Friday, October 14, 2011
Monday, April 27, 2009
Pining for the Fjords
OK, so I am forced to admit we "may" not make it in time for the race this year. And by "may" I mean no way in guacamole's green earth are we gonna make it.
We are not stopping however; currently we have sandwiches of cardboard to make the gear prototypes out of (decided not to try it on our limited supply of plywood first... is it possible Dad is learning from past mistakes??!?!?!). The legs are concurrently ample and supple... an beautiful thing. The only remaining ingredient is TIME... a magazine made entirely irrelevant by the intertubenodes. So, we need some of that, "and eBay ain't selling it".
That, and we need a name for the punter... The Walking Machine just ain't doing it anymore.
The new deadline: finish the Walking Machine in time to crash Chris & Mariekes wedding. And I do mean crash.
We are not stopping however; currently we have sandwiches of cardboard to make the gear prototypes out of (decided not to try it on our limited supply of plywood first... is it possible Dad is learning from past mistakes??!?!?!). The legs are concurrently ample and supple... an beautiful thing. The only remaining ingredient is TIME... a magazine made entirely irrelevant by the intertubenodes. So, we need some of that, "and eBay ain't selling it".
That, and we need a name for the punter... The Walking Machine just ain't doing it anymore.
The new deadline: finish the Walking Machine in time to crash Chris & Mariekes wedding. And I do mean crash.
Saturday, April 25, 2009
Legs Man
We have acheived legs. W00t! These are skis from an Army training base in Colorado... eight pair! Nice thick fiberglass with metal tips... and leather straps. Yes, I think these will do just fine. Just don't tip off the Army Staff Seargent that is looking to find where the skis went... appearently the drunken soldier that lost them to me in poker didn't quite have the authority to release them. Ah well. National property... taxpayer... it's a slippery slope - a double black diamond slippery slope. Onward!
Friday, April 24, 2009
I'm Not Dead Yet! (give us a moment, eh)
While we missed the deadline for entering the BKSR race, we are forging onward under the belief that if an eight foot walking contraption shows up at the race - and passes safety inspection - it'll be allowed to race. If not, then we'll be the first documented illegal interloper award recipient. Or in jail.Build has been on hold for a week and some days due to main builder dude being busy getting his school bus patched up enough to pass state inspection before the time limit expired and it turned into a pumpkin (a large rusting pumpkin); if only there were an exemption for "Brilliant Evil Mastermind Busy Building World Domination Device".... alas, no such luck. Only more reason to take over the world - get that law changed ASAP!
Current status: hand-optimizing the gear teeth shape for the 18 inch and 7 inch gears. Yes, we are duely ashamed that the measurements are in english instead of metric units.
Thursday, April 16, 2009
I am a Hobbing Machine - fear me!
Usually a hobbing machine is a tool that cuts gears. In my case, I am a hobbing machine that hobbles gears by cutting them poorly.
Turns out, gears aren't just square teeth; if that were the case the driven gear would jitter - the speed would vary as the teeth slid by each other. This is what mechanical engineers like to call "bad".
As you can see from the diagram on the right (from the wikipedia Gear entry), there are many parameters that need to mesh in order for a spur gear to not bind, break, slip, backlash, splinter, wobble, or catch on fire topple over and fall into the swamp.
The real key to the kingdom is the curve on each face of the gear tooth. This curve is called the involute curve (click link to see animated curve).
See how these gears mesh; the velocity is kept constant, and the point of stress slides along nicely:
(Click to see below pic nicely animated)
Mine will probably look more like a lurching, lumbering epileptic one-legged ex-movie starlet going through detox, but I'm fine with that - should help the cheering when it inevitably gives up the ghost and sinks into the morass of the Baltimore Inner Harbour. Yeah me ;-)
And remember kids: Try this at home!
Useful links uncovered in this sub-quest:
- Chesapeake Area Metalworking Society - great list of local resources
- MITCalc - semi-free (30 days) Excel based spur gear profile calculations
Wednesday, April 8, 2009
Workshop Awards
Best use of old 12 oz fluid cylinder carrier cardboard box bottom: Warning Sign
Best smelling workshop in America bought to you by the top "super" from a honeybee hive sitting on the workbench. The wafting fragrance of the honey comb is just awesome; so awesome that I've overcome my trepidation of using the words "wafting", "fragerance", and "workshop" together... usually a very bad thing to do...
Best 1 inch circular steel reinforcement annunciation marker:
Worst use of recycled material:
Best smelling workshop in America bought to you by the top "super" from a honeybee hive sitting on the workbench. The wafting fragrance of the honey comb is just awesome; so awesome that I've overcome my trepidation of using the words "wafting", "fragerance", and "workshop" together... usually a very bad thing to do...
