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Simple metal fab — Parallax Forums

Simple metal fab

DonWDonW Posts: 37
edited 2005-10-26 05:31 in Robotics
One thing I am doing with the Hexcrawler project is bringing power switches and some charging jacks out to a small panel I plan to mount on the crawler.

My outdoor workshop is still in a bit of disarray as far as any kind of serious metal fabrication, and while this wouldn't be too difficult (I envision a small metal plate, with a bend allow me to mount it...holes drilled for switches and jacks..), it's easier for me right now to see if I can find someplace that will do a single peice for a reasonable price.

I know I have seen Servo and Nuts/Volts with ads for these kinds of services, but haven't looked to deeply into either magazine.

Hoping someone can point me to someone who they've already dealt with and had good results.

Comments

  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-10-21 15:27
    Don -

    Take a look in an auto parts store (aka red front store) for an under-dash mounted accessory switch panel. You may have to mount it upside dwn, but I don't see that as any particular challange. Usually they come with 1, 2, 3, 4 or 6 openings for ordinary "bat handled" switches (aka "appliance switches"). Shouldn't cost more than a few bucks.

    Regards,

    Bruce Bates
  • Kevin WoodKevin Wood Posts: 1,266
    edited 2005-10-22 01:56
    You could also check around to see if there is a local high school with a metalshop class / industrial arts program. If you talk to the instructor and explain what you are looking to do, you might be able to have a part custom made inexpensively.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2005-10-22 04:50
    Don,

    If it is as simple as you describe it - a right angle bracket with some different size holes drilled in it - then I can do it for you with a DXF/DWG file. You can e-mail it to me at kgracey@parallax.com. We have mills, drills, shear, brake at Parallax.

    Ken Gracey
    Parallax, Inc.
  • kelvin jameskelvin james Posts: 531
    edited 2005-10-22 06:29
    A little input here for Parallax. When i saw Kens' reply about fabricating a part for someone, i thought, now that is cool. Now i know Parallax probably does not want to get into a full fabricating service, as you guys are obviously busy with other things, but if you could do some custom fab work for customers, i think it could pay off fairly well. My experience so far, and i am sure with many others, will express utter grief and frustration attemping to find and get a part machined, and doing so for a reasonable cost. I have found just buying some steel and getting it sheared to be expensive, let alone having it milled, bent or put on a lathe. And the small shops are always busy with their gravy to set up a one piece run for someone, you will get it done, but don't hold your breath for it. And if you want a custom anything for precision machining, they want an order for at least 100, or one will cost the same. This is a big downside in prototyping, the electronics are pretty easy to come by, but the hardware vision can turn out to be a nightmare, causing some to give up all together. A "do it yourself" machine shop is not a reality, you would have to have a real big garage for a brake. I have spent a ton of time looking at robotics companies / suppliers, whatever, and there is not a lot of choice out there for any type of different hardware components. Most of it is geared to industrial use and not suitable for small robotic projects, some of the hobby shops carry some variety, but still are pretty limited. And the part is never exactly what is required. Anyway, maybe i am just unloading some frustration here, but it might be worth a thought.

    kelvin
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-10-22 14:39
    There is an on-line service that will take you from drawing to finished product in quanties from one and up. Obviously, you save more when you buy more.

    http://www.emachineshop.com/

    Also, take a look at the Virtual Machine Shop web site - Google for it.

    And, you might try aluminum rather than steel. In addition to being 'lightweight', it is much softer [noparse][[/noparse]thus easier] which allows hand work.

    There is a reason I put the quotes around lightweight, aluminum actually weighs more per cubic foot that concrete. It is the tensile strength that eliminates the need for a lot of it and makes it so useful.

    By the way, having done construction accounting in the State of California, the State Industrial Accident Insurance, the Union Dues, and all the rest is of the payroll taxes, benefits, and insurance are where your costs climb sky high.· Machine shops are high accident rate environments and California is suffering from too many rules and regulations.· Even if Parallax wants to get into providing such services, I suspect they would have to do it elsewhere·and 'drop ship'.

    Ken just happens to·be a very generous, hands-on businessman.·

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 10/22/2005 3:14:32 PM GMT
  • DonWDonW Posts: 37
    edited 2005-10-23 01:40
    Kramer..thanks...exactly what I was looking for..downloaded the software, and hurricane-willing, will work on it some tomorrow..
  • kelvin jameskelvin james Posts: 531
    edited 2005-10-23 04:53
    I find it a little amusing and somewhat disheartening to see people throw their cash away to the likes of emachineshop.com. Oh well, it's only money.

    kelvin
    maybe^not likely <= 0
  • bulkheadbulkhead Posts: 405
    edited 2005-10-23 05:35
    DON'T USE STEEL!! Aluminum==good!. Steel is much harder to work with and much heavier than aluminum. It takes me about 6 times longer to drill a hole in steel than in aluminum. It must weigh at least 5 times more (dont quote me on that). Now that thats out of the way...

    If your going to go into robotics, it might be a good idea (and cheaper) to invest in a little "workshop" of your own:

    Cordless drill (variable speed, easy to use) $30 - look for good brands like B & D
    Table clamp $10-a MUST for holding stuff, useful for bending too
    Drill bit set $5-for a decent one, skip on those $.99 sets at the dollar store
    mini-hack saw $3
    metal file (set) $3-you MUST file edges and holes after filing
    hammer + nail- come on, you should have these...

    You should also have, of course a ruler, a good screw driver, pliers. A carpenter's square is also helpful (I think thats what its called).

    These tools are ALL you need to work with the aluminum you can find from Home Depot or Lowes (usually between 1/16" and 1/8") and screws/washers/nuts. To drill aluminum, tap a dent with a nail and hammer first, so when you drill it, the drill bit will be guided in on the right spot. Always clamp the piece your working with. File all cut edges and drilled holes.

