What's wrong with my threading technique?

[J Tiers]

A typo in the chart does not invalidate the diagrams, which are self-consistent.

The diagrams DO show the apparently same insert being used both ways. Note the way they show LH and RH in 1 thru 4, which appear to be correct. Compare 1 & 6, 2 & 5, where they appear to show the same type insert cutting in opposite helices.

You have to make some assumptions to decide what they "must have meant"...... Which it is possible to do, they "must have meant" to show a LH where it appears identical to the RH..... but that rather invalidates the diagram as any sort of "authority" to be quoted, footnoted, etc.

[tomato coupe]

The diagrams DO show the apparently same insert being used both ways. Note the way they show LH and RH in 1 thru 4, which appear to be correct. Compare 1 & 6, 2 & 5, where they appear to show the same type insert cutting in opposite helices.

You have to make some assumptions to decide what they "must have meant"...... Which it is possible to do, they "must have meant" to show a LH where it appears identical to the RH..... but that rather invalidates the diagram as any sort of "authority" to be quoted, footnoted, etc.

I have no idea what point you're trying to make. The Korloy diagrams are fine, but you can completely dismiss them and introduce new ones if you prefer.

[J Tiers]

I have no idea what point you're trying to make. The Korloy diagrams are fine, but you can completely dismiss them and introduce new ones if you prefer.

OK, Dan....

Point nbeing that you cannot use the table on 5-8 as it is obviously wrong in one place. It also shows and lists both RH external tool and LH external tool as being used for opposite hand threads with same insert. Precisely what is being complained about.

Nice enough drawings, but you have to supply your own content as to what goes with which.

[tomato coupe]

Point being that you cannot use the table on 5-8 as it is obviously wrong in one place.

The only thing wrong is the CW/CCW entries have been flipped in the lower half of the chart.

It also shows and lists both RH external tool and LH external tool as being used for opposite hand threads with same insert.

RH inserts are not exclusively used for cutting a RH thread.

Precisely what is being complained about.

Who complained about what?

Nice enough drawings, but you have to supply your own content as to what goes with which.

Other than the noted typo, the diagrams are fine.

[PStechPaul]

The "EXT RH" and "EXT LH" in column 2 refer to the toolholder and the helix angle of the insert. I ground my threading tools to fit the helix angle. It was not as critical for 3/8"-16 standard threads, but makes a big difference for square threads.

[J Tiers]

.....
RH inserts are not exclusively used for cutting a RH thread.

.

The helix angle has been extensively commented on in posts above as part of the problem the OP is having, that the cutting is on the wrong side and so forth.

Here we have what appears to be you discounting all that, and suggesting that there is NO helix angle problem whatsoever in the illustrations, despite the angle for LH and the angle for RH being opposite, as a basic part of the thread.

Looking at the threads, one tilts to the left and the other to the right. An insert that is labeled for left hand, and one labeled for right hand, would be expected to have opposite tilts. If they do, then obviously one is not optimized for the opposite handed thread, when being held in the exact same position. Which is what would happen if the same holder and insert are used for the two different threads.

Only if the insert is made universal for either handed thread , would there be no issue.

However, the folks actually SHOW that there are 4 kinds of inserts.... in external, the coding for inserts shows that there are left and right handed inserts. That would certainly imply that there is a difference between the L and R handed inserts.

And, if there is, then why is the RH insert AND holder being suggested for both hands of threads?

[tomato coupe]

The helix angle has been extensively commented on in posts above as part of the problem the OP is having, that the cutting is on the wrong side and so forth.

Here we have what appears to be you discounting all that, and suggesting that there is NO helix angle problem whatsoever in the illustrations, despite the angle for LH and the angle for RH being opposite, as a basic part of the thread.

Looking at the threads, one tilts to the left and the other to the right. An insert that is labeled for left hand, and one labeled for right hand, would be expected to have opposite tilts. If they do, then obviously one is not optimized for the opposite handed thread, when being held in the exact same position. Which is what would happen if the same holder and insert are used for the two different threads.

Only if the insert is made universal for either handed thread , would there be no issue.

However, the folks actually SHOW that there are 4 kinds of inserts.... in external, the coding for inserts shows that there are left and right handed inserts. That would certainly imply that there is a difference, and that there is a difference between the L and R handed inserts.

You can use a RH insert to cut either LH threads or RH threads, but you use different shims for the two applications. The shims change the angle.

[J Tiers]

You can use a RH insert to cut either LH threads or RH threads, but you use different shims for the two applications. The shims change the angle.

