Using Heat-Set Threaded Inserts | 3D Printed Acorn CNC Controller and Ether1616 Expansion PCB Mounts

Today I need to make some 3D printed mounts for a Centroid Acorn CNC controller and Ether1616 Expansion board, and I'm going to try out a technique I've never used before: heat-set threaded inserts. We'll talk about the inserts, make a tool to install them, and try them out.
Spoiler: They're amazing.
Lots of people are asking about the perforated panel:
www.automationdirect.com/adc/...
Tools (and other stuff) used in this video:
*This site contains affiliate links for which I may be compensated
Heat-Set Threaded Inserts (Amazon*): amzn.to/3g8mDj6
Dynamite Hex Driver Metric Set (Amazon*): amzn.to/2AUGIbX
Milwaukee Brushless Impact Driver (Amazon*): amzn.to/2Xgcjjc
eSun Black PETG Filament, 1.75mm (Amazon*): amzn.to/2xib6H0
Starrett 6" Hook Rule Machinist Scale (Amazon*): amzn.to/37RUxVS
Hakko FX-888D Soldering Iron (*Amazon): amzn.to/3HkhaBK
5C Collet Chuck (eBay*): ebay.to/3lMVbbr
5C Collets Set - Imperial (Amazon*): amzn.to/3mOcmcQ
5C Collet Set - Metric (Amazon*): amzn.to/3rsBz00
Shars CCGX 21.52 insert for aluminum (eBay*): ebay.to/2Hcd5Fu
Scotch Brite Gray Ultra Fine (eBay*): ebay.to/2QRJUXN
Chicago Latrobe HSS Short Letter Drill Set (Amazon*): amzn.to/2PWx0dL
Chicago Latrobe HSS Short Number Drill Set (Amazon*): amzn.to/2Qgss0S
Chicago Latrobe HSS Short Franctional Drill Set (Amazon*): amzn.to/3mkmziD
Raw Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
creativecommons.org/licenses/b...

[@Clough42]

Lots of people are asking about the perforated panel: www.automationdirect.com/adc/shopping/catalog/n1p2020pp

[@robotskirts]

Thank you for explaining the perf panels. I've always seen them as options when buying cabinets but didn't know what hardware I should be using with them.

[@tablatronix]

You can also obtain plastic perf panels that have tapered grids and take self tapping course threaded screws, check the Bud Ind ones. Might be cheaper options than steel and machine screws

[@joansparky4439]

@Clough42 JFYI - you just need to say M3.. the pitch usually is not noted for standard series metric threads. M2, M2.5, M3, M5, M6, M8, M10, M12, M16, M20, M24, .. are standard sizes and have a defined standard pitch. They also are defined with other pitch (fine thread, etc) and there is 2nd choice series like M7 or M14 for example.. but one normally doesn't use them unless the application really really needs it. And only under such circumstances one notes the pitch or other special features. PS: I'd add washers and maybe springwashers to those PCB board mounting screws.. if it's a vibrating environment they might come loose other wise?

[@Clough42]

@@joansparky4439 the ISO standard is as you describe. ANSI still prescribes calling out the pitch.

[@joansparky4439]

@@Clough42 What can I say - you got an international audience, which isn't fluent in the amusing idiosyncrasies of thread descriptions per ANSI ;-)

[@cj691]

For more holding power, do through holes and use the insert from the back.

[@j.frankparnell6195]

You can also print a hex pocket and insert a nut.

[@LightCarver]

@@j.frankparnell6195 On the rare occasion I need to use one instead of a regular heat inset I will slightly undersize the hex pocket and heat insert the nut. Inserted nuts can be a pain when they take up too much room in a design, need installed in an awkward location during assembly or need inserted sideways through a slot that wont print well.

[@tHaH4x0r]

I always try to do this, its good practice, but really you don't need to be worried about strength too much when using good quality inserts. CNC kitchen has a video on some strength testing on M3 inserts, which showed that most inserts can easily handle over 1400N of force before pulling out (that is over 150kg on a single bolt!). The limit to torque you can apply was the bolts snapping. So if you are not having solid infill in your parts, the weakest link is most likely the plastic part, not the insert pulling out, which is good to know!

[@danielrichardson3613]

There's got to be a dirty joke there, right?

