Help with choosing parts for a first robot, please.

**harry hills** · 21st July 2015, 18:24

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.

**Ellis** · 21st July 2015, 21:59

That^

Even a cheapo thing, talking Â£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?

**typhoon_driver** · 21st July 2015, 22:05

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

**dotDominic** · 22nd July 2015, 06:40

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.

**harry hills** · 22nd July 2015, 09:27

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

**maddox10** · 22nd July 2015, 09:31

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.

**Ellis** · 22nd July 2015, 11:09

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.

**dotDominic** · 22nd July 2015, 13:31

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!

**dotDominic** · 28th July 2015, 12:15

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.