How to Save Money When Buying threading in lathe machine
Sep. 08, 2025
threading | Practical Machinist
If you've been using HSS exclusively and are on a manual lathe at slow speeds, you may set yourself up for disappointment with carbide inserts. OTOH, if you can speed things up a bit you may find great joy.
What I'd do is first consider if you also do any grooving, or want to in the future. If that's true and you really want to control your initial expenditure on tool holders, go with the Top Notch-style inserts. This is best for low volume and home shops as you can buy just one tool holder (assuming O.D. work) and have the holder for a wide variety of threads and grooves.
If you feel it's time for the best quality burr-free thread that you can get without thread milling, go with the lay-down style inserts, ER16 size is probably best. With that style holder, you can get general-purpose inserts that do a wide range of threads, or lead-specific full-form inserts that cut the crest of the threads as well as the roots. In the ER16 size of cresting inserts you can get UN, UNJ, ISO metric, Acme, Stub Acme, Buttress, and a wide variety of other thread forms. The UN, for example, are available from from 72tpi to about 8tpi.
It can be a little bit of money to set yourself up with lay-down threading, but worth it it is you want the quality. For a big percentage of threads made though, you will be fine with Top Notch. There are some limited full-form insert for that style holder, but the real advantage to it is adding all the grooving capability. One holder, lots of things you can do including easy-to-get custom shapes. It all depends upon the kind of work you do. threading with carbide inserts
using an insert made for a certain pitch is for CNC threading.
if you have a hss bit sharpened to a sharp vee on a cnc lathe you set what dia the tip is cutting but when you thread you use the side of bit. so you will find a nut will not go on the threads because they are too big.
if you put a flat (or radius) on tip of the bit you will find the dia the tip cuts and the threads the side of cutter closer to spec. if bit was of correct shape then dia cut and pitch diameter cut would both be correct.
on a CNC you can use a modifier or change offset setting but if tool bit is correct for pitch you could use the same bit for turning a correct dia and a proper or in spec thread pitch.
for manual lathe work I would say save your money, you can get by with manually ground hss tool bits. use a magnifying headband to see and sharpen bit. I keep a 60 degree "fish" or thread grinding template in my pocket at all times at work. tip flat is suppose to be 1/8 of pitch at 10tpi thats what about 0.012" flat on tip of threading bit. Check machinery's handbook for more details.
The specific advantage is lower cost because you need fewer inserts. Convenience is also a factor especially on a manual machine because if you have a part with two threads of different pitch you don't need change the threading tool.
A disadvantage of the multi-pitch inserts (as mentioned) is that the tip radius is only correct for the finest pitch in its range; this is okay if you are not doing critical work. However, if you are doing something like a shaft with a turned section followed by a thread and the thread root diameter is very close the the OD of the turned section the threading tool may gouge into it if you are cutting a thread near the upper end of its pitch range; this is because the smaller tip radius means the threading tool is 'too long'.
On really critical work using the multi-pitch insert at the top end of its range could increase the possibility of fatigue failure due to the deeper root diameter and smaller tip radius a creating an enhanced stress raiser compared to what is correct for that pitch. The "dedicated pitch inserts are for CNC" idea has arisen because many of these inserts are specced for speed'n feed rates that aren't practical on most manual machines (will the Hardinge and other single tooth dog clutch machine drivers stop smirking). As usual with carbide going too far from the makers specified operating conditions frequently gives crap results and poor tool life. I think full form carbide inserts were actually originally developed for CNC purposes. The snail shaped two or three thread HSS full form cutters were considered quite adequate for pure manual users being easy to regrind (therefore much cheaper over-all) and not usually unduly stressed at speeds geared to human reactions.
The march of progress means that there are now plenty of full form inserts that work just fine at manual speeds even if your reactions are way below F1 or Top Gun level. Best to verify what you are buying tho' especially the cheap offers.
Clive carbide insert costs
.......sure you can use carbide inserts for threading on a manual lathe. i am just considering the Chinese machinist spending $1 for a HSS bit and resharpening it 100 times and cutting 's of threads.
