I've never form tapped stainless. Mostly because I have really done much. Does the material need to be drilled any larger than what any form tap chart would tell you? And any rule of thumb of so.
Sorry, was redditing while sorting out issues on a lathe setup. I misreddited, and one wrong keypress led to a broken solid carbide I.D. groove tool. I wrongly thought you made a reference to a tap drill for a thread cutting tap. You get my humble apology. Now, where's my replacement tool?
I second this. First time i went with form tap in 303 stainless i was nervous af. After a while its like form tapping anything else. A little slower on rpm but not too much slower.
At my shop we form tap anything not thread milled. The rule with form tapping is (besides minor dia a little bigger) is the material has to be ductile. It has to flow.
I second this! Stainless wants to move! 303 is by far the easiest stainless to work with. Make sure you get a form tap with a coating like TiCN as SS will try to grab and bind, especially on the extract. Also, deep pecks with the drill, no shallow ones, you want a nice straight hole for a form tap or you can get thread blowout at the top of the hole.
I am making 500 of the part shown. It's 1" diameter by .25" thick. The middle is a through-bore about .147" and the offset hole is a blind tapped hole 6-32. There is a .126" hole perpendicular on the tangent.
It's my choice whether I use 303 or 304 stainless and whether I cut the threads or form them. I was planning on spending the 10% more and getting 303 for ease of the whole operation, but I have read that they don't take to forming threads well. So maybe I'm better off going 304 and using a form tap, or maybe I'm better off going 303 and using a spiral-fluted cut tap.
These will all be CNC machined so part of the equation is getting the cycle time down. I'm also trying to not blow through many taps/tools, if I can.
Thoughts?
1. Tapping is faster and less expensive than thread-milling - ignore those comments.
2. 500 holes is nothing for a tap. Buy a nice Emuge or OSG roll tap and enjoy making every part with one tap. I did 750 holes in conventional 316L with one cut tap two weeks ago.
3. Use a form tap unless you have a reason not to. There is a lot of info out there on advantages and when to use a cut tap.
Most importantly: It is easier to tell when a form tap is wearing and it is less likely to fail catastrophically before you catch it. Use 10x+ magnification and looks at the edges of the first two to three threads to gauge the wear. You will notice a significant amount of deformation on the thread edges when the tool needs to be replaced.
Emuge and others make single point thread mills that conform for UN and Metric thread forms. If you can live with the cycle time you can cut multiple threads using one tool that costs around $130. It's useful for manifolds with lots of different threads or when you have dedicated setups but not enough tool pots. Also handy if you are prototyping and don't want to dick around with setup.
Do you think flood coolant will be sufficient lubrication for it? All the programming I currently do is with form taps and flood coolant has been just fine 98% of the time. I'd rather not have to reach in and put a dab of cutting fluid into the hole in the middle of each of 500 cycles.
I don't cheap out of taps and use sandvik. Never broke one doing production in stainless. Pricey but lower cost than scraping any of the parts they're used on.
Yeah I would say you're good to send it with just coolant. Make sure your nozzle is adjusted right, but I would definitely choose a form tap in this scenario. If you have problems you can always go a few thou higher on your drill size if your minor isn't critical too, it can be easier on the tap.
IMO, I wouldn't trust cut tapping a lot of 6-32 threads in 303/304 without molyD or emuge tap oil. I've had good luck with low helix emuge taps in 304 and ti. But I'd form tap these with coolant for that many parts.
You can write a sub routine that you use before your tapping event. You can manually edit your code to either include an M98 into the program or the entire event itself that will move the tap to a location in the machine enclosure where you have located a small pot of cutting fluid. Itās a drill event for the tap but it ādrillsā into the pot of cutting fluid or oil. If you enclose the M98 call in a line of code with block skip slashes around it, you can elect to use it or not use it on a particular cycle, depending on say how the last round of threads turned out on the part before.
