Drill shaft hub -> HDPE Wheels?

[Runsler]

So, i'm searching for a good way to mount HDPE-Wheels to a Drill shaft (Actually, to the Neptune Gearbox from Ranglebox, but the shaft seems to be the same 3/8 UNF outer thread and reverse M5 inner thread.

just hammering/melting a hex nut into the HDPE didn't stand up to the fight when i tried, couldn't go for more than one fight without at least one wheel coming off without real enemy contact. The HDPE basically just was too soft and the nut alone didn't provide enough friction/profile.

So i'm searching for some kind of a hub, preferably off the shelf (well, someones shelf), since i just don't have tools/equipment for that kind of metal work to do myself.

Other idea would be welding a round sheet of metal to the nut, drill holes through that sheet, and screw it right into the HDPE, to give a stronger connection of HDPE and nut. Just my welding skills are non existent, and even if they were i'd doubt i could get that so the wheel would be straight.

So any other ideas? Possibly shoppable solutions rather than those needing tools/machines i don't own?


(ideal solution might be a new shaft with fitting hub, but again, i can't do that).

[Maxamuslead]

On current bot, i am using keyed shaftes and a keyway drill straight into 30mm HDPE wheels. they have worked fine and am yet to see problem.

But what types of tools do you have ? if you have a welder you could use something like THIS and weld a larger plate onto it which you could put screws into the HDPE. But what thickness of HDPE are you using for wheels ? as i know of someone making 20mm HDPE wheels (CnC milled yes but nothing you cant make yourself) with a Hex pattern which allows the use of those Connectors i linked and they work great.

[Runsler]

10mm wheels (theyre kinda big, gabriel inspired, so making them thicker would greatly increase weight), and no common welder (or knowledge how to use it).

I do have a Laser we use for welding at work, and some basic knowledge to do simple stuff with it...
But being a dental technician, that thing is for really small parts, even impossible to use without looking through a microscope just from the setup. i don't think that would be up to the job, since i could weld only the surface, and not get deep into the material.

welding a plate on something like that (or just the nuts i have, don't see much difference if i use the screws through the plate for main connection anyway) would have been my first idea, just getting that straight so the wheel won't wobble around and making a good weld are my problems there. So, since that really takes a lot of time per piece to make with the laser welder at work, i'd hoped for some more ready solutions, since i figured i might not be the only one with that problem.
But if there isn't, i'll have to try and just get better with that.


Oh, additional tools available are about anything you could put into a Dremel on extacy and some proficiency on using it, as well as some basic hand tools and a cheap drill press. might be able to use some more tools from work, but can't imagine which one could be useful there. About all metal works we do there is "casting -> dremel if needed -> polish". and casting these parts didn't work out so far and is a pain to do, since i can't reuse the mold.

[Maxamuslead]

hmm one idea could be to make where the nut/connector goes thicker. i take it you is rounding off ?

[Runsler]

what do you mean with rounding off?

basically, the wheels are made like this: drill a 5mm hole into a 10mm thick piece of hdpe.
attach jigsaw to the table, screw the sheet into the table through that hole.
turn the sheet around the hole, and against the jigsaw to saw everything off that's further away from the hole than the jigsaw.

screw on bike tire and widen the hole to fit mount in.

so it's all the same thickness.
luckily i have found someone now who's gonna making me some hubs, basically just nuts with plates on, but made from one piece and not welded together. seems to be not that hard to do if you have a lathe...

[Eventorizon]

Check this video out by Ellis Ware of Pulsar - https://www.youtube.com/watch?v=AcIIUGBJzJM - May or may not be suited to you but this method does work pretty well.

[Runsler]

Yeah, that's the method i tried on the last version of the bot.
Sadly doesn't seem to work as good with HDPE instead of nylon and with wheels thrice the diameter as that
(Well, or i didn't do it right, but having a thinner wheel with bigger diameter just gives bad leverages here when someone applies sideways forces to the wheel.)

[Al_]

Just a note that it you use the melt the nut into the wheel method on HDPE wheels, the wheel will slide off the nut after about 30 seconds of use, the HDPE is just too slippy to hold it. However it is easily solved with a large washer either side of the brass nut to stop the wheel sliding off.

[Runsler]

It was not just the sliding off, but also the torque involved just made the wheel stay still while the nut slipped through inside.
That's why i'm looking for real hubs, and luckily get some made on a lathe now.