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Perpetual Project
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Discussion Starter · #1 ·
Put discussion in here --> http://www.customfighters.com/forums/showthread.php?p=549297#post549297

Sorry no date proof pic, I'll get one here shortly.

The project is to make a Spondon/Martek style swingarm for my Bandit 1200 project (see link in sig). This is my second attempt at making a swingarm for this bike, my first attempt was a major learing experience, so I hope to avoid a lot of the mistakes of the first round.

This is the style of swingarm that I'm going for:



Spondon used chromoly for theirs, but I don't have access to a TIG so mine will be steel. I'm using 1.5" OD, 0.065" wall, DOM tube. Got 18' of it for about $75, that should be about 6ft more than I need, but it will leave me lots for screwed up bends and practice welds.

The pivot tube is 1.75" OD, 1/8" wall. I'm going with a thicker wall tube for the pivot tube because one of the troubles I ran into last time was the pivot tube was too thin of a wall and too much heat got into it from welding and I ended up with a bowed pivot tube.

Here is the jig I put together to hold everything solid. Having clear chain travel by the over-brace was an issue with my first attempt so that is why the chain is on there.



Last attempt I had to get my bends made at an exhaust shop and the hydraulic ram style bender they used dimpled the center of the bends. I wanted to avoid that this time, and also be able to do my own bends in my own shop as I needed. So this time I saved up and bought these dies:


and built this tube bender: (plans can be bought online, but I just made mine from pics)

This is doing one of the bends I made for the left side that I started last night. It works well, but is hand-pump opperated so its fairly slow. I've been working on getting this swingarm together for about 6 months though so I'm used to taking things slow.

Here is the progress as of last night at 1:30. Both bends for the left side are done. What I have to figure out is how to get the taper I need on the pivot tube end; I need the two 1.5" tubes to taper down to join in to one 1.75" tube. Because of the bend in them already, I can't bend the 2 ends in and trim them down like this " => " Not with the bender I have at least.



And here is the previous attempt. I hang onto it in case I need a boat anchor someday.


Next will be to get the left side sorted, and I have to trim down the brake caliper bracket a little more to bring the right side axle adjuster in a little bit more. Plan is to have the left side tacked in place by the end of the week.
 

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Perpetual Project
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Discussion Starter · #2 ·
Thinking about mating the left side to the pivot tube. I think my only option is to weld the tubes together, put the end of them in a vice and squeeze it down from 3" to 1.75", then cut out the notch to mate it to the pivot tube.

I really wanted them to come together in a => shape, but I just can't figure how to bend them that way.
 

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Perpetual Project
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3,695 Posts
Discussion Starter · #3 ·
Got the spacing on the jig finalized last night, and got the left side tubes tacked together. I'll squash the pivot end and grind out the notch to mate it up tonight. Might get one piece for the right side bent too.
 

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Perpetual Project
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Discussion Starter · #4 ·
Well hit the first hickup. I screwed up notching the left side to the pivot, ended up taking way too much material off. Then tried to bend 2 new pieces out of the remainder of the length of tube and ended up miscalculating my length... So there went about 3ft worth of material wasted total so far, good thing I got extra. I only have enough for one more screwup though.

I did get a new left side bent, tacked, and squashed though; its just waiting for me to have another go at notching it out. Probly get to that tomorrow. I also have one piece of the right side bent up and notched.

So, once I get the left side notched, I'll get what I have so far tacked in place, and then I can try to tackle the upper right side tube. Getting it bent properly and at the same angle as the lower will be a challange. Expect pics tomorrow night of progress to-date, with hopefully no more screw ups :D
 

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Perpetual Project
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Discussion Starter · #5 ·
Pics of progress as of tonight. I got what I wanted done, left side is fitted and ready to be tacked in place, and lower right side tube is also. I will have to modify the axle adjuster block on that side a little bit to take the tube. I have to add a piece of metal to flush it up, but it will give it a nice taper down into the tube at that point I think. The piece you see on that side is just something I threw in there to get it to stay put for the pics, I made the actual piece up later.






I'm particularly happy with how the joints are shaping up this time, I learned my lesson an I'm being much more careful making them fit. Heres a pic of the one joint and for comparison the same joint on the old swingarm (no wonder the pivot tube warped eh?)



Next step is to get all this actually tacked in place, then bend and cut the upper piece for the right side. I do the welding at work and I'll be on the road all next week, so I may be at a standstill for a little while. Might be able to sneak in after hours wed and get it done, have to see.
 

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Perpetual Project
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Discussion Starter · #6 ·
Looks like I'll be getting some shop time to do some tacking tonight. No need to post pics of it cus it'll just look the same as above :D Tomorrow I'll have a go at bending the upper piece and cutting to fit. Fun fun fun. :metal:
 

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Discussion Starter · #7 ·
Got the other piece for the right side all fitted up. Major load off, it was the piece I was the most worried about fitting properly. I must have gone from the grinder to holding the piece against the swingarm at least a hundred times to get the joints flush and at just the right angle to match the lower tube. I tried to get as much contact as I could with the lower tube, and the result is more like the spondon pictured at the bottom.

I'll be tack welding it in place on monday.