........it is like the machinist who throws away drill bits rather than resharpen. sure if tooling costs are never questioned then go buy carbide inserts. I have seen many a manual machinist insist you have to have $+ in carbide inserts to do a 1 month job and I have seen other machinist do the same with $1 in tooling costs.
........ have to have to do a job and want to use because it saves a few hours of labor, i guess it depends on who is paying for the tooling costs.
....... on a cnc machine carbide inserts are useful as they allow changing and the new insert and should cut the same size within a 0.001" usually. Although if tooling is changed then resetting the tool offset should not take more than a minute or 2. on a manual lathe carbide tooling is optional for most jobs in my opinion not mandatory unless it is a hard metal like stainless.
....... Maybe thats why a Chinese machinist saving on tooling cost can afford to not charge so much to do a job. I have seen Americans spend millions of dollars on equipment to save labor costs and the Chinese employ more people sure at not that high of a wage (but higher wages than working on a farm) but they end up doing the job cheaper usually mostly by making better decisions on what to spend their money on.
......... I have seen Chinese machinist use big brazed carbide tooling and machine so fast they were throwing sparks but brazed tooling can be sharpened many times too. If I was given $+ a month for buying tooling I would be not always be using carbide inserts and keeping the money maybe to buy other stuff like new CNC machines. of course thats just a opinion on the subject.
I couldn't disagree more. Full profile inserts are way better than any HSS on any type of material. Plus thread OD is concentric with pitch diameter. Indexable inserts mean just having rotate the tool vs. grinding HSS under the loop.
As far as cut-off there is no comparison with my Iscar Do-Grip insert cutoff tool vs any HSS type on my manual lathe. The Do-Grip produces a chip narrower than slot being cut because of the geometry of the Do-Grip carbide insert. The same Do-Grip insert works on all material from SS, aluminum to Turcite. I will never use a HSS cutoff blade again after using the Do-grip cutoff blade held in a very rigid KDK Bar on my manual 12x36 lathe. See:
http://i72.photobucket.com/albums/i163/miltons_stuff/DoGripChip-1.jpg
http://i72.photobucket.com/albums/i163/miltons_stuff/DoGripCutoffKDKBar.jpg
If you like Chinese quality then... Lord, wish this had come up before I tried this:
Or this, ID threaded on spindle end too:
OK, my 40's something LeBlond is a very high speed lathe....NOT!
I have a collection of 3XXX carbide inserts, like the one in the faceplate with a generous radius to mimic the "proper" root contour for the 2-7/8 X 5 thread form and sharper ones for smaller threads. I've even been known to touch some to the diamond wheel on my carbide tool grinder, to bring them close to spec.
Top of thread? Well for prissy customers (or machinists), I guess there is something lacking, but it's purely esthetics, the "crown" on a thread misses everything, at least it should. The shoulders make the connection and the root contour provides miniature fillets for strength.
60° is 60°. Medium or big. Not production, so single pointing works great for me, so do inserts.
Now little stuff in mild steel?, yeah, HSS is best, carbide likes to be shoved in there, sharp HSS will just happily whittle away pretty little shavings.
Bob
What I'd do is first consider if you also do any grooving, or want to in the future. If that's true and you really want to control your initial expenditure on tool holders, go with the Top Notch-style inserts. This is best for low volume and home shops as you can buy just one tool holder (assuming O.D. work) and have the holder for a wide variety of threads and grooves.
If you feel it's time for the best quality burr-free thread that you can get without thread milling, go with the lay-down style inserts, ER16 size is probably best. With that style holder, you can get general-purpose inserts that do a wide range of threads, or lead-specific full-form inserts that cut the crest of the threads as well as the roots. In the ER16 size of cresting inserts you can get UN, UNJ, ISO metric, Acme, Stub Acme, Buttress, and a wide variety of other thread forms. The UN, for example, are available from from 72tpi to about 8tpi.
