Thursday, September 13, 2018

5C Lathe Part II: Power Supply and ESC

450 w 12 v server power supply connected to 25 amp ESC. With this arrangement, I get a very compact 1/2 HP variable speed motor for $100 or so. The parts are all pretty high quality too-

I made the aluminum enclosure from .062" aluminum found in the remnants bin at local metal supplier. The top handle and aluminum for knob came from a dumpster, and the pushbutton switch on the top was recycled from my wooden computer case build.

Servo tester with 'mode' switch and potentiometer breakout.

Wednesday, September 12, 2018

Thin .040" Parting Tool Holder


The slot has a dovetail shape to pull the parting blade towards the tool holder. It's really helpful if the blade can go right up next to the chuck. The parting tool holder made by Taig is weak in this department:

I skimmed maybe .075" off the blade clamp, but it still gets in the way all the time. I'm excited to have a holder that can part almost flush with the chuck!

To cut the dovetail on the new holder, I ground a safe edge on a cheap triangular file and finished the slot with it. It might have been faster to grind a single-point cutter, but this worked fine

It takes up half of the AXA tool holder; the other half will get a piece to hold a 1/4" facing tool at matching height to the cutoff tool.

Made for my 5c lathe. Ideally this would be made of 4140 or something like it, but I used the cold-rolled steel I had. I parted a 1/2" stainless rod and it worked a treat. I have never used a parting tool so thin, and it's a good match for small work and light lathes. I can get real stingy with my bar stock now :)

Sunday, September 2, 2018

5C Lathe Part I: Motor Mount

I'm putting together a new manual desktop lathe to replace the one I put together two years ago. The old one has been awesome, despite its weaknesses and size it is the most useful tool I have ever had.

The new one is made with light production in mind, for making drawer pulls and hand tool parts. It has a 5C spindle, quick-change tool post, and slots for mounting five or more tools in a gang arrangement.

Above was boring out the hole for the motor using a fly cutter. I adjusted the cutter with my most precise hammer and ended up with a darn accurate bore, a snug slip fit over the motor. :) The motor is a 450 w brushless DC motor, pretty spicy for a motor that's smaller than the lathe spindle itself...

I wanted the fit to be close so that the pinch bolt wouldn't have to stress the aluminum much to clamp it (it does clamp easily). The outer edge of the plate is pretty sloppy though; I got tired of filing the gummy aluminum. A mill or router would have been nice for that.

I roughed out the plate shape with a wax-lubed coping saw, which was actually pretty quick. The 18" frame saw also cuts through it plenty fast. I made the plate to fit the vee belt I had on hand (standard Taig lathe belt), after I machined both pulleys. It pivots on the bottom mounting screw and locks with the screw on the top to tension the belt. I erred on the long side for the slot travel since the belt is heavily used.

Approx 1:6.5 reduction. Small pulley machined of steel and secured to shaft with setscrew bearing on flat portion. Also managed to bore a tight slip fit on the motor shaft with a little honed carbide boring bar.

Used steel shaft collar to mate the plywood pulley to the spindle--I often grab the pulley and rotate by hand to tap holes and do other high-torque stuff. Setscrew just seems hackish for this.

Stay posted for the base, tooling, electronics, and maybe even an electronic leadscrew-

Monday, August 27, 2018

T-Slot Nuts: Minimum Effort Edition

Kind of humbling to have to make one's own T-slot nuts in this era. I did it once before using this method when I first started machining at home.

Couldn't find Taig-sized nuts from the usual suspects so I decided it would be best to just make them myself. I initially thought the style on the left (above) would be fast to make, but without a square collet and a rigid lathe it's a slog.

Yesterday I started bucking off 1/2" pieces from a bar of 1018. Absolutely unremarkable in every way except for the little fixture I made for drilling and tapping them this morning:

Nope, I think I was right the first time, absolutely unremarkable in every way. You may notice the slightly over-sized aluminum sub-plate there. I intend to use it for other things, have needed one for a while.

I made a dozen of the nuts:

one two three four six seven twelve

Despite being so rough and rushed, they ain't bad. The threads are square to the shoulders, they are steel, they are all nice and deburred, and there's more meat there than the 1/8" thick ones that came with it.

If the last ones are any indication, they'll do just fine for the next eight years.

Sunday, August 26, 2018

Frame Saw for Metal

I have wanted a frame saw something awful bad for a few years, to use for sawing metal. I think I was blessed (or cursed?) at birth to spend my life hacksawing. It's not as bad as people make it out to be; it's a very accurate tool. Accuracy at the saw is worth a pound of cure at the mill, or often in my case, the hand file. It's not difficult to saw +/- .010", and +/- .004" is not out of the question when all my ducks are in a row.

No matter how it's done, sawing steel is kind of a pain in the butt. Be it metal grit in your collar (glowing hot or just hot enough to burn), a mighty physical workout, or funky old coolant that dearly wants to find a way back to the earth, no method is without its drawbacks. I once bought and restored a little power hacksaw, but it was even slower than hacksawing by hand--I think due to the short stroke, wide kerf, and its lack of deductive reasoning ability. Who am I to blame though?

I once nearly bought an Ellis horizontal band saw, but kept the money instead--my favorite saws for metal are dedicated vertical bandsaws. They are relatively peaceful and versatile.