[@underourrock]

A tip for avoiding pullout forces: Leave the insert very slightly proud instead of embedding it all the way in. Immediately after getting the insert 95 to 98% of the way flush, turn the part over and press it against a hard flat heat resistant surface or use a flat block of wood, steel chunk, or really any flat surface to press the insert flush with the surface it is being embedded into. When you press it below the surface, any part that goes on top of it ends up prying the heat set insert back out of the hole. If you don't over tighten your screws that is less of a problem, but once an insert starts to weaken, it pretty much loses it's strength. Allowing the material around the top surface of the insert to help shed that stress is better.

[@skolmnvikes]

McMaster also specs/sells soldering iron tips for their threaded inserts. Another fun fact - Molded in threaded inserts are common in Injection Molding, but so is 'heat staking' after the part is made. This is essentially the same process as you are exploring. The soldering iron in that application usually looks like an arbor press but with a heated tip.

[@blahblahblahblah2933]

When I started using inserts, I got the iron tip from McMaster, but I ended up just using a normal conical tip. In my experience it works fine, and I'm able to get the insert straight without effort.

[@fuzzy1dk]

just be sure to get the right kind.The ones made for molding, isn't as suited for staking as those made for staking and vice versa

[@firstmkb]

Is there anything I want that McMaster doesn’t sell?

[@flyingcoyote5]

McMaster also provides CAD models of most of their parts, no account needed.

[@Neptune730]

I figured you knew about the inserts. CNC Kitchen has a video about the twist and pull out strength of various types of threaded inserts. I just uploaded my design for a Heat-set insert press to Cults3D. Along with a soldering fume extractor. Same name as my KZbin name. I can't wait to see the new machine you're working on.

[@Clough42]

Yeah, I saw that video was there. The topic has been covered, but this is what I was working on, so...

[@adamsherman]

I can’t find you, how about a pointer?

[@tablatronix]

Yes! , there are so many types of knurling/nibs out there, good to know which are best for fdm etc

[@LightCarver]

@@tablatronix The style in this video is the best.

[@mrp19285]

Yay centroid Acorn! Glad someone else is getting into it.

[@Dieselfitter01]

Always a pleasure tuning in. Great content as always.

[@jasonstewart5942]

It's funny because you and I both found a new found love for heat set inserts while doing the same thing....a Centroid Acorn controller build. I made as well a 3d printed mount for the Acorn board with M3 inserts.

[@dannywilsher4165]

Looking good James! Brings back memories of designing and building control boards and boxes in my past.

[@Ale_Lab]

I literally insert a lot of the same M3 inserts for a 3D printing upgrade today. Then your videos came out. Cool!

[@sebastianuchman3145]

James, very cute idea with the soldering iron tool for inserts. The design of the control cabinet: better than perfect!

[@jaybarratt5787]

Another happy Centroid Acorn user here. I've been using it with my Sherline/A2Z/G540 mill for over three years now and it's been great! Thanks for the threaded insert video and I'm really looking forward to your Centroid build.

[@nigeleaton5715]

Hey James, I thought you might like to know that I had a need for this tonight, and I remembered this video. I reviewed it, knocked up a soldering iron bit on the lathe, and now have eight beautiful inserts fitted to printed parts. Thank you so much for sharing your knowledge and skills. I'm super happy with the results.

[@mith5168]

Your lathe video portion is at the “next level”…nicely done.

[@g.tucker8682]

Thanks for this tip. It may not be flashy, but promises to be oh-so-useful!

[@scoty7392]

You’re going to love the Centroid Acorn gear. Looking forward to the video on that.

[@MikeyFirst]

Yet another inspiring video! Thanks, James!

[@jhawker2895]

Although I doubt I will need many inserts - I love your presentation. Your teaching ability is nothing short of amazing ... Thanks for sharing ... Stay Safe ...

[@subuser9627]

I had the same problem some years ago. Made also brass element for my Weller, works great. Nice you made a video of it, this will help a lot of people. There are a lot bad inserts around, from what I see you have the propper inserts. I buy my inserts from Ruthex, the same type of model you use. It is sometimes the small things that make the difference...

[@opticalmechanic]

Great video. I’ve used those inserts a lot for military helmet mounted display optics and they’re very good. The housings needed to be light weight so we’re machined from an injection moulded polymer. To get adequate strength though and to avoid pulling them out when tightening the screws, it’s important to match the temperature of the insert with the specific material. You need enough flow of material to encapsulate the insert grooves so that it is positively keyed into the material. It looked like it worked well there.

