Angle Jigs

     To the right are pictured some jigs I use to weld frame pieces at the proper angles.  They're all made from pieces of 1/8" mild steel angle iron and have a flange that can be clamped to the table to free up my hands.

• top left is a 30º jig for holding the main frame rails on my trikes
• bottom left (the red one) is a 15º jig I use for welding the angle on my trike crossmember
• far right are two 15º jigs that I use to set the proper angle for where the front end of the frame rails meet the crossmember.  This creates the 15º of caster I use.

BB Shell Alignment Jig

     To the right is an alignment jig I made so I could make sure the BB shell was perpendicular to the boom, or center line of my bent.  I was doing it by rough clamping before, but every now and then there was a small mis-alignment (nothing major) that would bother me.  So, I made this jig out of some beefy 2" x 1/8" square tube, with some ¼" x 1" tabs and a couple pieces of ¼" x 2" angle iron.

     In the top picture, a single 1¼" square boom tube is clamped to a 2" x ¼" piece of angle iron that can accomodate up to 2" stock.  The angle iron is parallel to the center line of the jig, and perpendicular to the BB shell clamp.  The BB shell is clamped in place with some 5/8" threaded rod which is pulled forward and down by two 1/2" bolts.  One bolt is welded to the 5/8" rod at one end, while the other bolt is welded to some 5/8" flat washers that slip over the other end of the threaded rod so the shell can go on and off.  When you tighten the bolts down, they pull forward and down, and secure the BB shell against the two faces of another piece of ¼" x 2" angle iron.  I marked center line on the jig to make centering the BB shell easier.  I'm going to add a little arm that holds the derailleur tube in the proper position too.  It's in the works.

     The bottom picture shows a folding style boom in the same jig.  I added the extra 1" x ¼" steel tabs so I could make any kind of boom I wish, including round ones (ick . . . :)) and I can use it to fabricate booms that can later be mounted to my two wheeled jig (which is still in construction phase).  The bottom piece of the folding boom is welded in place once the pictured section of boom is bolted on the trike.  The top V section is the hardest to align and the bottom piece of boom is a single straight piece, so I wasn't worried about accomodating that in the jig.  I might add some Quick Clamps later.

BB Jig Update . . .

     I added a front derailleur tube holding jig as well.  This is made from pieces of 1/8" and 1/4" mild steel and is welded to the front of the jig and can accomodate any angle for the tube.  The tube is clamped in place with a small butterfly clamp that holds the tube in side a piece of 1" angle iron.  Works like a charm.

Braze-on Jig

     While I call it a "braze-on" jig, I still actually have to learn to braze, as my first attempt failed miserably and I ended up going back to welding on my homemade cable stops.  Some day I hope to actually be able to braze on real cable stops, like an adult.

     The holding jig is made from a piece of 1" box tube and a couple pieces of 1" x ¼" flat steel.  The clamp post is made of a couple peieces of 3/8" threaded rod.  A 3/8" nut is welded to the top and bottom of the end of the top piece of flat bar.  The top nut is drilled out to act as a guide while the lower nut remains threaded.  I welded a couple pieces of ¼" rod to a third 3/8" nut to act as handles to spin the nut up and down the clamping post.  To use it, I clamp the jig to the frame, as pictured.  I spin the nut handles counter clockwise to move the nut up the threaded rod which has a groove ground in the bottom of it.  I use the handle on top of the threaded rod to orient the cable guide/stop at the proper angle, and then spin the nut handles up some more until they push up against the bottom of the jig, which in turn applies clamping force down on the braze-on.  Works like a charm and I can have a stop welded on in less than 2 minutes.  Very happy with it.

Fork Jig

     With my journey into two wheelers with low chainlines, I needed a jig to standardize the process of modifying narrow legged forks to fit smaller wheels, so after building the first fork by hand, I used it as a pattern for the fork jig.  I was happy with the performance of the first fork, so I used the 2" of rake for the jig and I'll just experiment with the head tube angle until I find the sweet spot.  The jig is made out of .188" x 2" square steel for rigidity, and a couple pieces of square steel are stacked and welded at the drop-out end to produce the desired rake.  I took a piece of the same 2" box steel, and turned it on it's edge, and used a ½" bolt with a T-handle to clamp the head tube in place inside of it.

