Saturday, February 27, 2016

Point of no return

One kind of point of no return was achieved this week. After spending almost two days impeccably placing the frame on the table situation finally calls for action - it is time to start sawing of the rear parts in order to turn the old swing to hard tail.


When the pendulum stops this precisely over the marker on the table it means that it's time to go. For the reference, below is the frame as it was.


And below here it is how it is now. you can see the idea. The part that was not needed is gone. You can imagine almost straight lines going from the axle plate on the right hand side to where the frame ends. 


You probably have noticed that I tend to write down the stuff I didn't know - which is almost everything. But honestly, I found this interesting little detail: Below is the cast iron piece attached to central post of the frame. Through it, the frame tube goes and when it was sawn off with and angle grinder like this it should come off. Once again I have to take my hat of for my friends helping me out. His precision is immaculate as he first saw off precisely the welding seam without so much as touching the material of the original tubing. In the pic below, you can see a seam between what is left of the tube and the cast iron piece and notice they are no more welded together.


From this point a nail punch was applied. Finding a correct angle and gently tapping it the last piece of tubing comes off and we are left with rather intact nesting for a tube. We do not know for sure yet, if the new tubing will precisely fit to this cradle, but it can be adjusted if so needed. And we can always discard it completely if it is not needed, but nothing is lost and everything can be used. 


The next step is to be sure we have enough room for the chain between the wheel and the frame tubing and making sure we have a proper distance between the rear axle and the frame. The proper distance is determined by the size of the rear wheel and the criteria, that if rear axle is too close to the frame the wheel will touch gearbox - which obviously is not an option. Being too far away is not that critical but it will impact the visual appearance of the bike quite dramatically. 

In the original setup the distance of rear axle from a reference point is about 34cm and we think we can squeeze the same measure to 32cm effectively shortening the wheelbase with 2cm which also makes the rear more tightly packed looking. It makes sense for the style I'm after, but were I building a chopper, I'd probably bring rear wheel a centimeter or two backwards for pertaining a geometry. For today I learnt that chopper should make a wide "A" shape letter where front wheel and rear wheel are equally far from the top of the steering axle. This makes sense - google images for "swedish style choppers" and you will see it. I'm not going for a chopper so it's not relevant for my case but it's nice observation that makes you look long bikes tiny bit differently.




Framing the scene and jiggin the frame

After getting the axle plates I'm running out of excuses to get started with the frame. So here we go, for better or worse. 

First a little about certain principles and philosophies of how to conduct the business. If you look at the videos on youtube there are _plenty_ where people just have the frame on the floor un-tied and weld with t-shirts on. And the end product is typically pretty as a picture, no complaints there. The problem here is that if you don't do any levelling and weld with such low currents that you feel comfortable with bare arms - you probably won't be riding that bike. Which is perfectly alright if it is made for showcase and not for riding. 

I'm making mine for riding but still there is a spectrum of approaches. One is where you do all the preparations to a immaculate precision. After that things will be nice and tidy. The other school is based maybe more on the principle of "if you are not sure, try". We took this route, partially because of practical reasons. 

The practical reason is that we don't have a proper frame jig. We have been discussing for almost a year of doing one, but it simply is not going to be there in time for my project. The idea of a frame jig is that it's rigid - it's big ass piece of steel beam that you know once you level it out, it'll be level even after a modest earthquake. And that is what we didn't have so this is what we did.


We have a steel covered welding table, to which we welded couple of rather rigid beams to mark the rear axle place. The axle it self, is height-wise exactly where it'll be in reality.


To the rear axle we placed the axle plates I've been writing about earlier. If you have a keen eye, you can see they now are steel grey and not black since I removed the paint with chemicals and a steel brush.


Modern men as we are, we rely on modern methods - the plumb, straight angle and patience (something I lack) takes you a long way. What we exactly did is that first we levelled the table the best we could, meaning to a fraction of a degree. This is my assessment is that accuracy of a degree is not enough but as soon as you can squeeze it to be some fraction of a degree, it'll be all alright. 


So the measurements tells us that we have the frame as level as possible and as straight (perpendicular) to the table as possible. The frame is bit skewed which to my understanding is rather normal for 70's HD frames. And it is less off it'd be after a head collision so we assume the frame is intact but it was born a little twisted.

This is very amateur, yet rather efficient way, of doing things. If you have a material for a proper jig, it probably pays off to make one. But if you don't have one, it's not the and of the world - you can substitute overly engineering with patience and insight. Anyway, this table and these pieces of beams are our jig - frame is welded to the table and they are rather immobile so it'll be just as steady as it needs to be.

  

Plates and axles

While ago I told I bought a swing. Got it really cheap since no one ever needs original softail swings. People usually sell them, and so was this case as well, for the reason that they want to have wider rear wheel and therefore need a wider swing. It is possible to widen the swing, of course, by sawing the connecting tubes apart and welding a lengthening piece of a connecting tube there. Sounds easy, and probably is if you are a decent welder, have the tools and place to execute. Not for everybody is it possible, feasible nor interesting to do that sort of things so the easiest way is to purchase a new swing and sell the old one.

So this is the reason why someone sold a swing, and here is the reason someone bought it. To remind, here is the swing as it was and the parts I wanted from it.




Then the question is that why I wanted them. Well, part of the answer is that I needed them, the other part is that this is cheap. As said, it's not everybody who needs an old original swing. There are also beautiful stock parts available but they tend to be expensive. Just the other week I went to exhibition called Kustom Kulture (sic) and discussed with retailer who sold cast iron axle plates. They were good quality and nice looking but the price was four times what I paid for these.



Rusty nasty wheels

Ok, one more place to spend a few bucks. Look at this rim, it looks like the surface of Mars even after trying to clean it up. To be precise it looks like it may be useful but the problem is this - the surface is so rough that I'm afraid that when I will try to get a new tyre on it, it'll take more force and pressure than the tyre can take to get to slip on it's place. And that is a bad deal - the rear tyre costs more than three times what a new rim would. So, it makes no sense to risk the rubber in trying to avoid purchasing new parts.


But the center bore seems fine. Of course all the moving parts need to be changed, or it makes sense to change them, especially the bearings. I do not know the history of the blank I'm working with - for all I know someone may have ridden hundred thousand miles with the bearings in there so now that it is in parts anyway there is no excuse for not changing the parts susceptible to wear.

But who cares about that. What is interesting is that now I can blast the center piece and paint it in what ever colour I wish to. Yeah, that is right - there is no law saying this little bugger needs to be black if I don't want it to be black. Who knows what it'll turn into, this one here:



Also I wanted to mention the fact that I had no idea how to get the plastic and rubber seal of the axle tunnel away. The bottom picture has the actual axle tunnel and the disposable bearings and seals on the table and the remaining central piece. The upper picture represents the installation my invaluable friend used to actually do the job. The seal can be fitted in place by freezing it over when it shrinks and then using a suitable sized socket as a punch. So, to reverse this some considerable amount of brute force is needed - and it needs to be applied from the opposing side. Using a hammer and a steel rod ( on the table behind the part ) it can be banged out. Put the rod in through the opposing side, find the small shoulder of the seal inside, on the side facing the table, and hit. Remember to hit from all the sides because the seal comes the easiest off when kept in level position. It really needs to be hit hard, so don't be shy, but be sure you know what you are hitting.