[@jeffkthompson]

Never thought to make the insert tool (I just use a standard iron tip) but that’s a fun easy lathe project. Inserts work great on laser-cut acrylic too!

[@mikemarriam]

That was a simple and elegant solution.

[@SeanTaffert]

Finally! Welcome to the '90s. Good vid. Big fan. Love the ClearPath servos.

[@stephenjohnson6841]

Looks like a great solution! Thanks again James!

[@NeGRaDiCaLz]

That’s a pretty packed cabinet. I like to use deeper wire way when it’s crammed like that and you can only go so wide.

[@StevePrior]

Minor tip I picked up last Fall while building a Voron 3D printer - If you heat up and push in the insert almost the entire way and then use a small flexible putty knife to push it in that final bit, you end up the insert really nice and flush against the surface with a good plastic finish. It's something I wish I had known about a month earlier.

[@joeldriver381]

I am working on a similar project with an Acorn, and have been printing similar parts. My brass inserts arrive today! This will also be my first time using them after years threading prints🤣

[@AmateurRedneckWorkshop]

Very neat build. Well organized. Keep on keeping on.

[@gareth4168]

We had an injection moulding tool for ABS parts designed at work years ago. They used inserts for anything which might require frequent disassembly and specific plastic screws for lighter duty fastenings. I think the brand name was plastite, they have a coarser thread than machine bolts and are self-tapping to screw straight into a boss.

[@prototype3a]

Yep. I almost got some Plastite screws recently for a project. Also, "plastite" is a valid search term on McMaster.

[@richardtww]

That was so neat putting the inserts in, well done you

[@deuterium8236]

I have been to this rodeo which is my plan B. In ABS I usually cold form threads, print the hole undersize, run the correct drill through the hole, and finally use a cold forming tap chucked in a cordless drill to finish the threads. Cold forming in plastic has enough friction that it's a melting process so don't touch the tap quickly after forming a few threads. Cheers-Peter

[@Splits-man]

I never knew that these existed! Brilliant! Thanks for sharing.

[@samvoelkel2046]

I sometimes thread directly into the plastic, sometimes use the "captured nut" technique (what a pain!). I will be trying this next; it looks very good. Thanks.

[@jasonrussell6534]

Another option for something you don't need to take apart and reassemble a bunch is plas-tite screws from McMaster. Self tapping and high helix angle specifically for plastic. Between those and these heat-set inserts, plastic has never been so much fun.

[@tablatronix]

I always wondered what these were actually called, I have been buying "laptop screws" etc made for injection standoffs/boss

[@rugwalle]

Been looking at these for a while but your video got me to order some to try in some of my designs. Thanks for another great video

[@CuttinInIdaho]

The press or jigs are helpful when making things for production. If the screws need to go in perfect, and your reputation depends on it, you can use a jig or a press to save a headache. Otherwise, for most people this is excellent. You are good with your hands and did a perfect job.

[@johnpardoe9920]

Great video as usual.. Looking forward to seeing more on your Acorn CNC project. I recently completed a lathe CNC inversion using an Acorn Controller, which is working well - having seen your layout I will be building a new back panel.

[@ahbushnell1]

i just use the soldering iron tip I use for PCB's and put it in the hole in the insert and push it in. Works great. I left the temperature at the soldering temperature. It pushes in fast. Nice Video

[@rent2ownnz]

Great Video. Cheers for taking the time.

[@artmckay6704]

Thank you for sharing this! I love the adapter you made for your soldering iron, it's perfect! :)

[@karennoyce1015]

Have a project coming up and will be using heated inserts after seeing this video - thank you James love your channel

[@MkmeOrg]

I think I found the first project on my new mini lathe. Great video

[@bruinflight1]

That is SLICK!!! What a great idea!

[@rpavlik1]

Looks like great "turning to a shoulder" practice 😁

[@rdnybowersox]

Way to leave us hanging on the upcoming project...interested as to what project is coming up

[@DNomer]

Pretty cool. Good application of multi-material design. Also good use of 3D printing.

[@jonathanhendry9759]

I found an old Dremel Model 210 "drill press" at Goodwill that I think might make a nice rig for heat setting inserts, by putting a soldering iron in the press instead of a Dremel.

