Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Cleaning up the end of the broken shaft let me shove it into a drilled ball:
Helmet Mirror Ball Mount – repaired – drilled balls
The insert and random screw came from the stub end of the broken shaft: ramming it into the cleaned-up end makes the job look Good Enough™.
Clamp the repaired stalk into the spare mount, drop the drilled balls & lathe fixture back in their bag, and maybe it’ll be another six years before they’re needed.
Before turning the PVC conduit to the proper diameter for the Shopvac hose adapter, I set up a 20-50-32-80 change gear train for a 100 TPI finish. While the urethane adhesive cured in the hose, I fed the BC gear pair into my change gear generator:
Mini-lathe stacked change gears – 32-50T – solid model
It’s ready for the next time I cut something down to size:
Mini-lathe 100 TPI change gears
One reference suggests a 256 TPI finish for “general turning”, which works out to 20-80-20-80:
Mini-lathe stacked change gears – 20-80T – solid model
That’s just crazy talk, because the BC washer overlaps the D gear teeth:
Mini-lathe 256 TPI change gears
If all else fails and I really need a 256 TPI finish, lathes are pretty good at making washers.
The tapered adapter drags the OpenSCAD code into the BOSL2 era:
Spiral Hose – 1.25in nozzle adapter – solid model
The ID of the hose determined the OD of the lathe-turned PVC tube inside the 3D printed adapter, so a straight pipe would just slide right into both parts.
It would be possible to skip the 3D printing and make the adapter from a single piece of PVC:
Turn one end of the conduit to fit the hose ID
Maneuver the lathe compound to the required 1.05° half-angle
Turn the taper to fit the crevice tool
Clean up the original OD between the two sections
Just turning the whole pipe to a smaller OD and sliding the taper on was definitely easier, particularly given the mini-lathe’s cramped quarters with the compound nearly parallel to the bed.
A generous helping of JB PlasticBonder urethane adhesive bonds the PVC pipe inside the vacuum hose and the tapered adapter.
The as-printed taper perfectly fits the crevice tool shown in the picture and is one wrap of electrical tape smaller than another crevice tool of “the same size”. The Finesse variable handles that situation, should it matter to you.
The OpenSCAD source code:
// Shopvac spiral hose to 1.25 in nozzle
// Ed Nisley - KE4ZNU
// 2026-07-25
include <BOSL2/std.scad>
Finesse = 0.2; // [-0.5:0.1:0.5]
// PVC pipe liner final OD
PipeOD = 28.5;
/* [Hidden] */
NumSides = 4*3*4;
$fn=NumSides;
Protrusion = 0.1; // make holes end cleanly
HoleWindage = 0.2; // make holes large enough to fit
//----------------------
// Dimensions
TAPER_MIN = 0;
TAPER_MAX = 1;
TAPER_LENGTH = 2;
Tool = [30.0,31.1,30.0] + [Finesse,Finesse,0];
FlangeOD = 37.0;
FlangeLength = 5.0;
//render()
difference() {
union() {
cyl(FlangeLength,d=FlangeOD,anchor=BOTTOM) position(TOP)
cyl(Tool[TAPER_LENGTH],d1=Tool[TAPER_MAX],d2=Tool[TAPER_MIN],anchor=BOTTOM);
}
down(Protrusion)
cyl(2*Tool[TAPER_LENGTH] + FlangeLength,d=PipeOD + HoleWindage,anchor=BOTTOM);
}
The idea came from the June/July 2026 Machinist’s Workshop, wherein I learned Dremel nuts / chucks fit on a 0.275 inch = 9/32 inch 40 TPI threaded body, drilled through 11/64 inch.
Making such a thing involved some pleasant lathe time:
Dremel Collet Chuck Handle – lathe work
The business end of the body has a slight taper to (ideally) match the collets:
Dremel Collet Chuck Handle – threaded body recess
However, the collets have tapers ranging from 20° to 35°, so I defined a 60° center drill to be Good Enough™ and got a free taper while drilling the central hole.
