All Things CAD, Design, Prototyping and Fabrication


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Bicycle jigs and tools

In  the course of building a few of my own bicycles I’ve built quite a bit of my own tooling to hold, fixture, etc… Based on pictures of some of the nicer Anvil and Sputnik tooling, I decided to draw up and machine my own.

The first necessity was being able to hold tubes in the vice. Made a set for a couple different tube sizes.

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The chainstay tooling is most similar to the Anvil.

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Seat stay tool is like the Sputnik.

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I used mostly aluminum for everything and machined on a bridgeport style mill.

Frame jig is of the 80/20 variety with custom made bits to interface with the bike. Mounting of the dropouts has changed a few times. The first iteration wasn’t perfect!

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Need your own set of tools designed or built? Let me know at christopherswaim@gmail.com.


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Dropouts

I design dropouts. Here’s a couple examples… This first set went on my personal track bike.

Frame 3 Dropout

I build my bikes exclusively welding… no brazing skillz here so I like hoods!

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These cross/road dropouts have a polished stainless cover too.

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Here’s a set that I reverse engineered. A very common dropout supplier was on back order. I re-designed, mocked up with the 3D printer, then had 20 sets CNC’ed.

Drive Side 5

Here’s what the cross/road dropouts looked like part way through the process…

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Do you want your own custom set? Email me and let me know! christopherswaim@gmail.com


Electric Fan

One of the main reasons I went away from the 283 Chevy motor and chose the 4.3 Vortec V6 was to make some room for cooling. I have an earlier Jeep, a 1967 CJ5, so it has a shorter nose than the later CJ5’s and CJ7’s. The 4.3 allows for a bit more room (like, enough room for me to stand) than the 283 did.

When I had Novak redo the wiring harness (they did an awesome job BTW) and reprogram the ECM, I had them put in the circuit for the electric fan. This option has the computer kick on and turn off the fan at a preset temperature and includes the additional relay and wiring to the fan.

Along with the wiring side, I had to get an electric fan. I headed over one of the junkyards down on S. Congress (I think it was Aaron’s – aaronsautopartstx.com‎) in search of a mid 90’s Ford Taurus electric fan to modify and hook up to my modified mustang radiator. After I looked at pretty much every car on the lot I ended up going with a fan from a 96 Pontiac Firebird that had the V6. It had the closest dimensions based on the napkin sketch I had in my pocket.

I almost passed this up originally because it looks way wider than it actually is. Once you start to get it apart. It’s almost exactly the same dimensions as my radiator.

Once I had it home I hacked off the extra pieces I didn’t need prior to fabricating the brackets. Here’s a few pictures before, during and after the unnecessary pieces were removed.

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Once I was down to bare bones I test fit the fan. One thing I did not realize before making the cutout for the radiator inlet at the top, was that the fan had a large recess in one of the corners. I made the cut for the radiator inlet but ended up rotating the fan 90 degrees for the final fit. It has a much more factory look now (with the exception of the gaping hole). I’ll have to 3D print a piece of angle to cover the first cut out.

Lastly I used small pieces of aluminum angle to fasten the fan to the radiator. I was able to use existing holes on the radiator to mount the aluminum angles then drilled a couple of holes and used some large fender washers on the inside of the fan to attach the fan to the brackets.

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I’m pretty happy with how it fits up so far. I haven’t test the fan yet as the wiring isn’t setup and I don’t have a good battery. Much better than the mechanical fan with no shroud that I was running before!


Jeep Crossmember

Over the last year I decided that it was time to get my Jeep back up and running again. A couple years ago I decided to pull the 283 Chevy motor out of the ’67 CJ 5 and drop in a 4.3 Vortec V6 from a ’98 Blazer. The project sat for a longtime but I’ve slowly been putting it back together.  More about the individual Jeep projects to come.

