Friday, September 23, 2016

Elaborately etched Ottoman shamshir blade

Beautiful etched shamshir, 19th century. This kind of blade would not be much fun to carve due to it being wootz, but using resist/etch to create a bit of relief would be relatively easy and much more efficient. There are many documents showing etching of pattern welded steel in gun barrels and swords. From the old manuscripts about forging gun barrels from strips of steel and iron, the final steps before honing the bore involved soaking the barrel in a mild acid in a hole in the ground. There were many different formulas for etching solutions. A 1:1 mix of nitric acid and water will do a deep etch on hardened steel in a short time. 8:1 water/nitric acid will do a smoother etch over a longer period of time. The etch resist can be as simple as wax, but something thinner is desirable for painting on a pattern like this one. 

Wednesday, July 27, 2016

500 SEC repair todo list

Your S-Class runs and drives? GTFO! STFU!

Here’s a list of things that I KNOW are currently wrong with my mercobenz which need fixin:

1. Rear brake hardlines blown. No rear brake pressure.

2. Fuel leak from send and return lines. YAY! All of the Bosch nonsense out back needs replacing.

3. Fuel hard lines are rotten. Needs replacing front to back.

4. Something not right in the driveshaft. All new center bearing and flex couplings, but there’s still a vibration from it when I pull away with any vigor.

5. Alignment is off, can’t go over 60mph without death wobble.

6. Sunroof switch is dead. Need a new one. Sunroof works though!

7. AC is completely not working. I could throw a belt on it, but I’m sure there are other things preventing its functioning at all...

8. Cold idle enrichment injector not behaving. I don’t see the point of this thing. It just causes the thing to run like shit when it’s cold.

9. Missing vital interior wood.

10. The carpet is something I cut out from a nearly matching color carpet found at home depot after the original was destroyed by one of many previous owners. I’m not great at installing carpet. Learned that the hard way. I don’t think anyone can tell though.

11. Passenger-side door card will not stay on. I’ve tried everything, but once integral plastic clips are broken an alternative fastening method is needed. Sheet metal screws.

12. Rear window is starting to delam. That’s an unfixable problem afaik. Water sits in the corners, capillary effect draws it up between the sheets of glass. I don’t know what the glass was bonded with, but it stopped working.

Wednesday, May 18, 2016

Evanston Violence

I posted the following over on the Nextdoor board for my neighborhood, edited here for context:

Evanston has a serious gang problem.

There are many single, younger parents (mostly mothers) who are raising teenagers without much help from family or the community. These are women in their 30's who never had the education opportunities that most middle class high schoolers have. They didn't have the money or the grades for college, and were probably stuck in the same situation as their kids are now. One of the gang members I know was living in Skokie with his mother and her boyfriend in a small apartment. The boyfriend (who is an old friend of mine) tried to support them and find work and better living arrangements. The mother got fired from lower than minimum wage jobs where the owners/managers were only interested in exploiting people and making more money. She had to attend endless court cases at Cook County to keep her son out of jail. She couldn't afford transportation to court, couldn't afford to miss work, and had a hard time dealing with all of that stress. She was on the edge of a breakdown, and had no support. She doesn't know her extended family well (a few distant aunts and uncles in Tennessee and Kentucky) and really had no help at all except what she can get from men who would take advantage of her situation. Her son, who the Evanston and Skokie police know pretty well by now, got into trouble by being young, jobless, out of school (he's 18 or 19) and living in an area saturated by small gang offshoots who's territories are constantly changing. It was the same way when I was in high school. There were countless small gangs with 4-5 members who claimed allegiance to a bigger gang, or were hoping to align with a bigger gang in order to get drugs to sell, guns for protection, and protection from other gangs. Some of the small time gang members are just there for their peers. At that age it's difficult to choose your friends. Your friends are the peers who accept you, and that's pretty much all you get. Anyhow, this kid got involved with a girl who lived in an area claimed by one of these small gang offshoots. Unknown to him at the time, that was a death warrant. That could have been someone's sister or cousin, doesn't matter. The gang decided they had to shoot him on the street. He and his group of 3 or 4 friends from high school were getting shot at, and sometimes hit by this gang. So they started their own gang so they could get some strength in numbers, align with a bigger gang and maybe get some support from the older, more established gangbangers.
There are no jobs for these guys, no programs they want to get involved in, no activities they can afford to get interested in, just the promise of making money selling drugs and the protection of cheap guns and a bigger 'family' of gangbangers.
This situation is out of the mother's control now, and the boyfriend had to stop supporting them because the kid was getting too crazy, stealing stuff from the apartment and getting in more trouble with his friends. He can't get a job because if the other gang finds out where he is, they'll go shoot him. His only option is to hide out with his friends, stay on the move in a very small area and hope the other gang gets locked up or killed. He's got no family he can escape to out of state, no other support besides his peers who are in the same situation.
I hope this little window into this kid and his mother's life makes it clearer what's going on here with all the shooting. If we don't provide any opportunities for people to improve their lives, they're going to get stuck in this cycle of violence, drugs, and getting stuck in a legal system they can't afford.

