Axle has arrived; upcoming plans

After a battle with a nasty 48 hour bug this week I managed to snap this photo of the new axle I bought from McMaster-Carr.

Axle
It is partially keyed - 14" on one side, 4" on the other. So, more then enough space for a wheel, drive sprocket and brake sprocket. It is made of 303 Stainless Steel - I'm darned happy because it is shiny, and it's going to stay that way. I would hate having a rusty steel axle and be fighting to remove all the sprockets from it in the future. The disadvantage is that the tensile strength is much lower, but still around 70,000lbs - It seems like a lot to me, but I'm sure the forces in this kind of system are intense.




For scale, the 1" bar in front is 12" long (30cm). The drive motor is properly aligned with the axle sprocket but perhaps too close together, I really need a frame to mock that up properly.

Frame
Speaking of frame, that's my task for this week, to go shopping at Metal Supermarkets, and to get a red flag or something to hang off the metal I'm sure will be sticking from the rear of my car. Thinking 1 1/2 square rather than 1 1/4 most (gas karts) use because of the extra weight I'll be lugging around in batteries.

Batteries
Still waiting for my contact at a certain battery company to get back to me. I have a contact who put me in touch with the sales manager, so I'm hoping to swing a great deal from them. It would cut a lot off the purchase price.
Interestingly I was also told to consider using NiMH - either industrial packs or sub-C cells - and making my own battery pack. Well that's the advantage of talking to people in the know, I would never have considered such a plan.
Apparently on Monster Garage they converted an old Bel Air to run on cordless drill batteries! Have to check that out some time.

Brakes
I've been reading a lot on www.diygokarts.com and a lot of people have been helpful there. A certain member who lives relatively close to me not only offered me advice and pictures of his experience, but also offered to sell me a set of working hydraulic brakes for a steal, only $60! Remember the bike shop earlier quoted $150 for the same exact deal - one set of used brake parts. Different models I am sure, but in both cases, just whatever was lying around.
I'm ecstatic! It might be a pain getting over to see him but totally worth it. I'm sure I will get a lot of sage advice too. Anyone else considering a similar project to this *really* needs to spend time on forums, there are some awesome people on the internet (i.e. in real life, that you can communicate with on the internet hehe)

Trailer
On a completely different note, I have been considering how to move this kart around when it's finished. Most people are settled and build these in their back yards... seeing as I am in an apartment this is a problem.
I have recently realized that my go kart has trailer tires, and the front (will have) actual trailer stub axles. So - get the kart licensed as a trailer, and tow it backwards! I'm thinking to build a pin into the steering mechanism to lock the steering straight for towing, and leaving a place to attach a long trailer hitch arm to the rear of the kart.
The Ontario website does not indicate much in the way of requirements for trailers so I think it should be relatively easy to get it plated.

Until next time...

Princess Auto shopping trip

This weekend I spent three hours (and several hundred dollars, sigh) on a bunch of mechanical parts for the project, and a little in the way of tools. 

I ended up buying the tires that were on sale, they are Carlisle trailer tires, 16.5 inches diameter. Unfortunately they only had 3 in store, so I got a rain check and will have to go back to get the fourth.

I chose #50 chain and a 1"  rear axle. Here are the rear sprocket and the motor sprocket, chosen for a gear ratio of about 2.5. I ended up with 48 and 18 teeth, for an actual ratio of 2.66.

 The rear wheels are on a live axle, so I have to solidly attach the wheel to the axle. I decided to use a small sprocket, and bolt the sprocket to the tire.

 The is just small enough to fit inside the rim, on a 4 x 4" bolt pattern. First I tack-welded the sprocket to the hub, and made sure it was properly seated and square. I drilled 1/4" holes on a 4" circle - the milling machine and rotary table at work came in very handy here. You could do it by hand but it would be *even more* time consuming.

All the sprockets I used are designed to be welded onto the hubs which are keyed to attach to the axle.
So here is the first real welding I have done in a few years, for the rim attachments.
It is fairly ugly, and was hard to take a picture of. A wire brushing would have helped, but I did bang off the slag with my welding hammer. The second hub went much better than the first, but still needs a some more improvement.

Still the first hub. It really is a solid weld, both components are melted and there is decent penetration. I know this is one of the more critical welds in the project for my safety, and I am comfortable with them.

 I then expanded the holes with 3/8 and 7/16 drills. The bolts I am using were designed for tire applications, to be hammered into the hub. Of course the dimensions are not handy; the threaded section is 1/2" but the flat area is 0.53" and the ridged area which provides the holding effort is about 0.55".

I had to use the mill here again to get the dimensions right; I don't know exactly how big the hole was but just over 0.53".

See the ridges don't quite fit? This is perfect. Now you have to beat the shit out of the bold head to drive it into this sprocket, which I swear is hardened steel. It was very difficult - if I made the holes larger it would have been easier, but there would have been less grip strength in rotation.

 Hey, it fits!

Here's the bolt side.
You can't tell but the ridged area is too wide, so the nuts don't completely seat. I need to add spacers for a better fit. I should have used thicker sprockets instead.

Both sprockets together

Hammered-in detail. See the sprocket was deformed by my intense hammering.

Here's the posi-lube stub axle which I will be using for the front axles.

Stub axle detail.Very overkill, but it's a bearing and hub I don't have to assembly. Weighs a ton.

Brass bushings and 5/8" bolt as kingpin. Will use half of each bushing, take the other half for the other side.

Motor sprocket on the motor.

1/8" aircraft cable, and accessories for brake and gas.

1" pillow blocks with scrap 1" bar lying around the shop. I chose 1" axle because the 1 1/4" pillow blocks at Princess were not assembled so I would have had to use a torch I don't have to assemble them.. not fun.

The brake rotor -another sprocket, surprise! with the axle gear.

Both tires bolted to hubs and on the scrap 1" bar again.

Motor and rear axle mockup, again with scrap piece.

Next I have to buy a 1" keyed axle, some keystock, locking collars, and a bunch of metal from Metal Supermarket.