Lathe Threading tools

Does Asmbly have any lathe threading tools (external)?

Something like this perhaps- DORIAN 58020 - MTVOR10-3B-C, 5/8" Shank On-Edge Holder / Monoblock for TNMA32 Inserts, Right Hand

I don’t believe we do; @mkmiller6 or @Jon would know for certain. Is that item what you would recommend? Is it compatible with our existing tool holders? (More for Matt and Jon:) Are there alternatives from sources we’ve used before, possible cheaper?

Having the ability to make external threads on a shaft is a common lathe task. It opens up a lot of options in terms of fasteners, axles, etc. It’s also a topic that falls on the advanced side of lathing, and could be a good topic for a class by itself.

Most of the tooling is currently on a 1/2" shank, but I think a 5/8" shank will fit the tool holders. Fatter is always better so that’s what I specified in my the link.

With very few exceptions, I’ve always paid $80-$100 for carbide insert tool holders. The $93 price on the Dorian tool is in line with that. You can find cheaper Chinese insert holders, but that’s mostly for really generic tools like for CNMG inserts.

One place where I have had really good luck with cheap Chinese hardware is with buying the quick change tool post tool adapters. If we add more lathe tooling, they will also be needed. I think I paid $30/ea.

I am going to caution shopping any kind of machine tooling on Amazon. It never fails to disappoint. Travers, MSC, Grainger are the best I’ve found. You know exactly what you are getting.

Threading tools for the lathe have definitely been on our tool acquisition list. I see threading inserts on our budget sheet, but not the holders, so I don’t know the specific plans. We have had good results buying tooling from Shars. Matt and Jon will be able to say more.

There were comments when the new lathe came along the lines of “incorrect threading operations can actually harm the lathe–we’ll have a class on it”. I haven’t really heard much after that.

There is one new external threading tool. Details on inserts and a link to the shars catalog entry are on the wiki Grizzly G0509G Lathe - Asmbly Wiki

There might also be some old ones kicking around, and you could always grind your own HSS tool

We don’t have any internal or acme threading tools that I’m aware of.

Right, I’d forgotten about the lathe tool list on the wiki. To be fair, it has only been mentioned 2-3 times in the last week. :man_facepalming:

Fwiw, the 1/2" tooling is mostly leftovers; the new ones we’ve bought are 3/4". Any small/random tool that’s seeing a lot of use is a candidate for replacement.

One exception is boring bars - we need to keep some small ones around to accommodate smaller holes.

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If by “incorrect threading operations” you mean “crashing the machine”… then yes it can harm the lathe :rofl:

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Like Jon said, the space has a right handed threading tool. I also have a left handed threading tool (check out this video if you aren’t aware of the left-handed-reversed-chuck threading technique that’s much safer for the lathe) and an internal threading tool that I’d probably be okay with leaving out and letting others use. An advanced lathe class, likely including both threading and tapers, is indeed something we talked about but haven’t managed to actually get developed yet.

Well, I haven’t seen anybody jumping up and down in this thread, so I guess it’s acceptable for me to just pull the manual and try some threading operations. :slight_smile:

There was mumbling about better quick change tool holders coming. Is that in pipe?


Seek and ye shall find. Ask and ye shall receive.

This is exactly what I was looking for. BTW, I like how Shars puts all the tool details on the side! No more hunting for the right torx wrench, or trying to figure out what size inserts or screw.

I found one TNMA insert in the drawer to fit so that leaves 4 good tips. I did not see any cut-off inserts in the drawer, and the cut-off / grooving blade was pretty banged up. Might to be time to get a small order together.

I also found one empty QCTP tool holder there on the bench.

I wasn’t aware of Shars until now. I’m impressed!

Yes, we’re working on the cutoff tool issue. I think it’s gotten pretty banged up because people have been using it for grooving – it is ONLY for parting.

I don’t see any room for improvement on the QCTP tool holders. They are just a static piece of metal that holds the tool with some rigidity. There might be room for improvement with a higher-dollar QCTP itself, but I don’t think the $800 would be justified.

A DRO for the lathe is probably the #1 priority if you had $~800 to spend.

If you really want some threading practice, I have a project where I need to put an M36 x 1 thread on a 1018 steel rod making 100 of these parts- Fusion.

Better quick tool holders came, several months ago.

What’s the difference between parting and grooving? Isn’t a part-off just a groove that goes all the way through the center?

Every time I’ve broken or damaged a cut-off tool, it’s been because of one or a combination of the following (assuming your insert is in good shape)-

  1. too high rpm (better to run 30-50% slower than typical facing/turning operations of the same material/diameter)
  2. inadequate or wrong coolant/lube
  3. width to depth aspect ratio was too high and didn’t allow for chip clearing. If I anticipate this, now I’ll start with a 3mm cut-off tool, go half-way in, then switch to a 2mm once I’m cutting < 1.5" diameter
  4. did I mention lack of lubrication?
  5. feed to fast (because linear rate at towards the center of a part is much lower than at the outside)

Is it just me, or does the lathe chuck handle interfere with the side of the gearbox?

I’ll make a post about the issue later – but you can look at the construction of the parting tool and see that, unlike a more general grooving tool, it cannot tolerate ANY lateral forces – nothing holds the insert into place against such forces. It is strictly for parting – pure radial cuts in the middle of the material.

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There isn’t anything inherently different between parting and grooving, unless you’re trying to make Z-axis (in lathe terms) cuts with the tool. There’s nothing stopping you from making adjacent grooves to accomplish the same goal though. You just have to be careful there because it’s easy to have the tool want to follow the groove you’ve already made, similar to drilling two holes too close to one another. For those cases, I tend to leave ~1/2 the width of the parting tool between grooves, then come back and clean those high spots up.