[@buidelrat132]

The Skyentific channel (home-grown robot arms, motor testing) often uses a captured nut technique to great effect as well. Love heat-set inserts and your impeccably neat work, thanks for the video!

[@robertbauer9230]

Your channel is fascinating. Thank you for these videos.

[@DoRC]

Threaded inserts are great. One suggestion would be to undersize the holes a bit. I found that if you make them a little too small and end up having material ooze out when you install the insert you get a much better connection between the insert and the part. The ooze is pretty easy to clean up afterward

[@tablatronix]

Just be careful to add clearance at the bottom or else you can get plastic inside your insert

[@DoRC]

@@tablatronix very true

[@MichaelLloyd]

The perforated back panel is genius. I like the threaded inserts. I'll be able to use those in the 3D printed avionics bays of my high power amateur rockets!

[@aschreiber]

One of the tricks I've used for these over the years is to remove the iron when the insert is a bit proud of the hole and use a flat piece of metal to push it flush. This means it's flush to your plastic and does seem to help a bit with them being square. Course, I just use a super cheap soldering iron for the with a tapered tip so it works across a variety of sizes.

[@Clough42]

I think I would want them slightly below flush, to get solid bearing on the plastic, but you have a point about squareness.

[@kennethnilsson6976]

By making them flush, you also prevent them from being pulled out, ever so slightly, if the screw is torqued a bit.

[@tablatronix]

ooh this might help with preventing getting some plastic melt inside the bottom of the hole, I make my holes extra deep now, or it will really mess your threads up

[@aschreiber]

@@tablatronix I tend to model them as drilled so I get some clearance at the bottom for the molten plastic in the taper. I really should figure out how to do custom hole definitions in Onshape so I can just add a library of the shapes for it with a bit of a counterbore to help align. I’ve cheated and made models for forms to Boolean out too which does work and could even get the taper they suggest.

[@seanw1550]

Great idea! I'll try that. I've been using threaded inserts for awhile now. It's important to get the insert at the surface or it gets pulled up and cracks the print when tightening (I use an electric screwdriver). I've ruined more than a few 3D prints that way. If the inserts are on the surface, then the print doesn't crack.

[@crazytrutas]

That´s a beautiful setup.

[@mattmanyam]

20:30 Regarding the "self-drilling" screws... In material like that perforated board, especially with existing pilot holes, you'll probably experience better long-term performance with the stinger point version of those fasteners. In thin sheet goods, the chisel point removes too much material for the thread-form to develop, while the pointed ones displace the sheet metal, and leave more "threadable" material behind. It depends on the thickness of the material, though, but I would definitely try it!

[@KernsJW]

Surprised you hadnt used them sooner. They work great for sure!

[@joopterwijn]

Looking great!

[@summerforever6736]

nicely done!!!

[@Werz99]

Thanks for the idea with the special tooltip. I will make one too. One recommendation for "one time/seldom use" plastic threads: I never understood why drilling and tapping the hole. I just 3D print the threaded holes, which are simple to design in fusion 360 (dont forget to check "Modeled" in the tthreds dialog otherwise it will not be in the stl!). I also print screws if needed in the same way (100% infill).-Give it a try!

[@GrossGeneralization]

I used to use brass inserts, but then I discovered self tapping screws with a thread profile designed for injection molded plastic parts. I find them preferable for general assembly, though I guess inserts are still useful if the screw needs to be in and out a lot.

[@ChazzC]

Nice video, James. I’ve used heat-set inserts in a couple of my printed builds, and toyed with the idea of making a jig, but like you find that freehand is more than adequate. My first experience with heat-set inserts was many, many years ago assembling a piece of HeathKit test equipment (I think it was the low-end RF & Audio Signal Generators that had plastic cases, but it make have been on the “Most Accurate Clock” case): the instructions called for using a standard pencil iron tip and just pushing them in the same way you did.

[@AdamDaley1]

So satisfying

[@Trust_me_I_am_an_Engineer]

Thank you for the video! Turning a tooltip for the soldering iron out of brass for is a great idea !

[@Trust_me_I_am_an_Engineer]

Ignore the for behind brass :)

[@EPaulIII]

After all those years using standoffs to mount PC boards ... I am ordering some inserts. TODAY!