Take a look at the types of guns turning up in arrests lately. These are mostly low cost, extremely low quality Walmart specials. These are "Ring of Fire" guns, mostly from Irvine, CA companies operating under a bunch of different brand names over the last 30 years that built the lowest cost guns for people who wanted cheap personal protection. Saturday night specials die cast in ZAMAK. These are not bought by responsible gun owners. They easily slip through the cracks and find their way to the street. Every time someone breaks into a home they're looking for anything they can fit into a backpack or suitcase: the cheap guns people buy for bedside protection, jewelry, watches, game systems, cash and change. People who buy crappy guns and then let them lay around the house to get stolen are feeding this system. Lock them up, or better yet, turn them in for $100 bucks (much more than they're worth at a pawn shop) and let the police pick them up and crush 'em.

Let's ask the city, ask the local government what they're doing about these problems. We still need to keep the community and police forces engaged and communicating, but these problems start outside of the reach of either. For one thing, we have lost so much beneficial industry in this area where trade skills were needed.
 Strange Engineering moved to Morton Grove, their old factory turned into expensive lofts by Renaissance Realty. Shure Microphones HQ moved to Niles IL. Klein Tools moved to Texas.
Most of the careers in Evanston now are in Education (Northwestern) and Healthcare (also Northwestern). Most of the jobs near the median income in Evanston (~$60k) require at least college education if not a master's degree. While some of the neighborhoods have improved esthetically by some standards, there is not much economic benefit to the areas that need it most. Chicago "solved" its housing problems by leveling the projects and pushing people out to the oil and gas wastelands of the south shore. We need better solutions and better ideas than just building more and more restaurants and retail shops for higher tax revenues. There's a serious problem and scaling up is not going to make it go away.

Wednesday, April 13, 2016

Onshape + Kiri:Moto does 2.5 axis toolpath gen in one interface

At first I was like 2.5 axis? What good is half an axis? Then I realized this was related to 3D printing and laser cutting. AH, that makes sense. In this context, the half an axis control is the 3D printer's waterline. The waterline only increments once per layer of print, and it increments by the thickness of the deposition layer.

This is a nice tool to add to Onshape for prototyping. There are other CAM plugins for generating gcode from Onshape models, but they are pretty much export tools to move models into desktop software. So Kiri:Moto is pretty cool because the toolpaths are generated right in Onshape.
Besides CAM, the other thing I'd like to do with Onshape models is FEA (finite element analysis).
Good 3D CAD can get pricey. Good desktop FEA software is expensive, and for a good reason. It's expensive to develop! These are not simple problems to solve. They took decades of research and refinement to get where they are now. At the time of this writing, it is still not possible to automatically generate optimal 5-axis tool paths. It's a complex problem!
If you're a small shop or one man operation without the big $$ to purchase a $10k software license for a desktop machine, there are some newer options that are going to become very popular. Cloud based services can sell you compute time by the hour.
Fidesys has a new simulation plugin for Onshape that looks like it would suit the needs of a small shop well:

Thursday, April 7, 2016

One side of a 4-link assembly. Looking for interferences etc. It uses standard grade 8  9/16"x4" bolts and lock nuts,  1" and 1.75" .120 wall tube, sleeves and poly bushings. It can be adjusted (after welding up properly) for pinion angle at different levels of squat. The shock mounts are adjustable for any laterally bolted shock or coil-over set. It has 10" of adjustment for the shock mount position.
 I'm going to try a version with high misalignment rod ends instead of 2 5/8" bushings. I've seen a lot of kits with rod ends, but they're much narrower. This is only the 4 link, no other locating bars included. This design requires a Panhard bar to locate the rear end side to side.

Tuesday, April 5, 2016

Ford 9" 4 link brackets for jet/plasma cutting. Looking for someone to make four of each bracket.

Thursday, March 17, 2016

Rolling mill design changes. The previous mill frame was huge and difficult to make without making some big iron castings. I don't know anyone who can make a high quality ductile or nodular iron casting in the hundreds of pounds for a one off part without it being way too expensive. The critical/stressed members of the frame do not need to be integrated directly into the parts that keep the frame from falling over. The above frame ^^^ is machined from 2x3x8" 1018CR or hot roll bar stock. with alloy/chrome wear proof steel guide rods also running in bronze bushings. All bores are press fit. There are no standard sized pillow block bearings in this design, just 1 1/4" ID bronze bushings or some heavy duty roller or maybe double taper bearings. I'd like to load this into solidworks for FEA to see if my dimensions are sane. This model is built in OnShape, which is a cloud based CAD SAAS. It would be really really cool if they did FEA.