It can be a little bit of money to set yourself up with lay-down threading, but worth it it is you want the quality. For a big percentage of threads made though, you will be fine with Top Notch. There are some limited full-form insert for that style holder, but the real advantage to it is adding all the grooving capability. One holder, lots of things you can do including easy-to-get custom shapes. It all depends upon the kind of work you do. threading with carbide inserts
using an insert made for a certain pitch is for CNC threading.
if you have a hss bit sharpened to a sharp vee on a cnc lathe you set what dia the tip is cutting but when you thread you use the side of bit. so you will find a nut will not go on the threads because they are too big.
if you put a flat (or radius) on tip of the bit you will find the dia the tip cuts and the threads the side of cutter closer to spec. if bit was of correct shape then dia cut and pitch diameter cut would both be correct.
on a CNC you can use a modifier or change offset setting but if tool bit is correct for pitch you could use the same bit for turning a correct dia and a proper or in spec thread pitch.
for manual lathe work I would say save your money, you can get by with manually ground hss tool bits. use a magnifying headband to see and sharpen bit. I keep a 60 degree "fish" or thread grinding template in my pocket at all times at work. tip flat is suppose to be 1/8 of pitch at 10tpi thats what about 0.012" flat on tip of threading bit. Check machinery's handbook for more details.
...what are the advantages of going to a certain pitch or just bying one to cover all. thanks for your info.
The specific advantage is lower cost because you need fewer inserts. Convenience is also a factor especially on a manual machine because if you have a part with two threads of different pitch you don't need change the threading tool.
A disadvantage of the multi-pitch inserts (as mentioned) is that the tip radius is only correct for the finest pitch in its range; this is okay if you are not doing critical work. However, if you are doing something like a shaft with a turned section followed by a thread and the thread root diameter is very close the the OD of the turned section the threading tool may gouge into it if you are cutting a thread near the upper end of its pitch range; this is because the smaller tip radius means the threading tool is 'too long'.
On really critical work using the multi-pitch insert at the top end of its range could increase the possibility of fatigue failure due to the deeper root diameter and smaller tip radius a creating an enhanced stress raiser compared to what is correct for that pitch. The "dedicated pitch inserts are for CNC" idea has arisen because many of these inserts are specced for speed'n feed rates that aren't practical on most manual machines (will the Hardinge and other single tooth dog clutch machine drivers stop smirking). As usual with carbide going too far from the makers specified operating conditions frequently gives crap results and poor tool life. I think full form carbide inserts were actually originally developed for CNC purposes. The snail shaped two or three thread HSS full form cutters were considered quite adequate for pure manual users being easy to regrind (therefore much cheaper over-all) and not usually unduly stressed at speeds geared to human reactions.
The march of progress means that there are now plenty of full form inserts that work just fine at manual speeds even if your reactions are way below F1 or Top Gun level. Best to verify what you are buying tho' especially the cheap offers.
Clive carbide insert costs
.......sure you can use carbide inserts for threading on a manual lathe. i am just considering the Chinese machinist spending $1 for a HSS bit and resharpening it 100 times and cutting 's of threads.
........it is like the machinist who throws away drill bits rather than resharpen. sure if tooling costs are never questioned then go buy carbide inserts. I have seen many a manual machinist insist you have to have $+ in carbide inserts to do a 1 month job and I have seen other machinist do the same with $1 in tooling costs.
........ have to have to do a job and want to use because it saves a few hours of labor, i guess it depends on who is paying for the tooling costs.
....... on a cnc machine carbide inserts are useful as they allow changing and the new insert and should cut the same size within a 0.001" usually. Although if tooling is changed then resetting the tool offset should not take more than a minute or 2. on a manual lathe carbide tooling is optional for most jobs in my opinion not mandatory unless it is a hard metal like stainless.
....... Maybe thats why a Chinese machinist saving on tooling cost can afford to not charge so much to do a job. I have seen Americans spend millions of dollars on equipment to save labor costs and the Chinese employ more people sure at not that high of a wage (but higher wages than working on a farm) but they end up doing the job cheaper usually mostly by making better decisions on what to spend their money on.
