Bot Building Questions!

[Hogi]

I too would quite like to know the answer to the ti cutting question. I thought it was one of those things that required specialist equipment but I would be interested to know if there was a cheaper tool that would be up to the job.

[bigsi111]

I too would quite like to know the answer to the ti cutting question. I thought it was one of those things that required specialist equipment but I would be interested to know if there was a cheaper tool that would be up to the job.

Tin snips can cut through 1mm titanium without any difficulty

[joey_picus]

Tin snips will do Ti, but I wouldn't honestly reccommend it as the resulting edges are a bit terrible and it ends up bending/warping a little from the cut You can probably get a nicer finish by cutting a little oversize and filing to fit though. A Dremel with a grinding disc will do the job quite nicely (although be prepared to go through a few discs!), as will a PCB guillotine - I believe Peter uses one of those - and at the top end of the scale, I had my latest batch of Ti parts waterjet cut - which worked out at less than £10 with me supplying the material, although I do live close enough to the waterjet place that I can take the bus and walk there to save postage!

Also Maplin are a gigantic ripoff I find when it comes to switches or any small electrical components, or anything that isn't a beanie hat with speakers built in (long story!). Technobots have always been good for me with reasonably priced, very quick delivery for switches, LEDs, and all sorts, with eBay being your best bet for the absolute lowest price. (there's always the Principality Of Hobbies as well for some funkier lighting effects...)

[peterwaller]

I do have a guillotine but it struggles a bit with anything over 1mm and even then It is very difficult to stop the material twisting .
I usually try and buy small off cuts from ebay that are about the right width and just use a hacksaw to cut them to length.
Then any shaping I do on the grider.

[bot_bandit]

Thanks ll for your advice and sharing your metal cutting experience! Not sure I have the right tools to make it worth trying to add one armour plate to my robot but perhaps something to think about for the future

[bot_bandit]

So after reading about the difficulties had with Ti I went for 1mm aluminium which cut more easily than polycarbonate did! I just used a regular pair of scissors.

Anyway, I'm back with more questions! I'd like to build a vertical grabber robot next. I was wondering what servo is recommended here? As well as this, whether it is more effective to attach the claw directly to the servo arm or whether to use a four-bar method (like a reverse flipper)?

[Shakey]

Just be aware the easier it is for you to work the easier it is for a spinner to destroy!

A direct attachment is less robust but normally you lose some power in the 4 bar methods so it's really a trade off you have to decide between.

[bot_bandit]

I'd barely hit send and you've already replied Alex! Thanks again for the advice.
The thin armour shouldn't be too much of an issue as it's on top of 1.5mm polycarb giving 2.5mm armour total. It was more to add weight and to make the bot look cool than any serious protection (although it will help).
It's a hard choice to make between the two!
I was also thinking of covering the front wedge of the grabbing robot in some kind of rubber to make it grippy and help trap the other bot. Would this be against the rules in any way? I don't think I've seen it done before

[Occashokka]

I don't see why a grippy pad would be banned, in fact Pete put one on a flipper so I don't see why not, the only issue with a vertical grabber is that if you bring the top claw down they still have wheels on the ground and you need to be able to out push them and if you lift both or the bottom claw then you need to balance it so you don't fall forwards under the 150g temporarily at the very front. But that doesn't mean to say you can't build a good grabber and not many people have them do don't let me dissuade you

[AntRoboteer]

The only issue I foresee with a grippy pad is that the opposing robot would have to get dragged all the way up the pad in order to get stuck on it. If the grippy pad is grippy enough to hold the robot, the robot will probably not even make it's way up the pad at all or at least enough to be effective. That's the reason why I've always stayed away from this in my grabbers.