Making a Nut, Trunnion, and Screw: Hemingway Sensitive Knurling Tool - Part 4

Today we're continuing work on the Hemingway Sensitive Knurler kit. I've had my eye on this knurling tool ever since I first got my lathe, and now I'm finally building it. This is one of the classic British toolmaking kits, and building from someone else's design will be a new experience for me. Today, we're working on the nut, trunnion, and pressure screw. There'll be plenty of lathe work, mill work, and screw-ups to fix.

Tools used in this video:
*This site contains affiliate links for which I may be compensated

Licensed under Creative Commons: By Attribution 3.0 License

"Please Stand By" graphic courtesy of SparkFun
Licenced under Creative Commons: Attribution 2.0 Generic License

00:00 Intro
00:30 Turning the nut
03:06 Milling the nut
06:08 Turning the trunnion
06:47 Drilling the trunnion
08:43 Milling the trunnion
14:00 Fitting the screw end chamfer
16:22 Turning the screw grooves
18:51 Threading the screw (poorly)
21:15 Conclusion

[techshedlington]

You WILL remake that threaded part.. You won't sleep till you do ..🤣 You are a perfectionist 👍🏻

[jescheffler]

You've taken the first step down that very dark road. "It's good... enough." 😀 I am enjoying this series!

[Tribalwerewolf]

Heritage Machining I believe is doing a build kit like this as well.

[Steviegtr]

It was great to see how someone else makes the same parts. With the lack of instructions with the knurling tool . It's up to the individual to do it there way. Brilliant work.
Regards.
Steve.

[DavidHerscher]

Your comment about the spotting drill was a fantastic explanation of how they work and why/when to use them. I’d never given it much thought before, now that little gem of wisdom will stick with me forever. 👍

[chrisjg]

Center drills are for lathe centers. Spotting drills are for spotting. Stefan Gotteswinter (you spell it without googling) has a great explanation of this .

[anmafab]

The level of detail you go to in your explanations is really great. I will probably never make one of these knurling tools but the application of what you do is definitely worth the watch!

[tonyurquhart]

Haha! "For now, this is good... enough"
James, I love your sense of humour!

[chuckmayerchak]

Great video series! I especially like watching your machining skills. You are a perfectionist.
Being you mentioned the ELS, I built one for my Atlad 618 a year ago and love it! Couldn't imagine machining with out it now! Thanks for the ELS and your videos. Keeps an old man happy and busey!

[GuyMarsdenMakesStuff]

Thanks for educating us about spotting drills. I just ordered some. As a home hobby machinist I'm still learning - from the Master! :) Thanks again.

[e.scottdaugherty]

A fret eraser is the same thing as your big boy thingee, plus you can get different grits.

[Adventure_Van_Upgrades]

tuning in from the uk, really enjoy your videos always well produced, clear & concise .

[rak]

When I bought a spotting drill a while back I did some research on whether the angle should be greater than or less than the drill point angle. Guess what? You'll find arguments/reasons supporting either one. I went with your logic and use a 120 degree one. Great to see the small pieces you are producing for this project. Even your deliberately scrapped part to make us all feel better about our work. 😁

[jobkneppers]

James, I watched with pleasure like always. One suggestion; YouTube machinist are really font of scratch passes when they start thread cutting. I know better safe than sorry but I use a different trick without any scratching needed. I put the machine in neutral and engage the thread cutting nut on the carriage. I turn the spindle by hand so that it references "a" feature at 12 o'clock. Camlock hole, number one chuckjaw; it doesn't matter as long it's a clear indication at that moment for where you are in the 360 degree spindle domain. After establishing this point for yourself, hit the y zero button on the DRO and make a full turn with the spindle using your established marker point. After doing so your DRO should show you the pitch you aimed for within a small enough uncertainty. Using a setup on a gear driven machine the reading will show you a wrong setting of the levers on your machine. Remember to turn the spindle in one direction so you don't encounter backlash issues in the gear set-up. Just a scratchless way to check the set pitch. 99.9 percent of the time I'm right but this avoids booboo's for the remaining 0, 01% percent without any scratching the part. I hope this makes sense and helps you and/or other machinist in their machining journey . Thank you and all the best! Job

[Cjarka_]

About the spotting drill
That's why I only use the straight part of the center drill and not the tapered part, the center of the drill lines up pretty well and the flutes don't touch first

[TheAyrCaveShop]

Nicely done James, that's going to be one sweet tool 👍👍

[fasousa]

Inheritance Machining just uploaded his own version on that very same Hemingway kit

[DK-vxzc]

Lookin excellent! great narration and videography

[mhoover]

My Dad taught me to cut the threads oversize and chase them with a die for correct size and good surface finish.

[alwayscensored]

Brass is my favourite metal. Just need to mod drill bits to zero rake to stop grabbing.