Help with choosing parts for a first robot, please.

[shakesc]

Good work
The pillar drill will certainly help accuracy

[dotDominic]

Just finished cutting the HDPE. Could've been tidier, but it all fits together so it should be ok. Also the pillar drill arrived in the mail yesterday so I'll be able to assemble it all soon.

[dotDominic]

Thanks for the responses!

I really don't have the cash for one of those bigger pillar drills, but I'll definitely check out getting a cheaper one.
And if I'm going to buy a pillar drill I'll use Ellis' melting method for the wheels rather than hammering it.

Thanks so much for your help!

[Ellis]

Only major issue I've found, having owned two cheapo smallest-scale pillar drills, is that you need to stick some wood under the table so it doesn't flex when doing anything more than popping small holes in soft materials. Aside from that they have surprisingly little chuck wobble, etc. Of course I'd love to have a nicer, bigger piece of kit (with some slower speeds) but, funding.

I still strongly recommend you try and get one, it's a massive evolution from hand-held. Used via Ebay/Gumtree is certainly an option for cutting costs further.

As for the wheel bores, it seems that you'll likely need a pillar drill to do either thing: drill out the bore with any accuracy, or use it as a form of press to do the heat-insert method with the stock bore. Problem with hammering into the (probably nylon or polypropylene) wheels is that they will likely crack and wheel-wobble, even if it doesn't, will be bad.

With the heat method the plastic actually captures the nut in all directions, from the sides as well as rotationally. The wheels in our old how-to videos are still completely solid after dozens of harsh fights several years on.

[maddox10]

Don't go for the holders, unless you need to drill a lot of holes in stone using a hamerdrill. (never found a pillar drill with hammer function)
In any respect, those are just a third rate backup.

I only can advice, go for a real pillar drill, and not the smallest ones either. I had one of those, and Kos made me a longer pillar, making it a lot more useable.
But on the other hand, those are cheaper than a good brand batterydrill ,and they can drill a straight hole.

I have this one, and I'm going to get a bigger one as soon funds allow.


Maybe this one.

[harry hills]

I wouldn't hammer them in if I were you. It seems like a recipe for wonkeyness. Use a press or even heat the nut and use the drill press like a press (like Ellis's video) and its much better

[dotDominic]

Thanks very much for your responses!
Sounds like a good idea to hunt down a cheap pillar drill.

@Ellis
Yeah, the bore is originally 12mm, and the inserts are 15 mm across. I'd read in other threads regarding wheels that the nut insert could be hammered into the bore if it was increased to 14 mm. I've watched your videos where you melt the insert into position, but without the more precise movement of a pillar drill I was a bit cautious about trying it out.

[typhoon_driver]

You can usually find small pillar drills going on gumtree for around £20 up this way. Your other option is a holder for a hand drill that turns it into a pillar drill.

[Ellis]

That^

Even a cheapo thing, talking £50 region, will serve you well. They aren't quality tools but they are a world away from handheld. I have owned and abused 2 such cheap things and with a bit of care they aren't bad.

Also, I assume the bore of the wheel is already fairly large. In soft plastics, drilling a hole to a size only a little bigger than its starting size often causes the material to tear and compress, which a lot of the time results in violently grabbing the bit. Either the part/drill shift violently, the bit snaps, or the drill stalls. Sounds like you're experiencing the latter. It's good practice with plastics to, where possible, drill a small pilot hole or none at all. I try to stick to pilots no bigger than 1/3rd the next drill's size.

What size bore are they to begin with? I did the melted-nut-bore thing a long time ago and if I recall melted them straight into the 12mm bore the 100mm wheels had as standard. Are yours not 12mm?

[harry hills]

Black and decker are generally pretty bad now so i'm not surprised.Putting holes in plastic most drills just fall though, its weird you can't do it. Maybe charge the drill and try again but...

I would advise getting a cheap drill press though mate. Even a basic one will mean you can do straighter holes than by hand (which you need for doing the wheels and stuff) and just general work its a great tool to have. I was without one for years and I don't know how i survived.

[dotDominic]

Ok, so the other day I was trying to increase the bore of those Blue Bearing Boys wheels to 14 mm, so I could hammer in the Brass Inserts needed to attach the wheel to the drive shaft of the drill motor. (Finally got the damn screws out about a month and a half ago!)

But my drill made literally no impression on the plastic of the wheel. Pretty much right after the bit made contact with the wheel it stopped, leaving a few very minor cuts in the plastic. It's a relatively cheapo Black & Decker drill (Coincidentally it's the exact same model I was initially going to use for drive motors.), but I'm not sure if it's the drill's naff-ness that's at fault or some cruddy drilling technique of mine.

Just wondering how anyone else has gone about doing this? Is there some way of doing it or is it more so a matter of buying a drill with more oomph? Do I need something high-end for this sort of thing? Any help/responses would be really appreciated, thanks! (I hope you guys aren't getting sick of all us new folks asking so many questions!)

Also, just to show that I am actually building stuffs/making some progress here's snaps of the 99% complete battery mount thingy, and also slight changes/more details to the design of the robot. (Hopefully it looks marginally less boxy and basic now, though it still omits the fuse, link and LED.)

https://www.flickr.com/photos/134836804@N02/

I still need to drill holes in the base of the battery mount so it can be bolted to the base of the robot. Annoyingly my drill (or my potentially shoddy technique.) couldn't get through the 3 mm aluminium. :/

Again if there's anything horribly wrong with anything I've done so far please say so!

I'm also thinking of naming the robot Venator (Means "Hunter" in Latin.) if it's not been taken already.

Thanks for reading if you've made it this far. Sorry this post was so long!

[dotDominic]

Hello, just starting to sort out the wiring and stuff, and I was just wondering what would be an appropriate rated fuse for this LiPo battery, please:
http://www.hobbyking.co.uk/hobbyking...mah%204s%2030c

I've read that the fuse has to rated lower than the maximum current draw of the battery, but how much lower is necessary? I obviously don't want the fuse to be rated too low.

Also read that using Maxi fuses with the holder from technobotsonline can also be the removable link. Is that reasonably straight forward to set up? I've also noticed that the wire in the holder uses 8 awg wire, whereas the rest of my robot will use 12 awg (with the exception of the battery which uses 10 awg.) Does mixing wire ratings cause any problems or is it ok?

Not started building much yet but I pretty much have everything except a few bits and pieces, so hopefully progress should speed up soon!

Thanks!

[dotDominic]

Yes, I've been leaving the drill assembled in it's casing when trying to remove the chuck. For the other 3 drills, I've had to use the Allen Key Hammer Whacking technique to unscrew the chucks once the screw was out, and for that I clamped the drill by it's casing.

[Max]

I assume you are leaving the motors in the drill casing when trying to remove the chuck? You should always remove the chuck before disassembling the drill as it gives you a better lever to undo the screw than just trying the grip the motor.

[dotDominic]

Ok, thanks. I've tried to jolt it loose again on low torque but it still won't budge. :/ Luckily I had the drills delivered, and one of the drill cardboard boxes has this big bash in it. Hopefully I can pretend the drill has been damaged as a result and I can exchange it for another one. :P