......... I have seen Chinese machinist use big brazed carbide tooling and machine so fast they were throwing sparks but brazed tooling can be sharpened many times too. If I was given $+ a month for buying tooling I would be not always be using carbide inserts and keeping the money maybe to buy other stuff like new CNC machines. of course thats just a opinion on the subject.
Unless the material is too hard to cut otherwise, carbide threading inserts are a luxury item on a manual lathe. If the company is buying them, go for it. If you are buying them for the home shop, don't bother. HSS really shines on this application, as well as cutoff. Both are slow speed operations no matter what you do. Carbide will allow you to thread at far higher spindle speeds.... I hated fine threading at 150rpm on that crappy Jet. Why would I want to try to thread faster?
I couldn't disagree more. Full profile inserts are way better than any HSS on any type of material. Plus thread OD is concentric with pitch diameter. Indexable inserts mean just having rotate the tool vs. grinding HSS under the loop.
As far as cut-off there is no comparison with my Iscar Do-Grip insert cutoff tool vs any HSS type on my manual lathe. The Do-Grip produces a chip narrower than slot being cut because of the geometry of the Do-Grip carbide insert. The same Do-Grip insert works on all material from SS, aluminum to Turcite. I will never use a HSS cutoff blade again after using the Do-grip cutoff blade held in a very rigid KDK Bar on my manual 12x36 lathe. See:
http://i72.photobucket.com/albums/i163/miltons_stuff/DoGripChip-1.jpg
http://i72.photobucket.com/albums/i163/miltons_stuff/DoGripCutoffKDKBar.jpg
....... Maybe thats why a Chinese machinist saving on tooling cost can afford to not charge so much to do a job. I have seen Americans spend millions of dollars on equipment to save labor costs and the Chinese employ more people sure at not that high of a wage (but higher wages than working on a farm) but they end up doing the job cheaper usually mostly by making better decisions on what to spend their money on.
......... I have seen Chinese machinist use big brazed carbide tooling and machine so fast they were throwing sparks but brazed tooling can be sharpened many times too. If I was given $+ a month for buying tooling I would be not always be using carbide inserts and keeping the money maybe to buy other stuff like new CNC machines. of course thats just a opinion on the subject.
If you like Chinese quality then... Lord, wish this had come up before I tried this:
Or this, ID threaded on spindle end too:
OK, my 40's something LeBlond is a very high speed lathe....NOT!
I have a collection of 3XXX carbide inserts, like the one in the faceplate with a generous radius to mimic the "proper" root contour for the 2-7/8 X 5 thread form and sharper ones for smaller threads. I've even been known to touch some to the diamond wheel on my carbide tool grinder, to bring them close to spec.
Top of thread? Well for prissy customers (or machinists), I guess there is something lacking, but it's purely esthetics, the "crown" on a thread misses everything, at least it should. The shoulders make the connection and the root contour provides miniature fillets for strength.
60° is 60°. Medium or big. Not production, so single pointing works great for me, so do inserts.
Now little stuff in mild steel?, yeah, HSS is best, carbide likes to be shoved in there, sharp HSS will just happily whittle away pretty little shavings.
Bob
Tips for saving money on tooling for small jobshop? | Page 3
Great feedback from many on this subject, but I have another perspective to offer too.
I had a business partner.
First class machinist...did truly excellent work. but he had a really hard time being profitable because he invoked exactly the same philosophy I'm seeing from some contributors here.
He was spending more on cutters in a month than I was spending in a year, and his work was no better than mine.
New job...all new cutters.
Need something oddball...buy three in case you fuck one up.
Specialty cutter comes on the market...I'm going to buy some, and wait for the cutter for a week, because the new cutter is going to be SO AWESOME!!!.
Now there's a whole cabinet full of weird shit that works only a little bit better than the 15 dollar Garr cutter I can buy from Skinner's and have same day
Now we were jobbing, and there were very few high volume jobs that came our way, so the gains from the uber productive cutter almost never materialized.
Of course it would have been totally different had we run high volume jobs on high end machines, but we were not.
