Thursday, October 25, 2018

Pantograph Mill Tracer Pins


After I told a local knifemaker about the lathe I put together, he asked me to make him some tracer pins for his old pantograph mill. He asked how accurate my lathe was, I guessed I could do +/-.0002" diameter on a good day. If I was just a little wiser I'd have said something like .001". The X axis is graduated in .001" (radius), so .0002" diameter is a tenth of that. Nevertheless, I more or less managed to stay true to my word.


The difficulty was compounded by the required concentricity between shank and working end. I thought I might be able to turn the working end, advance the stock in the collet without rotating it, and then turn the shank. No matter how careful I was, this made at least .001" TIR which didn't feel right. So I just stuck the bar out the full length of the finished part, like a tree in a windstorm. T.T

I contemplated making a follow rest, or shimming the headstock to reduce taper. It would have been clever to get 3/8" bar stock to increase rigidity while turning the tip, that's probably how they would do it in a production setting. All of those options would have taken a few extra days- and made my time worth even less. So I just sharpened the heck out of the tool (m42 hss), and kept sharpening it after just about every pin-


The working ends don't have measurable taper, but the shanks have about .0004" over their length. The old router-style collet that holds it shouldn't complain, and the taper is in the favorable direction. Material is 30 RC 1144 steel.


I press-fit magnets into the back so the knifemaker can stick them onto that beautiful old chunk of iron.


Say, I've never posted a picture of my finished lathe because it's always dirty and with an ugly backdrop. So here's a candid shot-


Yes, I do manage to squeeze my ass in there.

Saturday, October 20, 2018

Mountain Bike


Gave my commuter bike an overhaul to make mountain biking a little friendlier. It had fenders and road 28x700c tires before, now it has 40's and knobs and no fenders to tangle with.

To put on the bigger tires, I had to get a new front derailleur and find a way to mount the lights without the fenders. I made little aluminum brackets for the front and rear:




I also got a smaller handlebar bag. I don't know what sort of G-forces a CX bike front end endures on galbraith mountain, but it was enough to really give the bigger handlebar bag a beating. With the smaller one I still don't have to wear a backpack, but I can still carry tube, tools, garlic press, and a few servings of hash browns.


This version of the bike has been named Monty by my sister.


Hurried to go on a ride with her yesterday, and one bar plug short of a full set, I whittled one out of fir in 12.2 seconds.

The bike is still far from a mountain bike, but after riding the 28mm road tires for a year it feels like I can do anything on it :)


Monday, October 15, 2018

Shelf


Courtney asked for a shelf for her dearest plants, as they were all crammed onto a tiny wire nightstand.


I made some of the pieces in a proper shop, and some in the apartment shop with hand tools. Cutting dadoes is a very different experience on the table saw vs. hand saw/chisel/router plane; half of them were cut by each method. As the front uprights angled inwards towards the top, cutting them by hand was actually desirable in ways. For the back ones, I'd take the table saw any day, but would have instead made them dovetails if I did it by hand.


The shelves are aluminum offcuts from a local metal supplier. I had to trim three of them- you can see the bottom two aren't quite deep enough, but I saved a lot of money by not making them cut up a large sheet.


This is how I carried the wooden pieces back from the big shop- it was rainy and 10pm but overall a peaceful and quiet ride


Here was carrying the aluminum back with my groceries- I'm starting to grow attached to this bike. To me they start as inanimate machines, and gradually become more like animals or friends.

Thursday, October 11, 2018

Weighted Blanket


A therapist/healer hired me to make some weighted blankets. Many people like a soft, heavy weight atop them; they find it calming.


The therapist wanted me to make them because I was local, and I could fill them with tiny glass beads instead of the usual polyethylene plastic pellets. So far I have bought all the fabric in Bellingham. The glass beads are very nice and smooth to the touch. It feels a bit like sand, but since each grain is a smooth sphere they flow more easily.



The first blanket I made had a zippered cover; this one has the same number of layers but is sewn as a single piece. It weighs about 10 lb (4.5 kg) and is 54 x 40 in (140 x 100 cm). If you are interested in buying one, one this size costs about $150. A small one would be closer to $80.


Saturday, October 6, 2018

Sprinkler Stand II

The last sprinkler stand I made is still sprinkling, but dad needed a second one. The turned hubs of the first one have cracked from getting wet and drying out so many times.

I made the new one to be more waterproof-



Made of aluminum, delrin, and stainless steel.



I could have made the delrin inserts a press-fit, but I wanted them to be easily replaceable. They are each secured with a sheet-metal screw.

 

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-