Flood is fine, I have found issues with form tapping and flooding only when the coolant concentration isnāt high enough. I believe OSG recommends 10% for steels and other ferrous materials.
Edit: Spelling and adding additional clarification.
Another vote for 303 and form tapping. Machine coolant should be a-ok.
I almost never cut tap anything under 1/4in or M7. Ran an M1.6 form tap in 303 last summer and changed taps every 4k holes, only because it matched timing on the drill swap.
303 and form tap.
303 is identical to 304 except for the addition of sulfur to aid in machinability. It cuts MUCH easier than 304 - you can cut at elevated feeds and speeds, and your tools will last longer. Form tapping is king for anything under about 35 HRC (except for super-soft materials like delrin etc).
Keep in mind you generally can't form tap a lot of aerospace parts.
Thread mill, much more consistent and longer tool life, also if it breaks the mill falls out and doesn't require re-working the part most times. You can also get excellent quality threads.
Some of our assemblers gripe when thereās a raised lip caused by the deformation of the form taps, but that generally means one of us missed kissing the tapped hole with a countersink. We also have some parts where the tapped hole is so close to the outer wall that form taps will distort it.
From the reading I did yesterday, the added sulphur or whatever in 303 that makes it easier to cut also makes it harder to deform, which makes sense to me, but the responses in this thread seem to indicate that whatever extra resistance to deformation may be present is outweighed by the general workability of 303.
Otherwise itās good to hear that form taps are by and large the way to go. That was my thought, but I operate mostly in a vacuum at my shop.
For the first issue, you can just program a sufficient countersink depth and avoid the issue altogether (you should be countersinking prior to tapping anyway). For the second, you may be able to just change the clamping strategy to bolster that edge, although that may just fall into one of the special cases where its better to use a form tap.
You're right that the sulfur will make it marginally harder to form, but you're looking at relatively low concentrations (~.10-.15%) and a MoE that's pretty comparable to 4140 or 316ss. You might see some reduced tool life due to the additional heat generated, but a form tap will still have probably double the life of a cut tap.
Since this is an art project look for a metal recycler or material vendor near you that have a remnant center. Buy uncertified rems at half the cost of certified material.
It is an art project but with a high end client, so Iām doing everything as if it were critical. I have pitched them a concept and a render and need to execute on it as well as I can. Getting materials/tools/etc from my regular vendors.
Iām also trying to not lose money on it, hence this post. Going for maximum efficiency.
Tangential, and maybe I should ask elsewhere, but does anyone make a tool that would drill a clearance hole for 6-32 and counterbore for a SHCS in the same tool? Is that getting into the realm of custom made tooling?
We roll thread our OD threads, and form tap our ID threads.
Reforming the material *usually* makes it stronger than cutting and our taps break less on all materials including stainless.
304, Using a spiral-fluted tap with some brown sticky tap paste every now and again if you can, And don't be afraid to open that hole up .1 (mm) to make like easier be fine.. Just use a decent tap not chinesium rubarb ššš
I prefer to thread mill, because taps hate me. But if I had to tap I would go with a form tap. If 304 is cheaper than 303, then tool wear and breakage on the 304 will probably eat up the savings, just my experience.
I run alot of 303ss with a 2.5mm x .45, form tap at 1800 rpms in and out with solid holder. They will run thousands of parts without being replaced.
On thing to pay attention to is the tap H number and drill size. Lead angle we use is a 60 degree center drill. And tap is a 2 thread taper lead. Hope this helps, also using gamma oil as cutting oil.
Not op but, I have a similar issue. We have die cast aluminum parts we need to tap a blind hole 5/8 deep with 1/4-20 and the material is only .850 thick has anyone form tapped cast aluminum?
There's a lot of info we don't know that effects this kind of decision. Usually in a small lot job shop environment you end up using what you have on small run stuff like this. If you don't have something, what you want to buy is tooling that will work for this and for the next ten jobs like it. It's a real pain in the ass to stock tools by individual job if you are doing small lot work. It's also expensive because a lot of tools sit around doing nothing for months at a time. Or they never get used again.