So the 200 dollar Vari Flute Holy Shit Awesome Cutter would save 10 minutes on the roughing...big fucking deal.
More time was spent picking noses and agonizing about how to set up the job than could ever be gained by roughing it a bit faster.
Also as many of you know, I do a lot of cutter grinding because I'm old school, and I can do it cheaper, faster and better if I pick the jobs on which I'm going to do it this way.
AB Tools is great when you need a whole fistful of identical form cutters, but not if you need exactly ONE cutter, nobody cares that much if it's perfect, and you're going to run it on ONE aluminum part and then never use it again.
So horses for courses...all depends on what kind of work you hope to attract, and how much you're prepared to invest to get good at cutter grinding yourself.
BTW...I have a Darex SP drill grinder that I picked up used on Ebay for bucks.
I can point and split any drill from 1/16" to 1" in under a minute (yes I just timed myself on a 3/16" drill...39 seconds from when I turned the machine on to when I turned it back off)
I charge $2.00 CAD per minute for my time. so that drill cost me a bit over a buck to grind...I leave it to you to decide if I left significant money on the table.
Also if I fuck up my last drill on a Saturday, I'm not screwed...I can just re-point it and go on.
Obviously the OP gets to do it however he prefers...but in a small job shop the old fashioned way does work pretty good if you're doing mostly low volume high mix work.
If you're running balls-out production, you need the whole integrated package to compete...a beast of a machine, solid fixturing, solid programming and the best tooling you can get, so you can grab every last fraction of gain from the better tools.
You're way better off IMO, trading in the tired old girl for a nice new Okuma than you are putting Whippo Zippo 200 dollar Emuge cutters into a Tormach..
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
Not sure your Scenario with your old partner applies here. I have endmills in my machine right now with over 20 hours of cutting time on them. Several hundred parts. Also, with a CNC, why would you need to buy specialty tools for every job? I understand some jobs absolutely need it, but I have standard tools in the machine, ., .093, .125, .250...... These are used for any job (material specific) that is their size or larger.... 1/8 is used to machine any area it can fit into until the next larger size fits. Drills, standard size drills in the machine then use an endmill to enlarge it if it can unless it has a tight tolerance or im doing a lot of those specific size holes to make it worth buying the expensive tools I like to use.
Most here do not have your skill to clean up their own tool or do not have the machinery for that so buying the expensive tools which if programmed right do last longer and do a better job.
I had a business partner.
First class machinist...did truly excellent work. but he had a really hard time being profitable because he invoked exactly the same philosophy I'm seeing from some contributors here.
He was spending more on cutters in a month than I was spending in a year, and his work was no better than mine.
New job...all new cutters.
Need something oddball...buy three in case you fuck one up.
Specialty cutter comes on the market...I'm going to buy some, and wait for the cutter for a week, because the new cutter is going to be SO AWESOME!!!.
Now there's a whole cabinet full of weird shit that works only a little bit better than the 15 dollar Garr cutter I can buy from Skinner's and have same day
Now we were jobbing, and there were very few high volume jobs that came our way, so the gains from the uber productive cutter almost never materialized.
Of course it would have been totally different had we run high volume jobs on high end machines, but we were not.
So the 200 dollar Vari Flute Holy Shit Awesome Cutter would save 10 minutes on the roughing...big fucking deal.
More time was spent picking noses and agonizing about how to set up the job than could ever be gained by roughing it a bit faster.
Also as many of you know, I do a lot of cutter grinding because I'm old school, and I can do it cheaper, faster and better if I pick the jobs on which I'm going to do it this way.
AB Tools is great when you need a whole fistful of identical form cutters, but not if you need exactly ONE cutter, nobody cares that much if it's perfect, and you're going to run it on ONE aluminum part and then never use it again.
So horses for courses...all depends on what kind of work you hope to attract, and how much you're prepared to invest to get good at cutter grinding yourself.
BTW...I have a Darex SP drill grinder that I picked up used on Ebay for bucks.
