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Archive for March, 2011

Mini MAME Arcade!

March 25, 2011 Leave a comment

Ok. Building a dedicated MAME arcade cabinet is something that has been on the list of things to do for a long long while, but I have always pushed it off since it would cost a lot of money and time to build or convert a full-size cabinet. That is… until I had ran across this at edsjunk.net, who built this mini, tabletop, portable, full-featured arcade cabinet that is powered by plug or a battery.

Ed hacks a cheap netbook, separating the LCD and using it as the arcade screen, and keeping the main body with its battery packed inside a small portable-ish MDF enclosure, complete with graphic decals and plexiglass shiny-ness. Along with a simple arcade joystick, he adds an external USB port and power button to keep the cabinet fully enclosed. This mod doesn’t require much, just a spare netbook or old laptop, joystick, some soldering and wiring skills, and access to basic woodworking tools. I have say, this is way freakin’ cool, especially the fact that it can be completely battery operated.

Categories: General Ramblings

“The machine is just the down payment for the tools.”

March 23, 2011 Leave a comment

Before I purchased the mill, a machinist friend mentioned:

The machine is just the down payment for the tools.. Ain’t that the truth.”   -Machinist Mike

I thought he was joking, until he later helped me compile the list of things I would need to get a basic manual mill setup and running. So for those of you endeavoring to create your own milling machine shop, here’s the list of things you will need.

Measurement and Setup Tools:

  • Dial Indicator (1″ travel, 0.001″ min graduation)
  • Test Indicator (0-15-0 travel, 0.0005″ min graduation)
  • Dial Caliper(s)
  • Micrometer(s)
  • Depth Gauge Base (For accurate caliper depth measurements)
  • Parallels Set (3″ lengths for Sherline mills)
  • 1-2-3 Blocks
  • Machinist Square
  • Edge and Center Finder
  • Steel Rule(s) and Protractor
  • Step Block Hold-Down Set
  • Milling Vise

Mill Tooling:

  • Drill Bit Set (Screw Machine 115-pc recommended for Sherline, HSS or better)
  • Center Drill Set (Pre-drills and chamfers holes)
  • Fly Cutter (Large surface machining)
  • Mill Collets and Holders
  • Drill Chuck
  • End Mill Set
  • Boring Tool and Bars (For machining large precision holes.)
  • Specialty End Mills (Reamers, Ball-End, Dovetail, etc. as needed.)

Things You Will Eventually May Need:

  • Surface Plate (Ground granite metrology block for accurate measurement)
  • Surface Gauge
  • Indicator Holders
  • Height Gauge and/or Gauge Blocks (To determine height from known flat surface)
  • Scribing Tool (For layout techniques)
  • Grinder (To sharpen dull bits and tools)
  • Air Compressor (Makes cleaning chips much easier. Needed to fabricate a Kool-Mist type spray lubricant for CNC.)

Ex cetera:

  • Machinist’s Handbook (The bible for all machining referencing)
  • Tap and Die Set
  • Cutting Stick Lubricant (For cutting metals on bandsaw)
  • Super Lube (Teflon-based spray lubricant for leadscrews and tables)
  • Coconut Oil (or your choice of a milling lubricant)
  • Stiff Brushes (For cleaning and applying lubricant)
  • Vice (For rough cutting material and holding parts not on the mill.)
  • Hand Files of Various Sizes (Chamfering milled sharp edges)
  • Bandsaw (and/or a Hacksaw)
  • De-burring Tool
  • Eye Protection
  • Someplace to put everything, i.e. Tool Cabinet.
  • General Home Tooling (Hammers, screwdrivers, wrenches, rags, etc.)

AND, don’t forget to buy the stock material that you will inevitably need.

AND, this is not including the cost and equipment needed for a CNC mill conversion.

Even going with nearly all imported and the cheapest available equipment, which still is more than sufficient for a home machine shop, the cost of everything is easily equal to or beyond the cost of the mill itself…. Ain’t that the truth.

Categories: CNC, Machining

A Complete Bike Fit Calculator

March 17, 2011 Leave a comment

I had recently spent a lot of time trying to figure out how to properly fit a bike. I had myself fit by a few different specialists at local bike shops, rummaged through a dozen cycling books, searched through numerous websites, and even read a few journal articles. (I know I’m crazy.) The most important and consistent thing between everything I found was the relative position of your knee over your pedals and the corresponding seat height.