A couple months ago I found the saw design of Blackburn Tools, which struck me as especially pretty--I just sort of memorized the general form and sketched it out on the wood I had. The wood came from the ReStore, I think it might be alder. I got the idea for the pins from Sean Hellman. The whole thing, including making the three blades, took a full day of work and maybe $20 in materials.

I had put it off for a long time because I thought I didn't have the technology for drilling holes in the hardened blade. I really worked it up in my mind that it was a difficult undertaking. Yesterday I took an $8.50 diamond 'stone' to a $2.60 carbide tipped masonry bit to sharpen it. It drilled so easily and quickly, I felt like an idiot for putting it off so long. To cut the blade, I just clamped it in the vise and bent it back and forth.

The whole thing feels absurdly light to me. I used Kevlar thread for the tensioning string. Like a spoked wheel, it's such an elegant design.

Below is the hacksaw it mostly replaces. I finally snapped yesterday while using it because the thick coating of paint on the blade was making the blade steer unpredictably. It also squeals! Whether the blade is loose or tight, wax-lubed or bone-dry, pressed hard or gently, it really can get loud. I work mostly in a shared apartment, and do my best to keep the people around me happy. I often pressed the pinky of my leading hand against the blade to quiet it down, which feels a bit risky; fortunately I haven't slipped yet. I have even clamped large rubber dampers to the frame and blade, which reduces the noise at expense of stroke length. Which brings my to my last gripe, the short stroke! I am a tall and lanky machine, I feel like I'm pedaling a children's bike with a 12" hacksaw.

I must have sewn through logs of solid steel with that hacksaw by now. Below are some recent victims. 1" x 3" 1018 on the top left, .75 x 3" top right, and underneath is a .75" x 6" slice off a plate of hardened (RC 30) 4140 to make a hatchet stake. New ones are expensive, alright?

Today I put ol' faithful head-to-head with the saw I just made. I tested it on these blanks for odd-sized t-slot-nuts, .25" x .75" 1018 steel. I also tested it against my powered jigsaw at its lowest speed (I'm in an apartment, remember).

Frame saw: 1 min 30 sec - 3 min 30 sec
Hacksaw: 2 min - 4 min
Jigsaw: 1 min 30 sec

The slow speeds represent accurate cuts at comfortable pace. The fast speeds represent breaking-a-sweat speed with less attention to accuracy. All new blades, which might actually be a handicap to the hacksaw due to the idiot at the factory that paints them with ten coats of truck bed liner. The jigsaw, while fastest, was not nearly as accurate. All the pieces were within a .015" window in length :)

The frame saw is also quieter than the other two. I can't bear to put the blade in my hacksaw backwards, but the frame saw is quieter and more confident cutting on the pull stroke. I think once I get comfortable with it, I'll be ready to race the 2500 lb hyd-mech bandsaw at the tech school* ;)

I look forward to trying other blade types in it. The blades I made for it are 14 tpi modified-raker set, and it's clear that vibration was the biggest thing holding it back. I wonder if wavy-set or variable pitch blades would cut better. In any case, the Starrett bandsaw blade stock feels a lot sharper and more precise than any hacksaw blade I've used.

*material cut: 1/4" aluminum tube

Saturday, August 18, 2018

Bar Stool - Hand Tool vs Power

Finished this bar stool after carrying around the pieces for two years. The main pieces were ripped on the bandsaw, but otherwise it was pretty much made on potato power. Douglas fir is so ornery to work with hand tools, in the sneakiest ways. It probably would have been more precise and faster to make in another wood, but I like the character of the finished chair. Not afraid to scratch it-

The side stretchers are recycled stilts I made for my girlfriend. She didn't use them and gave me permission to cut 'em up.

This chair is now sitting beside another chair which has a lot in common with it: made of douglas fir, a one-off design made by the seat of the pants, both made in free time. They share some interesting differences though-

The one on the right was made by my dad almost entirely with power tools. The legs were bandsawn of 4x4's, the seat was carved with an angle grinder and bandsaw, and it is jointed with mortise-and-tenons done with mortising machine/table saw. It was finished with a random orbital sander and rasps.

The one on the left was made in a 4' square space, using various hand saws and planes. The top was carved with a hatchet, and it is jointed with cherry dowels I cut and turned by hand. It was finished with rasps and a little bit of sanding. I think the designs reflect the tools they were made with; each would be a pain in the ass to make with the other method.

The one I made is less comfortable and has a rougher finish, but is lighter and used probably a 20% of the wood as the other one. It is equally comfortable to sit on frontwards/backwards. The one dad made is better suited to a wider range of butts, but feels weird to sit on backwards. Being a stool, it does get sat on in all directions. It's worth pointing out that dad has made much nicer stools since-

One more stool of interest! I made this one on the floor of a carport (where dad later built his shop) right after I moved to Bellingham. The wood came from a dumpster next door where my neighbors were building their house; it's also made of douglas fir. I used an awful hand saw, a block plane, a jigsaw, and a drill. Still, it has been a lovely stool! It's very rigid and has been sat on by many a butt in the four years it's been around.

Tuesday, August 14, 2018

Phone Case Mark Two

I TOLD YOU there would be a rev. 2!!!


Stitching wool liner with wooden form (above)

Made of cotton duck this time.

Inside is a bit how-ya-doin', but the hand-sewing allows the outside to keep clean lines. If the last five years are any indication, it's not going to fray anytime soon either.