Friday, February 5, 2016

Lodge & Shipley Model A 14" Lathe specs

I've been hunting down brochures and manuals for the L&S Model A lathes.  Here are some numbers:

L&S Model A 14 Engine lathe:
Swing over bed and carriage wings: 16 1/2"
Swing over cross slide: 10 1/2"
Center distance: 30"
Key drive spindle nose size: No. 1
Spindle through clearance: 1 3/4"
Morse taper of centers: No. 4
Spindle speeds: 12
Spindle speed range: 18-540 RPM
Threads and feed changes: 55
Motor horsepower: 7 1/2
Machine net weight: 5400 lbs. (I was guessing 3500# but it's a lot heavier)

It can swing 16.5 inches over the ways, which is more capacity than I figured on.

Thursday, January 28, 2016

Lodge and Shipley lathe

I bid on this lathe not expecting to win it, but hey, be careful what you bid on, you just might get it!

So Raphael from the rigging company that listed it was nice enough to send two of his guys over with a forklift to unload it. 

More pics over on instagram:
A photo posted by Brian Madigan (@brian.madigan) on

The lathe doesn't have the most huge swing, (classified as 14"), and no gap in the bed, but it has a lot of other things I like. The motor is 240v 3 phase and located underneath the headstock casting behind those nice louvered iron doors, driving the main shaft via a gang of v-belts. I haven't run the motor, but going through the gears and rotating the spindle I don't feel any big crunchies. I don't know the year this one was made, but most of them were made during or just after WW2, and they're extremely well made. So unless it was abused horribly it should be working nicely within a reasonable envelope of wear. We'll see if there are any missing teeth in that gearbox...
The whole thing is really, really greasy on the outside and the grease is full of aluminum oxide abrasive. I can't think of a worse combination of things to be on a lathe! I found a 14" aluminum oxide PSA backed disc sitting by the faceplate. It was stuck onto the faceplate at some point like a big disc grinder. Whoever used this lathe as a big disc grinder didn't bother to cover the ways to keep the dust off. So once I move it inside it's going to need a thorough tear down, degrease and cleaning. I'll be taking pictures of all that as I go, from making some machinery skates to getting it back up and running. Just moving this thing becomes a big project!
I'll keep the Instagram pics coming as this one progresses.

Tuesday, January 26, 2016

Using Onshape to create a proper drawing for this rolling mill. I have not drawn a few parts like the guides, sprocket teeth, roller chain, motor etc. 

Wednesday, August 19, 2015

The three most beautiful British sports cars within reach of the enthusiast with a limited budget

50's Triumph TR3A: Swooping fenders, low slung, reasonable power and handling with 1930's technology.

MG MGA: The 56 to 62 MGA is a classic looking car, with swooping fenders and a long hood ('bonnet' if you prefer). High export percentages mean that they're not very rare in the US.

Austin-Healey 100/4. Another beauty. The Austin 3000 is more sought after I think, and the prices of those in good condition reflect that ($80+k in the US)
The 100/4 is not as powerful or smooth as the 3000, but it is very good looking. They can be had in running condition for less than $20k.

All of these were available in other forms: convertible roadsters and removable and fixed hard top roadsters and coupes. There were also fiberglass creations made to fit on these car's frames.
So if you are a fan of open tops, tall skinny tires on wire wheels, manual everything, light weight and good power to weight ratio for the time, these are the perfect British cars with pedigree and class for the same money as a typical American muscle car. These are the pre-pre prototypes for the AC Cobra and other big engined roadsters. They have a more refined, classic look though, without the giant fender flares and the necessity for huge rubber to handle the V8s.

Tuesday, July 28, 2015

Apache Cassandra

I'm writing a post about Cassandra for Orbitz's tech blog. I just thought I'd leave this here because it may not be appropriate there...

That is all.

Wednesday, March 18, 2015

Find steel locally

I've built equipment mostly from local steel. Stuff I can't find locally is from They are good at small orders. However, for bigger things that weigh over a hundred pounds, local is better. Also some of these might just have big drops they can't find a use for.
SB Specialty Metals Cincinnati Tool Steel co Key Metals

Update: Metal Supermarkets has distributors all over. There's one 5 miles from my house, and I can order anything and have Zero Shipping Costs, as long as I pick it up myself.