Dr. Andy Pruitt, who regularly fits pro-cyclists, states that the seat height should be high enough such that your leg is nearly fully extended at the bottom of your stroke, with a very slight bend in the knee, and no hip rocking during pedaling. And, from the front of your kneecap, hang a plumb-bob and its point should be intersect the end of your crank in the horizontal position. This gives you the optimal lower body position for minimal joint stress and maximum power output for road racing. For off-road biking, he recommends to shorten the seat by about an inch, but maintain your knee-crank alignment. And, of course, everyone’s body is different and things can vary slightly.

As for the rest of the bike fit and upper body, it all seemed like everyone had their own opinion and seemed to depend on riding style and desired comfort. Some fit opinions agreed and others were way, way different. But, this bike fit calculator on competitivecyclist.com seems to have a complete calculator better than some bike shops pay to have at their store, if they have one at all. They go through the critical measurements and provide you with 3 different riding style fits for road biking, along with multiple fits for both mountain and triathlon biking. Keep in mind that these fits are for competition and are geared for more aggressive riding positions. So, if comfort is key, a higher and closer handlebar is usually the first thing to change to give you a more comfortable, more upright riding position.

Who knows if they’re right for you or for anyone else, but it will give you some perspective, when a bike shop fit specialist tries to sell you on a bike. This is not to say these bike fits are the only way to ride a bike. Especially when the best way to fit a bike is to actually ride one, but it should provide an excellent starting point to tweak from.

Categories: Bikes

US Migration Interactive Map

March 15, 2011 Leave a comment

Ran across this the other day and thought it was really interesting. Michigan is not surprisingly hemorrhaging population, but L.A. is too. Everyone seems to scrambling to the Pacific Northwest, the South, and Rockies, anywhere but the east coast. The only people moving into L.A., it seems, are the east coasters. Weird.

Categories: General Ramblings

$10 Bike Pannier Conversion for a Messenger Bag

March 14, 2011 Leave a comment

I’m going to just come out and say it: store-bought bike panniers suck. They’re ridiculously expensive, uncomfortable to carry, and aren’t much good for anything else. For light commuting, I don’t want to have to shell out a ton of cash for carrying stuff on a bike rack, even though my back is starting to argue with me.

Most of the pannier conversions online require some kind of modification to your bag, which results in either a pannier just as bad as the store bought ones or rips in the fabric because the bag isn’t design to take the load.

So, here’s a bike pannier conversion you can make for $10 (or so), if you have access to some basic tools. It doesn’t require any modifications to your bag. All you need is a bag that has a strong place to mount from, i.e. steel rings, heavy duty nylon webbing, or even your backpack straps. Anywhere the bag is already designed to carried from and to take the load and beating over the lifetime of the bag.  My Timbuk2 bag has nice steel rings, where the shoulder straps connect to, and are the perfect place to mount a bag to your bike.

Things you will need:

  • (2ft) 2×2 pressure-treated/outdoor wood, a.k.a. deck railing. Found at any home store.
  • (2x) Threaded eye bolts for wood
  • (2x) 2.5″ J-bolts with washers and NYLON locking nuts (At my local Tru-value. Could use U-bolts too.)
  • (2x) Cheap aluminum carabiners ( Or go more expensive and get some Nite-Ize S-Biners )
  • Optional: (2x) Eye bolts and zip-ties

Measure the length of your bag from mounting point to mounting point. For me, this is about 20″ from steel ring to steel ring on my Timbuk2. Two eye bolts will be placed at each end of the 2×2, so subtract about 2″ to compensate for them. Then, cut the 2×2 wood to length (18″ for me).

Shape the 2×2 so that it sits flush on your bike rack. The wood can be somewhat soft. I used a handsaw to get most of the material off and use a screwdriver like a chisel to get the rest. Don’t go nuts on this and leave as much material as you can. Just try to make sure that you don’t make sharp corners or weak points, because you wouldn’t want your bag to fall off your bike, if the wood breaks.

Drill pilot holes for your eye bolts at each end of the 2×2. Screw them in so they are snug but not going to split the wood.

The J-hooks secures the 2×2 and your bag to your bike rack by hooking the railing of your bike rack through the 2×2. The nylon nut keeps it tight and ensure that it won’t loosen over time. Locate a couple of good places to drill through-holes for your J-hooks and bolt down the 2×2 with a washer and locking nylon nut. Get it snug and tight, so the 2×2 is fixed to the bike rack. If you’re so inclined, hacksaw off the excess thread on the J-hooks.