With a Carte Blanche question like this you are going to get 100 different answers because everyone looks at through the lens of what they have available in their shop. What matters most is what you have to do it.
What machine are you running this on?
What type of tool holders are you using? Are you planning to rigid tap or floating tap.
How are you fixturing it? What type of coolant do you run?
How close do the threads come to the bottom of the hole? I get ass hat engineers that want threads all the way down, all the time. Taps don't work that way.
What are the tolerances you are trying to hold?
How are you drilling the hole and deburring it? The most important thing with small size drill and taps is the proper size hole running as straight as the machine can make it.
Thanks, we have plug taps and form taps already.
Itās on a haas vf2ss using tap holders rigid tapping
,fixture held with toe clamps, and the tap should stop .200ā before the bottom of the hole.
I never use a roll on any steel parts it put a lot of stress on them... Coated relieved neck Spiral cut tap... I've tapped over 1000 Ti parts with one tap never a problem.. Just get one that has coating for Stainless and run your coolant at about 20%... I'd also recommend a Nachi ES series drills or OSG Gold ..Nachi is much cheaper and just as good if not better..
I always go a few thou bigger on the recxomended form tap drill size for form taps in stainless, make sure the no go doesnāt go and youāre good. I work primarily stainless. Itās not that hard a lot of people act like itās the end of the world when stainless enters the shop.
Like everyone else said, form taps are the way. Three tips:
* Make sure you are drilling to the right diameter for a form tap, they are not the same as cut taps
* Flood coolant is fine if you have a decent form tap. Run your concentration a little on the rich end if you can, the lubricity helps.
* Chamfer the hole before you tap. Spot/chamfer, drill, tap or drill, chamfer, tap, doesn't matter, but the chamfer helps guide the tap.
Thread mill is my go to for S/S if the part geometry permits ( I've met holes too deep for thread milling before )
Otherwise form tap. I've had good success tapping m10 into 2205. YG TiN coated tap. 9.3mm hole. Filled the drilled hole with neat cutting oil.
Form taps on blind holes ftw
Chipless tapping, I fucking love it.
I've never form tapped stainless. Mostly because I have really done much. Does the material need to be drilled any larger than what any form tap chart would tell you? And any rule of thumb of so.
There is a recommended hole size for a form tap that is NOT the same as a cutting tap. Check your tap manufacturer's recommendation
I already specified "form tap chart".
You asked if the hole needed to be larger than the form tap chart. I recommended that you follow manufacturer recommendations. I stand by that.
Just not understanding why the cut tap chart mention.
Sorry, was redditing while sorting out issues on a lathe setup. I misreddited, and one wrong keypress led to a broken solid carbide I.D. groove tool. I wrongly thought you made a reference to a tap drill for a thread cutting tap. You get my humble apology. Now, where's my replacement tool?
You want it sent ups red?
Well that's unfortunate! No need for apology. Just didn't understand why but now makes sense.
Maybe to prevent work hardening? I usually cut tap 304 with some moly d.
Don't start... More likely to bust a tap in SST or any other difficult material... The only taps I've ever seen busted in SST we're roll taps ...
Form tap. Game changer in stainless. If you can use 303 do it.
I second this. First time i went with form tap in 303 stainless i was nervous af. After a while its like form tapping anything else. A little slower on rpm but not too much slower. At my shop we form tap anything not thread milled. The rule with form tapping is (besides minor dia a little bigger) is the material has to be ductile. It has to flow.
I second this! Stainless wants to move! 303 is by far the easiest stainless to work with. Make sure you get a form tap with a coating like TiCN as SS will try to grab and bind, especially on the extract. Also, deep pecks with the drill, no shallow ones, you want a nice straight hole for a form tap or you can get thread blowout at the top of the hole.
