G'day Chris here, and welcome back to Clickspring.
I'm in the process of making this set of rope knurls for some future Clickspring projects,
and to use them I need a holder like this.
It's a basic bump style knurling tool that can be mounted onto the lathe toolpost,
and then pushed into the work to form the pattern.
It's a nice simple design; just a steel body section and a threaded axle.
The main body section doesn't really need to be hardened, but I'd like it to last well,
so I'm going to make it from O1 tool steel.
The axle will definitely benefit from being hardened, so I'm making that from En8 carbon steel,
so I can quench harden it later.
So let's get started!
I loaded the rod stock into the lathe, and turned the basic profile of the axle.
A quick check of the axle diameter confirms that the knurl will be a close fit,
and that it will also run freely.
This thread is quite short, and I've designed it to end flush with the outside of the tool body.
I'd like to be able to get the knurling tool in as close as possible to the chuck when its in use,
to minimise any flex in the part that's being knurled.
After parting off, the axle was rechucked the other way,
given a light facing cut and then taken over to the mill to form a screwdriver slot.
At this point all of the main features of the axle are in place,
it just needs to be quench hardened, and then tempered.
I've tempered it to a medium straw color, which means that it remains quite hard
but its also quite tough too and so should last well.
A quick touch with emery paper to pretty it up a little, and its done.
So now it's on to the main tool body, and for the most part, these features are best
formed on the mill, so the first step was to get it set up and located in the vise.
I drilled the work all the way through with the tapping drill size, and then half way
through with a drill that was just a little less than the clearance drill size.
That way can follow that part of the hole with a reamer, and make sure that the axle will be
a close fit in the tool body.
OK, so at this point I have the holes I want at each end,
I just need to remove that waste stock in the middle.
To make that cut, I need the work standing upright in the mill vise,
but of course if I just stood it up without any support it'd be way to flexible.
So I've strapped it into the vise with some 1,2,3 blocks to give it some more rigidity.
Once confirmed vertical, I used some toolmaker clamps to further lock that top section in place.
One side was tapped to accept the thread of the axle, and at this point most of the hard work has been done.
But I do think it would be better to round those corners,
so I took care of that next.
First with a quick marking out, followed by a few minutes on the belt sander
So here's the end result.
The knurls have a little bit of end shake, and run nice and free on the axle.
And best of all the holder has a clean edge on the side that will be closest to the chuck.
Thanks for watching, I'll see you later.
If you'd like to see this knurling tool being used , here's the video where I use it to make some knurled thumbwheels.
And if you're new to Clickspring, thanks for dropping by.
I post regular home machine shop project videos, so be sure to subscribe
Thanks again for watching, I'll catch you on the next video