If you have a U-lock, I added a place to mount my bike lock, which also keeps my bag from swinging into the rear wheel. Otherwise, you’ll probably have to attach some kind of stand-off to your rack, so your bag doesn’t get sucked in and destroy your wheel or bag. For added peace of mind, you can zip-tie the 2×2 to your bike rack, but if you did it right, you shouldn’t have to.

And, don’t forget to tuck the loose straps!

Categories: Bikes

FROM STEEL: The Making of a Soulcraft

March 13, 2011 Leave a comment

Watching any expert craftman perform their art, from a seamstress, painter, sushi chef, or even your local barista, can been mezmerizing. Sean Walling from Soulcraft Bikes, who builds custom bikes from tubes to complete bike, is no exception.

Categories: Bikes

Choosing a benchtop mill

March 12, 2011 13 comments

Have you ever found yourself wandering a hardware store looking for some piece of hardware that might work for a project? I’ve probably spent hours and hours doing this, just to find the right thing, but getting home and finding out that it won’t work. Then, if you have the energy, you gotta go back to return it or just accept the loss of both time and money.

Having machine shop capabilities at home can solve this problem. You can make your own stuff: how you want it, when you want it, and out a really strong material. Wood is great and cheap, but metals really make a huge difference in what you can do and make.

Buying a mill and lathe has been on my mind for a long time, especially with a CNC setup, but holy cow it’s an investment. But, the way I see it is that it’s a life long investment. If you have a mill and lathe, you can literally build or fix any machine: motors, grinders, bike hubs, casting molds, milling PCB boards, tooling setups, new pistons for your car, fix your laundry machine, upgrade a cheap saw with better parts, etc. The list can go on and on.

For now, I’m only looking at a mill. The lathe will come later.

Here are things I’m looking for in a home mill:

  • Benchtop sized – Small and relatively light. I don’t have much space for a full blown machine shop and I don’t want to have to use a forklift to move this thing.  If it takes two people to move it, it’s still too heavy. The idea of using a spare closet for a small machine shop is not out of the question, especially because an extra closet is in the temperature controlled niceness of your home.
  • Precision – Out of the box precision. I really don’t want to spend several weekends tweaking and fixing a cheap, sub-par mill. Like Apple products, spending a little more on a quality product will give you less headaches and overall a better, happier, more pleasant, and productive experience. More time making, less time fixing. Precision is really important for more complicated parts. For every machining operation you do, the error of the machine compounds into your part. So for a complex part, a good precision mill can be the difference between making a good complex part the first time, rather than the second or third time around.
  • Support – Not customer support, but an online forum or large user base and long history. With a lot of people already using the machine, they will all have some tips and tricks to fix any issues or how to do a job faster and better. They will have also worked out any problems with the machine and the manufacturer will have likely solved it. Books and magazines are a big plus.
  • Machinist Approved – I work with some great machinists, who eat, breath, and sleep this stuff. There were only a few that they would recommend in the benchtop size range and what I would use it for.

The contenders:

  • Sherline 5000/5400 mill- They make great small 35lb, high precision machines and have been doing it for a long time. There is a ton of literature with people using them. The working area is relatively smaller compared to a lot of other mills (5″x9″ to 7″x9″). First mill recommended by my machinist friends. They don’t look very robust (not a problem , see later), but can create very intricate, highly precise parts out of the box. Lots and lots of off-the-shelf parts and good upgrades.
  • Taig mill – A middle ground machine. (5.5″ x 9.5″ to 5.5″ x 12″) 65 lb. Heavier and more stout than Sherlines for the same or slightly larger work area. Can machine steel very well. Claims to efficiently “hog” out material due to stiffer setup. Seems to be an answer to what Sherlines are not. In production for nearly as long as Sherline. Fairly large online community. High precision, but not sure that it matches the Sherline out of the box.
  • Smithy – Large machines. Make great combo mills and lathes. Expensive, but can make large parts and quickly. If I had more room and a forklift/not plan on moving in the next 10 years, I would get one of these. Highly recommended by machinists.
  • Harbor Freight/Seig X2/HiTorque/Grizzly mills – These definite “look” the part. Big, heavy, and stout, but looks can be deceiving. The work area is the same or SMALLER (4″ x 9″ to 5.1″ x 11.8″) and weigh roughly 130lbs! All manufactured off-shore, which makes for a low-cost machine but a crap shoot in quality. Most owners of these machines online seem to post more about upgrading/fixing the mills than actually using them for projects. I can’t deny the cost, but I don’t have a lot of spare time these days. I’d much rather be making stuff than tweaking the mill to a high precision. I think this is worth the extra cost on its own. These are also very, very heavy for their size. They are made with large portions of cast-iron, which is cheap, heavy, brittle, and prone to cracking. I have also seen reports that people receive warped work tables due to improper cooling and aging of the cast iron by the manufacturers. If precision is not in your list of needs, there’s nothing wrong with these machines, just don’t be surprised that some of you parts might come out a little off.
  • DIY Hobby CNC Mill – Not really an option, as it is more of a router than mill. As fun as a project making one myself could be, most of these options are made of wood or plastic, which makes for a not very stiff mill. You end up with a mill that only do certain materials well, but metals are pretty much out of the question. Aluminum is doable, but not recommended. There is too much flex to get any reasonable precision and is really limited to making PCBs, stencils, and delrin plastic. The cost isn’t too different from a machining mill, but one plus is that you can make it just about any size you want.