Cutting ISO threads (by trial and error, mostly error)

 I recently got a 8" Bison 6-jaw Set Tru scroll chuck for about $100. These are forged steel, made in Poland, and are generally around $2000 for a new one. I figured this one would be worn out, since there are more moving parts in a scroll chuck than an independent jaw chuck. The internal ring gear is pretty well sealed, so it doesn't usually wear out if kept greased, but the centrifugal forces of the spinning chuck sling the grease out and pack it into places where no mechanical engagement happens, and over time the grease hardens and doesn't do much good. The ring gear can wear if the grease isn't replaced, from contamination or just from age. There's not much wear on this ring gear or the turning gears at all. They still have the original machining marks, just a little polishing on top of that.

The Bison scroll chuck (taken apart for cleaning and lube). I didn't show the Set Tru screws :( or the shoulder where the chuck registers. So this is just the chuck, in pieces.

The 8" backing plate blank. Cut from 1 1/8" 1018 round, ~2" length.

Boring/threading 1 3/4 x 8 TPI thread. Shop made boring bar from a 1" 1018 bar with HSS bit ground to 60°. You can just see a few threads about 1" in from the face. The back plate is drilled from the back and bolted to a slotted face plate that's trued to the spindle. 

I don't have ANY kind of thread gauge, or a snap gauge, or any way to measure bores deeper than 1/2". I'm cutting this to 1.80 on the outer bore. An ISO thread should have all of the dimensions below included:

So one way to cut threads (single pointing) is to grind the tool to ~60°, and set the compound angle 29.5°, which is .5 less than half. A hair less than half is basically the idea here, because when you move the tool into the thread by a few thousandths per cut, only the leading edge of the tool has to cut, and the trailing edge is not 'dragging' because of the added clearance angle.  The dragging side of the tool would create heat and ruin the tool and maybe the part. Plus, the tool will try to get ahead of the lead screw (where there is backlash), and tend to make the pitch longer as the thread advances.  

 This is how threading is taught in schools, where the lathe is an old South Bend 9" with a not very stiff lantern tool post. If you plunge cut both sides of a thread in that setup, straight in with no compound angle, you'll get a lot of howling from the tool, broken tools and not very good threads. Especially if you're threading from the end of a boring bar.

Another way to single point a thread is to use a half tool without the back cutting edge and feeding with the compound at 30ยบ.  Any flex in the tool or cross slide will probably make the left face of the thread rough, but the 1/2 degree is taken out of the equation. This thread would require more cleanup.

Regardless of how the tool is ground, there's the question of how much the total compound feed needs to be to complete the thread. The rule of thumb equation is .708/threads per inch. So in this instance .708/8tpi = 0.0885". So your compound needs to feed forward from zero to 0.0885 in increments of a few thousandths per cut. That's one method.

The no calculation involved method, is called the zero-to-zero method.
Touch the tool to the major diameter, set the compound and cross slide to zero. Back out the cross feed enough to clear the part, move the cross slide out free of the part, reset cross slide to zero, and advance the compound until the desired depth of cut is measured. A dial test indicator on the compound touching the major diameter will measure the desired depth. Reset the compound's dial to zero.
Starting your cut from the major dia., advance until the compound reaches zero.

At the end of either method, a really light spring cut is taken using the cross slide feeding into the cut straight to clean up both sides of any marks from wobbly gibs or tool flex. A file is run over the tops of the threads to remove any burs.

I didn't mention anything about change gears, gear box or threading operations besides the angles involved here. Gearing is specific to the lathe, and threading operation is best shown by demonstration.

Friday, February 14, 2014

Blanking and grinding

A few blades blanked and rough ground. 1095 and O1 steel. 

Trailing point double edge
Straight tanto point

Thursday, May 16, 2013

Package structure

Package structure is not something to be considered idly.
The first thing I do when I look at an application is
$ tree -d src/
And I get something like this:

 |-- core
 |   |-- dao
 |   |-- domain
 |   `-- engine
 |-- service
 |   |-- business
 |   |-- adapter
 |   |-- exception

What do I know about this application from its package structure? Not much. It has a core, an engine, that's exciting. But not at all descriptive of what it does. Sounds like a spaceship! or an alien weapon!

However, if I were building a spaceship, I'd do something like this:

|-- lifesupport
|  |-- atmosphere
|  |-- gravity
|  |-- replicator
|-- communications
|-- propulsion
|  |-- thruster
|  |-- impulse
|  |-- warp
|-- defense
|  |-- shield
|-- weapons
|  |-- phaser
|  |-- torpedo

OK, so a space ship is much much easier to design than a piece of software! I have all the major features described at the top level. I can tell what the ship does, what its major components are.
The ship's design is organized by Features of the ship. Not by layer or any other attribute. For example, a builder or a command isn't a feature of a piece of software. Neither is an exception, a dao, a domain, an adapter..
These are all layers or programmatic idioms. Grouping classes by layer or type is a common mistake in designing software. It is always taught that one should design by feature, not by implementation detail.