[@insignio1]

OMG! I couldn't believe you never used these before! Threaded inserts are great and whenever I design a part that needs screws, I use them. Even if I think I'll never take it apart afterwards. I used to buy the cheaper ones until I started watching some of the video's of the Voron guys. They taught me to use the right inserts (the ones you got). If you use the cheaper ones and your holes are not the right size, they either drop out or clog up the screw hole..

[@Andy-rq9ni]

i use all the inserts i can find and for the "wrong ones" i just turn a grub screw in the insert , then insert it into the plastic and when its cooled doen i remove the grub screw

[@Clough42]

There are moments in life that you remember forever: your first kiss, your first Doctor, where you were on January 28, 1986, and the day you discovered heat-set inserts.

[@carycleland9506]

That’s a great idea!

[@tristonzismer1590]

Ironic I made a comment on your Welding cart video about noticing the boxes for another cnc last night and loan and behold this is your new video lol good stuff James excited for you and cant wait to see more content

[@chadkrause6574]

Funny you made that - I made the exact same thing for my Hakko to do threaded inserts! Hard part is keeping the insert normal to the part

[@temyraverdana6421]

Thakns, a very useful tool!

[@RRINTHESHOP]

Looking Great, nice method of inserting.

[@alphaomegaboom]

Great Video ! Thanks !

[@ron827]

Extremely clever and very useful. tnx

[@TomChame]

Very neat, thanks.

[@yngndrw.]

I usually tap holes when prototyping parts and then once I'm happy with the spacing and clearance switch to inserts so that I'm not wasting them. I just use my standard conical soldering iron tip for them and do find that they occasionally don't go in straight, but it's pretty easy to straighten them up afterwards just by re-heating them. I do always drill the hole out to the correct diameter so that they go in just right, otherwise I find the excess plastic sometimes pushes the insert back out after I remove the soldering iron. I'd suggest that you consider switching to larger cable channel for the right-hand vertical channel as you have a lot of wires to put into there. I've seen others use those self-drilling screws with solid back-panels but when I used to do control panels with my dad many years ago, we used to drill and tap every hole in a solid panel - That used to take the best part of a day on a larger panel. Don't forget to number your wires, both on your drawings and at both ends of the wire. The little push-on plastic numbers work well.

[@SlamminGraham]

I sometimes use rivets for a super simple, fast, and low-profile connection to a 3D printed part.

[@DK-vx1zc]

clever. thanks for sharing

[@EZ_shop]

Love it! Now I'm gonna have to make a Haiko brass tip. BTW the CrossFire motor backplates came out great, and had no grounding issues so far after adding the Z axis. Thanks. Ciao, Marco.

[@N0FPV]

Bro I used your ity bitty extruder on my i3v years ago. I still have that machine but it's been fully rebuilt multiple times now. So glad I came across this video!

[@Clough42]

I'm still running mine, though the printers are being replaced one by one.

[@jbrownson]

Cool, thanks for the video

[@phil.tsao.]

I love that you turned a tool for this haha. Standard soldering iron tips do work though, especially if you have enough clearance under the insert or are inserting into a blind hole!

[@automaticprojects]

I just used the M3 brass inserts from Adafruit for the first time yesterday. Worked great, although I don’t have a metal lathe, so just bought the soldering insert tool from Virtjoule. Was cheap and looks just like the one you made but would’ve been more fun to make.

[@Ddabig40mac]

A tidy control box is its own reward. Also, with that coy reference to CEE, I noted your fluency using both Metric and Imperial measurements.

[@Clough42]

It's a necessity where I live. Locally available machines, materials, and cutting tools are all denominated in inches. The dimensions on the soldering iron, the tip, and the fasteners all originated in millimeters, but the dials on my lathe are in inches, so that's how I output the drawings.

[@Andy-rq9ni]

now i would like to see you build a insert press , with all your technical knowledge id say you would build a master piece

[@Clough42]

It would be fun, but then I'd have to store it somewhere. :)

[@harrywoods9784]

Great how to video👍👍

[@outsidescrewball]

Enjoyed…tks for sharing …clean/sano/install

[@johncrisman576]

Bravo. Impressive ingenuity. I see a whole bunch of Amazon vendors have already adapted your Hakko hack.