     To use the jig, I measure back from the drop outs the distance that I want the bottom of the fork crown to be.  I slide the head tube in or out to that distance and clamp it in position, parallel to the table top.  I mount each fork leg individually and mark the correct length, take them out to cut them to length, then remount and weld them.  With a little forethought, I cut the right hand side of the axle housing ½" shorter than the left side.  I did this so that I could build offset forks (in the bottom picture) and this allows the right fork leg to be straighter and makes it easier to route the chain past the fork leg.  The front wheel is simply dished to the right to center the wheel under the fork crown.

     With this jig, I can build forks that are symmetrical, offset, disc brake capable and monoblade.

Frame Jig

     This is a frame jig I made to speed up and help align frame sections of both three and two wheeled bents.  The main jig rails are made from scrap sections of steel C-beams that have 2" flanges, are about 5" deep and are ¼" thick.  They are welded back to back with 2" box tube sections in between them, at both ends, to act as spacers and sockets for the jig's legs.  The legs are made of 1½" x .100" box steel and have ¼" bolts at the ends of the feet to act as levellers on uneven floors.  I'm going to add small casters as it'll make it easier to move around.

     I have 4 fixtures made for it so far.  At either end, painted red, are the drop-out jigs.  The rear one is vertical and has 3/8" threaded rod at 20" and 26" axle heights and is permanently bolted in place.  The front jig is tilted forward at a 15º angle so the different axle heights won't interfere with each other.  The 3/8" axles are set at 16", 20" and 26" axle height, and both drop-out fixtures are also drilled for 24" wheels too.  The front jig can move back and forth and can accomodate a 72" wheelbase - way more than I will ever need, I figure, except for possibly a tandem.  Both fixtures are made from 2" x .188" steel box, with 2" x ¼" angle iron bases and the top of the jig rails are teated as ground level.  The two center fixtures are for aligning the center sections of a backbone or boom.  They can accomodate up to 2" tubing and I simply use 1/8" and ¼" steel to jig smaller dimensioned steel. They are made from 2" x .188" box steel about 14" long and have a 6" long piece of 2" x ¼" angle iron welded to the top of them.  Once the backbone fixtures are in place, I clamp the sides of the jig rails or I tighten a ½" bolt to squeeze the rails together and freeze the fixture in place.  I'll be drilling more ½" holes in the jig rails as needed and add more ½" pinch bolts.

Update 21/01/07:

     I made a jig to align various frame components of my twin-rail trike frames.  The two areas where the clamps are set measure slightly wider than 135mm (5 3/8") and set the spacing for a standard rear wheel these days.  This fixture also mounts in between the frame jig's rails but I just clamped it to the table to fabricate the front end that is pictured for a FWD RWS delta trike.  The idea is to take the completed frame rails with drop outs mounted, mount them to the rear axle jig, and then clamp them to the frame fixture and weld in the crossmembers.  The fixture also holds the front frame crossmember and the front section of the frame that the boom connects to.

     I'll be building more fixtures as I need them and hang them all off the legs and bottom of the jig rails for storage.  I'll be making a longer boom jig as well as a headtube alignment fixture.  One thing is for sure, I need more C-clamps. :)

Seat Rail Jig

     On trikes or bents with a single backbone, I felt it was a waste of time, weight and material to weld on two 1" strips of 1/8" steel with a bunch of holes drilled in it for mounting hte seat to.  I had tried just drilling holes in the main backbone before, but it was pretty hard to line them up in pairs both vertically and horizontally.  So, I made a small jig out of two pieces of 1" angle iron welded edge to edge that fits over a 1½" square tube and allows me to line up a set of 3 pairs of holes, perfectly, every time.  I don't even need to measure out the holes because I just put the edge of the lig at about the ½ way point of the last hole, clamp it and it is lined up at ¾" intervals for the next set of holes.  I also set the jig so that the holes wolud be as close to the top as possible so top flat section of backbone would prevent the sides from being caved in when tightening the seat mounts.  The holes are one size under the size of a 65mm skewer, (which is what is used to clamp the seat onto the rail) because a small drill bit will wear away less of the jig than a bigger bit will.  After picking up the holes, I redrill them to the required size.