The collets sit in the taper:
Dremel Collet Chuck Handle – collet installed
Tightening the nut closes the collet:
Dremel Collet Chuck Handle – threaded body – nut installed
The article described a nicely turned wooden handle, but a somewhat uglier 3D printed handle is fine with me:
Dremel Collet Chuck Handle – solid model – top view
The variables match the threaded body to my fingers:
Protrusion = 0.1; // make holes end cleanly
HoleWindage = 0.2; // make holes large enough to fit
ShaftOD = 6.9; // collet closer thread - 40 TPI 0.275 OD
ShaftID = 4.3; // … internal clearance
HandleOD = 15.0;
HandleLength = 45.0;
Knurling = "trunc_diamonds";
The motivation for all this was to put the smallest taps in a holder suitable for delicate jobs. The smallest chuck on my real tap driver bottoms out on an M3 tap and can’t grip the M2 tap:
Dremel Collet Chuck Handle – M3 vs M2 taps
I try very hard to not tap small holes, but sometimes you gotta do what you gotta do and now I’m better prepared.
Incidentally, the first threaded body I made absolutely did not fit the Dremel nuts. After eliminating everything else, I discovered I’d set up the lathe change gears with a 20-65-45 train, rather than the 20-65-50 train required for 40 TPI with the lathe’s 16 TPI leadscrew.
Protip: Even the best threading job (which I didn’t do on any of those things) can’t make a 36 TPI screw fit into a 40 TPI nut.
The tilt (it’s really “pitch”, but I can’t make a case for being that pedantic) adjustment on a recently arrived monitor stand / arm was nonfunctional, because the metal clamp had been bent about a millimeter too narrow to fit the plastic core. This is how it should look:
Monitor tilt adjustment – installed
As delivered, the plastic core was 32-ish mm wide and the gap at the base of the metal clamp was 31 mm, so the clamp arms stuck out at an angle on both ends of the core .
Because the cap screw bottomed out on the threads in the far side of the clamp, it couldn’t be tightened enough to force the clamp arms against the core.
Well, if the core is a millimeter too large for the clamp, shortening it should solve the problem; I can always shorten the screw if it comes to that.
Quick! To the mini-lathe:
Monitor tilt adjustment – lathe setup
Shaving half a millimeter from each side:
Monitor tilt adjustment – shaved
Twirling a deburring bit in each hole got rid of the swarf.
Rather than trimming the cap screw, a pair of fender washers keep it from bottoming out. With the core fitting into the clamp, the arms grip the core firmly on both sides with plenty of friction:
Monitor tilt adjustment – tweaked
I’ve bought this brand of arm before and the most recent pair have definitely been cheapnified from earlier ones. Because only one had a bad tilt clamp, the OEM may be in the middle of a changeover and shipped it with mismatched parts.
I wonder how many stands / arms get returned because they just don’t work?
The OXO pepper mill replacing our worn-out pepper mill arrived filled with peppercorns and, during the ensuing nine months, we established its finest grind setting produced bigger pepper flakes than we prefer. I figured there had to be a way to get the ceramic stones just a little bit closer, even though it has no user-serviceable components inside.
So, we begin.
After rinsing out most of the pepper flakes (the remainder appearing in the pictures below) and determining the two obvious screws didn’t release the housing, the Jesus clip on the shaft extending through the peppercorn compartment came under consideration:
OXO Pepper Mill – E-clip on shaft
The washer beyond the clip bears on the black plastic spider. It turns out the thickness of that washer determines the distance between the grind stones at the minimum setting: making it thicker reduces the stone gap and produces a finer grind.
Knowing full well it would be impossible to get the clip back on the shaft in that position, I pried it off.
Spoiler: Don’t do that!
The grind adjustment lever turns the chunky black ring inside the gray housing:
OXO Pepper Mill – grind adjustment rings
Three protrusions on that ring step along notched ramps around the perimeter of the black spider in the clear housing on the right.
The shaft slides out to reveal the spring under the inner stone, with a second washer bearing against the bore of the gray plastic housing:
OXO Pepper Mill – upper shaft parts layout
As a result, the spring tries to push the shaft and inner stone out of the housing (toward the left). The protrusions on the grind adjustment control how far the shaft can move, with the washer + clip locking the shaft to the spider.
Gentle persuasion extracts the chunky black ring:
OXO Pepper Mill – grind adjust slider
The outer stone fits into a recess in the gray housing:
OXO Pepper Mill – outer stone
One might 3D print a washer fitting under that stone to close the gap between it and the inner stone, but the two screw holes interrupt the ledge enough to suggest the washer would be in two parts divided. If I didn’t have a mini-lathe, that’d be the best way to go.
