My first beetle weight, just some questions

[Wattersto08]

thanks a lot for all the help guys now i need to go and get some cash

[Wattersto08]

What is the best way of mounting those motors? I was thinking a hope mounting hole and some kind of clamp or just making a plate to mount he front of the motor to, will that be strong enough?

[harry hills]

http://www.youtube.com/watch?v=c_j0W1cAKOA
Is how I made mine

[plargen]

i just used a bit of 2mm aluminium u channel to mount my 4 motors but you can buy ready made brackets off ebay and amazon

http://www.amazon.co.uk/Pololu-Metal...eywords=Pololu

http://www.ebay.co.uk/itm/2-pcs-Stee...item417753aa06

http://www.ebay.co.uk/itm/25mm-Motor...item33781e0245

[Wattersto08]

I think I'm going to make one out if the 10mm hdpe sheet I have orders, to mount things to the top and bottom, can I thread it or will it be too soft, or are there wallplug type things I can get I can get?

[Ellis]

I wouldn't go any smaller than m4, or any bigger than m6, into 10mm HDPE. My beetle, Gonzales, is put together with m4 bolts into the 10mm HDPE. The joints feel pretty strong. Do be careful to not cross-thread, though, put a bolt in an already threaded hole badly and it'll never hold a decent thread again. I only start holes with a tap, then let the bolt form its own thread into the rest of the hole. The result is satisfying enough.

For the record, it is considered fairly bad practice to thread HDPE with bolts, although in my experience it does work. Woodscrews (or any coarse threaded screw) will hold nicely in HDPE, but the strength of the join will weaken the more you take the screw in and out, like in wood.

There are push-in inserts which are rough on the outside, and are tapped to a metric thread on the inside, which are kind of a happy medium. They can be pulled out, but I don't know how easily, never used them. Another kind, which I'd expect to be pretty sturdy, is this sort of thing: http://www.ebay.co.uk/itm/M4-x-15mm-...item4175771d12 - might experiment with these sometime, I imagine they're good into thick enough material (10mm might be on the edge).

Another method is the bed-bolt style, also known as barrelnuts: http://www.finewoodworking.com/uploa...olts-01_lg.jpg - these involve some quite fine aligning, but done right they're probably the sturdiest method of attaching things to plastic. Used these for the entire construction of our featherweight, and a bit in the beetle mentioned above, and they are very strong. I don't seem to see them smaller than for m6 bolts, though. I made some m4 ones for my beetle.

[Wattersto08]

Those inserts look great for attaching a top plate I may just wing it for my first bot and try the first method with a reinforcing block along the inside as it is going to be more or less rectangular so I can make it quite strong!

[Wattersto08]

Hi guys, whats the best way to cut hdpe? i have a jigsaw at my disposal and a wood saw, which would you recommend?

also in the next few days i will start at a build diary

thanks

[shakesc]

Both work fine to cut hdpe. I also use a circular saw to good effect though lots of swarf

[Max]

If using the jigsaw use a course wood blade or else it will clog up.

[Wattersto08]

i did some test cuts and the jigsaw seemed ok, will go with that also what is the delivery time for roughly for botbitz?

[Wattersto08]

ok just about to post a build diary, my stuff has arrived