Best 1 inch circular steel reinforcement annunciation marker:
Worst use of recycled material:
Rosie The Riveters Granddaughter
Don't tell the labor department, but Rosie The Riveters granddaughter is an awesome worker. She drilled and riveted the corner without once going on strike; Boeing should be so lucky.
Pay no attention to that stop sign, dear... it's for the doubters.
Pay no attention to that stop sign, dear... it's for the doubters.
Friday, April 3, 2009
Thursday, April 2, 2009
BKSR Entry by April 20th, Race is May 2nd
News Flash
The Dreaded Deadline has been set! They've released the 2009 Race Entry form which due by April 20th. So we have 2+ weeks to get this monster far enough before we have to commit cash. Not sure if the co-pilots have to be set by the April 20th date; hopefully there is some wiggle room there for last minute pilot changes.
Still trying to work out the second seat so the the kids can co-pilot and shoot the crowd with alien eggs.
So far, the roster includes:
The Dreaded Deadline has been set! They've released the 2009 Race Entry form which due by April 20th. So we have 2+ weeks to get this monster far enough before we have to commit cash. Not sure if the co-pilots have to be set by the April 20th date; hopefully there is some wiggle room there for last minute pilot changes.
Still trying to work out the second seat so the the kids can co-pilot and shoot the crowd with alien eggs.
So far, the roster includes:
- Carlos - pilot
- Max - pilot
- Kira - copilot / cannon
- Ian - copilot / cannon
How to Build a Corner
Here are the steps to build a corner using the tube-and-gusset method. Click on the pictures to zoom in for a closer look at the *cough cough* fine workmanship.
1. Build the beams; see last post in blog for comments on this.
2. Line up the beams using a square edge. Chalk or pencil on the garage florr helps, and sliding a piece of Duct Tape under the corner, sticky side up, will help hold the angle prior to clamping or riveting.
3. Cut the gusset out of steel flashing material. Should be from relatively not-thin material; could be aluminum. The critical measurement here is the 90 degree corner of the gusset, and that is only to make the bending easier; the diagonal length, angles don't really matter as long as there is enough metal to actually act as a gusset and hold the corner together. Note when sizing the cut, the material should hang a good half inch over the edge since this will be folded down to wrap the edges of the beam, and then riveted.
4. Shape the gusset. Bend the edges over using flat pliers, a table edge, or your square sense of humor. The pliers shown here are made expressly for bending thin metal into straight edges; the mouth is about 3 inches wide. As should be self evident, these bends should be at a 90 degree angle; if gusset piece was cut to 90, you can use the marking on the edge of the pliers, or just measure and mark with a sharpie marker. A small cut will be needed in the corner.
5. Rivet gusset top. Three rivets per beam, or more but they should not be closer than a half inch fto each other. Note the sides are not riveted yet, that is done in the last step - not sure why I ended up with that habit but there you go.
6. Make the corner brace. This is made from a section of beam that has not been riveted together yet. Prepare to lose a about a quart of blood while cutting, sizing, fitting, and re-cutting these pieces. Note the piece's edge flaps will need to be flattened out where they will be slid under the main beams; while a hammer is satisfying, a pair of pliers will do just fine here. These corner pieces are roughly 10 inches long, the inner flaps that get folded 45 degrees are about and inch and a half here; the outer piece's flaps are shorter only because I was too cheap to cut a longer piece out. These flaps will end up with a rivet (inner) or two (outer) at the end of the day, so they need to be long enough for that, eh.
7. Fit the corner brace; prepare to do this several hundred times making small adjustments. Note the pieces are not riveted together just yet - you need to be able to slide them in relation to each other in order to get the 90 degree angle.
8. Rivet corner brace. Drill one hole, insert rivet (put do not pull rivet yet), drill furthest hole from the first one, insert rivet (but do not pull yet), repeat. Don't forget yer flaps, eh.
9. Drill and rivet gusset sides.
10. Gusset other side. When reverse side is accessible, build and attach a gusset to it. Remember to rivet the other side of the diagonal corner beam as well if you did not prior to installation. If both sides are accessible at the same time, or if you care enough to gerryrig the very best, you can make a "wrap around" gusset using an L shaped piece that has the elbow of the L riveted to one side, and the legs of the L wrapped around and riveted to the reverse side.
11. Repeat. About 63 more times, not counting mess-ups.
....and that's all I have to say about that.
