The Bucket Foundry

[Flettner]

Power valve all set up.

[Frits Overmars]

Power valve all set up.

Now all it needs is two wheels Neil .
BTW: you might want to pull a rubber hose over that coupling, or cover it with some silicon gasket compound in order to dampen vibrations there.
Yes, I know there's a balance shaft, which is great. Still...

[WilDun]

Power valve all set up.

All looking good!
Three feet ( or is it one metre?) off the ground, for a while?

[Flettner]

Will do Will

[ken seeber]

SLIDER (& MORE) REPORTING.


Just thought I’d check in and let you know that I’m still alive & well and still in country (A). After a series of distractions (wedding anniversaries and birthdays, both significant it seems), karting, karting politics and work focus, getting back into it. However, this could all be bullshit 'cos a friend says, “if you’ve got more than one excuse, then you've got no excuse at all”. One job at work has been casting lead into the pockets of these counterweight wheels. They weigh 70 kg empty and 125 kg when filled. We had to do another 24. Bit of a task for different reasons, but got there.



For some reason they are called, possibly affectionately, “exciter wheels”, which are mounted on a gearbox with two contra rotating shafts. Not too sure, but believe these are for vibratory screening machines for use in the mining industry of which is quite extensive in Western Oz..



OK, the slider. Couldn’t be stuffed fixing the actuating rod, so just removed the entire arm mechanism. Did this on the basis that the sliding cylinder, from previous observations always has a tendency to work its way downwards, ie into a low port height position. This is sort of logical in that the nett piston ring friction will be higher on the power/downstroke, so it will naturally want to lower the cylinder, all other things being equal.



So, after reviewing the water connections, we gave it another brief run this arvo, and it did seem slightly better in terms of holding a speed, but when it comes onto the pipe, it just runs away. Too much power? Full credit to that Fletto for designing such an efficient scavenging & gas flowing cylinder design. Anyways, will give it another bash tomorrow morning(Saturday), when those winging industrial neighbours won’t be around. If I can’t get any sense, then I dunno what to do. Try an inertia dyno, do some form of disc brake load mechanism, chuck it on a go kart (might be interesting with the exhausts) or , or, or, or ??

[Frits Overmars]

... we gave it another brief run this arvo, and it did seem slightly better in terms of holding a speed, but when it comes onto the pipe, it just runs away. Too much power?

That water brake is doing what it can be expected to do Ken: https://www.kiwibiker.co.nz/forums/s...post1130937167

[WilDun]

That water brake is doing what it can be expected to do Ken: https://www.kiwibiker.co.nz/forums/s...post1130937167

I realize that this has possibly been discussed somewhere here before, but how effective are the eddy current retarder units for trucks when used as the basis of a homebuilt dynamometer? - expensive or cheap way to go? (assuming the use of secondhand parts of course).

Maybe even a disc brake on it's own?

[diesel62]

I realize that this has possibly been discussed somewhere here before, but how effective are the eddy current retarder units for trucks when used as the basis of a homebuilt dynamometer? - expensive or cheap way to go? (assuming the use of secondhand parts of course).

Maybe even a disc brake on it's own?

I'm using eddy current retarders with aftermarket controls on 4x4 chassis dyno. Working well can also just use it as an inertia dyno.

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[Frits Overmars]

how effective are the eddy current retarder units for trucks when used as the basis of a homebuilt dynamometer? - expensive or cheap way to go? (assuming the use of secondhand parts of course). Maybe even a disc brake on it's own?

I wouldn't name an eddy current retarder as the basis for a homebuilt dyno; that would be a flywheel. But the retarder would be a fine extension, and not expensive at all in secondhand form.
One thing you need to know: its braking torque is not linear with exciter input and it will also vary when the retarder's temperature climbs during a brake session.

A disc brake is fine for slowing a flywheel down after a dyno run, but I would not recommend it as a measurement instrument. It can be done, with a torque arm, but the generated heat will play havoc with the desired constant temperature in a dyno room. And in case you fancy outdoor dynoing, you should know that braking sessions will be severy limited by disc cooling down periods.
In the early 1970's we experimented with a brake disc running in a water bath. I can now say 'don't go there' .

[WilDun]

I wouldn't name an eddy current retarder as the basis for a homebuilt dyno; that would be a flywheel. But the retarder would be a fine extension, and not expensive at all in secondhand form.
.............A disc brake is fine for slowing a flywheel down after a dyno run, ............ And in case you fancy outdoor dynoing, you should know that braking sessions will be severy limited by disc cooling down periods.
In the early 1970's we experimented with a brake disc running in a water bath. I can now say 'don't go there' .

I guess the easiest answer for the garden shed experimenter would be the one Alex made with the big electric motor!
At least he did it, so we now know it can be done, but was he being very brave in trying it? -
Probably all depends on who built the motor and how strong it is to begin with, but I'm sure it wasn't built for such high revs!

Then we do take our lives in our own hands racing bikes - except in my case, I now specialize in falling off excercycles,
mobility scooters and the odd ladder etc. - but that's just life!
Racing bikes is all just trial and error anyway, so really, what's difference between that and trying a (potentially unsafe) dyno?

[Ocean1]

Racing bikes is all just trial and error anyway, so really, what's difference between that and trying a (potentially unsafe) dyno?

Well, in my experience the shrapnel usually comes from the engine...

[diesel62]

Have a look at dtec.net.au should give you a good idea of what you want

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[WilDun]

Have a look at dtec.net.au should give you a good idea of what you want

Thanks there is a lot of good stuff there!.
Quite honestly I don't think I'll ever experience shrapnel from any bike engine of mine - haven't got one likely to run!

[ken seeber]

AMBIENT TEMPERATURE CASTING MOULD.

Well, not really foundry, but it is casting. We had to do a quick prototype mould for encapsulating a circuit board in a 20 mm dia section using pourable resin. Rather than making it in metal, which would have cost lots, both in time and $s, so sparking up the 3D printer was the logical choice. Not completely ideal in that one has to contend with contour line that are evident on angled faces. Our printer was set at 0.3 Z increments. Could go a lot finer (eg down to 0.05), but is a compromise between a practical build time (around 4+ hours) and waiting much,much longer, with the not unusual disappointment when something goes wrong when close to finishing. So, after a dose of spot putty, primer surfacer and sanding, we (they actually) have something to work with.



We have also done small coreboxes using this technique, obviously limited to C02 or Fenotec type room temp processes.

[F5 Dave]

So I'm guessing it's SLA. FDM is going to be well bumpy without heaps of work. Pissing around too much with our Polyjet at work of late. Great for prototypes but a drag for production. Good finish though.