 

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Perpetual Project
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Discussion Starter · #8 ·
Brace tacked on, some pics of it in the frame. I'll be welding on what I have so far, then I'll make the last 2 brace pieces. There will be one that goes from the upper overbrace down to the pivot tube, just right of the chain travel path. ANd there will also be one that goes from sidearm-to-sidearm down low.

Pretty nervous about the welding, I'll be starting it tonight.



 

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Perpetual Project
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Discussion Starter · #9 ·
No pics, but wanted to update. Got the welding done last night, it went much quicker and easier than I had expected. I still need to cut the 2 brace pieces and weld them in, and then the shock mount.

Some of the welds turned out good, others not so good. The welds where the arms meet the axle adjusters were the tricky ones, because it was welding very thin steel to very thick steel, and also because of the angle that they met, made there very little room to lay weld down. It will need some dressing up there, and I may end up using some filler to just smooth the welds over at that point to make it look clean. A pro could have done much better I'm sure, but, it it what it is.

Anyone have any tips on filler material to smooth off welds??

All the other welds look good enough, and I'm really pleased with how the right side looks now that its welded up. Good news is I'm fairly sure that there was no distortion to the pivot tube this time. I'll have to put it in the frame and put the wheel on again before I'm convinced all is square. Looks good so far, I'm happy.:D
 

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Perpetual Project
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Discussion Starter · #10 ·
I think I just found a way to get bearings/bushings for this thing. I found bearings that have the right OD, and I think I can make my own inner races easy enough = problem solved. I was looking at getting custom bushings made, paying machinests rates... these bearings will be $10 each and then just a few bucks for metal for inner races.
 

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Perpetual Project
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Discussion Starter · #11 ·
Pics of things all welded up. Welds are not picture perfect, but I'm going to use a filler to smooth off some of the less attractive edges of the welds around the axle adjuster blocks, then I'll Powdercoat or POR15 it. Either one of those will fill in enough to make things look presentable. So when she's all prettied up hopefully you guys are the only ones that will know the welds weren't perfect ;)

I am particularly happy with the welds on the right side of the arm, those were the ones I really wanted to look right, and I think they do.:D

I threw the bodywork on for these pics, my garage is too narrow to get a full-bike shot, and no shock mount yet so I can't roll her outside for a pic, but that will come soon.




Supa-sexy - at least I think so :D:D:D

headlight modification too BTW

 

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Perpetual Project
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Discussion Starter · #12 ·
No pics, but I got the shock mount and one of the braces notched last night. Also figured I need to make a new caliper mount, which should be done today. Then I just need to notch the last brace piece, weld the last few bits on, and make a brake bar and she'll be ready.

I ordered my bearings yesterday, but I think I may have got them a hair too small. Gotta check and see. Should at least have a good roller by next week, get some better pics then of the bike as a whole. I'll try to get it weighed then too.
 

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Perpetual Project
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Discussion Starter · #13 ·
Well, I brought my USB stick to work today all ready to post up finished pics, but looks like the pics failed to load last night so sorry boys, you'll have to wait till tomorrow.

I got the braces welded in last night, and the shock mount too, so for the first time since the end of last summer the Bandit rolled out of the garage. And boy does she ever look good:metal::metal:

I'll need to weld on a mount for the brake bar now, and a couple tabs for the chain slide, and that will be all the welding I need to do.

Pics for tomorrow
 

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Perpetual Project
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Discussion Starter · #14 ·
Plans for the brake bar. Notice how Spondon puts a mounting bolt up inside the swingarm to hold the upper mount for the brake bar. Tucking the brake bar in behind the swingarm I never really liked, and it would put the brake bar at a funky angle too.



What I plan to do is weld a tab onto the bottom of the arm and mount the brake bar there. I'll use a heim joint for the caliper bracket end.

 

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Discussion Starter · #16 ·
Pic-less update. Started work on cutting and shaping the mounting tabs for the chain slider. I had a couple spare sliders kicking around and it looks like I can make one fit without too much trouble at all, should look real good.

Also, thanks to Shift, I'm re-thinking my caliper mount and brake bar. Shouldn't take too much to modify it, just a little cutting and welding. The caliper will be mounted on top of the arm - which I like - and the brake bar will mount there also. I'll have to cut off the old brake bar mount off the caliper too.

On a downer, I think my bearing idea will not work. So what I'm thinking of doing is getting a couple steel plugs made to fit in either end of the pivot tube, and have them machined to take the bushings I need. Its a lesson learned, just one minor screw-up; heck of a lot better than the dozen ones I had with the last attempt.:shootme:

Then just the axle... need a 20mm rod, threaded (probly on each side), 13" outside-to-outside of arms. I'm going to have to get it made, and finding a machine shop with a die to tap for 20mm might be fun. Other option would be to get a 20mm rod, and have the ends turned down to a tap-able diameter. Unfortunately paying for machine time is money I don't have quite yet.
 

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Perpetual Project
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Discussion Starter · #17 ·
Weight of swingarm is 18.25lbs.

Going to get plugs made to take new bearings, might have that done in a couple weeks. Then have to wait till end of May to have the money to get the axle made to finish things up. Wheres an extra $30 when ya need it:doh:
 
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