[@Clough42]

Or did I steal their idea? Makes you wonder... :)

[@cjtroutt8092]

Nice Workman ship James on the layout I can't wait to see the new build it looks like we talk about a month ago on something as subject matter lol

[@CraigLYoung]

Thanks for sharing 👍

[@giantm2323]

I've put in a ton of these, the only real trick is exactly what you've done, buy the inserts with the crosshatching in the middle rather than the straight, parallel to the bore type. That is critical for grip. The way the plastic relocates during the process, generally pushing some down, I would think a taper would be worse, assuming your printed hole is to spec in the first place. You generally want less extra molten plastic trying to relocate, not more. I've always printed straight holes carefully calibrated to be at spec for the insert and have had no issues, when using the good inserts.

[@kimber1958]

Outstanding

[@blaisechampagne8680]

Great video! What printing plastic material did you used (ABS, ASA,PLA,...)?

[@bobblaine1437]

Tips for doing this are available for Hakko FX-888D for various sizes of inserts. No need to make them if you have that soldering station. I think getting them in squarely is more of a challenge if you use a traditional tapered tip, or if you use the ones that don't have that little extra locating collar.

[@tablatronix]

Yeah I found a set on amazon, I kept my old hakko just for inserts! Its nice having a tip on it and ready to go

[@dhollm]

I suppose you could press in a length of allthread in a similar way (using heat) and then use a nut to hold the board onto the mount. One advantage there could be that with the use of some spacers you could stack multiple components on longer sections of allthread.

[@CJ-ty8sv]

Heat set inserts are great over direct thread or tapped thread in plastics. Another thing I do fairly often if the print setup allows for it is print in place hex nuts of sorts. Essentially just print the right hex size recess and close over the recess for the hex a couple layers above the height that I would start to close over the nut and then add in a pause at the start of that layer so that I can drop the nuts into the hex recesses and just print right over top of them with just a hole the right diameter for the screw. This isn't necessarily as good as a heat set insert but it works great and I have tons of hex nuts of all sorts of sizes and they are cheaper than heat set inserts (about a 3rd of the price) and more versatile since they are not restricted to just one particular use. The only time I avoid doing this is of the boss OD isn't large enough to have at least 4 perimeters beyond the circumscribed diameter of the hex. This however is just a personal preference for no particular reason since 2 and 3 perimeters seems to work fine.

[@chrissewell1608]

I wish I had your skills and lathe!

[@kevinwassellsr.5646]

40 years in industrial automation says be sure and exhaust air directional valves out of cabinet. Good looking cabinet so far

[@Clough42]

None of these are directional. There will be a small amount of air coming back from the spring-loaded ATC cylinder, though, so it's probably worth piping out the exhaust.

[@MrRfries]

That's ust too easy, I'll give a try for sure. Thanks

[@airgunningyup]

just finished an acorn lathe.. its a really nice controller compared to mach ,wayy more options .

[@wayneconstantin957]

Thanks!

[@cliffsmith4907]

So I have a solder station with both pencil & air. I use 3 different tnserts, but maybe will still turn down tips for the pencil. What I have been doing with great success is screw the insert onto a LONG bold, Heat the insert with air and push it in . El-cheapo leather gloves are fine and the long bolt gets the insert quite straight using the 'reckless eyeball'...

[@doseven]

Whenever I need a single use threaded hole I just draw the hole to be the minor diameter of the screw thread and then just run the screw into it, no tapping or drilling needed. It seems to work really well for UAVs with a lot of vibration. If you were going to be disassembling the part however these inserts are the way to go!

[@martinmckee5333]

I've used the minor diameter for mounting electronics on High-powered model rockets - also a high vibration environment. But yes, for single assembly, perfectly sufficient.

[@Clough42]

That's a good point (vibration resistance). One challenge with this is that the minor diameter of 3D printed holes is relatively hard to control well. Most people just starting out have lots and lots of trouble. When size is critical, I usually plan on reaming.

[@martinmckee5333]

@@Clough42 Very true. I have characterized my printer with my most used filaments and typically get dimensions better than 0.05mm, which is good enough for almost everything I do. But getting set up to do that was no small task.

[@Cenedd]

James' threaded inserts are definitely better (stronger, more durable etc) but if you've not got them or are iterating prints, I've had pretty good results (on weirdly similar parts just recently) just modelling the thread in Fusion and printing it as it. That gets the number of perimeters around the thread up for strength (vs printing to minor diameter) without having to increase them over the whole model. Then running a tap down them to bring them to dimension is quite easy - the tapered end of the tap, being smaller, catches the printed threads and it self feeds straight.