a chip.? Both chips develop into the same air space above the tool tip and collide there.? This causes stress that can cause metal tearing, lower surface finish quality, and even a broken tool bit tip.? Maybe not as prevalent in small parts work at low rates and such.? But it is definitely and issue with larger parts with heavier cuts.? There ARE reasons why this threading method is taught.
The collision problem is solved by cutting on only one edge - mostly.? It also cuts a little bit on the other edge (the reason to be a little under 30 degrees) so that other edge 1) also has a good surface finish from the light cut and 2) maintains good contact on that other edge for heat transfer.
You will sometimes hear people say that it results in a "stairstep" on one side.? This technique will NOT do that.? What is happening is that they are depending on an inaccurate degree marking on the compound and actually have the angle set to something greater than 30 degrees and/or the tool bit is not ground to the correct angle and/or the tool bit is not mounted straight.? All of these errors will cause problems with this threading technique.? You can get away with a lot of sloppiness with all of those problems with straight in threading.
Anyway, if you go straight in, and for what you are doing it works, then there is nothing wrong with that.? But that won't work well with everything.
Charles E. "Chuck" Kinzer
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On Thursday, January 25, 2024 at 04:59:20 AM PST, Craig Hopewell via groups.io <cch80124@...> wrote:
Good teaching image.
I fiddled with the 30 degree threading technique once.? ?I generally do well straight in.? ? May want to play with it more when time permits (not soon).
--
Lone Tree, Colorado? ?USA
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I read and have try 29.5° and straight both came out same.?
The 30° in the old books was use for feed so it feed 0.001 on dial it took off 0.001 on the diameter.?
They use for tool post? grinding and set compound from 5° to 11° for finer feed.?
Dave?
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Charles Kinzer
7:47am? ?
I believe the 29 (or 29.5, should NOT be 30) topic has been discussed before. You CAN go straight in, but there are cases where that can cause tearing or excess stress to the tool bit tip. This is less likely to be seen in the size work typically done on mini lathes, especially if using aluminum or brass, and the low speeds and light cuts typically taken
I just remembered why 29.5° is used on light lathes to cut very corse threads.? Until this lathe , I away had heavy lathes and did not have worry about it. Dave?
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One other way to make it cut on one side is to leave the lathe in the standard set-up and advance the tool 1 unit toward or away from from the chuck and 2 units into the part. This advances the tool at a 26.5 degree angle. You can use any base unit you want. I decrease the base unit as I get deeper. Make sure you always move the same direction on each cut and advance the tool into the part as the second part. Paul M
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Is there a particular reason why this thread is called BIND threading ??? ??
On Thu, Jan 25, 2024 at 10:36?AM paul mcclintic via <cannontandem= aim.com@groups.io> wrote: One other way to make it cut on one side is to leave the lathe in the standard set-up and advance the tool 1 unit toward or away from from the chuck and 2 units into the part. This advances the tool at a 26.5 degree angle. You can use any base unit you want. I decrease the base unit as I get deeper. Make sure you always move the same direction on each cut and advance the tool into the part as the second part. Paul M
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.... or are we simply acknowledging reality ??
Is there a particular reason why this thread is called BIND threading ??? ??
On Thu, Jan 25, 2024 at 10:36?AM paul mcclintic via <cannontandem= aim.com@groups.io> wrote: One other way to make it cut on one side is to leave the lathe in the standard set-up and advance the tool 1 unit toward or away from from the chuck and 2 units into the part. This advances the tool at a 26.5 degree angle. You can use any base unit you want. I decrease the base unit as I get deeper. Make sure you always move the same direction on each cut and advance the tool into the part as the second part. Paul M
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so after reading all of this thread
is there a reason to NOT set the compound to 29.5
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The compound handwheel relationship to removal is typically viewed the same if using 29 or 29.5 degrees because the result of the sine of the angle is so close to that of 30 degrees (sine of 0.485, 0.492, and 0.5 respectively) that the error of not being 0.5 is quite low in the handwheel=depth direct relationship as a total area for typical thread depths.
The reason for the angled compound is really not primarily to change the math on the handwheel turns to removal rate.? It is for the reasons I outlined.? If having the handwheel relationship were a goal, then it would be a goal for most any of the other machining people do also.
There is, however, another reason and that is the general convenience of using that angle so that the compound handwheel is out of the way and not directly above and blocking the cross slide handwheel.? This can actually be even more useful in mini lathe since they are so close together that you find yourself bumping one handwheel when turning the other.? So quite a few people leave it that way for convenience (or put the compound parallel to the ways) and also so it is always ready for threading.? I have never met one machinist that set the angle because they needed the help in dealing with the usual relationship of the compound when centered.? And, again, don't use 30 degrees for threading.? It must be sufficiently lower than that to ensure a light cut on one tool edge.
Regarding, "both came out the same".? That may be true, or even "close enough" for many cases.? Even some fairly aggressive and larger high speed CNC systems might go "straight in" if the alloy permits it.? It is most definitely NOT the same for all cases.? An anecdotal example should not be considered remotely definitive.? If you are cutting something like 1" - 8 threads in something like 304 stainless, or stainless that is even more unfriendly, and wanting to do it fairly quickly, you find yourself thankful that you learned the optimum thread cutting technique in your training.? ?If you happen to be trying to cut threads in something a little tough and are going straight in and are having some finish or tearing problems, try doing it at the angle and it will probably solve your problem.??
Charles E. "Chuck" Kinzer
On Thursday, January 25, 2024 at 08:27:40 AM PST, davesmith1800 <davesmith1@...> wrote:
I read and have try 29.5° and straight both came out same.?