    Its surprising what can be done with such simple tools and materials and a lot of imagination. Now add some lexan ($4 a sheet for paper size), spray paint, and back lighting LEDs for a cool clear/protective/backlit twist to your robot. Of course, if you're building a combat robot, you might want to seek construction methods other than these, althought the only difference is that you are using heavier duty materials. Check out

    www.geocities.com/robotbuilding/tank/

    for a robot-in-progress I'm making using these contruction methods and tools (and a javelin stamp).

    Post Edited (bulkhead) : 10/23/2005 5:38:58 AM GMT
  • DonWDonW Posts: 37
    edited 2005-10-23 12:05
    Kelvin..can you expand on your comments?

    Curious if..

    you have had a bad experience with emachineshop..?

    have the time and tools to avoid having to have a third party do it?

    other..??

    As noted above...the workshop isn't in the shape it needs to be for me to create something like what I need...with some upcoming time off..I hope to change that situation...but for now, it is something I need to "send out"...

    Bulkhead..thanks for the comments also..would love to look at your bot, but your link doesn't work...
  • kelvin jameskelvin james Posts: 531
    edited 2005-10-23 19:50
    I should have been more descriptive in my post, sorry about the confusion. I have not dealt with emachineshop personally, they are probably a reputable service for what they do. But i think their prices are a rip-off. Looks to me that they are taking advantage of a next to nill service available for average consumers. I have spent years in a fabricating enviroment, so i know what is involved in making parts with different machines. Unfortunately, i can not use any of the machines for personal use, so i am stuck in the same boat. I have used their software to design very simple parts, and the pricing just astounds me, give it a shot and you will see what i mean. You would have to order hundreds to make it cost effective. I realize there is programming, setup time, etc., but i can not justify paying out that kind of cash for a relatively simple part. Obviously, they are looking for high volume orders, so we are back to square one, nothing available. Working with steel or aluminum is not for the meek, the equipment is expensive for fairly good stuff, and you can get injured easily if you don't know what you are doing. Just for example, how are you going to get a precision cut? It's not like you can use a hacksaw, basically you would have to use a shear, and that is something you can't put in the basement. And without a brake, trying to bend something is futile. There may be some tool and die guys around that have some home shops, that are able to do some limited work for a half decent price. I am going to start having a look around in that area myself. Anyway, it is a big problem, maybe someone will start up a small service for this type of work. If i come up with anything i will let you know.

    kelvin
  • jeffrey morrisjeffrey morris Posts: 52
    edited 2005-10-23 20:53
    Any suggestions for a metal brake/bender? What about metal parts from Vex Robotics Kit and add-on kits?
  • kelvin jameskelvin james Posts: 531
    edited 2005-10-24 04:43
    Something like this for bending
    www.eastwoodco.com/shopping/product/detailmain.jsp?itemID=1566&itemType=PRODUCT&iMainCat=1406&iSubCat=1408&iProductID=1566
    Looks like it would be good for most hobby work. Not bad price, would probably cost more to make one yourself.

    kelvin
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-10-24 06:24
    Kevin,
    The economics of technology is what attracts us to it. Since not everyone can understand and afford it, we try to use our brains to build equity and get rich.

    But at some point the simple economic production fact of 'economies of scale' begins to enter the picture.

    Proto-types require you to go to a lot of auctions and buy yourself a shop or to depend on 'proto-type services' If you don't like what you see on the web, try the Yellow Pages, as any big city has a few. Sometimes you have to travel a bit [noparse][[/noparse]in San Francisco, it is best to go to Berkeley or Oakand], but they are around and enjoy doing a good job.

    These shops can also solve a lot of material problems. Often metal is not necessary and you can do a lot more, a lot faster on a milling machine in polyethlene or other plastics.

    Also, don't rule out brass. While heavier than aluminum, it is in somecases a good compromise between steel and the softer grades of pure aluminum [noparse][[/noparse]there are higher strength air-craft alloys]. The Vitural Machine Shop explores the properties of materials when machined. Alot of high strength alloys are very difficult to work. Often epoxy is a good alternative to welding or threading.

    Also, don't rule out pipe and conduit. A lot can be done with a hydralic bender to build excellent lightweight structures. Newer welding technology will allow you to easily weld thin material into a high strength joint.

    Go wood. Masonite and marine plywood [noparse][[/noparse]no voids in the core] are excellent proto-type material as they allow you to visualize not only the finished product, but the real problems of assembly.

    Casting and drilling plastic can work well for small hubs.

    As you can see a machineist is a special type of person that moves between many kinds of materials and processes to get the best fit of availablity, cost, duriblity, and resources.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-10-24 06:27
    Jeff -

    Although I've never used one, and its use is very gauge limited (12 gauge aluminum as I remember) you may still want to do a search for "Bendito" on the Internet. Physical size was limited as well, as would be expected of a small brake.

    Regards,

    Bruce Bates
  • John R.John R. Posts: 1,376
    edited 2005-10-25 21:38
    For a light gauge metal brake try the following (similar to, or the same as mentioned above):

    http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82817

    (you may have to paste that back together).

    They (http://www.micromark.com is the home page) also haver a couple other small breaks and other metal working tools. You can also check other "Model Railroad" or "Modeling" supply houses.

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    John R.

    8 + 8 = 10
  • kelvin jameskelvin james Posts: 531
    edited 2005-10-26 05:31
    Some added info for anyone interested in metal or aluminum fab, there is some technical stuff available that should be looked at, such as bend allowance, strength, etc. This is one good site, has some charts and calculators to make things easier.

    www.engineersedge.com/sheet_metal_design.shtml

    kelvin
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