Joe90's BIG RAT Build.

[AndyUK]

That would be some big machine

Yes, 1000kVA would be about 750 hp. You'd need your own substation to be installed. Even 500kVA / 380hp would be pushing it. You can safely drop the k....

Yes, I think there's been a couple of 'k's inserted where they shouldn't be. Lol

Ooops. :)

Force of habit I'm afraid... work requires kV / MV... You know what I meant!!

[joe.ninety]

I think you're all missing the important part of this thread. How's the beer? (if you don't mind I might PM you over this - I've a similar interest, or at least an interest in getting the missus interested).

Well it would probably be a case of the blind leading the blind, as I've never attempted an all-grain brew before. To be honest, it's typical of me to go out and splurge instead of dipping my toe in slowly. Some people start with large pot/pans and commercial tea kettles/boilers but that would have meant too much time in the kitchen and under SWMBO's feet.
I only made the plunge last week and it hasn't even been delivered yet. It'll have a decent sell on value so it I decide it's not for me then I'll just stick it on fleabay.

I've done plenty of home brew but only from kits, nothing where I've made the wort from scratch. In fact a good deal of enthusiasts don't even consider that home brewing, I guess it's the male equivalent of making a sponge cake from a mix rather than individual ingredients.

Getting the missus interested is a bit of a double edged sword... It helps with approval for financial outlay, but I've now found mine drinks too much of the stuff I make and I've had to take to hiding it

Anyway, give it a couple of months and I'll probably be in the position to offer some advice. In the mean time check out this guys channel on YouTube...

https://www.youtube.com/channel/UCb3...aVDeulH1mZGW1Q

One of the best I've found, an English guy living in Denmark who works in the industry. Really informative without all the added guff... Not like a lot of the US brewing channels you find.

Cheers

[joe.ninety]

Ooops. :)

Force of habit I'm afraid... work requires kV / MV... You know what I meant!!

I think everyone knew what you meant, even me. When I joked about it, I'd missed the fact that Muzzer had already followed up on Clive's original subtle highlight of it, otherwise I'd have said nowt.

Cheers

[Kitwn]

Ooops. :)

Force of habit I'm afraid... work requires kV / MV... You know what I meant!!

KV (Strictly NOT kV if I'm correct) and MW is one thing, I do those every working day. But MV (as opposed to mV)... That really is fun and games! The trick is keeping it in the wires.

[joe.ninety]

Is the choice to design a machine using belts and pulleys between the stepper and ballscrew down to the size of the machine or due to what materials you intend to cut and the ability to control the speeds better.

So would a much smaller machine, say a 6040 be more likely to be driven directly than by belts and pulleys?

Cheers

[AndyUK]

Is the choice to design a machine using belts and pulleys between the stepper and ballscrew down to the size of the machine or due to what materials you intend to cut and the ability to control the speeds better.

So would a much smaller machine, say a 6040 be more likely to be driven directly than by belts and pulleys?

Its a combination of both. Lets start a pros/cons list! Hopefully everyone can add/remove. I don't think you can make a general statement about what sizes of machine would be more or less likely to have belts and pulleys?

Advantages are:

• Ability to gear up/down, particularly relevant with servos I believe.
• Ability to position motors more flexibly, potentially reducing the footprint.
• Can drive multiple screws per motor.

Disadvantages are:

• Potentially more complex system, especially if needing tensioners?
• More opportunities for backlash.

? Finger-trap potential?
? Replacement requirements?
? Expense?

[joe.ninety]

Been doing some serious thinking over the past week or so and have decided to scale back my ambitions considerably. Was stuck between going for a 8060 or a 6040, then thought a 7050 might be the ideal compromise.

With that in mind, if I wanted to use profiles for the frame of the machine, what would people consider the minimum size of profile to use? I'm assuming that 4590 in an L configuration is fine for the gantry, but just wondered what I'd need for the long sides... I'd originally thought I'd use 80160s with the rails running along the top and the screws on the sides, now I wondering if that's a bit overkill and if I could get away with something smaller and obviously cheaper.
As stated ages ago, the design would be based off of AndyUKs but obviously using profile instead of the steel Andy used.

Cheers

[joe.ninety]

When selecting aluminium plate for gantry sides etc. do people tend to use the most expensive Ecocast variety, or is the the 6082-T6 type OK to use instead?

Are you more likely to get perfectly flat pieces with the Ecocast?

Cheers

[JAZZCNC]

When selecting aluminium plate for gantry sides etc. do people tend to use the most expensive Ecocast variety, or is the the 6082-T6 type OK to use instead?

Are you more likely to get perfectly flat pieces with the Ecocast?

Cheers

You only need Eco cast or ground plate for critical surfaces like bearing plates or Z axis etc that require parallel surfaces. Gantry sides are not so critical in terms that they need to be perfectly flat or parallel surfaces. Thou I find the difference in prices isn't always huge and the cast plate is so much nicer to work with so I just use it for everything.

[Muzzer]

JAZZCNC - I've never knowingly used cast plate - where do you get yours and what grade is it?

Recently bought some 15mm plate from Poland and assumed it was rolled. That was EN-AW 2017 T451 and it machines very nicely. Also pretty flat.