I can point and split any drill from 1/16" to 1" in under a minute (yes I just timed myself on a 3/16" drill...39 seconds from when I turned the machine on to when I turned it back off)
I charge $2.00 CAD per minute for my time. so that drill cost me a bit over a buck to grind...I leave it to you to decide if I left significant money on the table.
Also if I fuck up my last drill on a Saturday, I'm not screwed...I can just re-point it and go on.
Obviously the OP gets to do it however he prefers...but in a small job shop the old fashioned way does work pretty good if you're doing mostly low volume high mix work.
If you're running balls-out production, you need the whole integrated package to compete...a beast of a machine, solid fixturing, solid programming and the best tooling you can get, so you can grab every last fraction of gain from the better tools.
You're way better off IMO, trading in the tired old girl for a nice new Okuma than you are putting Whippo Zippo 200 dollar Emuge cutters into a Tormach..
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
Great feedback from many on this subject, but I have another perspective to offer too.
I had a business partner.
First class machinist...did truly excellent work. but he had a really hard time being profitable because he invoked exactly the same philosophy I'm seeing from some contributors here.
He was spending more on cutters in a month than I was spending in a year, and his work was no better than mine.
New job...all new cutters.
Need something oddball...buy three in case you fuck one up.
Specialty cutter comes on the market...I'm going to buy some, and wait for the cutter for a week, because the new cutter is going to be SO AWESOME!!!.
Now there's a whole cabinet full of weird shit that works only a little bit better than the 15 dollar Garr cutter I can buy from Skinner's and have same day
Now we were jobbing, and there were very few high volume jobs that came our way, so the gains from the uber productive cutter almost never materialized.
Of course it would have been totally different had we run high volume jobs on high end machines, but we were not.
So the 200 dollar Vari Flute Holy Shit Awesome Cutter would save 10 minutes on the roughing...big fucking deal.
More time was spent picking noses and agonizing about how to set up the job than could ever be gained by roughing it a bit faster.
Also as many of you know, I do a lot of cutter grinding because I'm old school, and I can do it cheaper, faster and better if I pick the jobs on which I'm going to do it this way.
AB Tools is great when you need a whole fistful of identical form cutters, but not if you need exactly ONE cutter, nobody cares that much if it's perfect, and you're going to run it on ONE aluminum part and then never use it again.
So horses for courses...all depends on what kind of work you hope to attract, and how much you're prepared to invest to get good at cutter grinding yourself.
BTW...I have a Darex SP drill grinder that I picked up used on Ebay for bucks.
I can point and split any drill from 1/16" to 1" in under a minute (yes I just timed myself on a 3/16" drill...39 seconds from when I turned the machine on to when I turned it back off)
I charge $2.00 CAD per minute for my time. so that drill cost me a bit over a buck to grind...I leave it to you to decide if I left significant money on the table.
Also if I fuck up my last drill on a Saturday, I'm not screwed...I can just re-point it and go on.
Obviously the OP gets to do it however he prefers...but in a small job shop the old fashioned way does work pretty good if you're doing mostly low volume high mix work.
If you're running balls-out production, you need the whole integrated package to compete...a beast of a machine, solid fixturing, solid programming and the best tooling you can get, so you can grab every last fraction of gain from the better tools.
You're way better off IMO, trading in the tired old girl for a nice new Okuma than you are putting Whippo Zippo 200 dollar Emuge cutters into a Tormach..
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
Not sure your Scenario with your old partner applies here. I have endmills in my machine right now with over 20 hours of cutting time on them. Several hundred parts. Also, with a CNC, why would you need to buy specialty tools for every job? I understand some jobs absolutely need it, but I have standard tools in the machine, ., .093, .125, .250...... These are used for any job (material specific) that is their size or larger.... 1/8 is used to machine any area it can fit into until the next larger size fits. Drills, standard size drills in the machine then use an endmill to enlarge it if it can unless it has a tight tolerance or im doing a lot of those specific size holes to make it worth buying the expensive tools I like to use.
Most here do not have your skill to clean up their own tool or do not have the machinery for that so buying the expensive tools which if programmed right do last longer and do a better job.
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