1. Build the beams; see last post in blog for comments on this.
2. Line up the beams using a square edge. Chalk or pencil on the garage florr helps, and sliding a piece of Duct Tape under the corner, sticky side up, will help hold the angle prior to clamping or riveting.
3. Cut the gusset out of steel flashing material. Should be from relatively not-thin material; could be aluminum. The critical measurement here is the 90 degree corner of the gusset, and that is only to make the bending easier; the diagonal length, angles don't really matter as long as there is enough metal to actually act as a gusset and hold the corner together. Note when sizing the cut, the material should hang a good half inch over the edge since this will be folded down to wrap the edges of the beam, and then riveted.
4. Shape the gusset. Bend the edges over using flat pliers, a table edge, or your square sense of humor. The pliers shown here are made expressly for bending thin metal into straight edges; the mouth is about 3 inches wide. As should be self evident, these bends should be at a 90 degree angle; if gusset piece was cut to 90, you can use the marking on the edge of the pliers, or just measure and mark with a sharpie marker. A small cut will be needed in the corner.
5. Rivet gusset top. Three rivets per beam, or more but they should not be closer than a half inch fto each other. Note the sides are not riveted yet, that is done in the last step - not sure why I ended up with that habit but there you go.
6. Make the corner brace. This is made from a section of beam that has not been riveted together yet. Prepare to lose a about a quart of blood while cutting, sizing, fitting, and re-cutting these pieces. Note the piece's edge flaps will need to be flattened out where they will be slid under the main beams; while a hammer is satisfying, a pair of pliers will do just fine here. These corner pieces are roughly 10 inches long, the inner flaps that get folded 45 degrees are about and inch and a half here; the outer piece's flaps are shorter only because I was too cheap to cut a longer piece out. These flaps will end up with a rivet (inner) or two (outer) at the end of the day, so they need to be long enough for that, eh.
7. Fit the corner brace; prepare to do this several hundred times making small adjustments. Note the pieces are not riveted together just yet - you need to be able to slide them in relation to each other in order to get the 90 degree angle.
8. Rivet corner brace. Drill one hole, insert rivet (put do not pull rivet yet), drill furthest hole from the first one, insert rivet (but do not pull yet), repeat. Don't forget yer flaps, eh.
9. Drill and rivet gusset sides.
10. Gusset other side. When reverse side is accessible, build and attach a gusset to it. Remember to rivet the other side of the diagonal corner beam as well if you did not prior to installation. If both sides are accessible at the same time, or if you care enough to gerryrig the very best, you can make a "wrap around" gusset using an L shaped piece that has the elbow of the L riveted to one side, and the legs of the L wrapped around and riveted to the reverse side.
11. Repeat. About 63 more times, not counting mess-ups.
....and that's all I have to say about that.
Beams
Most of the Walking Machine is built using the old tube-and-gusset aircraft building technique, except we couldn't afford the aluminum tubing so it's really steelbeam-and-gusset technique.The beams are made out of drywall U beams which are very light steel but somewhat structural.
It's a simple method:
- Align two beams facing each other and cram together
- Apply pressure to get the edge folds to clamp over the other beam
- Apply rivets liberally
Each 8 foot beam, assembled, costs about $6.50, not including the electricity for the drill or the band-aids for the builder.
Introducing the Walking Machine
First posted on http://HattenBlog.blogspot.com
Dad here. Still trying to build a race vehicle for the Baltimore Kinetic Sculpture Race which is on May 2nd this year. To the right is the inspiration for the design. The race requires that the vehicle be human powered, complete the 13 miles course, and even swim through part of the Baltimore Inner Harbor... which as you can imagine causes many, uh, unintended baths.
I've got a book full of design details that I've been working on for almost a year now (since 'K' and I cheered on last years race) however we just now started building... only about 3 weeks to go, and some of that time is already taken for gymnastics, bus conversion, soccer, etc.
Dad here. Still trying to build a race vehicle for the Baltimore Kinetic Sculpture Race which is on May 2nd this year. To the right is the inspiration for the design. The race requires that the vehicle be human powered, complete the 13 miles course, and even swim through part of the Baltimore Inner Harbor... which as you can imagine causes many, uh, unintended baths.I've got a book full of design details that I've been working on for almost a year now (since 'K' and I cheered on last years race) however we just now started building... only about 3 weeks to go, and some of that time is already taken for gymnastics, bus conversion, soccer, etc.
Here is a pic where you can see the quality engineering that is going into this monster... anybody out there know the sheer streangth of duct tape? We are building beams from drywall studs for lightness; duct tape for the prototype / layout, rivit & welding for the build. Stay tuned for more disasterous details! w00t!
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