The 30° in the old books was use for feed so it feed 0.001 on dial it took off 0.001 on the diameter.?
They use for tool post? grinding and set compound from 5° to 11° for finer feed.?
Dave?
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I do not if everyone knows of standard reading dials and direct reading dials.
Most maybe all mini lathes have standard reading dials. So what direct reading dial you set compound to 30°.
Dave?
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The L missed gettin put in the word Bind Should be " Blind"
animal
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The thread dial and the compound angle have nothing to do with each other.? One is related to where the thread starts.? The other is related to how the tool bit is advanced into the workpiece.
Charles E. "Chuck" Kinzer
On Thursday, January 25, 2024 at 12:05:01 PM PST, davesmith1800 <davesmith1@...> wrote:
I do not if everyone knows of standard reading dials and direct reading dials.
Most maybe all mini lathes have standard reading dials. So what direct reading dial you set compound to 30°.
Dave?
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mario mohl
8:49am? ?
Is there a particular reason why this thread is called BIND threading ???
It simple call a typo. The moderator is the one fix the typos in the titles.? I would if could and tried . Dave?
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Hi Dave. Or maybe posters should proof read their emails before clicking on send !!! ??????????? Ellis ? ? ? mario mohl
8:49am? ?
Is there a particular reason why this thread is called BIND threading ???
It simple call a typo.
The moderator is the one fix the typos in the titles.?
I would if could and tried .
Dave?
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Ellis Cory
2:07pm? ?
Hi Dave. Or maybe posters should proof read their emails before clicking on send
I do just after I hit send.?
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On Thu, Jan 25, 2024 at 10:47 AM, Charles Kinzer wrote:
The root issue is chip production control.? When going straight in, the left and right edges both produce a chip.? Both chips develop into the same air space above the tool tip and collide there.? This causes stress that can cause metal tearing, lower surface finish quality, and even a broken tool bit tip.?
That's not correct.? Whether chips collide or stay clear of each other will have nothing to do with the loads seen on a tool when threading.? They could collide a quarter inch above the tool; there's no way that can apply a load to the tool.? The problem is that the act of making a chip requires force to be applied by the tool and making two chips of the same size doubles the load on the tool.? There is also the matter of heating (the energy required to make a chip goes partly into the chip, partly into the work, and partly into the tool).? If colliding chips was the problem cutting a small 40 tpi thread would be worse than cutting a 2 tpi thread because the sides of tool on the bigger thread are farther apart hence less likely to result in a chip collision. Kurt Laughlin
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They don't collide a "quarter inch above the tool."? They collide directly at the tool tip putting it under stress.? Imagine just taking a tool and dragging it in a straight line as it tries to dig into the metal.
Making to chips at the same time only doubles the load with the same depth of cut.? But, actually, it more than doubles the load because of the energy lost in the two chips mashing against each other.
You are incorrect that the thread pitch makes chip collision less likely.? It occurs with all thread pitches.
Charles E. "Chuck" Kizner
On Thursday, January 25, 2024 at 05:48:50 PM PST, KURT <kurt.laughlin@...> wrote:
On Thu, Jan 25, 2024 at 10:47 AM, Charles Kinzer wrote:
The root issue is chip production control.? When going straight in, the left and right edges both produce a chip.? Both chips develop into the same air space above the tool tip and collide there.? This causes stress that can cause metal tearing, lower surface finish quality, and even a broken tool bit tip.?
That's not correct.? Whether chips collide or stay clear of each other will have nothing to do with the loads seen on a tool when threading.? They could collide a quarter inch above the tool; there's no way that can apply a load to the tool.? The problem is that the act of making a chip requires force to be applied by the tool and making two chips of the same size doubles the load on the tool.? There is also the matter of heating (the energy required to make a chip goes partly into the chip, partly into the work, and partly into the tool).? If colliding chips was the problem cutting a small 40 tpi thread would be worse than cutting a 2 tpi thread because the sides of tool on the bigger thread are farther apart hence less likely to result in a chip collision. Kurt Laughlin
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Here photo of almost the lathe one. But not compound angle also a thread stop for same lathe can only be straight in. This where it gets confusing new at using a lathe. I use the compound at 90° so I can make fast changes using the carriage stop.? Dave?   
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I can see how that can be confusing.
If you are threading using ONLY the cross slide, the "thread stop" can be used as a limit for the depth of the thread cut.? That's pretty straight forward.
But there is another purpose.? If using the compound at an angle, it is typical to use the cross slide to retract the tool, move it for the next cut, and then move it back in (returns tool bit to starting position at the last cutting depth) while leaving the compound position alone.? In this case, the "thread stop" can be used so that when you return the cross slide for the next cut, it always returns to the same place.? (You don't have to read the handwheel - and it keeps you from making mistakes.)? Then you move the compound in further for the next cut.? In this case, it isn't really being used as a thread stop, but just as a cross slide stop so you always return it to the same place..
If you wanted a thread stop on the compound to limit motion to the maximum thread depth, you would have to rig something up for that unless somebody sells such a thing.? Most everything you can think of probably exists somewhere, but I'm not aware of a commercial stop for the mini lathe compound.
Charles E. "Chuck" Kinzer
On Thursday, January 25, 2024 at 07:07:41 PM PST, davesmith1800 <davesmith1@...> wrote:
Here photo of almost the lathe one. But not compound angle also a thread stop for same lathe can only be straight in. This where it gets confusing new at using a lathe. I use the compound at 90° so I can make fast changes using the carriage stop.? Dave? ![]() ![]() ![]()
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