Nigel, you got me thinking about the wheels and it looks like I've made a mistake. Upon closer examination, the wheels that all this time I thought had 12 spokes really have only 10. So I ruined 4 perfectly good wheels...to make 4 incorrect wheels.
A lot of fiddling was required to make this bracket square. A critical operation, and I really struggle with it. I haven't yet been able to achieve two perfect, matching 90 degree bends
The bracket can at least be attached to the motor, which is a success in my book
In the photos of the rear end of the P133, there is some sort of bulkhead between the engine and the gearbox. Various components appear to be attached to this structure. This brass piece will assume that role. It is a bit of an experiment, as it is intended to be a structural component. I'm hoping that it will be robust enough to anchor several other components, such as shocks, sway bars, exhaust pipe cradles, suspension arms, hoses, etc.
Front chassis plate - complete with math error
Sub optimal dimensions while designing the front axle bracket didn't help, but poor drilling technique was the main cause of the problem with the hole for the axle tube. That gap in the brass surrounding the axle hole was not intended. The hole was drilled after bending the brass. The perimeter of the hole extends into the elbow of the bend, which complicated the operation. Poor execution
Rear uprights will be carved from this block of brass
Wheel upright mock up
Cutting rough shape of rear upright
Last Edit: Jan 8, 2016 3:01:26 GMT -5 by Aurora: broken photo links
Thanks Nigel. I'm sure your car will more than carry its weight on the B.R.M. team!
It's good to be back on the forum. Didn't have much in the way of updates, but I hope to make some progress and post more.
I've been drilling holes tonight. I just dodged a bullet a few minutes ago. A drill bit broke off in a piece of brass. Luckily, I had drilled all the way through the workpiece and was in the process of reaming the hole out when the bit broke. I was able to punch the bit through just enough so the tip of the bit protruded out of the hole, and then get grip on the tip of the bit with pliers and twist it out. I've had this happen before and it's never fun, but I got lucky this time.
Post by David Mitcham on Jun 16, 2015 14:50:12 GMT -5
Looks even more impressive than last year's Honda. Are you are building everything from scratch apart from the motor, gear and wheels? Those fine drill bits are very fragile aren't they? I must get through five or six 04 and 0.5 mm one's every build.
Nigel, I try to remember to wear eye protection - one of the few school lessons I took to heart.
I do break quite a few bits over the course of building a car...just had to buy some more today.
David, this car probably will be more detailed than my Honda RA300, if only because the P133 appears to have an even greater number of visible details that require modeling. I am trying to scratch build most of it.
I soldered the front end together but the axle was not level. A couple of things went wrong. First problem is the tolerances in my design are quite small and sometimes the parts don't line up all that well. That is an inherent problem that I can fix through improved design. The second problem is execution. I didn't drill accurately, so the holes required shimming, and the parts did not retain their alignment.
It is hard to see, but there are shims in place around the axle tube in an attempt to maintain alignment. A long time spent rigging this up....
...ends in failure $#%&*
The general idea
Rear end starting to materialize. Suspension uprights and brake calipers have been roughly shaped. The calipers are not the correct external dimension - I seem to have made a mistake calculating their scale size. They are not the correct shape either. At least the internal dimension is acceptable, which was the main concern - otherwise the discs might not rotate freely.
Last Edit: Jan 7, 2016 10:34:40 GMT -5 by Aurora: broken photo links
Hello Matt, I have just read through your thread and enjoyed seeing the hatching of what looks like another tremendous build.
One point re drilling holes, do you use a centre punch to first make the starting point for the hole? You know one with the spring loaded centre pin?
Another offer to yourself or anybody else....for a small fee I can mould and cast several bodies of your one off creation. You really only need to trust the mail service to New Zealand and my skills. The time and materials to mould and cast three or four bodies from a master isn't that great and a turn around time of a week is possible.
Congratulations on this build, it is fantastic. I hope the weather isn't too hot. Regards John
Hi Matt I can tell you that even professional tool makers and mechanical fitters have the same issues with tolerances and drilling as you are experiencing and you are coping extremely well. In these days of computer design accuracy the skills you are showing are being lost, along with the patience to obtain and use them. Even when you train for skills like this, as I did, when you don't use them all the time you get very rusty and feel like a beginner all over again. The chassis and work you have done looks first class and will be something special when finished. Regards Nigel
Thanks for the encouragement...I'm just about to give it another go.
John, I sometimes use a spring-loaded center punch, but usually I use a simple no-spring punch. Many of the parts are too small and don't offer enough surface area on which I can squarely set the spring punch. The problem as I see it isn't the starting location of the hole - I can usually locate the start point correctly. The problem is that the drill bit wanders. I drill every hole by hand and I don't have such a big problem with the smaller holes, say on the order of 0.2mm - 1mm. But I do struggle with the holes larger than 1mm. The shape of the work piece can also add to the challenge. I have difficulty drilling into complex shapes.
I frequently do use tape. There is some tape visible in a couple of the previous photos. It may help to some small degree, but not so much for the larger holes. When drilling large holes, I get the best results by drilling a small hole and then using a file to enlarge it to the correct size.