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Discussion Starter · #1 ·
I finally had some time to slot the rear brake pedal and complete the look of my modified gearshift linkage and shifter. Here's a link to that post from a few weeks ago.

Stock Shift Linkage - Slotted & Lightened - Triumph675.Net Forums

Unfortunately, some of those photos are no longer visible, so here's a couple for reference.







Although what few photos I took are not the greatest quality, here's the new machined slot fresh off the Bridgeport. The part was clamped so the right or outside of the pedal (when on the bike) faced up. A 1/8" diam. cutter was inserted just aft of the footpad and the slot cut rearward; parallel to the lower edge of the pedal (side view when on the bike). The process was repeated for the upper edge. This way, the slot increases in width toward the rear of the pedal… a look I wanted to create. A larger diameter bit was used to cut the rearmost pocket.



Why not cut the slot completely through the pedal like I did on the gearshift linkage parts? The peg retaining the two springs (pedal return and brake light switch) would be lost. I did mock up a new pedal return system that omitted the original return spring - and I could have just aced the rear brake light switch completely.

Although I don't use the rear brake much on the street, it's obviously needed to safely stop on a loose surface. More importantly, if excessive pressure was applied in an emergency or panic stop on the street, I would not want to risk the pedal twisting or breaking. Therefore, the slot was not milled completely through, producing the remaining 1.5mm (.060") thick wall. This wall provides the required strength to prevent twisting and really wasn't any more work than machining completely through the part.



When all the components are installed, I didn't see why the bottom of each spring couldn't share the same notch of the peg. I shortened the peg and extended the notch around the front and back of the peg to ensure the springs stay attached.



Here, I have removed all the casting and parting lines and added a radius to the edge of the slot. At this point, the part has been sanded with 320 grit paper. I takes a few passes with finer grades before you can begin to polish. A stock pedal is on the bottom.



With final polishing nearly complete, here's my genuine imitation "black hole"! It's actually adhesive backed vinyl that creates the illusion of a through slot. :rolleyes:



Final revised pedal vs. stock. I know, the photos don't really do justice to the work and polish job. OK, they suck. :laugh: Sorry Scott.





I found a spring at the local hardware store to replace the original. To ensure retention of both ends once installed, I trimmed the closed loop at the top and re-formed the hook at the bottom. The final part is on the left and the stock spring on the right.



Here's the backside of the assembly. The pedal return spring and its upper attachment tab were not modified.



And the finished part. Standing alongside the bike, you really can't tell the slot is not cut completely through the pedal.



That's DEFINETELY it. I'm done. This renews my membership in "Modders Anonymous". (the OG's will remember that club, eh?)

No more slotting. Well…………….. Maybe. :whistle:
 

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I'd hit it ! :thumbup:
 

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Bridgeport milling maching.......I'm betting that its Superlights favorite machine:thumbup:
 

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Pete, can I come and stay with you for a month and learn all these fabrication skills? It'll be the equivalent going to study martial arts under some hermit that lives in a cave or something.
 

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Nice work once again Pete! I always enjoy keeping track of your modding exploits...

Jeff
 

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Discussion Starter · #10 ·
Hey guys, thanks much. (I owe you a pm, Jeff! Keep forgetting. Sorry, mate.)

The Bridgeport was used on only (2) of the slots:
- the brake pedal: as I was not cutting completely through and needed to leave about 1.5mm of material as a "back wall" for strength
- and the long slot in the shifter

The other (3) holes in the two shift linkage parts were so small, I just make them by hand. That is, a drill press was used to make the initial holes at each "end" of the planned slot. Holes were then drilled between these to remove as much material as possible. Kinda like makin' swiss cheese out of aluminum. (Although I've never actually drilled a piece of cheese, I suspect it could get quite messy. "Clamping firmly in a vise" might be a challenge as well.) :smilielol5:

It's fairly easy to knock out what little aluminum remains between the holes with a sharp chisel. The more carefully you drill your holes, the less aluminum remains and the easier it is to knock out.

Slot clean up begins with a thin, coarse file to smooth the very ragged edges of the messy hole you've just created! A slightly finer file folows to remove the course file marks and smooth out the surface. This material isn't an especially high grade of aluminum so it's easy to work with and is removed rather easily with files. Once the slot is enlarged to the final size, I believe the progression of sandpaper was 180, 320, 600 and finally 1000 grit. Wrapping sandpaper around a wooden dowel produces a smooth and consistent radius at each end of the slot.

Obtaining a polishable surface on the inside of the slots wasn't too difficult either. Cut a narrow strip of sandpaper and work it back and forth like you're polishing a pair of shoes...you're just polishing the inside of the slot! By the time you get to 600 grit, the part is really pretty smooth and could be polished at this time. I go the extra mile (oh wow, that's a shocker!) and use 1000 grit to ensure all the small pits and holes are removed to produce an even and high luster finish. You just need to get down on your hands and knees to see the damn thing. :rofl2:

Using a wheel with various rouge compounds is difficult on these small parts. By the time I get to 1000 the part is so smooth anyway, a couple passes with Mother's metal polish is enough to make that puppy shine! Use the "polish the shoes" method inside the slot once again to complete the process.

Seems like a ton of work, (and I suppose it is if you've never done it before) but it didn't take all that long. Just take your time and be careful holding small parts with your hands using a drill press. I don't need to elaborate on what might happen if you're not.

And as Monty Python would say, "And now, something completely different", :topsy: Here's a mountain bike stand I made last night. Just thought I'd share with the forum.









I'll take it apart and stain or paint it later.

And yes, Burke, you are welcome any time you want, my friend. :cheers::pizza:

thanks again, guys.

:gomods:
 
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