The shim is not mentioned in the table or diagram, it is mentioned elsewhere. and another part of the info seems to associate one shim exclusively with ER, and the other with EL HOLDERS. Somewhat confusing

The various combinations and some of the given information manage to give the maximum appearance of conflict.... It starts to make sense once you decode a lot of the info and discount some of what appears to be said. The info in the table and diagram needs to be supplemented by info that is not referred to

An interesting system.

Apparently not what the OP has, so that special shim system does not apply in his case.

[tomato coupe]

The shim is not mentioned in the table or diagram, it is mentioned elsewhere. and another part of the info seems to associate one shim with ER, and the other with EL HOLDERS.

Information for selecting shims appears on the same page as the previously referenced chart and diagram. Regardless, it is standard procedure to select the proper shim when you use this type of threading insert.

The various combinations and some of the given information manage to give the maximum appearance of conflict.... It starts to make sense once you decode a lot of the info and discount some of what appears to be said.

That one typo sure has thrown you off the scent.

An interesting system.

Apparently not what the OP has, so that special shim system does not apply in his case.

There is nothing special or unusual about this type of shim system -- it is quite common. That being said, it is possible that the OPs holder does not have a shim, because small internal boring-bar-type holders are often made with an effective shim angle that corresponds to the limited pitch / diameter combinations that are likely to be cut using a holder / insert of that physical size.

The OP's setup suffers from another issue, however, in that he is using an internal thread insert to cut external threads at a relatively small diameter, so the radial clearance angle will not be correct.

Have you ever used this type of threading insert?

[J Tiers]

Those are laydown. I think I have some that came to me in a toolbox. Have not used them, IIRC they are "topping type" and I do not know what pitch they are for nor have I measured to find out.

have used the standup type quite a bit.

I was not quite appreciating the differences between the standard "insert" and the similar looking "laydown threading insert" as far as the way they fit the holder (and. yes, the typo was no help!). Some standard have shims, but they are not angled. I have piles of regular inserts, holders, boring bars, etc and use them.

[tomato coupe]

Those are laydown. I think I have some that came to me in a toolbox. Have not used them, IIRC they are "topping type" and I do not know what pitch they are for nor have I measured to find out.

have used the standup type quite a bit.

I was not quite appreciating the differences between the standard "insert" and the similar looking "laydown threading insert" as far as the way they fit the holder (and. yes, the typo was no help!). Some standard have shims, but they are not angled. I have piles of regular inserts, holders, boring bars, etc and use them.

Sorry, but I have to ask: Why do you argue about something you have no experience with and have limited knowledge of? What's the point? Do you just like to argue?

[tom_d]

A few pages back on this thread I posted a document link from a cutting tool supplier that showed the relationship between a thread's pitch, pitch diameter, and its helix angle. I was hoping this would help explain the interaction of those variables as a way to help the OP of this thread, and others, with some of the questions pertaining to problems encountered in his cutting technique. Unfortunately I neglected to proof read the documents, and it turns out there are some dependencies in some of the information provided. My apologies. Also, as a matter of full disclosure, I do not currently own any tooling from this supplier. I simply found that they had a wealth of information that I thought would be helpful here. After a little research I found an updated catalog from that same supplier, and it looks like they have identified and corrected those dependencies, so I'm going to risk offering a link to the revised pages: http://www.korloy.com/newkorloy/eng/..._Threading.pdf The chart in question appears on page 4 of the catalog, which is page 5 of the pdf.

[Richard P Wilson]

I just single point threads using a round HSS toolbit in a holder. The bit is clamped in with an Allen grub screw, and can be readily adjusted to the required angle for whatever pitch of thread I'm cutting, right hand or left hand. Similar arrangement in a boring type tool for internal threads. Works for me, avoids having loads of different inserts and avoids pages and pages of arguments about how they are used.

[danlb]

Emphasis mine:

I just single point threads using a round HSS toolbit in a holder. The bit is clamped in with an Allen grub screw, and can be readily adjusted to the required angle for whatever pitch of thread I'm cutting, right hand or left hand. Similar arrangement in a boring type tool for internal threads. Works for me, avoids having loads of different inserts and avoids pages and pages of arguments about how they are used.

Well, I agree that it will avoid having loads of different inserts. I'll leave it at that!

Dan

[3 Phase Lightbulb]

Sorry, but I have to ask: Why do you argue about something you have no experience with and have limited knowledge of? What's the point? Do you just like to argue?

His grandiosity is always hard at work.