The Sherline and Taig mills are probably the best bang for the buck and for a benchtop, precision, ‘light-weight’ mill. Both are great machines, but each with their pluses and minuses. Compared to the foreign-made mills, the cost difference is only a couple hundred of dollars, and less if you add in cost of freight shipping a 130lb mill compared to UPS for a 35lb mill. And if you’re a patriot, Sherline and Taig are made in the USA.

The most common complaints I’ve seen for the Sherline mill is that they look small, are only for miniature model makers, has an underpowered motor, or not stiff enough. These are all generally true. This is not a machine made for hogging out tons of material very fast, as you would want for production. But, it will cut and machine any type of standard material, but the harder ones, like stainless, will cut just a little slower. Since the machine is small and will not be making large parts, you’re really not going to waste a ton of time. For large parts, you will want a large machine like a Bridgeport or Smithy.

In my engineering opinion, the Sherline 5000/5400 mills are correctly sized for the work area. The amount and type of material are all in the right places, giving you the proper stiffness all in the right ways. It’s well designed. However, this can be good and bad. This gives you a lightweight, precise milling machine, but it’s already near its limit. You can’t upgrade it’s capabilities too much without sacrificing some stiffness and precision, unless you stiffen up and replace everything like A2Z mill parts do. I don’t like the milling column on the updated Sherline 2000 mill for this reason, which features an 8-way Bridegeport-like z-column. It looks to make for a too compliant z-axis, although Sherline claims otherwise. Forum users of the Sherline 2000 state, you can get almost as good stiffness as the standard Sherline 5000 series only when you pull the headstock as far back as you can. Anywhere else, there can be noticeable flexing. As an engineer, I would have to agree with this in theory and would think that vibration would be an issue.

Taig mills are a little rough around the edges, a design that looks cobbled together, but a great mill too. They can be upgraded without worrying about compliance, since they are overly-stiff/over engineered by design. Roughly the same price, slightly larger working size, and twice as heavy. The online community doesn’t seem as large as the Sherline community, but I could be wrong. There isn’t a catalog of readily available parts, tools, fixtures like Sherline has, which can be good and bad (cost). But, mainly, the Sherline parts are sized for the Sherline machine, meaning you won’t have search around for properly sized vice, rotary table, or any other specialty item for the Taig mill. It’s nice to know that these options are there if I need these speciality tools or fixtures for future projects.

It’s basically a toss up on what’s more important: Larger community of users, a large catalog of readily available parts and tools, light-weight, high precision VS. more robust, can machine faster, better for steel and hard metals machining.

Personally, I’m opting for the Sherline, mainly for the precision, weight, and the wealth of knowledge. I don’t plan on doing a lot of machining with steel, mostly aluminum. But, the reasoning that pushed me over the edge is the fact that a lightweight machine also makes it easier and cheaper to upgrade to a CNC setup. You don’t need larger, heavier, high-power motors to run it, which gets really expensive, really quickly, because you need to buy more powerful power supplies, expensive motor controllers (sometimes), and bigger motors. The plan is to build an Arduino based CNC with some cheap robotics motor controllers, an ATX power supply, manual control with a PS2 controller, and a DRO based on stepper increments. This should all cost less than $200 for the upgrade. The Taig could be done for marginally more, but it would require large motors which would make a large and heavy machine, larger and heavier.

More to come…

Categories: CNC