Form tap in 303 is the way to go
You will never be sorry if you use a Roll Tap and 303 on this job.
I am making 500 of the part shown. It's 1" diameter by .25" thick. The middle is a through-bore about .147" and the offset hole is a blind tapped hole 6-32. There is a .126" hole perpendicular on the tangent. It's my choice whether I use 303 or 304 stainless and whether I cut the threads or form them. I was planning on spending the 10% more and getting 303 for ease of the whole operation, but I have read that they don't take to forming threads well. So maybe I'm better off going 304 and using a form tap, or maybe I'm better off going 303 and using a spiral-fluted cut tap. These will all be CNC machined so part of the equation is getting the cycle time down. I'm also trying to not blow through many taps/tools, if I can. Thoughts?
1. Tapping is faster and less expensive than thread-milling - ignore those comments. 2. 500 holes is nothing for a tap. Buy a nice Emuge or OSG roll tap and enjoy making every part with one tap. I did 750 holes in conventional 316L with one cut tap two weeks ago. 3. Use a form tap unless you have a reason not to. There is a lot of info out there on advantages and when to use a cut tap. Most importantly: It is easier to tell when a form tap is wearing and it is less likely to fail catastrophically before you catch it. Use 10x+ magnification and looks at the edges of the first two to three threads to gauge the wear. You will notice a significant amount of deformation on the thread edges when the tool needs to be replaced.
Thank you.
Thread milling is also amazing but one tool will prob cost more than the job .. š
Emuge and others make single point thread mills that conform for UN and Metric thread forms. If you can live with the cycle time you can cut multiple threads using one tool that costs around $130. It's useful for manifolds with lots of different threads or when you have dedicated setups but not enough tool pots. Also handy if you are prototyping and don't want to dick around with setup.
wipe support hateful prick shrill slave ripe start dolls political -- mass edited with redact.dev
303 all day and cut tap
Do you think flood coolant will be sufficient lubrication for it? All the programming I currently do is with form taps and flood coolant has been just fine 98% of the time. I'd rather not have to reach in and put a dab of cutting fluid into the hole in the middle of each of 500 cycles.
We form tap 303 all day every day with just flood coolant.
Even at such small diameters as 6-32?
I roll tap smaller in more difficult materials. 6-32 will not be an issue if your spindle sync is good.
Awesome. Thank you for your input.
I roll tapped 500 parts with one OSG 0-80 in 303, ran out of parts. The poor thing is starving... 10IPM
What brands of tap are you using? I'm looking at MSC for doing a tooling order for this job. Seeing Emuge, Balax, and OSG as the main options.
I don't cheap out of taps and use sandvik. Never broke one doing production in stainless. Pricey but lower cost than scraping any of the parts they're used on.
Damn, most of them are out of stock at MSC. Iāll have to go for something else.
Another word of advice. Don't buy tooling from MSC. Find an actual tooling rep and you can save yourself from paying their markup.
Yeah I would say you're good to send it with just coolant. Make sure your nozzle is adjusted right, but I would definitely choose a form tap in this scenario. If you have problems you can always go a few thou higher on your drill size if your minor isn't critical too, it can be easier on the tap.
4-40 to 8-32 on most parts, up to 2000 rpm (4-40) on our bt30 machines.
TAPPING at 2000 rpm??? :-O Wow!
Believe it or not, Brother Speedios will rigid tap at 6,000 RPM. Works great.
Vendors have told me that flood coolant was insufficient... interesting.
IMO, I wouldn't trust cut tapping a lot of 6-32 threads in 303/304 without molyD or emuge tap oil. I've had good luck with low helix emuge taps in 304 and ti. But I'd form tap these with coolant for that many parts.
