In the previous video, I made the bed and the carrier bolts for the depthing tool.
In this video, I make the knurled carrier nuts as well as the adjusting screw.
So lots of knurling this week, and for me it can be a bit of a hit and miss affair.
I'm what you might call a reluctant knurler. One thing's for sure though, the start diameter is critical.
So using one of the online knurling calculators, I got the correct figure,
and then took a cut to reduce the stock down to that diameter.
Then I gently made a light imprint with the knurl, so I could check for any double tracking.
Once that looked good, I lightly increased the pressure, rotating by hand until the pattern was nicely established
And from there, I carried on under power at about 200 rpm,
Going up and back, until the knurls formed up to a nice clean peak.
I get best results just lightly nipping up the pressure after every pass.
and I use plenty of cutting fluid, and flush the work often to remove the little flakes.
Its a messy job though, and like I said. sometimes hit and miss.
There's a good section in the middle. I can use that.
I cut into the knurl pattern until I found an intersection that looked about right
To me half way into a knurl peak looks quite good.
Then I took it to full depth, and to be honest
at this point I just did it by eye until it looked about right. I'm only making two of
these, so this one's the blueprint for the second one.
I faced off the excess to a suitable length.
And then I drilled and tapped the center thread to match the carrier bolt.
The thread could do with a good undercut to give the nut a nice clean seating on the tool bed,
so I did that, and then broke the corners with a file, before parting off.
Thats one side of the nut taken care of, but that parted off surface needs to be cleaned up,
and I think the nut would look better if it had a similar cut in to the knurl pattern from this side too,
so I took care of that next.
And again, I cut into the knurl pattern until it just looked about right.
A quick break of the corners with a file. and the nuts almost done.
The inside edges just need a quick touch with a countersink, to finish the part off.
OK, now they're done
Now for the adjusting screw.
For the threaded portion, I'll make life a bit easier for myself by using some threaded rod.
The thumb grip will be machined in a similar way to the previous part.
First a trim of the stock to the correct diameter for knurling. The knurl pattern is lightly established.
And finally the full depth knurl is formed under power, with plenty of fluid to wash away the chips.
Again, I found a nice intersection point with the knurl pattern, and then cut to depth.
Now this is where this part deviates from the previous.
For this part I want a cone shape on the end, so I set the compound off at an angle,
faced to length with the cross-slide. and then cut the taper feeding in with the compound.
You can see I'm forming a little boss on the end
into which I'll drill and tap a hole that will soon accept the threaded rod.
Once this piece is parted off, I'll need to clean up that face as before,
so its back to the little lathe for some more tidy up operations.
And I'm going to hold the piece a little differently this time because it's so small.
The little boss section will fit neatly into this watchmakers collet.
And now I can do the same operations as for the nut.
Trim to length.
Cut into the knurl pattern,
and leave a nice finish.
The thumbwheel needs an indicator mark to show position, so I took care of that.
And that's the machining of the thumbwheel complete.
Threaded rod is definitely going to save me a lot of time for the shaft,
so I cut off a length of that.
Tidied up the cut ends on the lathe.
And then using a little loctite, bonded the rod into the thumbwheel.
While that was curing, it occurred to me that it might be a good idea to put a little threaded brass cap
on the other end of the thumb screw, since it will be pushing up against the carrier bolt when in use,
and I don't want that marred over time. So I made that.
And we're ready for a test fit.
So thats the thumbscrew complete.
In the third and final part of this series, I'll finish off the tool by making the runners and bushings,
and I'll also show a quick depthing.
Thanks for watching, I'll see you later.
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Thanks again for watching, I'll catch you on part 3.