Threadmilling on a manual lathe

I had work recently that required some ID threads with basicaly no leadout. I did them with a regular tap, followed by a bottoming tap that had all its lead ground away. As the material was 316 stainless, it was a rather painfull experience ;-)

Threadmilling could be a very good solution, as it is almost completely independent from the rotational speed of the workpiece.

Here is what I tried, with a heavy duty routermotor mounted to my lathe.

Also: Shopground threadmills, deburring and coldblue-application.

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[joepie]

I would have thoroughly enjoyed working side by side with you back in the day. I like the way you think. 100% Great video.

[Rob_]

Seems like we have a similar strategy on deburring:
Step 1: remove blood stains
Step 2: debur the part
Step 3: check part for blood stains. If any found, repeat at step 1

[juanrivero]

Wonderful video. Back in the time frame 1880 (and even before that) when electric motors were rare or unavailable there was the English Holzapffel ornamental lathe company .The double ff is no typo. The lathes were foot-powered. They had all kinds of attachments and extra-axis devices. Among the things they would do is mill threads. They would also allow you to e.g checker-pattern a piece or inscribe all kinds of patterns on work. The last Holzappfel was sold in 1920 or so. If you look under "ornamental turning"you will find quite a lot of info.

[aaronhammond]

The reverse set-screw interference fit bit is a nice trick.
Will be adding to my designs.

[gyrogearloose]

After telling the story about the maker who stood by his cannon for the first shot, then Stefan sanding and rubbing like mad again and again, he says "not crazy .." and keeps on sanding. Gotta love the guy and everything he does. Kudos Gotteswinter !

[iiredeye]

There's lots of good guys posting on youtube. But Stefan in my opinion is the most interesting person to listen too. Totally engaging, supremely knowledgeable, but extremely humble...A pleasure to watch.

[mpetersen]

"I'm not the first guy to do this". Stefan, by now I would think just about anything that could be done with a manual machine has been done. IMO the most impressive things done on manual machines are turbine impellers that were done pre cnc. And the interrupted threads on the breaches of large naval rifles. Given the pressures they had to withstand they had to be absolutely perfect.

Now if you had a way to run your cross slide at the proper ratio you could make chuck spirals. And I know they had set-ups to do that on manual lathes. Setting the router at the center of the included angle you could also cut buttress type threads.

Not germane to threadmilling but in the past I experimented with making roughing mill cutters out of taps. Grind a relief angle on the top of the teeth that gives a flat wide enough that all the flats are longer than your taps pitch. Grind a secondary relief angle. Works fine on softer materials. Not so much on tool steels. I worked with some machinists from Germany and they told me that in the 50s they used to have to make end mills out of twist drills.

[bobuk]

Hi Stefan. Nice to see the solution to a very old problem for which the model engineer's Guru George Thomas had a much more complex solution. Folks, when you slit into a previously bored hole there is a tendency for the bore to close in. Stefan's jack screw is a very simple and elegant solution. BobUK.

[whatevernamegoeshere]

"Should fit... or else I will edit it"
That's the youtube spirit

[arachnipope]

By using this same router setup with 2 flute, carbide wood-routing bits, you can make amazingly-accurate lathe cuts and deep grooves in rubber and soft urethane bars. I've used this on motor mounts and suspension bushings etc.
The trick is using compressed air for cooling along with a vacuum cleaner. Love the video!

[LarrysMachineShop]

Again, the magic happens, Awesome!! I learn new stuff every time. Thank you for all the time you put into these quality presentations

[LabRatJason]

Seems like you can cut knurls with a setup like that too. Reverse the feed without reversing the chuck direction.

[BernardSandler]

I've never seen this before! Beautiful little adapter and spectacular results. Seems so much more controlled and safer than single point threading. To me as an armchair machinist fan, you guys cutting threads always looks like some kind of ballet with chainsaws.

[EDesigns_FL]

I have a similar setup and have found that it works great for trepanning. I use an end mill in the die grinder and rotate the lathe chuck very slowly. It's much faster than using a conventional trepanning tool and there are no issues with chatter.

[stephencurtis]

Stefan is one of my favourites. I have to choose between Stefan, Joe Pie, Robin Renzetti and Tom Lipton. There are others of course. The steadfast adherence to practical as well as accuracy and precision is truly an art form and is common among them all. When I want a chuckle, as well as these qualities, I turn to 'This Old Tony' as I'm sure most who are interested in this subject will do. Abom79 is another stalwart - a big amiable kind hearted giant of a man. This is a special community, revelling in an under regarded set of skills. Hand to eye accomplishment is the best medicine for what ails thee. <3

[Preso]

I love that the thread just stops with no run out! Such a cool look.

[peteramor]

Its always nice to see a true craftsman doing his stuff Being an engineer ( millwright) for nearly 50yrs I know quality when I see it Great video Stefan Please keep making them Pete UK

[PaulWattsSpringGunning]

In my father's shop back in the seventies we used to do the final grind on hardened threads with a diamond embedded linen phenolic wheel mounted on a tool post grinder. It wouldn't take much off but it made the threads extremely slick. It was set up much like what you're doing except the cutter and/or lap was mounted on a mandrel. The angle could also be adjusted for clearance on larger threads by tilting the spindle up and down in the front. Fun stuff! Thanks for the video!

[shirothehero]

Cannon blowing up < bad deburr for sure.
Also, the set screw 'trick'/gimmick is frickin brilliant. I've never thought of that. So simple and amazing. Damn good thinking!

[ROBRENZ]

Very nice work Stefan! love the threadmilling.
ATB, Robin