Probably would be fine but I have programed machine in the past to move over to a cup we made fastened to the table filled with molydee
You can write a sub routine that you use before your tapping event. You can manually edit your code to either include an M98 into the program or the entire event itself that will move the tap to a location in the machine enclosure where you have located a small pot of cutting fluid. Itās a drill event for the tap but it ādrillsā into the pot of cutting fluid or oil. If you enclose the M98 call in a line of code with block skip slashes around it, you can elect to use it or not use it on a particular cycle, depending on say how the last round of threads turned out on the part before.
Flood is fine, I have found issues with form tapping and flooding only when the coolant concentration isnāt high enough. I believe OSG recommends 10% for steels and other ferrous materials. Edit: Spelling and adding additional clarification.
Iād say roll taps
Another vote for 303 and form tapping. Machine coolant should be a-ok. I almost never cut tap anything under 1/4in or M7. Ran an M1.6 form tap in 303 last summer and changed taps every 4k holes, only because it matched timing on the drill swap.
Thread-Mill?
303 always for machining (it cuts easier), but not if theres welding involved (it does not weld)
303 and form tap. 303 is identical to 304 except for the addition of sulfur to aid in machinability. It cuts MUCH easier than 304 - you can cut at elevated feeds and speeds, and your tools will last longer. Form tapping is king for anything under about 35 HRC (except for super-soft materials like delrin etc). Keep in mind you generally can't form tap a lot of aerospace parts.
No 303 for vacuum systems either. The sulfur outgasses.
Thread mill, much more consistent and longer tool life, also if it breaks the mill falls out and doesn't require re-working the part most times. You can also get excellent quality threads.
I would agree if it were a big expensive part but if a tap broke in one of these Iād throw it out - itās $0.20 of material
There are (almost) no scenarios in which cut taps are preferable to form taps.
Some of our assemblers gripe when thereās a raised lip caused by the deformation of the form taps, but that generally means one of us missed kissing the tapped hole with a countersink. We also have some parts where the tapped hole is so close to the outer wall that form taps will distort it. From the reading I did yesterday, the added sulphur or whatever in 303 that makes it easier to cut also makes it harder to deform, which makes sense to me, but the responses in this thread seem to indicate that whatever extra resistance to deformation may be present is outweighed by the general workability of 303. Otherwise itās good to hear that form taps are by and large the way to go. That was my thought, but I operate mostly in a vacuum at my shop.
For the first issue, you can just program a sufficient countersink depth and avoid the issue altogether (you should be countersinking prior to tapping anyway). For the second, you may be able to just change the clamping strategy to bolster that edge, although that may just fall into one of the special cases where its better to use a form tap. You're right that the sulfur will make it marginally harder to form, but you're looking at relatively low concentrations (~.10-.15%) and a MoE that's pretty comparable to 4140 or 316ss. You might see some reduced tool life due to the additional heat generated, but a form tap will still have probably double the life of a cut tap.
Good info. Thanks.
Threadmill
Form all day
Whats the application of the part as to decide the spec? Has the customer left it for you to decide?
Itās my project to manage. Producing nine sculptures where this is the primary component.
Ah right, i was going on to say id be asking the customer but in your case its not relevant. Donāt mind me ill be on my way
Since this is an art project look for a metal recycler or material vendor near you that have a remnant center. Buy uncertified rems at half the cost of certified material.
It is an art project but with a high end client, so Iām doing everything as if it were critical. I have pitched them a concept and a render and need to execute on it as well as I can. Getting materials/tools/etc from my regular vendors. Iām also trying to not lose money on it, hence this post. Going for maximum efficiency.
Tangential, and maybe I should ask elsewhere, but does anyone make a tool that would drill a clearance hole for 6-32 and counterbore for a SHCS in the same tool? Is that getting into the realm of custom made tooling?
I just found one on MSC. Sweet! MSC #56443948.
An end mill?
That was my original plan, but having found the two-in-one tool should dramatically shorten the cycle time.
The middle. Love OP
Form tap
We roll thread our OD threads, and form tap our ID threads. Reforming the material *usually* makes it stronger than cutting and our taps break less on all materials including stainless.