But I have a mini-lathe, so I made a steel washer slightly thicker than the OEM washer under the clip:
OXO Pepper Mill – turning new washer
The OEM washer:
ID 6.7 mm
OD 10.2 mm
Thick 0.6 mm
Not knowing the right answer, I made a 1 mm washer, which is visibly thicker:
OXO Pepper Mill – 1mm vs OEM washer
Which let me reassemble the pepper mill in reverse order, only to establish reinstalling the Jesus clip deep down inside the housing is, in fact, impossible.
Taking everything apart again let me contemplate the inner stone on the shaft, leading to the discovery it could slide very slightly on the shaft. More pondering revealed a slight seam in what I had taken as a monolithic black cap:
OXO Pepper Mill – inner stone assembled
Applying gentle suasion between the stone and the cap with a plastic razor blade enlarged the seam into a gap. Much to my surprise, further prying popped the top off the cap:
OXO Pepper Mill – inner stone cap
Happy dance in full effect!
Removing the screw let everything slide off the top of the shaft:
OXO Pepper Mill – inner stone parts
Freeing that end of the shaft meant I could install the clip on the bench, add various parts while sliding the shaft through the housing, then tighten the screw to snug everything down.
As with most activities, it’s trivially easy when you know the trick.
Whereupon I discovered the new 1 mm washer jammed the two stones firmly together at the finest grind setting, so the correct washer will be somewhere between 0.6 and 1.0 mm thick:
Back to the lathe for a 0.8 mm thick washer
Dismantle pepper mill
Swap washers
Reassemble
Verify smooth turning at finest setting
Fill with peppercorns
Give it a twist
A shower of pepper flakes in a cup:
OXO Pepper Mill – finer grind
The mill undergoes a full qualification test tomorrow morning, but those flakes look much better.
Fun fact: the OXO pepper mill holds 2.0 oz of peppercorns, so we use 0.033 oz = 940 mg of pepper every day.
The cart in Mary’s Vassar Farm plot returned in need of repair:
Garden Seat – fractured body
Those fractures near the end of the axle let the axle erode the side wall:
Garden Seat – eroded body
This will obviously require some sort of reinforcement on the body holding the axle, but the first challenge involved getting the wheels off the axle:
Garden Seat – axle cover
Some brute force revealed the hub covers snapped over an install-only locking fastener:
Garden Seat – axle retaining clip
More brute force cut those fasteners (a.k.a. star-lock washers) to get the wheels off the axles.
While contemplating the situation, a box of 606 bearings (as used in the PolyDryer auto-rewind spindles) failed to scamper out of the way and produced a victim fitting perfectly on the 8 mm axle:
Garden Seat – bearing idea
I regard such happenstance as a message from the Universe showing I’m on the right track. The alert reader will note the axle should not rotate, but does sport scars showing it’s done some turning in the recent past, so the bearing may not be a completely Bad Idea™.
Finding a Lexan snippet exactly as thick as the bearing suggested bolting a plate across the side of the body to support the bearing, like this:
Garden Seat – reinforcing plate installed
Some layout work in LightBurn produced a template to mark the body for hand-drilling the holes:
Garden Seat – drill marking template
In retrospect, that was a mistake. I should have:
Laser-cut an MDF sheet to make a drill jig
Drilled one hole and inserted a screw
Drilled the rest of the holes in exactly the right places
Instead, three of the holes in that nice Lexan sheet ended up slightly egg-shaped to adjust for mis-drilled holes in the body.
I squeezed 5 mm rivnuts into whatever fiber-reinforced plastic they used for the body, which worked better than I expected. They’re intended for sheet metal, so I set the tool for 5 mm compression and they seem secure. I hope using plenty of screws across a large plate will diffuse the stress on each screw.
In this situation, I regard JB KwikWeld epoxy as “removable with some effort”, as opposed to the destruction required with those star-lock washers. High-strength Locktite might also be suitable, but I do not anticipate ever having to remove these again for any reason and do not want the nuts to fall off in the garden.
The Smell of Molten Projects in the Morning 