Since the Jeep had sat for so long the rear gas tank was dry and rusty so I pulled it out to eventually get the tank cleaned. As any project like this goes, a simple afternoon project turned into a bunch of extra work.  It turns out that when the shocks had been installed a thick plate was welded to the front of the rear crossmember to gain some extra travel for the rear axle. Over time the crossmember cracked at the edges of the plate and it resulted in a crossmember that I could rotate significantly by hand.  The crossmember was almost completely torn in half and also cracked out in the corners.

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Corner torn clean off!

Cracked Jeep CJ5 Crossmember

Torn thru at corners of left shock mount plate

Jeep CJ 5 Crossmember

Torn thru on the right side too

Cracked Jeep CJ5 Crossmember

Cracks all the way thru back side

It was time for this old one to come out and a new one to be built and installed.

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Raw stock and the old crossmember

The old crossmember was riveted in place. Those rivets all came out with some gentle persuasion from the angle grinder, sawzall and 3 lb sledge. One more pass with the sawzall down the center and the old one was out.

I decided to go with 2″ x 4″ x 1/4″ wall tubing for the new one and also used a short piece of 1/4″ plate to get the extra height inside the frame rails. If I did it again, I probably wouldn’t have gone with the full 1/4″ wall thickness. I think it was a bit overkill. Both in terms of strength and that my air cooled TIG torch gets hot pretty quick at 200 amps.

I started by drawing everything out in Solidworks in 3D then transferring the lengths and angles to 2D.

Crossmember 3D Model

Crossmember 2D Drawing 1Crossmember 2D Drawing 2

Down at the shop I rotated the stop on the horizontal bandsaw to the correct angle, cut a test piece, checked it to the drawing and cut all the pieces. While I was down at the shop I also turned, drilled and tapped the bosses that would become the mounts for the upper shock mounts.

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Bandsaw making angled cuts.

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All the pieces cut.

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New shock mount bosses with shock stud partially installed.

Back home I beveled all of the edges on the grinder before getting everything welded up. I had to purchase some updates for my torch before welding the crossmember. I have mostly been welding very thin tubing for bike frames so I bought a new 1/8″ collet setup. Once all that was in place I welded everything up.

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Beads are laid

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Welding complete

Because the previous crossmember was riveted in place I welded nuts inside the crossmember on the tops and bottoms then welded nuts to the end caps and welded the end caps in place.

Crossmember-Shock Mount 1

Paint applied

A couple coats of gloss black and it’s ready to go back in.

I ended up having to cut out a stiffener on the frame to get the crossmember in that I weld back in place soon. I don’t have a MIG so it’s nearly impossible to get inside the frame rail with the TIG torch. I also had to cut out the mounts for the gas tank skid plate. Those pieces will all get welded back in when I get a chance to borrow a MIG.

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Fully installed

With the crossmember back in place I drilled and tapped a hole for the gas tank mount and also fabbed a new bracket for the brake lines and drilled and tapped a hole to mount that also. Mounted the shock studs and shocks and we’re back in business.


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3D printing for real science!

Recently, I sold a hardware kit to a Bioengineering student at UCSD named Chris. He printed up his own version of the Universal Microscope Phone Adapter and sent along a few pictures and even posted up a YouTube video!

Here’s the setup on a microscope.

Chris has been using the microscope adapter with a hemocytometer grid to count cells under the microscope. It sounds pretty interesting! Here’s a couple pictures he took with his iPhone 4S…

hemocytometer with universal smartphone microscope adapter 1

Aligning the camera to the microscope…

hemocytometer with universal smartphone microscope adapter 2

Close up of the hemocytometer using an iPhone4S.

Note: Photos are property of Christopher S Ahn, Bioengineering Ph.D student at University of California, San Diego

In addition to sending a few pictures over, he sent over this link to a video he made with the same setup of induced pluripotent stem cells, differentiated to heart muscle cells, beating in a dish. I have no idea what that really means but it sounds cool.

Chris also says that using the adapter he will likely publish a white paper using his iPhone4S to capture pictures and video for his research. Not bad for a few 3D printed components and $5 in hardware!

If you’re interested in hardware to put together an adapter, send me an email at christopherswaim@gmail.com. I also have a few other printed items for free at http://www.thingiverse.com/cswaim.

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