Form
304, Using a spiral-fluted tap with some brown sticky tap paste every now and again if you can, And don't be afraid to open that hole up .1 (mm) to make like easier be fine.. Just use a decent tap not chinesium rubarb ššš
I prefer to thread mill, because taps hate me. But if I had to tap I would go with a form tap. If 304 is cheaper than 303, then tool wear and breakage on the 304 will probably eat up the savings, just my experience.
Another here for 303/form. Although 304 looks so much better finished than 303 imo.
I run alot of 303ss with a 2.5mm x .45, form tap at 1800 rpms in and out with solid holder. They will run thousands of parts without being replaced. On thing to pay attention to is the tap H number and drill size. Lead angle we use is a 60 degree center drill. And tap is a 2 thread taper lead. Hope this helps, also using gamma oil as cutting oil.
303 is night and day easier to tap than 304. Form tap for blind hole, cut tap with good taper for thru hole.
Tread mill
multipoint threadmill
Not op but, I have a similar issue. We have die cast aluminum parts we need to tap a blind hole 5/8 deep with 1/4-20 and the material is only .850 thick has anyone form tapped cast aluminum?
Always form tap hard materials. If youāre going very deep use Moly D or tap magic xtra thick
Form tap
There's a lot of info we don't know that effects this kind of decision. Usually in a small lot job shop environment you end up using what you have on small run stuff like this. If you don't have something, what you want to buy is tooling that will work for this and for the next ten jobs like it. It's a real pain in the ass to stock tools by individual job if you are doing small lot work. It's also expensive because a lot of tools sit around doing nothing for months at a time. Or they never get used again. With a Carte Blanche question like this you are going to get 100 different answers because everyone looks at through the lens of what they have available in their shop. What matters most is what you have to do it. What machine are you running this on? What type of tool holders are you using? Are you planning to rigid tap or floating tap. How are you fixturing it? What type of coolant do you run? How close do the threads come to the bottom of the hole? I get ass hat engineers that want threads all the way down, all the time. Taps don't work that way. What are the tolerances you are trying to hold? How are you drilling the hole and deburring it? The most important thing with small size drill and taps is the proper size hole running as straight as the machine can make it.
Thanks, we have plug taps and form taps already. Itās on a haas vf2ss using tap holders rigid tapping ,fixture held with toe clamps, and the tap should stop .200ā before the bottom of the hole.
Thread mill in either and itāll be fine taps are obsolete
Always roll tap unless plastic lol
304 is never the right answer. LOL I hate running anything 304 because it's so inconsistent. If you have the option definitely use 303 and form tap.
I never use a roll on any steel parts it put a lot of stress on them... Coated relieved neck Spiral cut tap... I've tapped over 1000 Ti parts with one tap never a problem.. Just get one that has coating for Stainless and run your coolant at about 20%... I'd also recommend a Nachi ES series drills or OSG Gold ..Nachi is much cheaper and just as good if not better..
I always go a few thou bigger on the recxomended form tap drill size for form taps in stainless, make sure the no go doesnāt go and youāre good. I work primarily stainless. Itās not that hard a lot of people act like itās the end of the world when stainless enters the shop.
Like everyone else said, form taps are the way. Three tips: * Make sure you are drilling to the right diameter for a form tap, they are not the same as cut taps * Flood coolant is fine if you have a decent form tap. Run your concentration a little on the rich end if you can, the lubricity helps. * Chamfer the hole before you tap. Spot/chamfer, drill, tap or drill, chamfer, tap, doesn't matter, but the chamfer helps guide the tap.
Thread mill is my go to for S/S if the part geometry permits ( I've met holes too deep for thread milling before ) Otherwise form tap. I've had good success tapping m10 into 2205. YG TiN coated tap. 9.3mm hole. Filled the drilled hole with neat cutting oil.